Cutting Internal Left Hand Acme Threads on the Lathe: Monarch Lathe Restoration - Part 28
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- Опубліковано 7 вер 2024
- The cross slide nut on my Monarch Model K lathe was in need of replacing so I made a new one using some bronze stock. 7/8"-4 TPI Left Hand Internal Acme threads were cut using a special made threading bar by single point cutting them on a metal lathe.
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Hi Keith,
Thanks for the shout out. I saw we had about 100 new subscribers and knew you must have posted the video with the boring bar. Nice video, I watched it at work at break time. A big thanks to Robin who was a huge help on this project as well as supplying some of the materials.
Steve
"I have a machine shop. I can do that." - Keith Rucker A great line
Thanks Keith it's helpful for beginner to watch you work with things like this you explaining good detail
Glad that worked out well Keith! Nice to see it in action. Something not mentioned is to get the proper included angle of thread on the part with steep helix angles and the top face of the tool made perpendicular to the helix angle at the pitch diameter. You have to make the tool included angle smaller to end up with the correct form. Your tool is actually 28.84 degree included angle which ends up 29 degree on the part.
ATB. Robin
Glad to see the old Lodge & Shipley get a little love
Very useful post and info, Robin. Thank you so much!
Dean
WTF
That is the bench talk type calculations and the little tips that can save a guy a few hours sometimes. Lots of store bought tooling nowadays but it’s details such as those that can make the biggest impact on a project. Thanks for the details. So much to learn such little time to learn it all. 😂
One thing with centering with the dead center... I usually leave my tailstock snug but not locked down. As you approach center, the hypotenuse (the dead center) will grow and the tailstock needs to move back a bit. Thanks for another great video, Keith!
Thanks for a wonderful video. As a novice hobby machinist, I learn so much from this UA-cam community. Awesome job done on the design and fabrication of the boring bar as well. I'm watching every evening looking for more info on a regular basis. I started out with a little grizzly mill and lathe, but have upgraded to a Wells Index Mill, and a Le blond 15 x 54 lathe. I'm loving them. I have also acquired a chevalier surface grinder but its not hooked up yet. BTW My wife and kids know you all by name, LOL. Its like we are all best friends
Very nice work Keith. The nut you made for me fits great. It is tightest up toward the handwheel.
I have never seen anyone use a center to locate a center punch that way. I will be appropriating that idea.
I like the boring bar as well.
Great video as usual Keith, I love how you centered the block since I'm not a machinest; however, because of you, I had the courage to restore a 1953,15x42 LaBlond Regal round head lathe too. I picked it up from a local amusement park that had it in their machine shop.
Since I'm retired now, It took me about 6 months part time of cleaning and figuring what goes where, fixing what was broken (a worn modified acme cross feed) and bringing the parts down my basement with the help of my 2 sons. Now I'm looking for a 4 head chuck to be able to machine parts that are off of center. Thanks for everything you are doing. Keep up the great work from another satisfied subscriber.
Another great video and another shout out to Steve at Solid Rock. He took the time to explain something to me that was pretty basic for him and seemed to be beyond my grasp. The machinist UA-cam community is super.
great video, discussion, demonstration, build....awesome assist from Steve and Robin
A very unique way of removing a sticky backed label Keith! lol Enjoyed muchly.
Isn't it a joy to be machining nice clean bronze. Lovely material to work.
Nice video Keith. Your L & S has a 4-pitch lead screw and you're cutting a 4-pitch thread, no need to use the thread dial. You can engage the half nuts at any time and it'll pickup in the same place every time. I know, I still use the thread dial, too. Ken S.
Loving the crow conversation going on in the background!
I watched all the videos on the Solid Rock channel that covered design and fabrication of that boring bar. That is the only way to really appreciate what a fine tool it is and the theoretical and practical knowledge that stands behind it. A great collaborative effort by the community.
Thread cutting skill level - EXTREME!!! And a new UA-cam channel to check out. Thanks as always Keith. 👍
GReat job .First time I have seen a thread like tht cut. AIO WAS learning even at 70 years young
Something I've done on these internal acme thread is to use a narrower tool than full form and advance the compound to get the width. This technique is usually reserved for harder materials, harder than brass anyway. Really good video. Love it.
Half of the time is information about things that I didn't come to this video for
Steve's boring bar made that job look easy. Heafty cut hanging way out there.
Thanks Keith. I watched Steve's build on the bar and it is an absolute piece of art. Also want to thank Robin for his help and input. Some day I hope to be able to single point an internal Acme thread. Thanks again.
Enjoyed the video Keith, Steve and Robin did a great job on the cutter and looks like the threads turned out perfect, Nicely done!
Kieth you are a great teacher !!
had to stop your vid and go see Steve Barton make the bar first.. Great little channel.. I subscribed I think it will be a nice channel to watch during the shut down..
Keith, I used to machine acme thread screws for the block, and the last thing I did was lap the 2 parts together with lapping compound......🍁
Acme thread chat about what things should be but are not size wise. Watched Steve make the threading bar with help from Robin nice collaboration from them two and then to you nice videos of making this cutter for you.
👍it's good to be a machinist! Nice work to all.
That was an amazing piece of setup work, that boggled my mind and you hadn't even started the machining operation. Even if I had a machine shop, "I couldn't have done that", to paraphrase you. Thanks, as always for a great video.
It should be critical on the outside measurement’s so it will bolt back up in place so your lead screw will line back up where it’s supposed to be.
So half of 30 is 14 1/2. Huh, I never knew that. Learn something new every day.
Nice work Keith
I always enjoy your videos
Can't wait for a new video to pop out.
Nice work Keith great video, lot to think about cutting internal acme . I made a acme bronze rack for a Victoria u2 horizontal mill using a Bridgeport & horizontal arbor attachment with fly cutter with a piece of round hss ground to acme profile mounted, and appreciate the importance of setting up helix angle by offsetting ram on Bridgeport . I plunge cut using dro to index pitch of rack
Another boring video from Vintage Machinery Dot .Org 😉
Love it Keith. It is great to see so many UA-cam creators getting together and collaborating. Another benefit of the Good of the Land Fest put on by Justin in Lindale Texas.
Hi Keith,
Another fine machining video. The outside dimensions of the nut only need to be close. You will be using only one face as reference for milling the steps and also for boring the hole for the threads.
Another job well done, well it's done.
I appreciate the chance to "look over your shoulder" on this one. Familiarity with such a task, that has been gained through observation, is better than no familiarity at all.
Like it or not, that is a task that I'm going to need to do with the Mueller, along with correcting some issues with the cross slide. It appears that this one did a very high amount of repeat facing work at one time. In one place, you cannot tighten the (tapered) gib enough that it will lock. In fact, at the extreme in adjustment, it is barely tight enough for 'standard' work. In other areas you have to back it out because it gets so snug that you can barely move it. The amount of lead screw back lash varies as well. Wide differences in wear on the feed screw may well be the reason why I can't trust the dials on a critical dimension.
It's time to take an in depth look at things, map out where it is, take copious notes, and come up with a plan ... and decide if I'm going to need to "holler for 'hay-elp'."
Big thumb up Keith! Great video amigo.
Good job,team effort!!!
I've never done this, great video
hi... keith thanks for q very useful tips,,, i am a new machinest i need more tips , how to set-up lathe machine on acme threads
"We're going to take no more than we have to to get it cleaned up." *peels off the paper sticker in a condition where it could still be read*
That was great.
I could never really figure how paper is supposed to beat rock, but after seeing it's invulnerable to carbide I'm willing to believe anything... ;)
Yeah at first I was wondering if it would gum up the cutter (I'm a newb) but then, nope, peeled right off.
Another nice video,
There is somethings to be said for doing the threads slightly differently, for those of us who don't have access to Steve or Robin to grind the cutter for us. As it is easy enough to grind the cutter angles accurately, but not the flat to exact length, I propose the method where the flat is made 5 to 10 thou narrower than full size and cut the threads with the top slide parallel to the lathe axis using only the cross slide. You can then go to max diameter, plus clearance, and then widen the cut to get the fit you require using the top slide. I look forward to hearing your views. I will admit I have never cut an Acme thread but I have cut many trapezoidal ones which are the metric equivalent.
Regards
c
I always use a narrower acme tool, go full depth then side cut using compound slide, same method when cutting 2start acme threads also. I never dis-engage half nut , I always leave it engaged and reverse the Chuck rotation.
An alternate method is to bore out the old nut leaving the ends at original ID. Heavily dust the thread with graphite. Insert into nut, seal in with clay, pour in white metal.
Very nice video thanks for sharing.
Great video as always!
7:17 I can just see AvE using this process to remove a sticker - and shouting "Time!" the moment it all comes off. :-D
drinking game: take a shot every time Keith orders something from McMaster Carr
AIUI, the bronze has the marks because it's castt not extruded e.g. ua-cam.com/video/8i34xpgu66g/v-deo.html is continuous casting bronze - there's no pressure used when forming the shape as the material is liquid and then cooled before it leaves the machine, unlike extrusion where it's formed under pressure and heated enough to be soft but not liquid. You don't get the spiral marks in extrusions.
D=P/2 + .010 X 1.03 (SECANT OF 14°) ...I get 1.39" depth of cut on compound I realize you have to cut to fit but did I figure correctly
4:45 "Things like DEEZ NUTZ!" just kiddin!
I thought you had a k&t mill. haven't seen you use it in ages
Its like a sausage up an alley Keith lol
I didn't appreciate how much stiffer carbide (650GPa) is in comparison to steel (200GPa), will think about user for that in future
take one machine to make parts for another machine because you can
If you made a new screw and nut, at 8 TPI, wouldn't that turn it into a direct read Cross slide?
How do u determine the roll of the cutter for different thread pitches?
The double indicators was a bit redundant wasn't it? You were indicating the same movement of the tool post it looked like. Looks like it turned out well! I should have had you cut one for my CBB as well. I know it needs one since mine was split sometime long ago to take backlash out. :-)
I would argue that you don't need to have the whole profile on a trapezoidal threading tool asbyou can set the compound parallel (not ideal but...) and start shifting across to get the width after you first hit the width. With similar methods you can employ alternate flank infeed or do huge worms propellers and augers. I mean you wouldn't use a full form tool for an auger... Why use it on a thread?
7.50 Teeth on edge alert!
Wait!!! Shouldn't you be drilling with a left handed bit to get the start for a left handed thread?
Couldn't resist.
Nah, that's still bodging... _proper_ left handed threading needs a lathe with its chuck on the right side...
Why rotate the compound rest ? The tool degree is 14.5. So why chage the compound rest
Keith, at 2:15 on this video their is a voice like a slight whisper. I can't tell what it is saying. Please check this out. subliminal?
I Like the carbide boaring bar top tip will be making 1 in the not to distant future no body likes the bendy when boaring
hi keith.. i have a problem ,,, i need a nut making for my centec milling machine , that is 85 years old ,,and needs the kiss of life . i am slowly getting there but its a long long process. . i am stuck however on one part ,,, i need a nut an acme nut to be precise its left hand and the dimensions are ;;1/2"x 10 tpi left hand one inch long will be more than enough..in brass or steel it dont matter .. if you can help me i will sort you out $ i remain .. yours regards laurence..
Hey youtube machinists!
I recently bought a copy of the machinerys handbook (26th edition, just like new) from my university for 2€ , which i think is quite the steal. but now im curious what do these normally sell for?
I got the 25th for about $24US off ebay last year.
$20 U.S. normally. I bought the newest one, brand new, in large print and hardcover for $56.00. Shop around you'll see they're not as expensive most sites have them for.
QUESTION. I’m not a machinist. I understand the concept of using brass or bronze as the wear component in this application. Was wondering if they are interchangeable,. Are there applications where brass or bronze is the preferred metal? If so, why? Thanks.
Brass and bronze are NOT the same thing at all. Brass depending on it's alloy can be fairly soft. Bronze again depending on the alloy can be as hard or harder than most mild steels. Generally bronze would be used where the steel component is hardened. The coefficient of friction for brass and bronze is greatly reduced when compared to steel on steel so the bronze is an ideal material for items like feed nuts.
Turning Point Thanks for the reply. I reckon I learn as much from the viewers as from watching the vids. Be well. Salut
So that's how you peel pesky stickers off! No solvent needed...
For 4 TPI, can't you hit any mark on the Threading Dial?
7/8-4 taps here, LH or RH. www.widell.com/old_wid/acmespcl.htm
Do you capture brass separate from steel for recycling?
i flipt the tool over and run the op in reverse so im always going away from the chuck
Is there a reason why you didn't bore the hole and mill the top of the entire bar before you cut it into two pieces?
Thanks.@@CraigsWorkshop
Why aren't you using a cutting oil?
Single70s not needed on brass/bronze
👍🏻
For a new guy that's never turned threads before, are turning Acme threads any more difficult than the standard 60deg threads?
Looking at the comment from Robin Renzetti (ROBRENZ) it appears that shaping the tool properly is the more difficult job!
Acme threads are usually much coarser and deeper, so yes more difficult to deal with the cutting pressure.
Yes as the angle is 14.5 deg. And the amount of material removed in a single cut adds more pressure which can make it trickier. Soon get the hang of it tho.
What brand of optical center punch is that? It looks well made.
Veritas....available from Lee Valley Tools
@@tosborn56 - Hmm, Part# 05N59.01. Canadian price is around $60 so US will be lower. Looks like a cool tool :)
- Eddy
4:47 dees nuts lol
Why not make it out of oil light It sweats its own lubrication
Huew!
👉👍
You didn’t discuss the angle set on the compound. Signed Wannabe machinist
#1
Bro!
There is a LOT of difference between brass and bronze and they are not "interchangeable". Bronze contains copper and up to 30% tin by weight and at its softest tin is about 75% harder than copper and at its hardest it is more than twice as hard as annealed stainless steel and nearly four times as hard as mild steel. It maximum hardness exceeds the minimum hardness of case-hardened tool steel. It does NOT "self lubricate" in contact with steel and it makes bronze literally harder than "steel" and more than ten times harder than brass. Guess what you'll be replacing next using bronze for that nut? The lead screw. And that would be the case even if your threads were "perfect" and there's no way that"ll be the case. And I guarantee there IS significant, measurable wear on the screw already. You can't use a standard thread pitch gauge or ANY pitch gauge to inspect Acme thread for "wear". All you need to measure to know there's wear is measure the OD of the thread precisely and compare it to "specs" and whatever "slop" you have there will be multiplied on the thread "face" itself. Stick that bronze nut on there and you'll have that screw completely "destroyed" in no time. When a manufacturer selects a specific material for a "part", there's a reason for it and any "machinist" who doesn't know and respect THAT better have a "Plan B" for making a living once his "machine shop" gets a reputation for turning out junk because the machinist thinks he's a metallurgist, mechanical engine and alchemist when it comes to "substituting"unacceptable materials for the OEM materials he can't, or rather WON'T procure for a "replacement part".
I am replacing my nut on my lathe. I will check what the original material was. If it was bronze, I will use 660, oil impregnated.
Another variety of bronze, is aluminum bronze. I would NOT use that.
If it is brass , that would be my choice.
How can you cut LEFT-HAND THREADS WITH THE WORK AND CUTTER TURNING TO THE RIGHT IN RELATION TO EACH OTHER? Clearly you've never cut left-hand threads or at least none "better" than your non-existent "threads" in that new "nut" or you'd know that the thread cutter has to turn LEFT just like the SCREW that goes in the finished thread. And no, cutting threads from the "inside out" while your work and cutter are still turning RIGHT also does not make a left-hand thread. THREADS RETAIN THE "DIRECTION" NO MATTER WHICH END THEY'RE CUT OR VIEWED FROM. I guess you don't even know "righty-tighty/lefty-loosey", huh? But yeah, you could have made your own tap....
DEEREMEYER1 Oh dear.
I dont agree with that indicating metod.
Yes, the centermark will be correct in "dead center", but only in that plane.
The stock/brass piece was not checked for alignment.
Its probably straight enough, but there is a potential risk that the grip of the chuck on the brass piece is off, and then the hole isnt parallell with the sides.
How would you address this task then? My immediate thought is that Keith's method assures a 90deg angle of cut to his machined end face. The only error that can creep in would be if his milling operation has cut a non-square block (subject to his designed tolerances of course)..
@@dolvaran well, im not a machinists so I couldnt say what the best solution is. Regarding your comment, Keith did not check the plane for alignment (or face if you like) only the centermarks/one point location in space. The point can still be in the correct x,y & x position while the face is at an angle relative the axial tool.
But given the small length and width of the part it may not make a practical difference, perhaps Only a theoretical risk?
Maybe its possible to check the face runout to be certain.
Just out of curiosity, what procedure would you recommend for locating the center mark?
@@wirosk2916 If you're not a machinist, then you should shut up...
@@kevinbyrne4538 My point is not that the method for finding the centerpoint is wrong.
The point is that there were no check done that the whole piece is coaxial (in line) with the rotational axis.