Cutting wooden threads

Hi Guys,

I bought a grizzly wood tap and die recently (looks just like the one woodcraft sells) in 1 inch. I am wanting to use it to make a moxon vice tomorrow.

It works well enough and after adjusting the cutter a bit I got the threads the right tightness in the taped hole.

Here is the problem though, there is a lot of chip out / tear out along the threads. I did sharpen the cutter which helped a lot and also used mineral oil on the dowl which helped a bit, but its not as nice a result as I would have wanted. Anyway I had some thoughts but wanted to see if anyone else already had this sorted out.

1) I sharpened to 1200 on dmt diamond stone, I dont have a finer stone yet (although one is on its way right now and will be here mid next week) I could strop it though it that will make a big difference
2) I could try soaking in mineral oil so it absorbs more, or try another type of oil
3) I tired oak and poplar because that is what was stocked at menards, oak was better but is there another type of wood I should look for?
4) They just might not get much better with this type of tool...

Anyway appreciate any help

Thanks

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Originally Posted by Brandon SPEAKS

Hi Guys,

I bought a grizzly wood tap and die recently (looks just like the one woodcraft sells) in 1 inch. I am wanting to use it to make a moxon vice tomorrow.

It works well enough and after adjusting the cutter a bit I got the threads the right tightness in the taped hole.

Here is the problem though, there is a lot of chip out / tear out along the threads. I did sharpen the cutter which helped a lot and also used mineral oil on the dowl which helped a bit, but its not as nice a result as I would have wanted. Anyway I had some thoughts but wanted to see if anyone else already had this sorted out.

1) I sharpened to 1200 on dmt diamond stone, I dont have a finer stone yet (although one is on its way right now and will be here mid next week) I could strop it though it that will make a big difference
2) I could try soaking in mineral oil so it absorbs more, or try another type of oil
3) I tired oak and poplar because that is what was stocked at menards, oak was better but is there another type of wood I should look for?
4) They just might not get much better with this type of tool...

Anyway appreciate any help

Thanks

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The cutter must be sharp but the type of wood is important. For threads that will be used a lot such as for a vise I would want a strong, fine-grained wood. I'd probably try dogwood, bradford pear, sugar maple, or a hard exotic. You might also try stiffen softer or coarser wood with something like sanding sealer or CA glue.

I've used the tap and die in several woods with success, but not for something like a vise screw that would get turned a lot. This is walnut:

Attachment 379178

I don't remember any chipout. I did use some sanding sealer before cutting. I've never tried oil.

JKJ

If you intend to machine a lot of wooden threads you might consider purchasing the Beale Wood Threader. It uses a router to cut the male threads and the success rate is much higher on many wood species. I use mine for maple and walnut threads mostly and the threads are very sharp and the fit is excellent.

The trick is to saturate the dowel with oil (Danish oil works for me) and let sit overnight. The threads will come out much better.

I made a pair of handscrews last year and used Beech that was soaked with BLO mixed with mineral spirits and it worked well.

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Originally Posted by Don Orr

I made a pair of handscrews last year and used Beech that was soaked with BLO mixed with mineral spirits and it worked well.

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Nice work, Don! Did you use a tap/die set? I keep two sizes and they seem to work well but I haven't tried threads that long.

JKJ

This won't help the OP but I'll toss this in just to get the thinking juices going.

My father lived with me for a while after retiring. He was Danish and apprenticed to a wagon maker (Cartwright) when he was 14. He made and repaired furniture after that for the rest of his woodworking career. I had a tap and thread box that I could never get to work properly. He couldn't either so I suggested the Beall router jig mentioned above. He said no and wanted a blade for the table saw so I took a blade that came from a window or door joint machine of some kind to a saw sharpener nearby. He put new carbide on the teeth and sharpened them to 60 degree points with a small flat on the tips. My father made a jig that sat over the blade in the tables. Basically like a Beall except a blade instead of the router bit. When you feed the dowel in against the rotation of the blade it cut a perfect thread without any chip out unless it was crappy wood like cottonwood. He even cut a 4" diameter thread just to prove he could. It could cut from 3 to about 12 or more threads per inch depending on the tap it matched. I've never seen the technique used anywhere else and am keeping the blade and one of the jigs as a sample for the day when I want to do more.

Don, that is interesting and shows the all wood clamps have an advantage over the modern steel threads. Years ago I scraped all the accumulated glue off a big pile of the modern clamps and and coated them with a mixture like yours ....
plus melted bees wax. Believe it or not the bees wax made clamps in use unwind on their own right after having been tightened. So I then had to spray all the threads with carbureter cleaner.

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Originally Posted by Keith Outten

If you intend to machine a lot of wooden threads you might consider purchasing the Beale Wood Threader. It uses a router to cut the male threads and the success rate is much higher on many wood species. I use mine for maple and walnut threads mostly and the threads are very sharp and the fit is excellent.

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I have one of those, and it works great, but that is so *not* neander.

To the OP: If you want to do it by hand, look at all of the other posts. If you want to get it done fast and move on, then Keith is right about the Beale. I got mine because I wanted to build a bench jack in a hurry and with a minimum of fuss, and it was a good decision IMO. As Keith demonstrates it's kind of addictively hard to stop coming up with stuff to thread with it once you get started.

Hi Sean
I also made a set of threaded clamps some years ago with a thread box.Attachment 379236

I had the best luck with hard maple, tried iron wood and red oak. I soaked in BLO as others suggest, and have also heard that soaking in alcohol works even better but think the amount of alcohol needed for 1 inch thread might be prohibitive.
More important was the size of the dowel which should be slightly smaller than the nominal size of the thread i.e. 30-31/32 for 1 inch so that the threads are slightly flat on top.
I think if the threads come to a sharp peak they break off when the back side is cut. The tread should look a bit like an acme thread.
However don't sand the dowel finer, turn it on a lathe or all your sharpening of the v cutter will have been in vain.
Bill

Quote:

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Originally Posted by bill howes

...so that the threads are slightly flat on top.
I think if the threads come to a sharp peak they break off when the back side is cut. The tread should look a bit like an acme thread.
...

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Same thing with cutting threads on the wood lathe with a high-speed cutter an a jig or with hand chasing - the threads have to have a flat instead of a point to prevent chipping.

Yes John-standard, commonly available thread box & tap.