Tony, I overhauled ball screws for the Air Force for many years. You can rebuild ballscrews as long as the chrome on the screw is still intact AND there isn’t any wear on the inside of the ballnut. Wear inside the ballnut will appear as galling or fretting just on either side or the return tubes. The tracks should be shinny, but the worn areas will appear dull and the dull area will grow longer if they aren’t overhauled properly. The key part of overhauling ballscrews is having an assortment of ball bearings. We had dozens of sizes of balls that varied by 0.0004”. It’s trial and error to pick the best size. You want a minimum of 0.001” endplay when done correctly. Any tighter and the ballnut will feel notchy or rough and cause premature wear. Looser than about .004” and the bearings will bounce inside the track and wear the chrome of the screw and the inside of the ballnut. Get the endplay as low as you can, but it needs to feel smooth over the entire travel. Generally, you can overhaul a ballscrew one time before the ballnut of screw is trash. Aircraft ballscrews usually have oiled felt wipers to keep dirt out and a metal ring on top as an ice breaker to protect the felt.
Thank you for that. I often wonder about that . Ball screwa have made power steering systems work for many years in cars and trucks. When the screw in a tractor steering gear locks up, a very large man will not break it loose. I have seen it many times. Real dangerous situations. I dont fool around with steering components, unless it is just a simple leak. Operators have families too.
I had an engineering lecturer that had made his career in precision electromechanical systems, and when he was discussing linear actuator choices (lead screws, ball screws, roller screws) he spoke of roller screws with such reverence. Also said they were really expensive. Anyway, he brought one with really fine threads one day to show us what he'd been talking about, let us mess around with it and stuff. If I'm honest, I still think about it often. It was so smooth, so quiet, so heavy. Unbelievably satisfying. There's no story here, I just don't know who else to talk to about this. Other people in my life just don't want to hear about my college experiences with roller screws.
i made geared planetary roller screws once upon a time. they are quite a mousetrap. there is a reason they're not more common they're hard to make and have a lot of parts in the tolerance stack up, id ball park a screw for tonys mill would be 5k$ and have 3-6 month lead time. but unless he crashed it into the casting it may last 50 yrs. now on the other hand roller thrust bearings are the cats meow and not as hard to make but still probably 3-5 x the cost a normal thrust bearing not and not an off the shelf product. now if you think about this the lead ,number of starts, gearing on the rollers, roller dia., dia of screw all have to have a common denominator so to speak there's a lot of math that goes into the design side even before you get a tolerance stack up.
Perfectly stated, it's always educational to learn what is more effort and time to fix as opposed to replace, and which parts or elements can be replaced independently.
I have no interest at all in engineering or any kind of metalwork. I just chanced on this video (though I've watched This Old Tony videos in the past -- perhaps some of his collabs?). But this video was a sheer unalloyed pleasure for me from start to finish. As you say, 20 mins felt like 5. Most other UA-camrs make 5 minutes feel like 20.
When I was young and poor, I used to have to do the normal young-guy thing and keep a series of shitbox cars running. I learned early on to always, ALWAYS, start with "cheap and simple." You can always get more expensive, bit its good to rule out the cheap and easy fixes before that.
Always enjoy your videos. As a young engineer, I worked in a facility that made custom ball screws. I recall that a certain amount of the circuit is kept empty to facilitate the free travel of the balls and limit ball to ball friction. It changes based on ball size. The point being, next time you rebuild, you don’t want to put every ball you can fit into each circuit. Cheers!
I wonder if putting in teflon washers in between the balls could act as a cage, like on a modern roller bearing. Keeping the balls apart. I wonder if they would ever stay in place through the return channels. Then again, it seems to work just fine without a cage, so maybe i should not think about it.
Exactly the way I feel. I mean, who cares about ball nuts? Me, apparently. A perfect example of how humor, good writing, and great editing can make a video about absolutely anything interesting.
As someone who also tries alternatives to repair things, especially expensive things I really appreciate honest videos like this. The reality in so many cases is that sometimes the only real answer is buying another part. Far too many youtubers give this impression that anything can be fixed without buying anything, which simply isn't the case. Sure it is fun to try and absolutely a valuable learning experience, but sometimes you simply don't have a choice.
"I Fixed These Expensive Toys I Don't Actually Need For FREE! All you need is X, Y and Z, and some costly material you just happen to have sitting around! And it's all free cause all that stuff just magically appears out of thin air! Sure the fix will fail much sooner than later, but it's FREE! Don't forget to like and subscribe!"
Indeed, my hydraulic disc brakes on my electric kick bike had mysteriously lost all its mineral oil. So expecting an easy fix i bought myself a bleed kit to just refill them. And what do you know, once filled i did a really hard pull on the brake lever and POP, out flies the whole hydraulic line. So i bought a (compatible with the cylinder) new line and i wanted one a certain length but the store clerk said it was for the rear so i got confused and opted for the "correct" front brake line. Turns out i really needed the longer rear one because a kick bike is not a bicycle and there's more distance from the handlebar to the brake cylinder. Luckily i also bought a new nipple and olive (something you use to install the line in the brake handle that crushes around the line to keep it in place) and i got away with just re-using the old line and doing a PROPER install with the new nipple and olive, something the idiot assembling the bike hadn't done because the old olive (ball thing) wasn't even crushed. Time will tell if i lose my brakes going downhill at 50 mph though... Fun times.
Thanks a million Tony, your attempted reconditioning of the original has taught me a lot about ball nuts and how they work. There is always something to learn from destructive repair work :)
Nice video Tony, I used to make Ball screws for a company called Thompson IBL, they had a great name for quality in their day. Loading the balls we had solid shafts, no grease needed to hold the balls in place. We had draws of ball bearings in one micron increments and it wouldn't take much to go from backlash to a preloaded condition. Most ball screws had a preload tolerance which was measured with a spring balance. Wipers were always installed after the nut and were not tight against the nut as to not impact the preload.
Light Machines (now Intelitek) used IBL ball screws in their machines - a P5 rated rolled screw. 16mm x 0.2" with special preloaded square block nuts. Five years ago, Thomson quoted me nearly $2400 for a single 465mm long assembly, not even including shipping (from Germany), or taxes. Not surprisingly, I rebuilt it instead. I'd love to know more about how you measured the preload and what a typical preload for would be.
You know how to get your audience invested. I'm not a machinist and will probably never use a CNC mill but you still had my heart dropping when the new nut "spilled" balls 😂
My heart sank when the first repair didnt work. And I was horrified at the end of the second repair when the bearings were falling out. And then elated to see that all the back lash was removed. It was a real roller coaster of emotions. LOVE IT !!
I knew it was a gag because Tony never gets the screwups on camera perfectly framed. We only get to hear about them later. Makes me think me might be making up all these screwups for content.
You should remove the seals from the nut before putting it onto the arbor. It will help protect the seal since (the ones i sell) they aren't circular. Also consider checking to see if there are multiple starts since you can put the nut on a different start when reballing it (as long as the nut raceways are in good condition) I'm a linear application engineer and deal with these babies daily :)
I was having the tony withdrawal shakes.. they were getting bad. Cold sweats of cutting fluid, hands chattering at the wrong feeds, and hallucinations of disembodied hands presenting things everywhere. It was horrible.
The balls dropping out was classic!😂 You plan of doing $2000 of fixing while full well knowing you need to spend $3000 to do a 'proper' repair sounds all too familiar! Thank you Tony for posting this.
Hi TOT. My CNC has worn $$$ Japanese screws. Replaced the nuts to extend the assembly life. What I learned is I wish I’d set up non-precision jobs on the periphery of the table, to spread the wear out. I probably would have >doubled the life of the screws this way. Stay awesome 🤙
I used to work at a Ballscrew factory in Coventry 🇬🇧 we made precision Ballscrews for machine tools & aerospace, I worked there 38yrs till the end 2005, you did very well there Tony great video thanks for sharing 🇬🇧👍.
I once ran a super-expensive ball nut off the end of the screw (bad software design). After picking up as many balls as I could find off the floor of the lab, I had the uncomfortable phone call with the supplier "how many balls are there". They informed me there are two sizes of balls that alternate (a couple tenths difference) with load balls separating ball & nut radially and spacer balls (rotate in opposite direction) separating load balls without rubbing on screw or nut... I replaced the assembly...
Yes i said exactly the same thing...Ball screws have two sizes of balls, if you dont seperate the balls alternately they wont roll if they are close fitting.
My moral of this video is that cheap repair/overhaul rarely fix an important problem. So most of the time you have to do the service twice: the first with the cheap solution… and then with the good one. Thanks tony for your videos that educate to use the brain for not waste time and money
Well, balls to that! Great video Tony. I know that feeling of doom, on having to take the big machine apart! Me, myself and I can only get it right or wrong...nice touch with the sleeve to hold the bearings in the holder! No tap-dancing on bearings were performed during this video...that we saw anyway! Cheers Tony. Thanks for the time to put this together.
Hey Tony thay looks like a SFU20 or SFU25 "ball nut" You're using there. Take a look at the DFU20 or DFU25. They are "double ball nuts" and has twice the internal load bearing area and twice the amount of balls plus..... you can adjust the tolerance between the two and completely eliminate any backlash. Absolutely love You vids man.🎉
Outstanding...thanks. never heard of one of those things...must be a spin-off of Archimedes type thinking . Love watching your stuff...even when it's loose.
The double nuts are weird when you look into it. The two halves are not really fastened together except by the ballscrew itself. There is a little widget to maintain the angular relationship, and then the space between them is shimmed to take up the slack. Which I think means that you don't get double the load bearing capacity, as basically you are dividing the work, one half takes loads in one direction, and the other in the other.
One trick for the "Gravity fighting against you" when you're filling these, instead of the world stickiest grease that you probably don't want in there anyway - is just to pop a couple of small magnets on the body - that will hold the balls in position when you place them and you just pop them off after everything is on the ball nut. That means you can use your correct grease/lube instead of something full of tackifiers from the start. Also as someone else said - if there looks like there's space for one more ball, then you have the correct amount in there. You need free space to prevent rubbing and jamming issues.
Your home shop mathematics/economics are spot on Tony and I seem to get bit by this more often than not. " Turns out I can put up with quite a bit of hassle for three grand my plan of course is to spend at least two grand constantly swapping out these ball screws that fall apart and then I'll be ready to spend three grand on the good stuff" Priceless for all that can relate to, bin there done that 🤣 Moral of the story.....Buy once, cry once
@@1978garfield that's exactly what would happen to me in that situation... Spend the coin on make do and another much better option shows up just after the money is gone...... And the game goes on....
I have an even better alternative. Buy cheap stuff that's very durable, but leave something else in the quality to be desired. Then you can buy once, cry many times.
Entertaining as always Tony. Thanks so much for this. I'm not a machinist but always considering buying a mini-mill for my little garage shop mostly for the learning experience. Two things keep stopping me, 1) I don't know what I'd use it for and 2) watching these repair and tear down videos exposes so many opportunities I can really fowl things up. It's great watching others deal with it though. Thanks again, your devoted fan.
The video was over way too soon. Tony, thank you so much for sticking around and inviting us into your dark world and mind (not dark). It's always a very special and soul-healing time when you upload.
I'm not sure whether the motto is "Sloppy balls leaves you with too much 'end' shake" or "If you want a nice tight screw, make sure your balls are shiny and new". Either way, great Video Tony 👍👍
Thanks for showing this. I've always wanted to know how it works and if it can be rebuilt by hand! Now just need some real estate to get a milling machine. I'll keep watching you until then
Hey Old Tony . Been rewatching a lot of you old videos. Missed you man.... I bet A lot of the "likes" were clicked before even watching the video, mine was.
5/15/23;..replacing (~30 little) ball bearings/'ball nuts'..always enjoy yur sense of humor while teaching we armchair YT viewers lots of fabrication fundamentals, techniques, various welding types & shop tools..like that green 3-axis milling machine you repaired 2day. Great camera close-ups, lighting + that medical flex camera inserted into that...oil port (?) to confirm 'bottom-out' of oil drip-lube line. [LoL on tease spilling of tiny balls!😁]. Much enjoy your channel! Stay safe & carry on!👍👍👏👏⚙️🔧💪😊
Hi tony ,fun video . having replaced a number of ballscrews over the years and having the great fortune to travel to Japan for training at a large and well regarded cnc machine tool manufacturer perhaps I can offer some of what I have learned. 1) a high preload ballscrew and nut will feel lumpy ,in a smooth sort of way. a worn out high preload screw will actually turn very freely, in fact if you hold the screw vertical the nut will spin down on its own. Many machinists don't don''t like the feel of ballscrews on manual machines because they do not feel as smooth as a leadscrew. The lumpyness is caused by the ball returning from the recirculation tube /deflector. High preload is achieved by sizing the ball larger than the groove its running in. (for most 1 nut setups). 2) In japan, we spent some time in the ballscrew assembly department. you were right in your speculation about several size balls. The assembler placed the nut on the screw and then placed the appropiate number of balls into the nut through the deflector tube holes. once the balls were in place he would rotate the nut to see if the ball size was correct. interestlingly the way to know when it was right was to rapidly rotate the nut back and forth several times ,about 180 degrees, hesitatate for a second and then rotate the opposite way , there would be a tiny hesitation or "grab" before turning. As these were double nut screws this would be repeated with the second nut. then a large range of spacers were available to place between the two nuts to both line up the keyways and bars between the 2 nut and to achieve the proper preload between them. 3) most large machines use double nut ballscrews. single nut ballscrews use either oversized balls for compact nuts, or 2 sets of races , one with right hand preload and the other left.
That's a heck of a process. I wondered if running with fewer balls would give enough clearance for oversized balls to fit the screw. Any feedback on that crazy idea?
@@scottcates Hi Scott , what i saw at that factory (about 2001) was a very skilled and experienced assembler fitting the balls largely by trial and error. what i recall was a nominal sized ball and a range of +/- balls in about .001mm increments. he started with the nominal size and then almost immediatley was able to select the right size for the desired preload. he had been doing it for many year, I could imagine that a trainee would take months to become as proficient. Tony had referenced a ball bearing , this is sort of what a ball screw is, a bearing with benefits, so there is an ideal size ball for the job. like a ball bearing fewer balls would not allow for a larger diameter. A bit of additional information ballscrew races are usually(quite often ?) ground not as a perfect circle but in a 4 point contact or gothic arch profile, so that the balls are touching on their sides rather than top and bottom.
I was going to use this video to introduce Precision Ball Screws to my Pre-Engineering High School students, but the egregious nut ball slop humor might get me an extra long vacation 😂! You Sir Have made my day! -Castor Thanks as always
If high school as degraded to the point that egregious ball nut slop get you any extended vacation, your students better never the the engineering office. The Tradies will eat them alive at a job site.😳
Great to have you back Tony! I learned the hard way about taking the nut off the screw ! Got most of the balls back, thank goodness its only going on a tail vice for a wood working bench cause I think its got more than the 20 thou. slop that Tony's had.
This is awesome sir, always love watching your videos. I dont even own a milling machine, but there is something about listening to your voice while you play with your ball nuts that just turns my screw.
When you said that opening line, my brain immediately shot off on a Full Metal Jacket style rant. "This is my milling machine. There are many others like it, but this one is mine. My milling machine is my best friend. It is my life. I must master it as I must master my life. Without me, my milling machine is useless. Without my milling machine, I am useless. I must run my milling machine true. I must cut straighter than my error, who is trying to kill me. I must minimize him before he minimizes me. I will. Before God I swear this creed: my milling machine and myself are defenders of my accuracy, we are the masters of our tolerances, we are the saviors of my precision. So be it, until there is no enemy, but metric. Amen."
@@Harlequin43 You would have to live under a rock not to understand "Go UKRAINE", but then again, you are from ruSSia... Whatever float your Moskva boat. Actually, your Moskva submarine.
Tony. I really enjoyed this video. It came to mind, as I watched you sticking those tiny ball bearings into their gravity-defying slots, that you might try making a video on brain surgery. Should be right down your alley!
The important thing to take away. Everyone is just happy T.O.T uploaded a video. At this point, im convinced i would watch a video of tony stuck in traffic just for the professional dad jokes.
6:14 Even Sir D. Attenborough could not have come up with a better analogy for the 'circle of life'. Thank you Tony, my balls have seen the light because of this documentary.
Loved the little depiction of how the nut actually functions. I’ve had varying luck removing/reinstalling/reloading ballnuts in the past. Likely the best solution to your issue is to just buy a high quality ballscrew like a Hiwin.
As someone who very highly values being able to personally build/manufacture high quality tools, furniture, and other items, it makes me a bit sad that I'll likely never be able to afford to get into machining. ToT gives me a lot of joy anyway.
I know it's easy and relative cheap for you to buy a new nut and replace it, and I know you get a lot of crticism for not doing that in the first place... But for us who do not live in the US, or some countries on Europe, that's not that simple nor cheap, especially if we wanna get the best quality parts. So I really appreciate your effort for trying and documenting cheaper ways to fix stuff, cause that really helps people like me who lives on "developing" countries. Thanks for the content ❤
This video gave me heart sinking flash backs to when I pulled the rear socket set off my mountain bike years ago. Ball bearings and grease really did a number of my nerves 😂 thanks for the trip down memory lane ToT !
The intricate details of machinery that bring it to precision part making explained in a concise yet often comical way only to be found by following this old Tony. I will add without any hubris that was not meant to Crack a smile. Don't let the Mrs see this or she'll up your game somehow.
The moral of the story is that you have to have the balls to try these kind of repairs.... I always look forward to TOT and it makes my day to find a new one.
The ball nuts on my BP conversion are double circuit but each circuit is at least two possibly three turns. It's also much longer than your ball nut. In a good ball screw assembly the ball sizes have been selected to provide preload to each circuit to reduce or eliminate any backlash. Because preloading caused more drag on the rotation every other ball in the circuit is slightly small in diameter and acts as a spacer to reduce the drag while keeping the bearing area constant. They also have external return tubes which allows for easier ball loading. Tony is correct a really good ball nut and screw is quite expensive. The worst sound is hearing the those balls fall out onto the floor never to be seen again.
You’re the best Old Tony, have you ever thought of telling children’s stories? you would be excellent at it, not that you are not excellent on how you teach us so much with humour along the way. Thank you.
I'm in the early stages of building my own CNC router using ball screws and this was indirectly very helpful, I hope I won't have a moment of "52 ball pickup"!
I did as well. Cheap amazon ballscrews got me max .0015" Backlash. I use a bit of Vaseline, petroleum jelly, put a thin film on the screw, run it back and forth, then wipe it.
Fun to watch! I break out in a cold sweat changing the blade on my disposable razor, so could never hope to tackle something like this. Thanks for the great video!
Good fit for non preloaded ballnut. Most CNC ball screws are preloaded so basically you have 2 nuts pushing against each other to remove the backlash amd not depend on the clearance of the screw/nut/balls. For putting them together turn a bar the diameter of the shipping retainer with taper on the end. Also surprised you have such low backlash as thrust bearings are a common point of failure, and they are far from cheap themselves. Good video, as always
The moral of the story is some of us didn't have fathers who spent time with us screwing around with screws (or anything else) and this is giving us a warm fuzzy feeling.
I’m the type of guy that when somethings really broken, I’ll order the new part but still go ahead and fix the broken part. The new part arrives after I’ve fixed it and I feel good knowing that I’ve fixed the unfixable and I have a back up in the cupboard. Worst part is seeing that new part years later but thinking how good am I at fixing unfixables that’s still going strong years later. ToT is the man.
Nothing better than firing up youtube and finding a new TOT video! You seem to always make me smile. Glad you're back and able to make videos, can't wait until the next one.
The moral of the story is that the real ball nuts are the friends we made along the way
Maybe the real moral of the story is - if you rebuild a cheap ball-screw, you might end up screwed and bawling?
I BOUGHT A NEW ONE
*APPLAUSE* 👏👏👏
😂
The real real moral of the story is to just give the old pony some gas over the hills.
❤🎉
Tony, I overhauled ball screws for the Air Force for many years. You can rebuild ballscrews as long as the chrome on the screw is still intact AND there isn’t any wear on the inside of the ballnut. Wear inside the ballnut will appear as galling or fretting just on either side or the return tubes. The tracks should be shinny, but the worn areas will appear dull and the dull area will grow longer if they aren’t overhauled properly.
The key part of overhauling ballscrews is having an assortment of ball bearings. We had dozens of sizes of balls that varied by 0.0004”. It’s trial and error to pick the best size. You want a minimum of 0.001” endplay when done correctly. Any tighter and the ballnut will feel notchy or rough and cause premature wear. Looser than about .004” and the bearings will bounce inside the track and wear the chrome of the screw and the inside of the ballnut. Get the endplay as low as you can, but it needs to feel smooth over the entire travel. Generally, you can overhaul a ballscrew one time before the ballnut of screw is trash.
Aircraft ballscrews usually have oiled felt wipers to keep dirt out and a metal ring on top as an ice breaker to protect the felt.
It's always nice to learn something from people who worked in some specific industries! Thanks for that interesting comment!
👏
Thank you for that. I often wonder about that . Ball screwa have made power steering systems work for many years in cars and trucks. When the screw in a tractor steering gear locks up, a very large man will not break it loose. I have seen it many times. Real dangerous situations. I dont fool around with steering components, unless it is just a simple leak. Operators have families too.
Where does airforce use ball screws?
@@MonstertruckBadass I bet there is no shortage of equipment in maintenance shops. Some planes use jack screws for control surfaces too.
Thanks for the great video!
Very nice
Nice
Nice
yes. thanks!
👍
I had an engineering lecturer that had made his career in precision electromechanical systems, and when he was discussing linear actuator choices (lead screws, ball screws, roller screws) he spoke of roller screws with such reverence. Also said they were really expensive. Anyway, he brought one with really fine threads one day to show us what he'd been talking about, let us mess around with it and stuff. If I'm honest, I still think about it often. It was so smooth, so quiet, so heavy. Unbelievably satisfying. There's no story here, I just don't know who else to talk to about this. Other people in my life just don't want to hear about my college experiences with roller screws.
I have no use for one but now I want one
I love this story.. where you live? We can talk balls and screws every day
Oooo! Tell us More! Do!
I hear you bro. Its make stupid Dick Jokes where I work. They all want the answer to life in three seconds or its back to the clown show.
i made geared planetary roller screws once upon a time. they are quite a mousetrap. there is a reason they're not more common they're hard to make and have a lot of parts in the tolerance stack up, id ball park a screw for tonys mill would be 5k$ and have 3-6 month lead time. but unless he crashed it into the casting it may last 50 yrs. now on the other hand roller thrust bearings are the cats meow and not as hard to make but still probably 3-5 x the cost a normal thrust bearing not and not an off the shelf product. now if you think about this the lead ,number of starts, gearing on the rollers, roller dia., dia of screw all have to have a common denominator so to speak there's a lot of math that goes into the design side even before you get a tolerance stack up.
The moral of the story is: Don't lose your balls to a cheap screw.
Words to live life by.
Surprised I had to scroll down this far to get the storal of the mory,, many thanks !
noted.
This is great! I'm about to sit on the toilet for 20 minutes to escape my children and now I've got something to do! Thanks, TOT!
I hear that!
😂
I'm reading this while sitting on the toilet.
Should I check for surveillance?!?
I hide from my kids also 😂
that's exactly what I just did, now I need to go back and facing the cruel world
I believe the lesson is: even if fixing something doesn't work, the attempt is likely still educational, and therefore still worthwhile.
Exactly, nothing ventured nothing gained, but sometimes you just learn that certain things aren’t worth the hassle and avoid repeating later in life.
He learned not to bother trying to rebuild one again. Of course trying something once to find this out is always educational. :-)
LEARNING FTW
No, the lesson is that any project that entails referencing one's nuts and balls this many times, along with their relative slop, is never a failure.
Perfectly stated, it's always educational to learn what is more effort and time to fix as opposed to replace, and which parts or elements can be replaced independently.
There's VERY few UA-camrs that can make a 20 minute video feel like 5 minutes, and Tony is one of them. Every video is such a treat. Thank you.
I have no interest at all in engineering or any kind of metalwork. I just chanced on this video (though I've watched This Old Tony videos in the past -- perhaps some of his collabs?). But this video was a sheer unalloyed pleasure for me from start to finish. As you say, 20 mins felt like 5. Most other UA-camrs make 5 minutes feel like 20.
i don't know how ToT does it but he can make me watch a 20 minutes video about grass growing and still be the most entertaining thing of the week.
Amen to that.
Did you see his "Turn a CUBE on a LATHE?!" video?
@@TDDoooOOOooo I will have to find that video now.
I would actually be interested in TOT’s take on watching grass grow. Guaranteed to be a cinematic masterpiece
@@TDDoooOOOooo Yep, watched the whole thing if I remember correctly.
I think the real moral is that giving the cheap fix a try is almost always worth the knowledge gained alone, and sometimes it even works! 😅
When I was young and poor, I used to have to do the normal young-guy thing and keep a series of shitbox cars running. I learned early on to always, ALWAYS, start with "cheap and simple." You can always get more expensive, bit its good to rule out the cheap and easy fixes before that.
Always enjoy your videos. As a young engineer, I worked in a facility that made custom ball screws. I recall that a certain amount of the circuit is kept empty to facilitate the free travel of the balls and limit ball to ball friction. It changes based on ball size. The point being, next time you rebuild, you don’t want to put every ball you can fit into each circuit. Cheers!
Good tip , cheers . I’ve noticed the same rule on rebuilding large linear guide blocks for machine tool bed ways .
It's the same with the older style bearings on bicycles. Older style meaning ones able to be rebuilt. It's the number of balls that'll fit minus one.
I wonder if putting in teflon washers in between the balls could act as a cage, like on a modern roller bearing. Keeping the balls apart. I wonder if they would ever stay in place through the return channels.
Then again, it seems to work just fine without a cage, so maybe i should not think about it.
Ball to ball friction isn't always a bad thing
Here we are again, absolutely enthralled in a 20 minute video about a topic for which I have absolutely no aspirations of ever needing. I love it!. 🙃
Exactly the way I feel. I mean, who cares about ball nuts? Me, apparently. A perfect example of how humor, good writing, and great editing can make a video about absolutely anything interesting.
Yup
@@H457ur Writing and editing? These are off takes of the ToT's garrage live feed.
@@AnatoFIN This is ToT with balls to the wall, taking off in his garage.
As someone who also tries alternatives to repair things, especially expensive things I really appreciate honest videos like this. The reality in so many cases is that sometimes the only real answer is buying another part. Far too many youtubers give this impression that anything can be fixed without buying anything, which simply isn't the case. Sure it is fun to try and absolutely a valuable learning experience, but sometimes you simply don't have a choice.
"I Fixed These Expensive Toys I Don't Actually Need For FREE!
All you need is X, Y and Z, and some costly material you just happen to have sitting around! And it's all free cause all that stuff just magically appears out of thin air! Sure the fix will fail much sooner than later, but it's FREE! Don't forget to like and subscribe!"
Indeed, my hydraulic disc brakes on my electric kick bike had mysteriously lost all its mineral oil.
So expecting an easy fix i bought myself a bleed kit to just refill them. And what do you know, once filled i did a really hard pull on the brake lever and POP, out flies the whole hydraulic line.
So i bought a (compatible with the cylinder) new line and i wanted one a certain length but the store clerk said it was for the rear so i got confused and opted for the "correct" front brake line. Turns out i really needed the longer rear one because a kick bike is not a bicycle and there's more distance from the handlebar to the brake cylinder.
Luckily i also bought a new nipple and olive (something you use to install the line in the brake handle that crushes around the line to keep it in place) and i got away with just re-using the old line and doing a PROPER install with the new nipple and olive, something the idiot assembling the bike hadn't done because the old olive (ball thing) wasn't even crushed.
Time will tell if i lose my brakes going downhill at 50 mph though... Fun times.
@@FiltyIncognito I seethe with hatred when i see a video that promises DIY for only $25 and then breaks out $250 of "scrap material"
ToT takes it the right way around : try to fix with what you've got, if it doesn't work, put on your sad face and go buy a new part
Are you me?
Thanks a million Tony, your attempted reconditioning of the original has taught me a lot about ball nuts and how they work. There is always something to learn from destructive repair work :)
Nice video Tony, I used to make Ball screws for a company called Thompson IBL, they had a great name for quality in their day. Loading the balls we had solid shafts, no grease needed to hold the balls in place. We had draws of ball bearings in one micron increments and it wouldn't take much to go from backlash to a preloaded condition. Most ball screws had a preload tolerance which was measured with a spring balance. Wipers were always installed after the nut and were not tight against the nut as to not impact the preload.
Light Machines (now Intelitek) used IBL ball screws in their machines - a P5 rated rolled screw. 16mm x 0.2" with special preloaded square block nuts. Five years ago, Thomson quoted me nearly $2400 for a single 465mm long assembly, not even including shipping (from Germany), or taxes. Not surprisingly, I rebuilt it instead. I'd love to know more about how you measured the preload and what a typical preload for would be.
You know how to get your audience invested. I'm not a machinist and will probably never use a CNC mill but you still had my heart dropping when the new nut "spilled" balls 😂
I was on edge way too many times in this video. Ball nut edging? Wait...
That is so true, it is not even funny...
I was waiting for it cause I knew it was coming. I just thought it was gonna happen when he first took it out of the bag.
ok
My heart sank when the first repair didnt work. And I was horrified at the end of the second repair when the bearings were falling out. And then elated to see that all the back lash was removed. It was a real roller coaster of emotions. LOVE IT !!
I knew it was a gag because Tony never gets the screwups on camera perfectly framed. We only get to hear about them later. Makes me think me might be making up all these screwups for content.
Lol yea he got me too
You should remove the seals from the nut before putting it onto the arbor. It will help protect the seal since (the ones i sell) they aren't circular.
Also consider checking to see if there are multiple starts since you can put the nut on a different start when reballing it (as long as the nut raceways are in good condition)
I'm a linear application engineer and deal with these babies daily :)
But the real question is are you a good LAE? 😂
... It's such a shame that quality content takes time and motivation to produce. You deserve every single one of those 1.12 million subs, Tony!
I was having the tony withdrawal shakes.. they were getting bad. Cold sweats of cutting fluid, hands chattering at the wrong feeds, and hallucinations of disembodied hands presenting things everywhere. It was horrible.
LOL
I am not the only one that feels that way? That makes me feel better.
You forgot about having blocks of stock splitting into pieces as soon as you look at them.
@@bwyseymail I looked at the dog last night. I'm gona miss him
@@bwyseymail Nah, but as soon as i lay them out they break off in exact lengths to my dismay - is there a clinic or rehab anywhere near?
The balls dropping out was classic!😂 You plan of doing $2000 of fixing while full well knowing you need to spend $3000 to do a 'proper' repair sounds all too familiar! Thank you Tony for posting this.
Yes, but saving a thousand dollars prior to spending that three-thousand is what it’s all about!
Don’t forget to add the cost of broken cutters.
McMaster's prices are enough to make anyone's balls drop.
Yeah, he really had me going there for just a moment.
Hi TOT. My CNC has worn $$$ Japanese screws. Replaced the nuts to extend the assembly life. What I learned is I wish I’d set up non-precision jobs on the periphery of the table, to spread the wear out. I probably would have >doubled the life of the screws this way. Stay awesome 🤙
Impeccable analysis of several repairs vs. just initial replacement!!
I used to work at a Ballscrew factory in Coventry 🇬🇧 we made precision Ballscrews for machine tools & aerospace, I worked there 38yrs till the end 2005, you did very well there Tony great video thanks for sharing 🇬🇧👍.
Is the company still running ?
I once ran a super-expensive ball nut off the end of the screw (bad software design). After picking up as many balls as I could find off the floor of the lab, I had the uncomfortable phone call with the supplier "how many balls are there". They informed me there are two sizes of balls that alternate (a couple tenths difference) with load balls separating ball & nut radially and spacer balls (rotate in opposite direction) separating load balls without rubbing on screw or nut... I replaced the assembly...
Damn.
Yes i said exactly the same thing...Ball screws have two sizes of balls, if you dont seperate the balls alternately they wont roll if they are close fitting.
I didn’t know that. Thanks for that info
That allows one to hang lower than the other!
My condolences to your wallet
My moral of this video is that cheap repair/overhaul rarely fix an important problem. So most of the time you have to do the service twice: the first with the cheap solution… and then with the good one. Thanks tony for your videos that educate to use the brain for not waste time and money
Well, balls to that! Great video Tony. I know that feeling of doom, on having to take the big machine apart! Me, myself and I can only get it right or wrong...nice touch with the sleeve to hold the bearings in the holder! No tap-dancing on bearings were performed during this video...that we saw anyway! Cheers Tony. Thanks for the time to put this together.
Hey Tony thay looks like a SFU20 or SFU25 "ball nut" You're using there. Take a look at the DFU20 or DFU25. They are "double ball nuts" and has twice the internal load bearing area and twice the amount of balls plus..... you can adjust the tolerance between the two and completely eliminate any backlash. Absolutely love You vids man.🎉
Was thinking he could fix up that missing return loop.
The load bearing capacity should be around the same. It's only a matter of "if you can't make it perfect, make it adjustable"
Outstanding...thanks. never heard of one of those things...must be a spin-off of Archimedes type thinking . Love watching your stuff...even when it's loose.
@@MF175mp So that you can blame it not working properly on whoever adjusted it instead of the poor quality parts
The double nuts are weird when you look into it. The two halves are not really fastened together except by the ballscrew itself. There is a little widget to maintain the angular relationship, and then the space between them is shimmed to take up the slack.
Which I think means that you don't get double the load bearing capacity, as basically you are dividing the work, one half takes loads in one direction, and the other in the other.
Watching the balls falling out from the ball nuts caused a strong sensation of pain under the skin mixed to desperation, an emotion hard to describe.
One of life's greatest pleasures. Hands, machinery, snark, and a little lesson learned. Thanks Tony.
Was on the edge of my seat, like twice! Thank you!
I can safely say I will never rebuild a ball nut, but I'll happily take 20 minutes to watch This Old Tony try to do it. Missed you TOT!
The moral of the story is that This Old Tony videos are always worth waiting for 💖
One trick for the "Gravity fighting against you" when you're filling these, instead of the world stickiest grease that you probably don't want in there anyway - is just to pop a couple of small magnets on the body - that will hold the balls in position when you place them and you just pop them off after everything is on the ball nut. That means you can use your correct grease/lube instead of something full of tackifiers from the start.
Also as someone else said - if there looks like there's space for one more ball, then you have the correct amount in there. You need free space to prevent rubbing and jamming issues.
The fact TOT threw up a pic of GBH is so killer. My street punk heart melted ever so slightly... ;)
The moral of the story is I now want that pass-through ratchet you used to remove the bearing. Great video, Tony 😊
Looks to be a Williams ratcheting wrench
@@brianargo4595 thanks! Looks super handy, especially with the thumb wheel on the back.
I thought the moral of the story was that you need appropriately sized balls to get the job done.
@Timo "make sure what you do is a product of your own conclusions"
@@aaronb554 Can‘t argue with that 😊
Your home shop mathematics/economics are spot on Tony and I seem to get bit by this more often than not. " Turns out I can put up with quite a bit of hassle for three grand my plan of course is to spend at least two grand constantly swapping out these ball screws that fall apart and then I'll be ready to spend three grand on the good stuff" Priceless for all that can relate to, bin there done that 🤣 Moral of the story.....Buy once, cry once
My guess is after drops 3 grand on the good stuff he will find a deal on a bigger better mill.
@@1978garfield that's exactly what would happen to me in that situation... Spend the coin on make do and another much better option shows up just after the money is gone...... And the game goes on....
I have an even better alternative. Buy cheap stuff that's very durable, but leave something else in the quality to be desired. Then you can buy once, cry many times.
Entertaining as always Tony. Thanks so much for this. I'm not a machinist but always considering buying a mini-mill for my little garage shop mostly for the learning experience. Two things keep stopping me, 1) I don't know what I'd use it for and 2) watching these repair and tear down videos exposes so many opportunities I can really fowl things up. It's great watching others deal with it though. Thanks again, your devoted fan.
"I can really -fowl- foul things up"
Tony, you made my day, love it, you are so gentle and educating, Thanks
The video was over way too soon.
Tony, thank you so much for sticking around and inviting us into your dark world and mind (not dark). It's always a very special and soul-healing time when you upload.
I do wish he’d do some more long-form videos. I could watch him for hours.
Oxford comma to the rescue! “dark world, and mind” meaning is clear 😁
@@smbrown yes, indeed :o)
I'm just really impressed that you converted that mill in the first place. Kudos!
I’ve waited 7 days to find the perfect time to watch this video so I wouldn’t get distracted or interrupted. We’ll worth the wait.
I just watched it twice, once with kids in my face and once in my workshop.
Very glad you're back Tony, thanks for sharing the wisdom.
I'm not sure whether the motto is "Sloppy balls leaves you with too much 'end' shake" or "If you want a nice tight screw, make sure your balls are shiny and new".
Either way, great Video Tony 👍👍
Not reading down any further. This comment did the trick.
😂
Well said.
always love it when TOT talks about nuts and balls
Don’t forget about his 3 shafts and those important oilers.
@@markm0000 Proper oiling of the shaft is mandatory for smooth forwards and backwards motion
Let's just keep it between us. Don't talk about those with your neighbor. He might misunderstand.
...he will misunderstand.
Thanks for showing this. I've always wanted to know how it works and if it can be rebuilt by hand! Now just need some real estate to get a milling machine. I'll keep watching you until then
Poor man pays twice.
Excellent video as always Tony.
Like a hug from Grandma! You don't know how much you missed it, until you get one.
Hey Old Tony . Been rewatching a lot of you old videos. Missed you man....
I bet A lot of the "likes" were clicked before even watching the video, mine was.
5/15/23;..replacing (~30 little) ball bearings/'ball nuts'..always enjoy yur sense of humor while teaching we armchair YT viewers lots of fabrication fundamentals, techniques, various welding types & shop tools..like that green 3-axis milling machine you repaired 2day. Great camera close-ups, lighting + that medical flex camera inserted into that...oil port (?) to confirm 'bottom-out' of oil drip-lube line. [LoL on tease spilling of tiny balls!😁]. Much enjoy your channel! Stay safe & carry on!👍👍👏👏⚙️🔧💪😊
All that work for just replacing the piece in the end... this is nuts!
Get it?? I’m here all week!
Hi tony ,fun video . having replaced a number of ballscrews over the years and having the great fortune to travel to Japan for training at a large and well regarded cnc machine
tool manufacturer perhaps I can offer some of what I have learned.
1) a high preload ballscrew and nut will feel lumpy ,in a smooth sort of way. a worn out high preload screw will actually turn very freely, in fact if you hold the screw vertical
the nut will spin down on its own.
Many machinists don't don''t like the feel of ballscrews on manual machines because they do not feel as smooth as a leadscrew.
The lumpyness is caused by the ball returning from the recirculation tube /deflector. High preload is achieved by sizing the ball larger than the groove its running in. (for most 1 nut setups).
2) In japan, we spent some time in the ballscrew assembly department. you were right in your speculation about several size balls. The assembler placed the nut on the screw and then
placed the appropiate number of balls into the nut through the deflector tube holes. once the balls were in place he would rotate the nut to see if the ball size was correct. interestlingly
the way to know when it was right was to rapidly rotate the nut back and forth several times ,about 180 degrees, hesitatate for a second and then rotate the opposite way , there would be
a tiny hesitation or "grab" before turning.
As these were double nut screws this would be repeated with the second nut. then a large range of spacers were available to place between the two nuts to both line up the keyways and
bars between the 2 nut and to achieve the proper preload between them.
3) most large machines use double nut ballscrews. single nut ballscrews use either oversized balls for compact nuts, or 2 sets of races , one with right hand preload and the other left.
That's a heck of a process. I wondered if running with fewer balls would give enough clearance for oversized balls to fit the screw. Any feedback on that crazy idea?
@@scottcates Hi Scott , what i saw at that factory (about 2001) was a very skilled and experienced assembler fitting the balls largely by trial and error.
what i recall was a nominal sized ball and a range of +/- balls in about .001mm increments. he started with the nominal size and then almost immediatley
was able to select the right size for the desired preload. he had been doing it for many year, I could imagine that a trainee would take months to become as
proficient.
Tony had referenced a ball bearing , this is sort of what a ball screw is, a bearing with benefits, so there is an ideal size ball for the job.
like a ball bearing fewer balls would not allow for a larger diameter.
A bit of additional information ballscrew races are usually(quite often ?) ground not as a perfect circle but in a 4 point contact or gothic arch profile, so that the balls
are touching on their sides rather than top and bottom.
@@steveggca Thank you, Steve!
I was going to use this video to introduce Precision Ball Screws to my Pre-Engineering High School students, but the egregious nut ball slop humor might get me an extra long vacation 😂!
You Sir Have made my day!
-Castor
Thanks as always
If you install a pair of Z-Cups you'll get away with it.
@@Pithead I heard about that shop teacher...
They'll love it.
If high school as degraded to the point that egregious ball nut slop get you any extended vacation, your students better never the the engineering office. The Tradies will eat them alive at a job site.😳
Ahhh Man This is soooo Tempting!
Thanks for the production ToT! Really enjoy watching your video’s sir!
Balls! Balls! Cried the queen, if I had them I'd be king!
Seriously we appreciate you, Tony. Anytime I see a new video uploaded, it makes my day.
Ditto
Turns out the real ball buts were the friends we made along the way.
Great to have you back Tony! I learned the hard way about taking the nut off the screw ! Got most of the balls back, thank goodness its only going on a tail vice for a wood working bench cause I think its got more than the 20 thou. slop that Tony's had.
This is awesome sir, always love watching your videos. I dont even own a milling machine, but there is something about listening to your voice while you play with your ball nuts that just turns my screw.
Nice to see TOT back, thank you for the video
The moral of the story was to spend time together and learn a thing or two. Thank you for another entertaining video.
Man seeing the balls fall at the end, lol. You got me. Im glad it worked. I had no idea it existed until now. Great description
When you said that opening line, my brain immediately shot off on a Full Metal Jacket style rant.
"This is my milling machine.
There are many others like it, but this one is mine.
My milling machine is my best friend. It is my life. I must master it as I must master my life. Without me, my milling machine is useless. Without my milling machine, I am useless. I must run my milling machine true. I must cut straighter than my error, who is trying to kill me. I must minimize him before he minimizes me. I will. Before God I swear this creed: my milling machine and myself are defenders of my accuracy, we are the masters of our tolerances, we are the saviors of my precision. So be it, until there is no enemy, but metric. Amen."
Your channel is a goldmine for a newbie machinist like me . Keep up making those awesome vids. Best regards from Russia!
Go UKRAINE!
@@conanobrien1 not sure what Ukraine has to do with this.
Whatever floats your goat... I guess...
Reply
@@Harlequin43 You would have to live under a rock not to understand "Go UKRAINE", but then again, you are from ruSSia...
Whatever float your Moskva boat. Actually, your Moskva submarine.
@@conanobrien1 can’t we have moments without the antagonism?
@@Kevrek Tell that to the Ukrainian people and let me know what they say.
Tony. I really enjoyed this video. It came to mind, as I watched you sticking those tiny ball bearings into their gravity-defying slots, that you might try making a video on brain surgery. Should be right down your alley!
Always wondered how to get the tightness on the spindle. Learned something today.
The journey sometimes is more important that the destination. I learned something from this video that I had no idea about!
It's a good time watching some ball play on a slow Sunday afternoon, thanks! 👍🏻
The important thing to take away.
Everyone is just happy T.O.T uploaded a video.
At this point, im convinced i would watch a video of tony stuck in traffic just for the professional dad jokes.
6:14 Even Sir D. Attenborough could not have come up with a better analogy for the 'circle of life'.
Thank you Tony, my balls have seen the light because of this documentary.
I love learning the answers to questions I didn't know I had. Thank You!
I love it when one of your videos pops up in my feed. Educational, entertaining and amusing. Keep up the great work. 👍
Loved the little depiction of how the nut actually functions. I’ve had varying luck removing/reinstalling/reloading ballnuts in the past. Likely the best solution to your issue is to just buy a high quality ballscrew like a Hiwin.
That was a great little episode and experiment. Thanks for sharing. 🙂
"I bought a new one" killed me lol. Great editing, as always
As someone who very highly values being able to personally build/manufacture high quality tools, furniture, and other items, it makes me a bit sad that I'll likely never be able to afford to get into machining. ToT gives me a lot of joy anyway.
I was thinking .0005 oversize balls. When you said .004 I did a double-take. Great video, hope the affordable ball screw works.
So glad to see a new video! Funny and informative - two things that are at least on my top ten favorite things about UA-cam videos. 😂
The moral of the story is, never give up waiting for the next ToT video!
Tony never lets me down.
I know it's easy and relative cheap for you to buy a new nut and replace it, and I know you get a lot of crticism for not doing that in the first place...
But for us who do not live in the US, or some countries on Europe, that's not that simple nor cheap, especially if we wanna get the best quality parts.
So I really appreciate your effort for trying and documenting cheaper ways to fix stuff, cause that really helps people like me who lives on "developing" countries.
Thanks for the content ❤
I don't know if ToT is American. He may be a Canuk.
This video gave me heart sinking flash backs to when I pulled the rear socket set off my mountain bike years ago. Ball bearings and grease really did a number of my nerves 😂 thanks for the trip down memory lane ToT !
The intricate details of machinery that bring it to precision part making explained in a concise yet often comical way only to be found by following this old Tony. I will add without any hubris that was not meant to Crack a smile.
Don't let the Mrs see this or she'll up your game somehow.
The moral of the story is that you have to have the balls to try these kind of repairs.... I always look forward to TOT and it makes my day to find a new one.
The ball nuts on my BP conversion are double circuit but each circuit is at least two possibly three turns. It's also much longer than your ball nut. In a good ball screw assembly the ball sizes have been selected to provide preload to each circuit to reduce or eliminate any backlash. Because preloading caused more drag on the rotation every other ball in the circuit is slightly small in diameter and acts as a spacer to reduce the drag while keeping the bearing area constant. They also have external return tubes which allows for easier ball loading. Tony is correct a really good ball nut and screw is quite expensive. The worst sound is hearing the those balls fall out onto the floor never to be seen again.
You got me with the ball bearing dropping out at the end! You got my goose!
You’re the best Old Tony, have you ever thought of telling children’s stories? you would be excellent at it, not that you are not excellent on how you teach us so much with humour along the way. Thank you.
It is so good being able to enjoy the whole video without interruptions, add free! 👍
I'm not a machinist, I don't, and never will, have a CNC machine, but I watched this whole video with bated breath. I just love TOT videos!
Fantastic! Glad you're back!
Moral of the story: if you can fix or build something and learn something at the same time it's worth the cost, even if you could buy it for cheaper.
I'm in the early stages of building my own CNC router using ball screws and this was indirectly very helpful, I hope I won't have a moment of "52 ball pickup"!
I did as well. Cheap amazon ballscrews got me max .0015" Backlash. I use a bit of Vaseline, petroleum jelly, put a thin film on the screw, run it back and forth, then wipe it.
Fun to watch! I break out in a cold sweat changing the blade on my disposable razor, so could never hope to tackle something like this. Thanks for the great video!
Great to see another video! Always look forward to them 👍🏼
Great video and fabulous
Good fit for non preloaded ballnut. Most CNC ball screws are preloaded so basically you have 2 nuts pushing against each other to remove the backlash amd not depend on the clearance of the screw/nut/balls. For putting them together turn a bar the diameter of the shipping retainer with taper on the end. Also surprised you have such low backlash as thrust bearings are a common point of failure, and they are far from cheap themselves. Good video, as always
The moral of the story is some of us didn't have fathers who spent time with us screwing around with screws (or anything else) and this is giving us a warm fuzzy feeling.
I’m the type of guy that when somethings really broken, I’ll order the new part but still go ahead and fix the broken part.
The new part arrives after I’ve fixed it and I feel good knowing that I’ve fixed the unfixable and I have a back up in the cupboard.
Worst part is seeing that new part years later but thinking how good am I at fixing unfixables that’s still going strong years later.
ToT is the man.
Nothing better than firing up youtube and finding a new TOT video! You seem to always make me smile. Glad you're back and able to make videos, can't wait until the next one.
This was a video full of action and emotions. I was keeping my fingers crossed the whole time 🤞
New TOT video? World is placed on hold while I watch.