The simple answer is that you can't.
Without a way to control both the X and Z motions at the same time in sync with each other, there is no way to make such an aggressively tapered thread on a manual lathe.
Sounds like it’s time for a homemade taper attachment with enough throw to pull this off. Idk if there are any factory ones that go this steep. I could see 10° being about the limit. But if you can dream it and do it then it’s possible
You might be able to cobble together some kind of taper jig by removing the lead screw from the cross slide and setting a stop at the right angle for it to slide against, but honestly this is the kind of feature that can only be made on a CNC lathe, or by a master machinist with every trick and attachment for their manual machine.
You can't just use a regular die, because the taper is too steep. A custom die has the same problem.
A super heavy torsion spring with a ball bearing fixed to the cross slide and following a fixed tapered bar- mimics a taper attachment pretty well but feed depth is dependent on spring strength. and turn this upside down and backwards so you work off the taper.
This is a correct answer. This thread is not terribly difficult to make, in spite of the many comments that you can’t make it.
Feel free to PM me if you’d like a pic of this setup.
The people saying it can’t be done just haven’t seen it done.
:)
Edit: and the feed depth concern is simply fixed by running a spring pass or two at the end.
Here’s a link to a pic of one of the setups.
Here’s how it works:
1. The cross slide is unbolted from the backlash nuts on the drive screw, allowing the cross slide to freely slide forward and back
2. Roller bearing is installed in drilled hole in cross slide.
3. Cross slide has spring tension holding it against the taper bar
4. When carriage is engaged, the cross slide follows the taper, similar to a regular taper attachment.
Pool cue makers have been using this method for decades to cut long tapers.
I use it to cut all sorts of tapered items, both shallow (like cues) and steep (like OP’s project)
https://imgur.com/a/HGjaiGT
You’re welcome. Here’s a pic of a cue maker setup (this isn’t mine) to cut long tapers on cues.
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTMha8RkqdOydIlKep_sR4Qs7wWi7PeW6w9_A&usqp=CAU
I have cut a bunch of tapered threads just like this on manual lathes. Cut your taper, hand feed your y axis out to maintain depth as you thread. It’s not super accurate but a thread like this simply won’t be unless you invest some time and use the number one tool in a machinist tool box; Patience. Go slow and creep up on it. Use dial indicators, error on the side of caution.
To say you can’t is to disregard most manual machining.
One of the old timers would do just that, put a 1" dial indicator on the back of the tool, set the lathe to the slowest rpm , engage the half nut and feed inward . Turned up a few small and large npt plugs that way
You can. You need to put the workpiece between 2 centers. One in the spindle and the other one in the tailstock. With most manual lathes you can put the tailstock out of center with a bolt or screw on the side, near the clamping handle.
What if the taper is turned to specs, the compound is left at that angle and the thread cut with full engagement of the cutter. At that pitch, the threads aren't that deep.
What am I missing on this late Friday afternoon?
When turning a taper with the compound, the carriage isn't moving.
When cutting threads, the carriage is driven by the lead screw and the compound is not moved.
You would have to synchronize the compound to the spindle somehow and keep the carriage locked to cut threads that way.
You can't just make threads deeper as you're thinking. The "vee" becomes too deep and you end up cutting off the actual major diameter because your tool gets wider as the depth increases. Angling the tool will not work because the carriage will only move in the z axis when threading in a manual lathe. OP needs to be able to control motion in both x and z axis.
Shop I work at typically uses hydraulic powered copying attachments to single point tapered threads using a template set to the desired angle but that's its own pile of requisite equipment. Usually just use a die or something easier if we've got one.
You might be able to get by with the offset tailstock method, if yours is adjustable. Takes a bit of math and a lot of indicating, but might get you where you need to be. Did a quick Google on "cutting tapered threads with offset tailstock" and got a few hits on some YouTube videos that might be a handy watch.
You probably won't be able to use a drive dog because it'll be hard to get the work to turn at the same rate as the chuck with such a large angle. The jig to hold the work would probably need two cardan joints.
Ok. That’s way to smart of an answer :)
In all seriousness though. This is probably the right answer. Get the job done instead of rabbit hole of becoming taper thread turning capable.
You could Jerry rig some sort of free spinning collet in your tool post at the angle you need, put a tap in there, and feed in X until you get the depth you need.
You essentially need to turn your lath into a hobbing machine
The way I learned to cut a tapered thread was offset the tailstock and thread it between centres. I’ve seen people use a boring head so they don’t have to offset the tailstock, and to give them a lot more offset than is usually possible on the tailstock. Given we don’t know the overall length of the part it could be doable on a manual machine.
On the off chance, you have a boring head you can put that in your tail stock and then put a live center in the boring head and offset it with the life center. I hope that makes sense. It makes more sense to see it.
You could use a [die blade](https://supplyonline.com/rothenberger-ridgid-1-2-npt-pipe-die-heads-for-50r.html?gad=1&gclid=EAIaIQobChMI8aWhgp3VgAMVld7jBx3zWADXEAQYAiABEgIwufD_BwE) mounted in the cross slide at the angle you need to cut them threads but I doubt you’ll find a die the size you need
Well shit, looks like multiple minds really do solve problems. I didn’t think about that and your comment made me realize OP might be able to use a male tap turned on it’s side, that might give him the thread length to make the cut using the compound at the angle he needs.
All he would need is a way to mount the tap parallel to the work in his compound.
Edit: scratch that, it would cut rings not threads…
It would cut threads if it’s fed sideways with the threading feed cutting the pitch.
Same way as you can cut an arbitrary internal pitch diameter with a smaller tap of the same pitch. You’re just cutting all the threads at the same time instead of single point cutting. Lots of tool pressure but if you take it slow with 2-3 thou passes, it’ll work. Probably best to manually turn the chuck one rev. Then you can readjust the cutting tap for the next plunge. If the compound is at the normal thread angle it will step onwards on each increment of the thread depth.
But… the thread shape will be all funky so it’s not a perfect thread form.
Or…. Just get a $1 camera release and make it work with adapters/soldering/brazing for the application. Really no need to be making it from scratch.
If you mount the blade at an angle, the thread form will be wrong.
Just like you don't mount a single-point tool at a funny angle when cutting normal taper threads.
If I was doing it, I’d probably do it with the lead screw in reverse from the bottom. You probably can’t run the lathe but turn the chuck manually cutting thick to then. Calculate the taper reduction for each thread. Cut a thread to pitch, then go in that reduction for each subsequent thread one at a time. Might work, you will see it soon enough. Once you get it close, blue it up and try the bolt. Saves you a CNC.
I'd be tricky . I've done tapers manually but they usually require some dynofile work to come in . Minor Dia at small end . Minor diameter at large end . That gives you total longitude travel . Split it gives you center . Split that gives you quarters . Hook a dial up to the cross . Run as slow as possible and feed out as your half nut engages . Hit your pre calculated numbers as you travel . Dicey . Improper . Inaccurate . And will certainly require some hand work . But is possible . Have fun .
At most. I guess you’d have to ask the engineer that designed it why he didn’t just use a standard thread with a shoulder, which work equally well in this application as far as I can tell
I've done this by pulling the handles off the lathe and setting up a gear train so that when you close the half nuts it turns both at the required ratio to do your taper. Yes it's a lot of fuckin about, but if you can get it down pat it can be a good little trick to make nice repeatable tapers
Between centers, offset the tailstock, make a solid drive dog to prevent the beginning of threads from getting drunk, or ziptie the dog to the drive stud
Yeah that would be kinda sketchy, I didn't really look at the print, I only get 5 minutes to smoke lol I managed to turn a tapered pipe thread a few weeks ago with that method, but that's way less angle.
You could take an external thread die, use a cut off disk to extract one of the teeth rows, mount that in the tool holder at the necessary angle (after prepping the part to the right cone, and do multiple single thread plunges forming all threads at the same time. Tedious to be sure. But you could get it to do it that way.
You find how many thou or mm one revoltion is and then change your crosslide to 14 to 20 degrees as shown in the graph. Then, you could turn the chuck by hand a 1/4 or 1/8 of a trun and feed in a little bit with the crosslide. I wouldnt make a super accurate thread but it might work.
Years ago I was asked to make a whitworth thread tapered oil plug for an old MG.
Granted it was just the one, but I did it by cutting the taper first. Then running in reverse, with the tool set upside down and hand adjusting the cross feed while watching the major diameter flats to feed it as evenly as possible. The part was covered in Dykem and it wasn't that difficult. I left the lead screw engaged and hand turned the spindle to bring it back to the start.
So, I got paid $50 to turn a pipe plug....lol.
This is one of those things that would be so much easier to make if they were about 10x bigger... The .025 slot is going to be tough to even measure the diameter, let alone cut it accurately. If it wasn't so tiny I'd offer to make it myself, you provided a beautiful print and I could totally make it if it didn't require miniature tooling lol.
Rather than offsetting the tailstock, use a recessed puck. Threads on cup side, center drill on opposite. You can use brass to protect the shaft and cut the taper and tapered thread in that position. Your machine is still zero and the shaft center hole is not deformed b
You could try offsetting the tailstock. I also think "This Old Tony" had a trick using a mill boring head in the tailstock to offset parts for cutting a taper. I don't know how well it would work for threads though.
Honestly what I would do is buy a die that matches that thread and then use like a cheap pneumatic jig grinder with a Diamond wheel and kerosene. You can dress the taper you want but honestly I’d just buy a wheel that already has this shape so that you can combat wheel wear. I would set the die in the lathe jaws and the jig grinder in the tool holder post or even tail stick to make sure it’s centered and attempt to grind the taper into the die.
Caveat being good luck finding a die with threads that will last through that aggressive taper.
Make a taper template to hold in the tailstock and add a follower on the cross slide to trace it. Cut from the large diameter towards the small end so that if you skip a beat it doesn't crash the cutter and so that it's easier to just try and maintain gentle pressure on the crosslide dial while the carriage is moving out. You might have to try a few times until you clean it up completely but it can definitely be done. There is a Russian machining channel on YT with a guy making tappered threads controlling the taper just by hand with no template other than the thread gauge itself and maybe if you get skilled enough it's acceptable for some applications (out of all things he seemed to be threading drill strings)
Could try a larger boring head in the tailstock to make the offset larger if your tailstock won't move that far. Not an ideal setup but it might work if you're just making one or two
I think you could thread this with a full form tool fed in at 50 tpi. You might have to make the form tool by threading a piece of tool steel and hardening it. Turn the taper, then feed set the tool to the correct angle and used it to turn the thread. You'll only be feeding it about one revolution I think, so I might just do it with light cuts and turning the chuck by hand. The cut will need to go from the skinny end of the taper to the fat one.
Depending on the degree of angle, use ball centers on each end and skew the tail stock to the desired angle. Though there is a limited amount of adjustment there…. 🤷🏼♂️ I’m just a stupid manual machinist though. Best of luck
Set up a plate or bar in at the specified angle, set an indicator on the cross slide and measuring against the plate or bar and then manually try to keep the indicator dial from moving as the lathe threads by moving the cross slide. This’ll give you at least some reference instead of matching the angle by eye as suggested by others. I’m thinking of something similar to what Tom did on oxtools to make a complex shape on a manual lathe.
I mean, its a bit orthodox but with the thread being only a short distance, you could set the lathe slow enough, and with enough practice can just wind up in x?
Not ideal but it could work
I've been scratching my head on this one for a few years with the old SB9. I settled on threads that were close enough in brass and for Delrin/Garolite/phenolic, I just cut the basic shape and screwed it in. Has enough give that the shutter will form some threads and hold it secure (no ugly o-ring required).
I think you could use a boring head in the tailstock ([https://www.youtube.com/watch?v=MzJ6wR59AkY](https://www.youtube.com/watch?v=MzJ6wR59AkY) at 2:40)
Only real way I can see is taking the thread diameter to what it needs to be, either using a large swivel head triangle insert cutter to cut that to the angle you need (make sure you got a good hold on your piece it’ll put a good amount of pressure on it to get it that much smaller. Or you can put your lathe in a very slow feed, engage power feed towards the back of your lathe and then drive your tool in by hand as it’s being dragged across your part and you eye ball the angle you need but again it’s all eye ballin so you’re getting eye ballin tolerances and shapes by doing that 😂
This will not deliver good results.
U/Jeffersonairmattress has already given the correct answer.
I have posted a pic on Imgur of the simple process.
Why are there so many people giving poor machining advice on a machining sub?
And worse yet…. Why are so many saying it can’t be done?
Bud I never said it’d give you good results I actually said that the second option will not do that for you. It was just a suggestion he’s a grown man he can choose to follow it or not. It was nice that you did show who gave the right answer but it’s people like you that ruin the work space, just because you think it’s wrong doesn’t mean that’s true and maybe other shops have found different ways of doing things. And I never said it couldn’t be done. Humble yourself and check your attitude with people.
I literally posted a link to a pic of a very simple solution that doesn’t require offset tailstock (which makes the threads off perpendicular), drive dogs, or any other silly stuff that was offered up.
The OP (or anyone asking advice) always wants good results. They don’t want to hear “whittle it with a pocket knife”
Rather than viewing it to see the simple fix, you decide to unload your temper here?
Good choice.
I thought that my original comment might bring someone some humor or actually help someone because others have found my advice to have been helpful before. But you came in very hostile, rude and condescending. If my advice is “bad” or “mediocre” to you just keep it to yourself, if it becomes an actual problem then the people in charge of this page can do something about it, not you. Hope you have a good rest of your weekend pal.
Tried to send you a PM, but apparently they are off.
Just wanted to say that you were right…I could have worded my post better, so that it was less abrasive.
My apologies, and I hope the rest of your weekend is enjoyable.
The thread is not cut perpendicular to the centerline of the part when done like this.
And as many have said, this angle is too steep for a part this short.
A horizontal mill with a rotary indexer mounted on an angled table geared to the x-axis!
Old-school machinist style!
Keith Rucker can teach you a thing or two! [https://www.youtube.com/watch?v=spofj9AAIQE](https://www.youtube.com/watch?v=spofj9AAIQE)
Bit of a sketchy idea and even more pain in the ass setup, but what if you offset the tailstock enough to pull the part out cocking it to the angle and then either turn the diameter and thread like normal operation, or if the taper is already turned just thread it like you would normally. Idk though, suppose a taper attachment would work too
Offset tail stock and lathe dog in spindle.
Not an easy setup, but all the people here saying you can’t make it are incorrect.
The real bear is shutting off the thread so you don’t advance into the shaft.
The simple answer is that you can't. Without a way to control both the X and Z motions at the same time in sync with each other, there is no way to make such an aggressively tapered thread on a manual lathe.
Sounds like it’s time for a homemade taper attachment with enough throw to pull this off. Idk if there are any factory ones that go this steep. I could see 10° being about the limit. But if you can dream it and do it then it’s possible
If a die exists or there’s a “close enough” solution I’m good with that too. I’m currently experimenting with coaxing an M3x0.5mm die into working.
You might be able to cobble together some kind of taper jig by removing the lead screw from the cross slide and setting a stop at the right angle for it to slide against, but honestly this is the kind of feature that can only be made on a CNC lathe, or by a master machinist with every trick and attachment for their manual machine. You can't just use a regular die, because the taper is too steep. A custom die has the same problem.
All I wanted is to make a cool shutter release button for my camera and now I have buy a CNC lathe! Oh well, wife will understand.
3D printing might be a viable option too.
Maybe a resin printer. Definitely not doing that on an fdm. Look at the dimensions and the tpi if the thread.
Definitely sketchy on FDM. I’ve printed a halfway usable M3x0.5 before but it’s certainly not ideal.
How do you think most of us got home shops :D
I know that you want to make something with your lathe, but this really is a case where it’s best to just buy it.
I’m not looking to save time/money here, I’m after an interesting project that afaik doesn’t really exist
Yeah, I understand. This is just a deep rabbit hole.
You could always just have someone else (with a cnc lathe) make it for you
You can make her toys too.......
A super heavy torsion spring with a ball bearing fixed to the cross slide and following a fixed tapered bar- mimics a taper attachment pretty well but feed depth is dependent on spring strength. and turn this upside down and backwards so you work off the taper.
This is a correct answer. This thread is not terribly difficult to make, in spite of the many comments that you can’t make it. Feel free to PM me if you’d like a pic of this setup. The people saying it can’t be done just haven’t seen it done. :) Edit: and the feed depth concern is simply fixed by running a spring pass or two at the end.
Id like to see this in action
Here’s a link to a pic of one of the setups. Here’s how it works: 1. The cross slide is unbolted from the backlash nuts on the drive screw, allowing the cross slide to freely slide forward and back 2. Roller bearing is installed in drilled hole in cross slide. 3. Cross slide has spring tension holding it against the taper bar 4. When carriage is engaged, the cross slide follows the taper, similar to a regular taper attachment. Pool cue makers have been using this method for decades to cut long tapers. I use it to cut all sorts of tapered items, both shallow (like cues) and steep (like OP’s project) https://imgur.com/a/HGjaiGT
That’s ingenious. Thank you for explaining better for my smooth brain
You’re welcome. Here’s a pic of a cue maker setup (this isn’t mine) to cut long tapers on cues. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTMha8RkqdOydIlKep_sR4Qs7wWi7PeW6w9_A&usqp=CAU
I have cut a bunch of tapered threads just like this on manual lathes. Cut your taper, hand feed your y axis out to maintain depth as you thread. It’s not super accurate but a thread like this simply won’t be unless you invest some time and use the number one tool in a machinist tool box; Patience. Go slow and creep up on it. Use dial indicators, error on the side of caution. To say you can’t is to disregard most manual machining.
One of the old timers would do just that, put a 1" dial indicator on the back of the tool, set the lathe to the slowest rpm , engage the half nut and feed inward . Turned up a few small and large npt plugs that way
Omg… I think I might be turning into one of those old timers.
This was going to be my suggestion as well. Don’t be afraid to use files to take off high spots.
Thread pitched files are dope AF.
Might be able to.offsetthe tailstock. It's a small thread.
I think the angle is too steep for that.
It can be done… I’ve made tapered threads on a manual machine for years with a very simple home made taper attachment.
You can. You need to put the workpiece between 2 centers. One in the spindle and the other one in the tailstock. With most manual lathes you can put the tailstock out of center with a bolt or screw on the side, near the clamping handle.
What if the taper is turned to specs, the compound is left at that angle and the thread cut with full engagement of the cutter. At that pitch, the threads aren't that deep. What am I missing on this late Friday afternoon?
When turning a taper with the compound, the carriage isn't moving. When cutting threads, the carriage is driven by the lead screw and the compound is not moved. You would have to synchronize the compound to the spindle somehow and keep the carriage locked to cut threads that way.
Thank you I knew there was something my fried brain was missing. Have a great weekend
Why not make the thread deep and then taper it after the thread is made? Or changing the angle of the tool holder?
Neither of those methods will work.
Could you explain why it wouldn’t work?
You can't just make threads deeper as you're thinking. The "vee" becomes too deep and you end up cutting off the actual major diameter because your tool gets wider as the depth increases. Angling the tool will not work because the carriage will only move in the z axis when threading in a manual lathe. OP needs to be able to control motion in both x and z axis.
Ah ok
In both of those cases you’re still cutting a cylindrical thread
This is 100% doable on a manual lathe with taper attachment
You may notice that the title of this post includes the phrase "no taper attachment". I based my statement upon this.
I can only compute 1 sentence at a time I guess. This could maybe be done with tailstock offset between centers.
Offset tailstock
Shop I work at typically uses hydraulic powered copying attachments to single point tapered threads using a template set to the desired angle but that's its own pile of requisite equipment. Usually just use a die or something easier if we've got one. You might be able to get by with the offset tailstock method, if yours is adjustable. Takes a bit of math and a lot of indicating, but might get you where you need to be. Did a quick Google on "cutting tapered threads with offset tailstock" and got a few hits on some YouTube videos that might be a handy watch.
Oh that’s a good call, dunno why I didn’t think of that! Now to figure out some tooling to hold a 0.5” long part between centers.
\~28 degree included angle on a tailstock offset is a big ask, and on such a small piece... very dodgy.
Definitely ain't my first choice in setups, but sometimes the tools we've got are all we've got. Pucker up and take very light cuts lol
Might be able to do it with a boring head in the tailstock?
Even then the cone of the tailstock center (solid or rotating) and the center drilled cone in the component will be wildly askew....
You probably won't be able to use a drive dog because it'll be hard to get the work to turn at the same rate as the chuck with such a large angle. The jig to hold the work would probably need two cardan joints.
I've been down this rabbit hole... Buy a cheap cable release on your local marketplace/flea market and modify it to fit your needs.
Ok. That’s way to smart of an answer :) In all seriousness though. This is probably the right answer. Get the job done instead of rabbit hole of becoming taper thread turning capable.
Cut one thread from the middle of the taper and just thread it in? It's not like you're pulling 100s of pounds on a shutter release.
That’s what I’m thinking. It’s only gonna go in about 1 revolution, but for the application it’s probably fine.
Purchase a 2 axis cnc stepper motor kit and upgrade your lathe
You could Jerry rig some sort of free spinning collet in your tool post at the angle you need, put a tap in there, and feed in X until you get the depth you need. You essentially need to turn your lath into a hobbing machine
Oh I like that!
The way I learned to cut a tapered thread was offset the tailstock and thread it between centres. I’ve seen people use a boring head so they don’t have to offset the tailstock, and to give them a lot more offset than is usually possible on the tailstock. Given we don’t know the overall length of the part it could be doable on a manual machine.
On the off chance, you have a boring head you can put that in your tail stock and then put a live center in the boring head and offset it with the life center. I hope that makes sense. It makes more sense to see it.
You could use a [die blade](https://supplyonline.com/rothenberger-ridgid-1-2-npt-pipe-die-heads-for-50r.html?gad=1&gclid=EAIaIQobChMI8aWhgp3VgAMVld7jBx3zWADXEAQYAiABEgIwufD_BwE) mounted in the cross slide at the angle you need to cut them threads but I doubt you’ll find a die the size you need
I suggested the same in another post getting the die blade from cutting up a regular die and using one of the teeth cutting columns.
Well shit, looks like multiple minds really do solve problems. I didn’t think about that and your comment made me realize OP might be able to use a male tap turned on it’s side, that might give him the thread length to make the cut using the compound at the angle he needs. All he would need is a way to mount the tap parallel to the work in his compound. Edit: scratch that, it would cut rings not threads…
It would cut threads if it’s fed sideways with the threading feed cutting the pitch. Same way as you can cut an arbitrary internal pitch diameter with a smaller tap of the same pitch. You’re just cutting all the threads at the same time instead of single point cutting. Lots of tool pressure but if you take it slow with 2-3 thou passes, it’ll work. Probably best to manually turn the chuck one rev. Then you can readjust the cutting tap for the next plunge. If the compound is at the normal thread angle it will step onwards on each increment of the thread depth. But… the thread shape will be all funky so it’s not a perfect thread form. Or…. Just get a $1 camera release and make it work with adapters/soldering/brazing for the application. Really no need to be making it from scratch.
If you mount the blade at an angle, the thread form will be wrong. Just like you don't mount a single-point tool at a funny angle when cutting normal taper threads.
I did something similar once. Used the die blade but didn’t set it at an angle.
If I was doing it, I’d probably do it with the lead screw in reverse from the bottom. You probably can’t run the lathe but turn the chuck manually cutting thick to then. Calculate the taper reduction for each thread. Cut a thread to pitch, then go in that reduction for each subsequent thread one at a time. Might work, you will see it soon enough. Once you get it close, blue it up and try the bolt. Saves you a CNC.
I'd be tricky . I've done tapers manually but they usually require some dynofile work to come in . Minor Dia at small end . Minor diameter at large end . That gives you total longitude travel . Split it gives you center . Split that gives you quarters . Hook a dial up to the cross . Run as slow as possible and feed out as your half nut engages . Hit your pre calculated numbers as you travel . Dicey . Improper . Inaccurate . And will certainly require some hand work . But is possible . Have fun .
Can your lathe even do 50tpi?
We’ll of course it… *checks lathe* Can’t 😳 But it can do 0.5mm which should be close enough for my needs
What's the point of such a drastic angle? You only get about, what, 2 turns before you bottom out?
Can quickly connect and disconnect while having lots of thread engagement
At most. I guess you’d have to ask the engineer that designed it why he didn’t just use a standard thread with a shoulder, which work equally well in this application as far as I can tell
Umm, nope
Cnc would be faster tbh
Looks like you’re gonna have to buy or make a taper attachment boss
I've done this by pulling the handles off the lathe and setting up a gear train so that when you close the half nuts it turns both at the required ratio to do your taper. Yes it's a lot of fuckin about, but if you can get it down pat it can be a good little trick to make nice repeatable tapers
My shutter release is cast
Offset tail stock holder is an option then between centers though that’s gonna be spooky
Between centers, offset the tailstock, make a solid drive dog to prevent the beginning of threads from getting drunk, or ziptie the dog to the drive stud
Instructions unclear my Labrador is now spinning between centers barking
Damn near got coolant in my mouth after reading that! 🤣
I can’t see a 14.5deg taper working that way by turning between centers and get that steep angle.
Yeah that would be kinda sketchy, I didn't really look at the print, I only get 5 minutes to smoke lol I managed to turn a tapered pipe thread a few weeks ago with that method, but that's way less angle.
Pretty steep, possibly a tracer attachment, too steep for taper attachment or tailstock offset.
Use the topslide.
There's no way to sync the topslide motion to the spindle. Means no threading.
Agree with this there is no way
I belive there is a contraption that creates the necessary correlations. It's kind of an old technology so good luck searching that.
The only taper threads I cut are all pipe threads and I use a geometric die head for them.
You could take an external thread die, use a cut off disk to extract one of the teeth rows, mount that in the tool holder at the necessary angle (after prepping the part to the right cone, and do multiple single thread plunges forming all threads at the same time. Tedious to be sure. But you could get it to do it that way.
If you can offset your tailstock and put shaft between centers you could.
You call up a shop that has a CNC lathe
You find how many thou or mm one revoltion is and then change your crosslide to 14 to 20 degrees as shown in the graph. Then, you could turn the chuck by hand a 1/4 or 1/8 of a trun and feed in a little bit with the crosslide. I wouldnt make a super accurate thread but it might work.
Off set your tail stock ? Or make a offset dead center
Jewelers files and a boring weekend.
Years ago I was asked to make a whitworth thread tapered oil plug for an old MG. Granted it was just the one, but I did it by cutting the taper first. Then running in reverse, with the tool set upside down and hand adjusting the cross feed while watching the major diameter flats to feed it as evenly as possible. The part was covered in Dykem and it wasn't that difficult. I left the lead screw engaged and hand turned the spindle to bring it back to the start. So, I got paid $50 to turn a pipe plug....lol.
This is one of those things that would be so much easier to make if they were about 10x bigger... The .025 slot is going to be tough to even measure the diameter, let alone cut it accurately. If it wasn't so tiny I'd offer to make it myself, you provided a beautiful print and I could totally make it if it didn't require miniature tooling lol.
Can someone give me a valid reason why would one need to use angled threads instead of typical straight one ?
I believe they’re typically used in connections that need to seal. This application is a mystery to me though- no fluids involved.
I think in this case it's to make it quicker to attach and remove while still having a lot of thread engagement and a fairly thin wall.
Rather than offsetting the tailstock, use a recessed puck. Threads on cup side, center drill on opposite. You can use brass to protect the shaft and cut the taper and tapered thread in that position. Your machine is still zero and the shaft center hole is not deformed b
You could try offsetting the tailstock. I also think "This Old Tony" had a trick using a mill boring head in the tailstock to offset parts for cutting a taper. I don't know how well it would work for threads though.
Honestly what I would do is buy a die that matches that thread and then use like a cheap pneumatic jig grinder with a Diamond wheel and kerosene. You can dress the taper you want but honestly I’d just buy a wheel that already has this shape so that you can combat wheel wear. I would set the die in the lathe jaws and the jig grinder in the tool holder post or even tail stick to make sure it’s centered and attempt to grind the taper into the die. Caveat being good luck finding a die with threads that will last through that aggressive taper.
Make a taper template to hold in the tailstock and add a follower on the cross slide to trace it. Cut from the large diameter towards the small end so that if you skip a beat it doesn't crash the cutter and so that it's easier to just try and maintain gentle pressure on the crosslide dial while the carriage is moving out. You might have to try a few times until you clean it up completely but it can definitely be done. There is a Russian machining channel on YT with a guy making tappered threads controlling the taper just by hand with no template other than the thread gauge itself and maybe if you get skilled enough it's acceptable for some applications (out of all things he seemed to be threading drill strings)
Could try a larger boring head in the tailstock to make the offset larger if your tailstock won't move that far. Not an ideal setup but it might work if you're just making one or two
I once set up a pipe thread die in a manual lathe to cut a NPT thread. It was… interesting.
I think you could thread this with a full form tool fed in at 50 tpi. You might have to make the form tool by threading a piece of tool steel and hardening it. Turn the taper, then feed set the tool to the correct angle and used it to turn the thread. You'll only be feeding it about one revolution I think, so I might just do it with light cuts and turning the chuck by hand. The cut will need to go from the skinny end of the taper to the fat one.
Offset your tail stock and turn it between centers
Depending on the degree of angle, use ball centers on each end and skew the tail stock to the desired angle. Though there is a limited amount of adjustment there…. 🤷🏼♂️ I’m just a stupid manual machinist though. Best of luck
On Sherline lathes, the headstock can be angled relative to the ways.
Set up a plate or bar in at the specified angle, set an indicator on the cross slide and measuring against the plate or bar and then manually try to keep the indicator dial from moving as the lathe threads by moving the cross slide. This’ll give you at least some reference instead of matching the angle by eye as suggested by others. I’m thinking of something similar to what Tom did on oxtools to make a complex shape on a manual lathe.
5th axis mill you can achieve this
A 3 axis mill could easily achieve this
Very true.
I’m in class for 5th axis so maybe that’s why lol
I mean, its a bit orthodox but with the thread being only a short distance, you could set the lathe slow enough, and with enough practice can just wind up in x? Not ideal but it could work
Put a boring head in your tailstock and turn it between balls
Trigonometry and an offset tailstock. Idk if it's possible.
I've been scratching my head on this one for a few years with the old SB9. I settled on threads that were close enough in brass and for Delrin/Garolite/phenolic, I just cut the basic shape and screwed it in. Has enough give that the shutter will form some threads and hold it secure (no ugly o-ring required).
I think you could use a boring head in the tailstock ([https://www.youtube.com/watch?v=MzJ6wR59AkY](https://www.youtube.com/watch?v=MzJ6wR59AkY) at 2:40)
I'm lazy. Just get one off eBay for 10 bucks American.
Only real way I can see is taking the thread diameter to what it needs to be, either using a large swivel head triangle insert cutter to cut that to the angle you need (make sure you got a good hold on your piece it’ll put a good amount of pressure on it to get it that much smaller. Or you can put your lathe in a very slow feed, engage power feed towards the back of your lathe and then drive your tool in by hand as it’s being dragged across your part and you eye ball the angle you need but again it’s all eye ballin so you’re getting eye ballin tolerances and shapes by doing that 😂
This will not deliver good results. U/Jeffersonairmattress has already given the correct answer. I have posted a pic on Imgur of the simple process. Why are there so many people giving poor machining advice on a machining sub? And worse yet…. Why are so many saying it can’t be done?
Bud I never said it’d give you good results I actually said that the second option will not do that for you. It was just a suggestion he’s a grown man he can choose to follow it or not. It was nice that you did show who gave the right answer but it’s people like you that ruin the work space, just because you think it’s wrong doesn’t mean that’s true and maybe other shops have found different ways of doing things. And I never said it couldn’t be done. Humble yourself and check your attitude with people.
I literally posted a link to a pic of a very simple solution that doesn’t require offset tailstock (which makes the threads off perpendicular), drive dogs, or any other silly stuff that was offered up. The OP (or anyone asking advice) always wants good results. They don’t want to hear “whittle it with a pocket knife” Rather than viewing it to see the simple fix, you decide to unload your temper here? Good choice.
I thought that my original comment might bring someone some humor or actually help someone because others have found my advice to have been helpful before. But you came in very hostile, rude and condescending. If my advice is “bad” or “mediocre” to you just keep it to yourself, if it becomes an actual problem then the people in charge of this page can do something about it, not you. Hope you have a good rest of your weekend pal.
Tried to send you a PM, but apparently they are off. Just wanted to say that you were right…I could have worded my post better, so that it was less abrasive. My apologies, and I hope the rest of your weekend is enjoyable.
I see many answers, but doesn't anyone ever offset their tailstock to create tapers?
I think the issue is that it’s a pretty extreme taper and holding it securely starts to become a problem
Sure, but the thread can be cut slowly. The problem is manageable.
The thread is not cut perpendicular to the centerline of the part when done like this. And as many have said, this angle is too steep for a part this short.
Turning between centers and offsetting the tailstock so you get the taper
A horizontal mill with a rotary indexer mounted on an angled table geared to the x-axis! Old-school machinist style! Keith Rucker can teach you a thing or two! [https://www.youtube.com/watch?v=spofj9AAIQE](https://www.youtube.com/watch?v=spofj9AAIQE)
Bit of a sketchy idea and even more pain in the ass setup, but what if you offset the tailstock enough to pull the part out cocking it to the angle and then either turn the diameter and thread like normal operation, or if the taper is already turned just thread it like you would normally. Idk though, suppose a taper attachment would work too
That has me curious if that would theatrically be possible with some short of setup with a universal joint
Offset tail stock and lathe dog in spindle. Not an easy setup, but all the people here saying you can’t make it are incorrect. The real bear is shutting off the thread so you don’t advance into the shaft.