Crude but effective thread tracing

oneadam12

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Saskatchewan
I was looking at micro lathes and so on, and came across this thread duplicator. Crude and time consuming but effective, I kind of admire it:

http:// www.cartertools.com/brooketh.html
 
That's interesting and a very good idea for machines without a lead screw.

It would be like cutting metric threads with an English pitch lead screw and no proper change gears in that you would have to reverse the spindle to move the carriage back to a starting point to take the next cut.
Not a big issue.
 
You're limited to stock threads so it's utility is not that great for the amount of effort to build such a thing.

On the other hand a tail stock die holder will perform pretty darn good threading that is fairly well centered. Not AS centered as single point cutting. But with a bit of care centered enough. And there's tricks to aid in keeping it centered better. So for "quick and easy and good enough" threading it is a lot more convenient than this crazy rig.

And from a quick check the mini lathes all come with change gears anyway. Just learn to use them. It'll be a lot less trouble then trying to adapt a mini lathe to such a get up.

Keep in mind that the old Unimat and the still current Taig and Sherline do not have any ability to accept change gears or any sort of power lead screw. So they HAD to rely on Rube Goldberg setups of this sort. Interesting to study but well worth avoiding if you are looking at a machine which will perform threading in a more normal way.
 
Keep in mind that the old Unimat and the still current Taig and Sherline do not have any ability to accept change gears or any sort of power lead screw. So they HAD to rely on Rube Goldberg setups of this sort. Interesting to study but well worth avoiding if you are looking at a machine which will perform threading in a more normal way.

I quite agree. But it is just interesting.
 
You're limited to stock threads so it's utility is not that great for the amount of effort to build such a thing.

On the other hand a tail stock die holder will perform pretty darn good threading that is fairly well centered. Not AS centered as single point cutting. But with a bit of care centered enough. And there's tricks to aid in keeping it centered better. So for "quick and easy and good enough" threading it is a lot more convenient than this crazy rig.

And from a quick check the mini lathes all come with change gears anyway. Just learn to use them. It'll be a lot less trouble then trying to adapt a mini lathe to such a get up.

Keep in mind that the old Unimat and the still current Taig and Sherline do not have any ability to accept change gears or any sort of power lead screw. So they HAD to rely on Rube Goldberg setups of this sort. Interesting to study but well worth avoiding if you are looking at a machine which will perform threading in a more normal way.

This type of chaser with a sliding work head was used on a lot of old (very old) lathes. Holtzappfel (spelling) Ornamental Turning lathes esp. Hardinge, and a lot of the makers of precision Instrument Makers style lathes used a sort of similar system, without the sliding head, but with a system of master threads and matching followers.

Cheers
Trev
 
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