Jig for threading turned box and lid

[STB]

My version of A shop-built jig for threading lids on turned boxes. The picture is of a box and lid used for proof of concept, and it works but needs a couple of tweaks for the final version. Suggestions wood be helpful.

testp2.jpg (385.32 KiB) Viewed 486 times

[JPG]

A courser pitch feed screw?

I like what you have done.

[BuckeyeDennis]

That’s pretty slick! What’s the material that you’re threading? I understand that fine-grained hardwoods are best for threading.

What are you looking to improve with the tweaks?

If tearout on the threads is the problem, you could try stabilizing the wood prior to milling the threads, using multiple passes to cut the thread to full depth, or maybe experiment with different thread mills.

[STB]

A courser pitch feed screw?

I like what you have done.

That's definitely on the tweak list.

[STB]

That’s pretty slick! What’s the material that you’re threading? I understand that fine-grained hardwoods are best for threading.

What are you looking to improve with the tweaks?

If tearout on the threads is the problem, you could try stabilizing the wood prior to milling the threads, using multiple passes to cut the thread to full depth, or maybe experiment with different thread mills.

I tried several things spindle speed, feed rate, cut depth, applying minwax wood hardener, and a few other things. That's the reason the test pieces are so short I cut off the failures. One of my problems was that I used 5/8 all thread and it is a little under 5/8 diameter so my chuck was not stable. I think a 3/4 all thread with the end turned to the Quill diameter might work. I was also thinking CA glue to stabilize the threads but mine is dried up. The cheapest thread mill is around $45 and go up from there. Some harder wood with a denser grain is a good suggestion.

[algale]

I like that too! What kind of bit are you using in the chuck to cut the threads??

[STB]

I like that too! What kind of bit are you using in the chuck to cut the threads??

It is a thread mill bit typically used in vertical mills.

[Hobbyman2]

Very nice, how are you doing with the threads and chip out with that bit ? if it is excessive would a less aggressive bit make any difference ?

[STB]

Very nice, how are you doing with the threads and chip out with that bit ? if it is excessive would a less aggressive bit make any difference ?

As for chipout All my trials have been with the workpiece at 90 to the bit. I think my next try will be with the workpiece canted so only the face of the bit is cutting. I do not understand less aggressive bit. Do you mean less flutes?

[BuckeyeDennis]

I just thought of another issue. Studying the pic of your setup, it appears that the bit is climb cutting. I’ve experimented with both climb and conventional cuts on my CNC router. The best technique for me seems to be to do roughing passes with a climb cut, followed by a light finishing pass with a conventional cut. So you might try a light finish pass while threading out — that should give you a conventional cut on that pass.