Fixtures!! Woo hoo!

Thanks Butch I have read that thread and about every other out there that I could find on the subject. I have a cnc mill and was just looking for a way to do that in the same set up as I am using to bore and thread. I had been thinking of trying what Chad mentioned, but don't have a way to lock the spindle on my machine, so I am pondering that for the time being.

I have come up with a way to cut the relief by hand and it works well enough, I was just looking for a better way.

Thanks for the help and that is a neat looking rig, Jay Idaho also has made one of those that is found on one of these threads and while it is not quite as polished looks to work equally well.

Thanks Gary
 
Locking the spindle isnt exactly what I think chad means. A rigid tapping cycle matches the spindle rotation with the pitch of the thread relative to the Z movement (so it still rotates a little bit). It would be one neat solution to the problem if it worked but a special cutter would probably still be needed as a standard endmill wouldn't have the geometry for such a move.

I may have to try a sample of this on a few machines to see if they would even allow such a quick little move. The lathe may be able to do this same thing with a similar tapping cycle as long as the pitch doesn't exceed the limit. If there is one?

And may I add, neat fixtures. Two Kurts for a stock may be a bit of overkill but there's no such thing as too much rigidity. :)

sawyer
 
A lathe would be doable. You can do multiple start threads. We cut up to 3" pitch in our lathes and up to .625 deep.

Before I went to all that trouble, I'd build a fixture and use a broach.

Better yet just run it in your 5 axis;;)

By then you'd be better off buying someones action and using your 5 axis to make money.:rolleyes:
 
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If I may make a suggestion.

When we bought the big Kitamura centers at Nesika we were a bit nervous trying all this out for the first time. 1500ipm rapid rates mean things go boom quick if there is a problem.

My suggestion was to get blocks of machinable wax (sold through most of the larger industrial supply catalogs) and proof stuff out that way. In the end we used round delrin to proof everything.

Just a couple additional options.

There's no need that I can see to do this with a 5 axis machine. The rigid tapping cycle works, it's just a bit of programming work to get it right that's all.

Small Z shifts are the key as the shaper tool will only tolerate so much. Your real work will be in grinding the thing to the proper geometry.

Cheers,

C
 
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