Main take away here is how well you used what little you had, most people think you need machining equipment 100 times larger than what you have to make anything what we see you make in this video.
I've got two old lathes, both about 80 years old. They have acquired excessive backlash over their lifetimes (rather than having it factory-fitted) but I think I'll try your fix. At worst I can put the original parts back on and I'll have learnt something. Thanks for posting this.
Turned out excellent. I did a similar project to my Grizzly gunsmithing lathe about a decade ago. I simply bought a replacement nut and then cut it in half and inserted a spring of sufficient strength in between the two halves. The spring was held sandwiched in between the two halves of my new lead-screw-nut by four long-enough screws in each corner of the lead-screw nut. It too was adjustable but, my method was way harder to adjust than your design. I did it that way because I knew I could finish it in a day or less. It worked well for me though. I just couldn't afford to have my lathe down for any length of time.
It makes more sense to split the nut lengthwise. Attach one half to the crosslide and spring load the other half laterally. Because of the acme thread, provided there is tip clearance, this is like holding the half nuts closed with a spring force on a screwcutting lathe. This is how I got the idea: i noticed that my instrument lathe, which has a graduated dial on the screwcutting leadscrew handwheel, had no backlash on this (z) axis. (The halfnuts are held closed by a spring). Not much spring force is required because the Acme flanks are very steep (less than 15 degrees from square thread) which is less than the angle of friction. In the same way that a ladder will not slide regardless of weight if the angle is 15 degrees, the nuts will not open regardless of axial force.
Well done, sir. Setting aside the discussion over anti-backlash nuts, the bigger impact of this vid is showing how you can make quality parts with inexpensive hobbyist machinery. Lots of great work holding and tool holding tips in your vids. I'm a big fan.
absolutely agree! The actual replacement nut's design way a bit beyond me, but I learned so much about how the lathe can be used as a mill...really useful as a hobbyist who barely has place for a lathe :)
@@raelkoping5675Bit late to the party, so don't know if you'll see this, but whilst this is a great video (I've subbed on rbe basis of this video) and the content creator shows some great ideas, the way they hold milling cutters in the lathe chuck is a definite no-no. If you want to use the lathe as a mill (and if you don't have a mill, you should definitely give it a go; affordable benchtop mills are a relatively recent innovation and model engineers have been using their lathes as very workable makeshift mills for a long while), you should use a collet chuck. ER32 is a good choice; there are lots of reasonably priced ER32 collet chucks available for mini lathes. The reason for this is that milling cutters have hardened shanks, and lathe chucks have hardened jaws and so the jaws can't really grip the cutters shank sufficiently well. That lack of grip will, sooner or later, lead to the cutter slipping in the chuck jaws. You probably can get away with it for very light cuts but sooner or later it will probably bite you in the rear. At best you'll damage your cutter's shank, or the workpiece or both. At worst, because milling cutters tend to grab at the material, the tool could slip out of the jaws completely and end up damaging you! The only safe use of a milling cutter held in a lathe's chuck, if you absolutely don't have a choice, is using what is known as a 'slot drill' to either flatten the cone out of a blind hole drilled with a twist drill, or to make the flat bottomed blind hole in the first place. That's okay as the force back towards the chuck will prevent the cutter from ever pulling out. tl;dr: don't put milling cutters in lathe chuck jaws, get a reasonably priced ER collet chuck and a few collets in sizes you're most likely to use. 😉
Agree! Great video, great skill, and imagination! I also saw a video on the " we can do that better " channel, and he made an anti-backlash nut that was really great.
Ten years ago I changed my minilathe to a brand new Chinese lathe with 255kg and 1,3 kw after I improved everything you could and It became a quite precise minilathe I sold it to a professional Vespa restaurator and he uses it to improve the cylinder and other parts of the italian motorbikes . I also changed the Nut into a sliced Nut with screws you could get the backlash down to a minimum...
I would do it so too. That way the central rotating part can be done in one piece with outside plate. There are "wavy" washers, which are ideal for this purpose.
Like many here i absorb shit loads of shop & turning videos but I love lathe improvement, attachments, and upgrades the best. This project really shines because who the hell wouldn't love to reduce backlash to an absolute minimum? It's truly a rhetorical question. I'm going to investigate if I can adapt your excellent design to my old SB-H10 and Logan 920. Thanks for the very enjoyable and well done video. You did it with no monologue, yet the vid is clear enough to not suffer from its absence. Thanks! Wakodahatchee Chris
Interesting design. I've been able to remove almost all the backlash in my mini-lathe by cutting a slot longways on the underside of the nut and squeezing it slightly in the vice. (Similar to the approach in Taig mill). But eventually this will wear, at which point I may try something like this.
As usual you do really nice work. You got the backlash down to less than 0.001". Of course short of going to a ball screw, no one can eliminate backlash 100%, but instead only come close. It's why we always approach our work in such a way as to remove the backlash first. Even the most precise CNC operations are programmed to approach the work in such a way as to remove backlash.
Chinese mini-lathes like this one are metric, so double that assessment. ( I need to do this and more.. they are chatter machines after working steel for a while).
@@tsclly2377 Mostly due to a lack of mass but there is also the approach to machining required to minimize chatter. Very involved CNC machines will vary RPM on the fly for example to try and minimize chatter. Once chatter starts when machining a part you will of course have variations in the cut that are synchronized with the vibration requiring a change in RPM, and often taking a more aggressive cut for a short time to cut through those undulations in the material.
@RollinRat I've come to the same conclusion in hindsight. At some point I'll upgrade. I decided to spent a little more and buy a better milling machine than the Chinese offerings. I bought an A-head Bridgeport mill made in 1960. Loving it.
@rollinrat4850 totally disagree. there are very good chinese machines, with great engineering going into it! and they are getting even better every day.
@rollinrat4850 you seem to be stuck in the last century. i am a machinist myself, and I have more respect for chinese companies nowadays than for most german competition. japan is different, they didnt slack as hard as EU/US/UK did.. but china is only second to japan for me. compromise for profit is something every business does...and the chinese are way smarter about this than german engineers. thats what makes a good product for a good price! :) also, chinese customer support is excellent where i buy my stuff! and dont get me started on the communism trope when i am living in some modern soviet union(the EU).
That is brilliant and worth the effort, I have a huge milling machine Korean made and it had very annoying backlash on the x y access I was going to make new nuts but found they had already from the factory adjustable nuts in two halves that had a ball bearing roughly 8mm diameter that spread the two halves of the nut no need to dismantle the tables or remove any thing ,just loosen two cap screws on one half and turn in a grub screw on top of the ball to spread the nuts and take up the backlash .
It’s people like you that make people like me, just like you. This is an awesome mod, specially for the Mini-lathe. Though, I would think with a bit of measuring it can be modified to fit any lathe that needed this. Great job.
You could also have taken the existing spindle nut, drilled two holes axially for hard pins (3 mm?) and then cut the nut in half so that you have two short nuts. Mill off both parting surfaces at 5 degrees and make a wedge at 10 degrees with a hole in the middle that is several millimetres larger than the spindle. If you then make a thread on the slide between the two holes for fastening the threaded nut so that you can press on the wedge with a worm screw, you could also eliminate the thread play in this way.
Interesting way to do an adjustable backlash nut. I normally make a nut and bolt with a dowel an end plate on it then cut the thread. Then after this just take out the backlash with a shim and or grind. The problem with a rotating adjustment is it could move and lock it up. Its only a little lathe so it should be ok.
Nice project! But on a manually operated machine backlash is not really a problem as you compensate for it by always feeding in one direction and make sure to take up any backlash before making a cut. And a anti backlash nut will just wear faster until it has just as much backlash again as the old one.
The anti-backlash nut is adjustable, so you just adjust it when it wears. Sheesh! The gibs on the lathe are adjustable. Do you leave them loose, because if you adjust them tighter they might wear so you'd have to adjust them? Do you not tighten your shoe laces because that would make them loose so you would have to re-tie them?
@@johncoops6897 Still backlash is not a problem on a manual lathe. Because you can feel the backlash and compensate for it by only dialing in one direction, or take out all of the backlash when changing the direction.
@@titter3648 - you are correct, that backlash is more of an annoyance than a serious problem. However less backlash and slop makes the machine feel a lot nicer to use... more "precise" even though is isn't really. My original comment is about the statements made in your first post. I am not saying whether such a modification is a good idea.
@@johncoops6897 You are assuming all the wear is on the nut. However the problematic wear is to the feedscrew, because it always wears more in the middle than at the ends.The nut cannot be tightened to compensate, because it will bind at the ends.
Ultimately the screw will wear more in the region of the most frequent travel and then you have to leave some backlash anyway, otherwise the screw will bind up at either end. You must still develop the habit of making the last adjustment of the cross slide against the reactive force of the tool pressure.
Indeed. If I was going to this much trouble I would make a self adjusting nut which tightens wherever the feedscrew is worn and loosens where it is not. There are plenty of complicated ways this is done (eg on manual milling machines of high standard) but a very simple way is to use the geometry of the acme thread to your advantage. If the nut is split lengthwise (ie the split plane includes the rotation axis) the two halves can be spring loaded together. Because the spring (and adjustment movement) is orthogonal to the translation axis, the spring is not exposed to feed forces, so it need not be so tight as to promote undue friction and wear. I got this idea because my Myford lathe has a graduated handwheel on the leadscrew for precise moves of the carriage, and I noticed that if I applied a small downforce to the lever which closes the half nuts for screwcutting, and adjusted the stop which normally prevents the half nuts closing fully, the backlash is eliminated altogether. It is important when applying this idea to cut the nuts with generous clearance at both root and tip, so the the nuts close only on the flanks of the screw. I guess it is the lack of this clearance on most half nuts (at least, once they are worn) which prevents more people noticing the possibilities of this remarkably simple solution.
@@Gottenhimfella - seems valid, however an Acme thread is not a square thread. The flanks of the thread are indeed angled, and any pressure on the thread's axis will tend to open up a "spring closed" split nut. So, backlash can certainly be eliminated during no-load conditions using a spring, however as soon as force is applied to the tool, the cross slide/carriage would literally become rubber mounted and jump all over the place. It would take careful consideration anout the strength of spring required to be stable enough to cope with considerable and often intermittent loads from cutting tools. There is a certainly a mechanical advantage from the narrow 29° thread angle, but there would still need to be quite a lot of preload needed for the spring to cope with axial thread forces. That preload also applies at all times, whether the thread is loaded or not, so it might well be that the leadscrew becomes worn significantly more quickly by that continual abrasion.
@@johncoops6897 You're right in perfect (geometric) theory. A trapezoidal thread is not strictly orthogonal in the way that I (to keep the explanation simple) pretended. That would imply a square thread. However, real life materials, for once, come to the rescue, in practice, of something which should not work in theory. Geometric theory would tell the whole story if the split nut (and its guideways) were made of something as slippery as (say) wet ice. In the same way, a ladder made of wet ice would invariably skid out (particularly on a wet ice floor) at an angle of 15 degrees to the wall (which is about the angle, per side, of an acme thread). This "angle of friction" is exploited in mechanisms like Torsen diffs and Duff Norton jacks, to act a bit like a diode or a check valve. And that's what I'm doing here. It has to be a trapezoidal, rather than square, thread, or my proposal would not take up the backlash. But 15 degrees per side is about perfect (as I intuited from the fact that lathe half nuts do not try to open even when the carriage runs into the headstock)
It occurs to me that Myford lathes offer another example of this principle in action. I have an ML7 I inherited from my dad, and a Super 7 acquired decades later (when they finally became affordable). On the ML7, the tailstock barrel stays where you put it. On the Super 7, axial force can under some circumstances cause the barrel to retract if the clamp is not tightened. The reason is that the helix angle for the ML7 is well below the angle of friction. The Super 7 has a smaller diameter, three start thread, with a much higher helix angle, maybe four times as much. This is fantastic for drilling, being both quicker for withdrawing to clear chips and apply fresh fluid, and offering far better feel (important, for instance, with very small drills or reamers).
7:05 well identified! the parting issue of the mini lathe. Seems like you've done quite a bit work with it to fix it that way. In general I'd rather install a ballscrew than this one, and make a new crossslide.
instant sub. but also, perhaps a spring system might have been better? that way you'd be able to use less pressure (less wear on the nut), it wouldn't come loose with vibrations, and it would work for a lot longer without maintenance because as the nut would get pushed forward as it wears.
@@CarlosSilva-gc8ny I don't get why you guys are being so defensive about it, it's simple feedback, a possible improvement on an already great job. And if I even had a lathe I would have already done it bud, and then I wouldn't be suggesting anything.
The nut on the cross slide has backlash adjustment built in, using the set screw between the 2 attachment screws you can take out the backlash by snugging up one end and turning the set screw in until the backlash is gone, then tightening the attachment screws
I dunnoI watched this entire video and I still don't know what an Anti-backlash nut Chinese guy looks like! Humm, maybe I missed something. I enjoyed the video. Thank you, Sir!
That's not an anti backlash nut- it is designed to prevent end play of the lead screw. You will still have backlash as the threads in the nut wear. The Shoptask machines beginning in 1996 had both functions as standard. End play was taken care of by having thrust bearings on each side of the handle bracket. Back lash was adjustable as the screw wore by having 2 nuts in a spit clamp bracket with a spring between them. As the threads began to wear, you simply loosened the clamp on one of the nuts and the spring pushed them apart giving you contact on the leading and trailing face of the screw.
It was much easier, just give the existing nut a saw slot through the screw thread and then press with a screw that opens the saw slot, you have made a perfect backlash free nut that you can adjust. Costs you nothing and 10 minutes of work.
Bit late to the party, but I thought I should say that whilst this is a great video (I've subbed on the basis of this) and the content creator shows some great ideas, the way they hold milling cutters in the lathe chuck is a definite no-no. If you want to use the lathe as a mill (and if you don't have a mill, you should definitely give it a go; affordable benchtop mills are a relatively recent innovation and model engineers have been using their lathes as very workable makeshift mills for a long while), you should use a collet chuck. ER32 is a good choice; there are lots of reasonably priced ER32 collet chucks available for mini lathes. The reason for this is that milling cutters have hardened shanks, and lathe chucks have hardened jaws and so the jaws can't really grip the cutters shank sufficiently well. That lack of grip will, sooner or later, lead to the cutter slipping in the chuck jaws. You probably can get away with it for very light cuts but sooner or later it will probably bite you in the rear. At best you'll damage your cutter's shank, or the workpiece or both. At worst, because milling cutters tend to grab at the material, the tool could slip out of the jaws completely and end up damaging you! The only safe use of a milling cutter held in a lathe's chuck (ot a Jacobs style chuck too, for that matter), if you absolutely don't have a choice, is using what is known as a 'slot drill' to either flatten the cone out of a blind hole drilled with a twist drill, or to make the flat bottomed blind hole in the first place. That's okay as the force back towards the chuck will prevent the cutter from ever pulling out. tl;dr: don't put milling cutters in lathe chuck jaws, get a reasonably priced ER collet chuck and a few collets in sizes you're most likely to use. 😉
I can't begin to do precision work like the cuts you make. I have a cheap Jet lathe which has some kind of play which can make cutting tools dig in even on pretty small cuts.
I keep thinking there should be a way to make the Acme cross slide nut like an ER32 collet and holder, with a tension ring just behind the handwheel and dial. You could just turn it by hand to remove backlash.
very nice work, that nut you made defentaly improved the machine strenth... but you want some back lash, even some of the best lathes (mori, hardinge) are back lash machines. It ultimately is a screw. (the screw out of your machine dose not have the acme screw look, most cheap machines have a more traditional screw type thread rather than a acme type making back lash even more important. you don't want pressure on you screw)
Although, wonderfully machine and a clever design.. it appears to me, that it is more of a slipper clutch or break-over friction clutch then a system that is designed to control lash gap in a controllable measure? Perhaps, maybe I missed something. But, yes, modifying this dinky little machines is so much fun, and affordable. I enjoy your content.
I had an emco compact 5 which I inherited. Would have desperately needed this upgrade, even though it wouldnt have been possible, because the nut was actually just a cut thread in the cast part.
I think having minumum backlash is important especially on small machine or heavy cuts or turning square and etc.Would resist the tool getting pulled in especiallly your machine tool does not have sufficient gib lock or you are using that one axis for cutting.
Great approach for minimizing backlash on a mini lathe! It looks like you've already addressed the leadscrew floating where it attaches to the handle, I removed 0.012 backlash at the nut and another 0.008" movement of the leadscrew. Scraping the dovetails took a 0.009" bow of it. Still need to do the x axis, thats going to be an incredibly long a boring job as I don't own a surface grinder. Over 0.030" to remove! Almost not worth it.
I'm surprised if you take all the backlash out of the nut that it will even let you turn the handle at all without a lot of torque. It will not take long to wear it till you have backlash again.
@@andrewwilson6085 - backlash is an annoyance, both on lathes and in vices, as well as anything else (eg: adjustable wrenches) where it means you can only sneak up from one direction. Minimising backlash makes all tools far nicer to use. It's unreasonable to expect to eliminate it entirely, however removing most of it just makes tool operation so much more pleasant.
You should really use zero raked tools on brass, it makes a huge difference, backlash isn't much of a problem as your tooling does dive into the backlash anymore.
Отличная идея, скоро себе сварганю такую гайку, прижимные планки для продольной подачи уже сделал работают отлично, у меня вопрос по рпижимным планкам с клиньями, тебе не приходилось шлифовать станину снизу где скользят клинья или мне так повезло с моим *джетом 7*? Или эти станки все с одинаковыми болячками?
Sehr schön gemacht. Das Umkehrspiel ist immer ein Problem, weil der Drehstahl oder der Fräser ich auch in die Maschine hineinziehen kann. Sie wissen nie wann und wieviel das Werkzeug gezogen wird. An der Drehmaschine tragen sie dadurch schnell zuviel ab, bei der Fräsmaschine zerbrechen sie das Werkzeug und mehr. Einstellbare Spindelmuttern mit Federn lösen dieses Problem nicht. Es muss ein fest einstellbare Spindelmutter sein, deren Gewindeflanken auf beiden Seiten tragen.
yup, just upgrade the ball screw and all.. that old nut is nasty cast iron.. a wear monster in its own right.. what is missing is a plastic screw cleaner, both ends
nice job did you lose any cross slid travel ? with the longer nut ? its open on the one end and from the look of the org. the mounting bolt hole to the front end looks about the same so ?
I can't say I'm impressed by the design of this device at all........it's not CNC so some backlash is not a problem......a spring loaded double nut would work better as the screw itself wears in the middle.
@@johncoops6897 Well, you will have the same free movement with a screw that has been used a bit when the nut rides on the worn part usually around the middle........you cannot have a solid nut tight on a worn screw as you must allow for the unworn ends to mount the nut and as soon as you get to the worn part you have backlash.....not all screws are new.,,,,,a spring just allows you to reverse the screw without having to have lost motion.......it's a nut back up feature widely used.
@@gangleweed - doesn't matter. You cannot use a spring because it will yield under cutting forces. For example, you dial in a 5 thou cut but when the tool touches the work the cutting pressure will compress the spring and push the cross slide backwards. So you try for a certain depth of cut but have no control over what you end up with. Worse, when beginning a cut the material is not round. So the tool needs to be rigid and stay where it is to cut off the bump. Since the work is spinning there would be a harmonic movement caused by the spring rebound, and the tool would move around causing chatter or simply snapping the cutting tool. The number one criteria in lathe work is rigidity of the tool. Any loss if rigidity is really bad, and it doesn't get much less rigid than a spring. You are better having backlash (and allowing for it) than losing rigidity.
@@johncoops6897 No you are wrong.......the spring just adds back up pressure.....the cut is applied by the flank of the nut in contact with the screw......the spring will only push the back up nut against the opposite flank, it doesn't apply any pressure......winding the nut back in reverse against the spring is only a small force......you always apply forward pressure when you apply a cut.
Why make the second thread as an insert? You could have just made a threaded block, then cut it in half and tightened the 2 halves together with the 4 screws. Or 2 screws.
Main take away here is how well you used what little you had, most people think you need machining equipment 100 times larger than what you have to make anything what we see you make in this video.
I've got two old lathes, both about 80 years old. They have acquired excessive backlash over their lifetimes (rather than having it factory-fitted) but I think I'll try your fix. At worst I can put the original parts back on and I'll have learnt something. Thanks for posting this.
@sourand jaded thanks, I'll try that.
The lathe bed will also wear most near the chuck......
🎉Яяь
Turned out excellent.
I did a similar project to my Grizzly gunsmithing lathe about a decade ago. I simply bought a replacement nut and then cut it in half and inserted a spring of sufficient strength in between the two halves.
The spring was held sandwiched in between the two halves of my new lead-screw-nut by four long-enough screws in each corner of the lead-screw nut.
It too was adjustable but, my method was way harder to adjust than your design. I did it that way because I knew I could finish it in a day or less.
It worked well for me though. I just couldn't afford to have my lathe down for any length of time.
It makes more sense to split the nut lengthwise. Attach one half to the crosslide and spring load the other half laterally. Because of the acme thread, provided there is tip clearance, this is like holding the half nuts closed with a spring force on a screwcutting lathe. This is how I got the idea: i noticed that my instrument lathe, which has a graduated dial on the screwcutting leadscrew handwheel, had no backlash on this (z) axis. (The halfnuts are held closed by a spring).
Not much spring force is required because the Acme flanks are very steep (less than 15 degrees from square thread) which is less than the angle of friction. In the same way that a ladder will not slide regardless of weight if the angle is 15 degrees, the nuts will not open regardless of axial force.
Well done, sir. Setting aside the discussion over anti-backlash nuts, the bigger impact of this vid is showing how you can make quality parts with inexpensive hobbyist machinery. Lots of great work holding and tool holding tips in your vids. I'm a big fan.
absolutely agree! The actual replacement nut's design way a bit beyond me, but I learned so much about how the lathe can be used as a mill...really useful as a hobbyist who barely has place for a lathe :)
So good I thought you are a small fan,but you tell
It's really satisfying watching something transform on the lathe when others would have used a mill.
Very nice work being done in your videos. Good job.
@@raelkoping5675Bit late to the party, so don't know if you'll see this, but whilst this is a great video (I've subbed on rbe basis of this video) and the content creator shows some great ideas, the way they hold milling cutters in the lathe chuck is a definite no-no.
If you want to use the lathe as a mill (and if you don't have a mill, you should definitely give it a go; affordable benchtop mills are a relatively recent innovation and model engineers have been using their lathes as very workable makeshift mills for a long while), you should use a collet chuck. ER32 is a good choice; there are lots of reasonably priced ER32 collet chucks available for mini lathes.
The reason for this is that milling cutters have hardened shanks, and lathe chucks have hardened jaws and so the jaws can't really grip the cutters shank sufficiently well.
That lack of grip will, sooner or later, lead to the cutter slipping in the chuck jaws. You probably can get away with it for very light cuts but sooner or later it will probably bite you in the rear.
At best you'll damage your cutter's shank, or the workpiece or both.
At worst, because milling cutters tend to grab at the material, the tool could slip out of the jaws completely and end up damaging you!
The only safe use of a milling cutter held in a lathe's chuck, if you absolutely don't have a choice, is using what is known as a 'slot drill' to either flatten the cone out of a blind hole drilled with a twist drill, or to make the flat bottomed blind hole in the first place. That's okay as the force back towards the chuck will prevent the cutter from ever pulling out.
tl;dr: don't put milling cutters in lathe chuck jaws, get a reasonably priced ER collet chuck and a few collets in sizes you're most likely to use. 😉
This video is excellent in showing just how versatile a small lathe can be😊
I've seen so many machining videos that it would make your head spin, but this video is absolutely incredible. Really well done!
I have as well and whole heartedly agree. The machining creativity is spectacular.
Agree! Great video, great skill, and imagination! I also saw a video on the " we can do that better " channel, and he made an anti-backlash nut that was really great.
Очень хорошо ❤
Гайки из латуни -плохая идея. Только бронза , желательно антифрикционная
Ten years ago I changed my minilathe to a brand new Chinese lathe with 255kg and 1,3 kw after I improved everything you could and It became a quite precise minilathe I sold it to a professional Vespa restaurator and he uses it to improve the cylinder and other parts of the italian motorbikes . I also changed the Nut into a sliced Nut with screws you could get the backlash down to a minimum...
Chamfering a square block in the 4 jaw 👌 salute you there sir, love seeing a new trick
Brilliantly done, all on the lathe. Very impressive and works a treat!! Thanks for sharing this with us!!
Great job. I have one suggestion, and that is to spring load the 4 outward facing screws. It might make the final slack adjustment easier.
I would do it so too. That way the central rotating part can be done in one piece with outside plate. There are "wavy" washers, which are ideal for this purpose.
Like many here i absorb shit loads of shop & turning videos but I love lathe improvement, attachments, and upgrades the best. This project really shines because who the hell wouldn't love to reduce backlash to an absolute minimum? It's truly a rhetorical question. I'm going to investigate if I can adapt your excellent design to my old SB-H10 and Logan 920. Thanks for the very enjoyable and well done video. You did it with no monologue, yet the vid is clear enough to not suffer from its absence.
Thanks!
Wakodahatchee Chris
Really well executed! Super project. Haven't seen this way of making an adjustable nut yet. I definitely keep this in mind. Thanks for sharing!
Thank you!
thanks again mister.
Interesting design. I've been able to remove almost all the backlash in my mini-lathe by cutting a slot longways on the underside of the nut and squeezing it slightly in the vice. (Similar to the approach in Taig mill). But eventually this will wear, at which point I may try something like this.
add a screw and you can adjust it! its a nasty fix without longevity, but it sure works for a cheap operation like mine!
As usual you do really nice work. You got the backlash down to less than 0.001". Of course short of going to a ball screw, no one can eliminate backlash 100%, but instead only come close. It's why we always approach our work in such a way as to remove the backlash first. Even the most precise CNC operations are programmed to approach the work in such a way as to remove backlash.
Chinese mini-lathes like this one are metric, so double that assessment. ( I need to do this and more.. they are chatter machines after working steel for a while).
@@tsclly2377 Mostly due to a lack of mass but there is also the approach to machining required to minimize chatter. Very involved CNC machines will vary RPM on the fly for example to try and minimize chatter. Once chatter starts when machining a part you will of course have variations in the cut that are synchronized with the vibration requiring a change in RPM, and often taking a more aggressive cut for a short time to cut through those undulations in the material.
@RollinRat I've come to the same conclusion in hindsight. At some point I'll upgrade. I decided to spent a little more and buy a better milling machine than the Chinese offerings. I bought an A-head Bridgeport mill made in 1960. Loving it.
@rollinrat4850 totally disagree. there are very good chinese machines, with great engineering going into it! and they are getting even better every day.
@rollinrat4850 you seem to be stuck in the last century. i am a machinist myself, and I have more respect for chinese companies nowadays than for most german competition. japan is different, they didnt slack as hard as EU/US/UK did.. but china is only second to japan for me.
compromise for profit is something every business does...and the chinese are way smarter about this than german engineers. thats what makes a good product for a good price! :)
also, chinese customer support is excellent where i buy my stuff! and dont get me started on the communism trope when i am living in some modern soviet union(the EU).
Some pretty crazy positioning and machining on the lathe! Thank you sir, great work!
It's about time someone came up with an answer to backlash.
Instead of just living with it or recutting new threads.
Those were done pretty inventive setups there my man.... I loved the chamfers
Need to add a Belleville disc spring between the backlash screw and the body...
All done on a lathe. Who needs a mill when you have determination. Well done.
That is brilliant and worth the effort, I have a huge milling machine Korean made and it had very annoying backlash on the x y access I was going to make new nuts but found they had already from the factory adjustable nuts in two halves that had a ball bearing roughly 8mm diameter that spread the two halves of the nut no need to dismantle the tables or remove any thing ,just loosen two cap screws on one half and turn in a grub screw on top of the ball to spread the nuts and take up the backlash .
It’s people like you that make people like me, just like you. This is an awesome mod, specially for the Mini-lathe.
Though, I would think with a bit of measuring it can be modified to fit any lathe that needed this. Great job.
Continue making Chinese lathe upgrade videos . I have also similar lathe
A good way to machine a complicated part if you don't have a milling machine. The nut appears to work very well.
You perform as much mill work on the lathe as you do lathe work. Impressive.
You could also have taken the existing spindle nut, drilled two holes axially for hard pins (3 mm?) and then cut the nut in half so that you have two short nuts. Mill off both parting surfaces at 5 degrees and make a wedge at 10 degrees with a hole in the middle that is several millimetres larger than the spindle. If you then make a thread on the slide between the two holes for fastening the threaded nut so that you can press on the wedge with a worm screw, you could also eliminate the thread play in this way.
Skill is the great equalizer. Congratulations to you sir.
Interesting way to do an adjustable backlash nut. I normally make a nut and bolt with a dowel an end plate on it then cut the thread. Then after this just take out the backlash with a shim and or grind. The problem with a rotating adjustment is it could move and lock it up. Its only a little lathe so it should be ok.
Nice project! But on a manually operated machine backlash is not really a problem as you compensate for it by always feeding in one direction and make sure to take up any backlash before making a cut. And a anti backlash nut will just wear faster until it has just as much backlash again as the old one.
The anti-backlash nut is adjustable, so you just adjust it when it wears. Sheesh!
The gibs on the lathe are adjustable. Do you leave them loose, because if you adjust them tighter they might wear so you'd have to adjust them?
Do you not tighten your shoe laces because that would make them loose so you would have to re-tie them?
@@johncoops6897 Still backlash is not a problem on a manual lathe. Because you can feel the backlash and compensate for it by only dialing in one direction, or take out all of the backlash when changing the direction.
@@titter3648 - you are correct, that backlash is more of an annoyance than a serious problem. However less backlash and slop makes the machine feel a lot nicer to use... more "precise" even though is isn't really.
My original comment is about the statements made in your first post. I am not saying whether such a modification is a good idea.
Agreed.
@@johncoops6897 You are assuming all the wear is on the nut. However the problematic wear is to the feedscrew, because it always wears more in the middle than at the ends.The nut cannot be tightened to compensate, because it will bind at the ends.
Ultimately the screw will wear more in the region of the most frequent travel and then you have to leave some backlash anyway, otherwise the screw will bind up at either end. You must still develop the habit of making the last adjustment of the cross slide against the reactive force of the tool pressure.
Indeed. If I was going to this much trouble I would make a self adjusting nut which tightens wherever the feedscrew is worn and loosens where it is not. There are plenty of complicated ways this is done (eg on manual milling machines of high standard) but a very simple way is to use the geometry of the acme thread to your advantage. If the nut is split lengthwise (ie the split plane includes the rotation axis) the two halves can be spring loaded together. Because the spring (and adjustment movement) is orthogonal to the translation axis, the spring is not exposed to feed forces, so it need not be so tight as to promote undue friction and wear.
I got this idea because my Myford lathe has a graduated handwheel on the leadscrew for precise moves of the carriage, and I noticed that if I applied a small downforce to the lever which closes the half nuts for screwcutting, and adjusted the stop which normally prevents the half nuts closing fully, the backlash is eliminated altogether.
It is important when applying this idea to cut the nuts with generous clearance at both root and tip, so the the nuts close only on the flanks of the screw. I guess it is the lack of this clearance on most half nuts (at least, once they are worn) which prevents more people noticing the possibilities of this remarkably simple solution.
@@Gottenhimfella - seems valid, however an Acme thread is not a square thread. The flanks of the thread are indeed angled, and any pressure on the thread's axis will tend to open up a "spring closed" split nut.
So, backlash can certainly be eliminated during no-load conditions using a spring, however as soon as force is applied to the tool, the cross slide/carriage would literally become rubber mounted and jump all over the place.
It would take careful consideration anout the strength of spring required to be stable enough to cope with considerable and often intermittent loads from cutting tools.
There is a certainly a mechanical advantage from the narrow 29° thread angle, but there would still need to be quite a lot of preload needed for the spring to cope with axial thread forces. That preload also applies at all times, whether the thread is loaded or not, so it might well be that the leadscrew becomes worn significantly more quickly by that continual abrasion.
@@johncoops6897 You're right in perfect (geometric) theory. A trapezoidal thread is not strictly orthogonal in the way that I (to keep the explanation simple) pretended. That would imply a square thread. However, real life materials, for once, come to the rescue, in practice, of something which should not work in theory. Geometric theory would tell the whole story if the split nut (and its guideways) were made of something as slippery as (say) wet ice. In the same way, a ladder made of wet ice would invariably skid out (particularly on a wet ice floor) at an angle of 15 degrees to the wall (which is about the angle, per side, of an acme thread).
This "angle of friction" is exploited in mechanisms like Torsen diffs and Duff Norton jacks, to act a bit like a diode or a check valve. And that's what I'm doing here. It has to be a trapezoidal, rather than square, thread, or my proposal would not take up the backlash. But 15 degrees per side is about perfect (as I intuited from the fact that lathe half nuts do not try to open even when the carriage runs into the headstock)
It occurs to me that Myford lathes offer another example of this principle in action. I have an ML7 I inherited from my dad, and a Super 7 acquired decades later (when they finally became affordable). On the ML7, the tailstock barrel stays where you put it. On the Super 7, axial force can under some circumstances cause the barrel to retract if the clamp is not tightened. The reason is that the helix angle for the ML7 is well below the angle of friction. The Super 7 has a smaller diameter, three start thread, with a much higher helix angle, maybe four times as much. This is fantastic for drilling, being both quicker for withdrawing to clear chips and apply fresh fluid, and offering far better feel (important, for instance, with very small drills or reamers).
7:05 well identified! the parting issue of the mini lathe. Seems like you've done quite a bit work with it to fix it that way. In general I'd rather install a ballscrew than this one, and make a new crossslide.
Very nice - and a wonderful example of how to use a lathe as a milling machine!
instant sub.
but also, perhaps a spring system might have been better? that way you'd be able to use less pressure (less wear on the nut), it wouldn't come loose with vibrations, and it would work for a lot longer without maintenance because as the nut would get pushed forward as it wears.
And what happens if force is applied in the direction of the spring? backlash
Tris T, The solution you propose would be more interesting if you do it and show it to us in a video of yours.
@@heybabycometobutthead this might blow your mind, but springs of appropriate stiffness are real
@@Tristoo This might blow your mind, it won't work, that's why nobody has ever done it.
@@CarlosSilva-gc8ny I don't get why you guys are being so defensive about it, it's simple feedback, a possible improvement on an already great job.
And if I even had a lathe I would have already done it bud, and then I wouldn't be suggesting anything.
The nut on the cross slide has backlash adjustment built in, using the set screw between the 2 attachment screws you can take out the backlash by snugging up one end and turning the set screw in until the backlash is gone, then tightening the attachment screws
I dunnoI watched this entire video and I still don't know what an Anti-backlash nut Chinese guy looks like! Humm, maybe I missed something. I enjoyed the video. Thank you, Sir!
Incredible good work, I have a similar lathe but by far not your skills! I had to mount a caliper... Congratulations!
That's not an anti backlash nut- it is designed to prevent end play of the lead screw. You will still have backlash as the threads in the nut wear. The Shoptask machines beginning in 1996 had both functions as standard. End play was taken care of by having thrust bearings on each side of the handle bracket. Back lash was adjustable as the screw wore by having 2 nuts in a spit clamp bracket with a spring between them. As the threads began to wear, you simply loosened the clamp on one of the nuts and the spring pushed them apart giving you contact on the leading and trailing face of the screw.
Excellent work on the part and the video, thank you!
wspaniale robota wykonana znakomicie jestem pełen podziwu dla ciebie 👍👍
Excellent, the part I don't understand is how you can do all this work and not get your hands soiled? 'just saying'
It was much easier, just give the existing nut a saw slot through the screw thread and then press with a screw that opens the saw slot, you have made a perfect backlash free nut that you can adjust. Costs you nothing and 10 minutes of work.
I agree your its a much simple system I do not know if its worth all the precision engineering on a cheap Chinese lathe!!!!!!
@@johnhili8664
Well, it's not about being economical, but learning. It's all good exercise.
Bit late to the party, but I thought I should say that whilst this is a great video (I've subbed on the basis of this) and the content creator shows some great ideas, the way they hold milling cutters in the lathe chuck is a definite no-no.
If you want to use the lathe as a mill (and if you don't have a mill, you should definitely give it a go; affordable benchtop mills are a relatively recent innovation and model engineers have been using their lathes as very workable makeshift mills for a long while), you should use a collet chuck.
ER32 is a good choice; there are lots of reasonably priced ER32 collet chucks available for mini lathes.
The reason for this is that milling cutters have hardened shanks, and lathe chucks have hardened jaws and so the jaws can't really grip the cutters shank sufficiently well.
That lack of grip will, sooner or later, lead to the cutter slipping in the chuck jaws. You probably can get away with it for very light cuts but sooner or later it will probably bite you in the rear.
At best you'll damage your cutter's shank, or the workpiece or both.
At worst, because milling cutters tend to grab at the material, the tool could slip out of the jaws completely and end up damaging you!
The only safe use of a milling cutter held in a lathe's chuck (ot a Jacobs style chuck too, for that matter), if you absolutely don't have a choice, is using what is known as a 'slot drill' to either flatten the cone out of a blind hole drilled with a twist drill, or to make the flat bottomed blind hole in the first place. That's okay as the force back towards the chuck will prevent the cutter from ever pulling out.
tl;dr: don't put milling cutters in lathe chuck jaws, get a reasonably priced ER collet chuck and a few collets in sizes you're most likely to use. 😉
It was enough to make a pressure on the side of the guide to prevent the knife from being pulled in when cutting
A great video showing lots of interesting techniques 😯 ( whether you want backlash reduced or not 🤞) K
I've never seen this design, but I liked it a lot, thanks for sharing
Very nice work on the parts.
really good solution.
had fun watching
I can't begin to do precision work like the cuts you make. I have a cheap Jet lathe which has some kind of play which can make cutting tools dig in even on pretty small cuts.
I keep thinking there should be a way to make the Acme cross slide nut like an ER32 collet and holder, with a tension ring just behind the handwheel and dial. You could just turn it by hand to remove backlash.
very nice work, that nut you made defentaly improved the machine strenth... but you want some back lash, even some of the best lathes (mori, hardinge) are back lash machines. It ultimately is a screw. (the screw out of your machine dose not have the acme screw look, most cheap machines have a more traditional screw type thread rather than a acme type making back lash even more important. you don't want pressure on you screw)
Quedo muy bien la Tuerca Cuadrada, Medio Decimo y lo vas Registrando !!
Although, wonderfully machine and a clever design.. it appears to me, that it is more of a slipper clutch or break-over friction clutch then a system that is designed to control lash gap in a controllable measure? Perhaps, maybe I missed something. But, yes, modifying this dinky little machines is so much fun, and affordable. I enjoy your content.
Nice work. I'll have to see if I can apply this to my old Logan. Thanks for sharing.
I had an emco compact 5 which I inherited. Would have desperately needed this upgrade, even though it wouldnt have been possible, because the nut was actually just a cut thread in the cast part.
Wow just fantastic workmanship
I think having minumum backlash is important especially on small machine or heavy cuts or turning square and etc.Would resist the tool getting pulled in especiallly your machine tool does not have sufficient gib lock or you are using that one axis for cutting.
really nice work, great
is this ProCraft VMM800?
Great approach for minimizing backlash on a mini lathe! It looks like you've already addressed the leadscrew floating where it attaches to the handle, I removed 0.012 backlash at the nut and another 0.008" movement of the leadscrew. Scraping the dovetails took a 0.009" bow of it. Still need to do the x axis, thats going to be an incredibly long a boring job as I don't own a surface grinder. Over 0.030" to remove! Almost not worth it.
almost worth buying another.. so you can send it out.. maybe worth it if you are going to cnc part of it to use in serial production
other than the joy of 'doing it yourself', is there any disadvantage in using an acme tap and die? Nice job, BTW
I'm surprised if you take all the backlash out of the nut that it will even let you turn the handle at all without a lot of torque. It will not take long to wear it till you have backlash again.
That is why the nut is adjustable. When it wears, you adjust it. DOH
I agree, I use the slide lock and measure the backlash, and re-set the dials, never found backlash a problem, except on milling machines
@@andrewwilson6085 - backlash is an annoyance, both on lathes and in vices, as well as anything else (eg: adjustable wrenches) where it means you can only sneak up from one direction.
Minimising backlash makes all tools far nicer to use. It's unreasonable to expect to eliminate it entirely, however removing most of it just makes tool operation so much more pleasant.
Great project very well presented would love more detail so i could use for my 12 x 36 lathe
Thankyou
Well done, brilliant, better than mine, will copy, cheers
I know you most hear this a lot, but you are fkn AWESOME!!!
You should really use zero raked tools on brass, it makes a huge difference, backlash isn't much of a problem as your tooling does dive into the backlash anymore.
You are so amazing 👍
Nice upgrade!
Wonderful, veri nice Brainstorming, very good Job.
Do you have a video on how to turn short round stock ? Like very short, 1/2 inch short, diameter fits inside the jaws
Отличная идея, скоро себе сварганю такую гайку, прижимные планки для продольной подачи уже сделал работают отлично, у меня вопрос по рпижимным планкам с клиньями, тебе не приходилось шлифовать станину снизу где скользят клинья или мне так повезло с моим *джетом 7*? Или эти станки все с одинаковыми болячками?
У меня там все кривое, пока не придумал как просто выровнять те поверхности, но они особо не напрягают пока
@@hammerland4028 я вот думаю попробовать гравёром, закрепить на спорт и отшлифовать, но пока не придумал как подавать образив, глубину за проход.
Sehr schön gemacht. Das Umkehrspiel ist immer ein Problem, weil der Drehstahl oder der Fräser ich auch in die Maschine hineinziehen kann. Sie wissen nie wann und wieviel das Werkzeug gezogen wird. An der Drehmaschine tragen sie dadurch schnell zuviel ab, bei der Fräsmaschine zerbrechen sie das Werkzeug und mehr. Einstellbare Spindelmuttern mit Federn lösen dieses Problem nicht. Es muss ein fest einstellbare Spindelmutter sein, deren Gewindeflanken auf beiden Seiten tragen.
You should not throw the old nut, it is rocking on 3 screws to fight backlash. Just by adjusting the angle between nut and rod.
yup, just upgrade the ball screw and all.. that old nut is nasty cast iron.. a wear monster in its own right.. what is missing is a plastic screw cleaner, both ends
You're a lathe master :)
nice job did you lose any cross slid travel ? with the longer nut ? its open on the one end and from the look of the org. the mounting bolt hole to the front end looks about the same so ?
Great job. Thanks for sharing.
Awesome fix, would you sell that nut?
Stai cercando di trasformare una pecora in leone. Beh... per quanto possibile ci stai riuscendo. Bravo.
Excellent and innovative.
Nice video shot, thanks for sharing it :)
Impressive. Most impressive. Darth Vader.
Great job
хорошая гайка👍 только вот если ещё масленку туда приспособить, то она будет жить и жить✌
Should you not have machined the parts before throwing away the follower nut? ;-}
Nice design.
Would it also work with a spring that pushes the cariage towards the handle ? Hmm I guess not because you could only cut properly in one durection.
How much would you charge me to
make this exact same thing? I’ll pay for the material, labor, and shipping up front friend….
Nicely done, btw your lathe is so shiny do you wipe it every day 😇
Respekt! Tolle Arbeit
Impressive work, keep it up
Can you tell me what size is the mandrel used for the grinding/cutting discs and where you got it if possible.
Thanks
Excelente trabajo.
Un saludo.
Nice!
Thanks for sharing,
Cheers
I can't say I'm impressed by the design of this device at all........it's not CNC so some backlash is not a problem......a spring loaded double nut would work better as the screw itself wears in the middle.
No, a spring cannot be used. The tool would chatter like a MoFo under the normal pressure of turning operations.
@@johncoops6897 Well, you will have the same free movement with a screw that has been used a bit when the nut rides on the worn part usually around the middle........you cannot have a solid nut tight on a worn screw as you must allow for the unworn ends to mount the nut and as soon as you get to the worn part you have backlash.....not all screws are new.,,,,,a spring just allows you to reverse the screw without having to have lost motion.......it's a nut back up feature widely used.
@@gangleweed - doesn't matter. You cannot use a spring because it will yield under cutting forces. For example, you dial in a 5 thou cut but when the tool touches the work the cutting pressure will compress the spring and push the cross slide backwards. So you try for a certain depth of cut but have no control over what you end up with.
Worse, when beginning a cut the material is not round. So the tool needs to be rigid and stay where it is to cut off the bump. Since the work is spinning there would be a harmonic movement caused by the spring rebound, and the tool would move around causing chatter or simply snapping the cutting tool.
The number one criteria in lathe work is rigidity of the tool. Any loss if rigidity is really bad, and it doesn't get much less rigid than a spring.
You are better having backlash (and allowing for it) than losing rigidity.
@@johncoops6897 No you are wrong.......the spring just adds back up pressure.....the cut is applied by the flank of the nut in contact with the screw......the spring will only push the back up nut against the opposite flank, it doesn't apply any pressure......winding the nut back in reverse against the spring is only a small force......you always apply forward pressure when you apply a cut.
It’s still impressive to do all that in the lathe. Ian, I’m waiting to see what you do on your channel. Oh right, you don’t have one.
Vert clever design. I like it.
Good job👍👍
Nice job!
Wonder full job
Top-Job, Sir💪👌
Why make the second thread as an insert?
You could have just made a threaded block, then cut it in half and tightened the 2 halves together with the 4 screws. Or 2 screws.
With this design, it would be difficult to get the alignment of the two halves
@@hammerland4028 ... thanks for the reply. It still works, I have done it that way.
Your way is neater and more sophisticated. 👍
Was the nut made from brass or some bronze alloy?
Bronze alloy
so how much would you sell that part to stores for? $$$
excelente trabalho, parabens