Ball and other shape turning using a follower and pattern

[npalen]

https://patents.google.com/?q=(lathe+duplicating)&oq=lathe+duplicating

Some more bedtime reading?

[Rich Carlstedt]

I wrote up something to consider many years ago and can't find it , but here is a repost on the subject, but missing a few pictures
Basically, using a Aloris tool post, you have a threaded hole on the tail stock side of the tool post.
You mount the follower stylus to it and use it to follow a pattern on your tracing structure.
In the original post years ago, the poster wanted to know how to machine a perfect radius with a critical dimension so I used a radius gauge as a sample
The only criteria is the stylus and the tool Must be identical in shape and size is there are multiple angles.radiuses
For a simple end radius , I used a scrap bar as all that was needed was a square corner.
Rich
https://bbs.homeshopmachinist.net/forum/general/52786-how-accurately-can-you-copy-on-a-lathe

POST # 21

[BCRider]

That would put the pattern up on the side of the tailstock if we use the tailstock as support for longer parts. It would be not hard for me with a fairly square shape but not so nice for a lot with more rounded shapes.

But it would avoid having my template table where it would catch.a lot of chips.

[JRouche]

So here's the wooden mockup I did to get a feel for this. It's all rather crowded but with the setup shown I can reach in to the rotational center but I can also handle up to 1.5" diameter stock.

I read all of it, geeze Man take a day off huh? LOL

For me was the use of wood.

"So here's the wooden mockup I did to get a feel for this. It's all rather crowded but with the setup shown I can reach in to the rotational center but I can also handle up to 1.5" diameter stock."

I like what you are doing. And wordy as heck. Thats fine, keep it coming. JR

[BCRider]

JR, I took typing in high school Grade 9 as it had the most girls out of all the electives. And while that was OK it turned out that typing ended up being about the best thing I learned out of high school. I can rip off long posts like these in just a couple of minutes. Editing and clarifying takes longer than the actual typing. So I do tend to ramble at times....

[BCRider]

https://patents.google.com/?q=(lathe...he+duplicating

Some more bedtime reading?

I looked over that set. Most are options for lightweight wood lathe copy setups. One was for metal but for flat face copying. So not at all what I want. And those that are suitable for metal copying were based on a heavy bridge mounted to the rear bed to permit longer items to be copied. It's more than I need or want. And a LOT of work to build the bridge to hold the master or template.

Even so I thought a bridge was the way to go until I saw that ball being made by using the bearing template attached to the tail stock quill. That's was very much a "EUREKA!" moment. I'm looking at a much less work, parts and materials to go with this more compact option.

[Wirecutter]

JR, I took typing in high school Grade 9 as it had the most girls out of all the electives. And while that was OK it turned out that typing ended up being about the best thing I learned out of high school. I can rip off long posts like these in just a couple of minutes. Editing and clarifying takes longer than the actual typing. So I do tend to ramble at times....

I took typing in grade 10, but broke my hand (not typing) and had to withdraw from the class. I taught myself early in college by getting the printed Forth source code from the Forth Interest Group and typing in all 90 pages. Does anyone remember the Forth language?

More on-topic, though. I guess if you live long enough, you can accumulate all sorts of tools. I picked up a Holdridge model 3-D on eBay a while back. It's an interesting tool to setup, but it will turn balls and sockets up to 3 inches diameter.
-M

[BCRider]

I'm stoked by this idea because I wanted something more than just a circular shape tool. This setup will allow me to use a template to more or less fully shape a whole ball style hand crank. And more specifically a "speed handle" that has a tear drop shape along the lines of the one below which I did freehand. But it would be nice to use a template in case I need a close match. Not much hope of copying a shape like this other than with a tracer setup.

This is the crank handle I'm using for the shaper for raising and lowering the table and for cranking over the ram by hand to ensure I'm not colliding with anything solid.

[npalen]

I looked over that set. Most are options for lightweight wood lathe copy setups. One was for metal but for flat face copying. So not at all what I want. And those that are suitable for metal copying were based on a heavy bridge mounted to the rear bed to permit longer items to be copied. It's more than I need or want. And a LOT of work to build the bridge to hold the master or template.

Even so I thought a bridge was the way to go until I saw that ball being made by using the bearing template attached to the tail stock quill. That's was very much a "EUREKA!" moment. I'm looking at a much less work, parts and materials to go with this more compact option.

You must have looked only at the first page as there are 31,060 hits. You're assignment for tonight is to study the rest of them! Seriously, I'm surprised that no one has been along here to eloquently say that you're trying to reinvent the wheel, or creating a solution for a problem that doesn't exist or........... That said, I encourage you to not give up on your project. Its fun to tackle these ideas and filter all the input and great when a plan comes together.

[rickyb]

This is a version I think was from hsm magazine years ago that may give you some design ideas. Pattern clamps to the ways and the follower clamps to the cross slide. The cutting tool in this case must have the same radius as the follower pin for the copy to be identical

[BCRider]

Originally I was thinking of a clamp on bridge somewhat similar to that.. And a cross clamp for the stylus template follower. But this way is fewer and smaller pieces. Plus for a lot of the things I'm considering I need the tail stock for support anyway. So it rather makes sense to mount the template table off the tail stock.

[BCRider]

You must have looked only at the first page as there are 31,060 hits. You're assignment for tonight is to study the rest of them! Seriously, I'm surprised that no one has been along here to eloquently say that you're trying to reinvent the wheel, or creating a solution for a problem that doesn't exist or........... .....

I'll get right onto that in due time when I have the energy... I'll get back to you in about a decade....

A nice way of making something like a ball end hand crank is something that a lot of us might like to do. But it's not something easily done without a lot of risk of poorly shaping the balls and transitions between them. And I've been wanting to do this ball end handle for a while. I COULD just buy or make a round wheel. But that's no fun.

[npalen]

Would "decoupling the leadscrew" be simply a matter of removing the cross-slide handwheel and bracket then following the template with hand pressure on the cross slide? A lever arrangement might be better. Seems like someone might have suggested a lever in a previous post.

Will radial slack in the tailstock quill be an issue? Might have to preload it to take out the slack?

[BCRider]

Would "decoupling the leadscrew" be simply a matter of removing the cross-slide handwheel and bracket then following the template with hand pressure on the cross slide? A lever arrangement might be better. Seems like someone might have suggested a lever in a previous post.

Will radial slack in the tailstock quill be an issue? Might have to preload it to take out the slack?

I won't be using the lead screw at all. The best way to run a profile like this is to play the carriage and cross slide handwheels. And to get good results we always want to be traversing across a "falling" portion of the cut. A little constant pressure on one wheel while traversing makes this work pretty well. The tear drop hand crank pictured above was done that way. Working from the bigger to the smaller diameter with light pressure on the cross slide and controlled speed and travel on the carriage.

With a template I'd still work the controls like that just like the guy in the ball video did for his finishing cuts. Start from a "high" and work to a "low". For roughing dive in in the middle and then traverse each way to find a touch point on the template.

It's hard to picture perhaps but quite easy to do by "feel".

Since for anything other than a ball I'll be using tail stock support for the peice the stock will be center drilled, the live center set with the proper pressure than the quill locked. So it'll be steady. No fear of play. And for short pieces that don't need the center support I'd still lock the TS quill to prevent any shifting due to any play.

[npalen]

Won't you need more Z axis distance between the cutter and stylus? Maybe I'm missing something there?