Box Threading Jig





Introduction: Box Threading Jig

I wanted to be able to make threaded lids for boxes and other projects turned on my old Shop Smith lathe. The problem is that to turn threads you typically need a machine that will go pretty slowly; say between 300 and 500 revolutions per minute. Old Shop Smiths can only drop down to around 700.

So I built a threading jig that uses a 60 degree double sided cutter, a Jacob's chuck, and an odd sled jig that will hold the box parts for threading.

The video shows the build and the methods for using the jig.

For mobile users here is the link:

This was a fun project. Thanks for taking a look.



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    Your bearing press jig is the key; I'm going to have to rig up something for tapping straight. I'm using the same cutter as yours. I made a decent threaded box with my prototype #1 jig, but it only has a 1" x 6" long lead screw. I would like to use a long section of 1" 8tpi all thread as you did, but can not find it locally - it needs to be perfectly straight, as yours seems to be. Where did you get that all thread rod?



    1 reply

    Hi Bill. I just bought the threaded rod at the local hardware store, nothing fancy. Seemed plenty straight for this project. The modified bearing press is handy for stuff like this. Best of luck.

    Nice work, including your guitar music.

    So you cut 8 tpi threads with your jig; have you tried other lead screws for cutting other tpi? And did you post photos of your tapping press addition? I'm ordering the 60 degree cutter tonight, so I'm on my way to a threading jig for my lathe.

    Thanks much.

    1 reply

    Hi Bill. Thanks for your comments. I haven't tried other thread sizes, the 8tpi just matched a lot of stuff I had around so I stuck with that. It seemed pretty forgiving due to the larger size but with some modifications I'm sure smaller threads could be used. I don't have any other photos of the press. It's been a while since I tinkered with the design but it was a lot of fun to build and play with. Best of luck.

    Thanks. Fun stuff. I'm re-designing the tapping press to use the Shop Smith instead. I'll have to post some follow-up pics of that addition after I find some time to really play with it.