Acmes need plenty of rigidity and power for cutting . Easy way is to cut your thread using a regular 60 degree cutter the same pitch , picking the thread back up and then thread with the acme tool . Lot less wear and tear on the machine and tool .
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4 TPI Thread: How is this looking to you?
- Thread starter SmokeWalker
- Start date
An Acme thread should always be cut with the compound set at 14 1/2 degrees off the radial line, never plunge cut. The chips all interfere with each other and would tend to jam up.
If your lathe is an import, your compound angle may be 60 deg. I'll run out in the shop in a few to confirm, but my Clausing's compound at 0 deg. yields compound movement parallel to the cross feed. My Grizzly's compound at 0 deg. results in compound movement parallel to the longitudinal travel. So on the Clausing, I set 29.5 deg., on the Grizzly a touch past 60 deg.
Bruce
Bruce
This is a simple tool that can help along with the fishtail. Office supply stores have similar and online as well. Toolpost removed for clarity. You can get the compound set perfectly to whatever degree you want within the limits of the marked degrees.
You may be able to recover due to that at 60 degrees the tool has not cut as deep as it would have when set to 30. Whether the thread shape will match what you require is difficult to say. I think that you may end up with a smaller major diameter with a larger flat at the peak but a correct minor diameter. Will this cause trouble, you will have to just try it and report back.
I got a completed thread. Took hours, though. The follower was not cut to full depth, but it works. It even got the stamp of approval. Thanks for the advice, gentlemen.
