Shop Made Threading Jig

[James Combs]

Been planning on making myself a threading jig going on 2 years and finally got around to it this past week. The jig is similar to commercially available units that push $300. I have about $122 invested in this one.

These are some of the components that went into making the jig.
309608 (http://www.penturners.org/forum/attachments/f30/130911d1426985076-shop-made-threading-jig-img_0548.jpg)

Mounted it looks very similar to factory units.
309609 (http://www.penturners.org/forum/attachments/f30/130912d1426985076-shop-made-threading-jig-img_0551.jpg)

The cutter is identical to those use with factory jigs
309610 (http://www.penturners.org/forum/attachments/f30/130913d1426985076-shop-made-threading-jig-img_0552.jpg)

This is a close-up of the threads cut into a quickly turned plum box.
309611 (http://www.penturners.org/forum/attachments/f30/130914d1426985076-shop-made-threading-jig-img_0553.jpg)

It wasn't an exact fit on first pass but taking an extra slightly deeper pass on the lid made for a great fit. The threads on the lid did not get close enough to the lid flange but a parting tool cut next to the flange solved that problem.
309612 (http://www.penturners.org/forum/attachments/f30/130915d1426985076-shop-made-threading-jig-img_0554.jpg)

"Continued in the next post"

[James Combs]

These pics give some close ups of the construction. One of the more expensive components was the linear slide(item 1 in 1st pic). I really wanted a dovetailed slide but could not find anything reasonable priced. Got this on eBay for a reasonably price. Item 10 in pic is kind of the frame and has every thing mounted to it. The tool post(12) has been threaded and screws into the bottom of the frame(10) and the larger one inch diameter cleaned up(I think I must have used it for a punch at some time or another. The large end was slightly mushroomed.) Fitted with a shaft collar it provides mounting in my Jet 1642 banjo.
309613 (http://www.penturners.org/forum/attachments/f30/130916d1426985700-shop-made-threading-jig-img_0557.jpg)

Item 11 holds items 2,3,4,5,7, and 8 in place. These parts make up the business end of the jig. The 3/4"10tpi threaded rod(4) is turned to turn the mounted part and "gauges" the 10tpi threads cut into the box or lid. The coupler(5) and jam nut(8) have one of the wave washers(7) sandwiched between them which removes any play/wobble in the turning of the rod and mounted chuck/box. The MDF knob on the end of threaded rod provides ample grip to turn the rod/chuck/box against the cutter.
309615 (http://www.penturners.org/forum/attachments/f30/130917d1426985700-shop-made-threading-jig-img_0559.jpg)

The set screws seen in the housing(11) capture and center the coupler and nut and the threaded rod. The two hex head bolts are acting as set screws also. The set screws and bolts allow the threaded rod to be removed and another with a different TPI installed. There is enough room in the housing(11) to go up to 1"-8tpi. The chuck spindle adapter is made for a 5/8" Shopsmith spindle. Any future threaded rod would have a short section of one end turned down to 5/8" and fitted to the adapter.
309616 (http://www.penturners.org/forum/attachments/f30/130918d1426985700-shop-made-threading-jig-img_0561.jpg)

The depth of cut adjustment is a piece of 5/16" threaded rod similar to the one shown in the component pic between items (7) and (12). It is threaded into the block at the side of housing(11) and spins inside a slip fit hole in the frame(10). A lock nut and wave spring keep it snug to the housing and takes out any play. The knob and threaded rod on the depth adjustment is from a Rockler set of knobs and bolts intended for jig making.
309617 (http://www.penturners.org/forum/attachments/f30/130919d1426985700-shop-made-threading-jig-img_0562.jpg)

All comments and critiques appreciated.

[Hilton Ralphs]

This looks to be mighty ingenious of you James. I'm not a turner yet but I'll keep this jig in mind.

Very well thought out.

[Malcolm Schweizer]

standing ovation! Bravo!!!!

[Frederick Skelly]

Wow. That's quite a job. Well done Sir.

I'm assuming the threads expand/contract with humidity. How to you adjust your jig, and the resulting threads to account for it?

Really nice tool!
Fred

[James Combs]

This looks to be mighty ingenious of you James. I'm not a turner yet but I'll keep this jig in mind.
Very well thought out.
Thanks for commenting Hilton, Been wanting to try my hand at threading and new my "hand" just wouldn't do it so need some help from a jig. Commercially available ones run upwards of $300 so I decided to build my own.


standing ovation! Bravo!!!!
Thanks Malcolm, ovations are always appreciated especially standing ones.;)


Wow. That's quite a job. Well done Sir.
I'm assuming the threads expand/contract with humidity. How to you adjust your jig, and the resulting threads to account for it?
Really nice tool!
Fred
Thanks Fred, I don't have any experience with products that use wooden threads so I can't speak for the effects of humidity but I would think that if the threads were loose enough there would not be a problem. Wooden threaded items have been around for probably centuries and I haven't seen or heard of any problems with them other then the fact that they are wood.

[Peter Fabricius]

Hi James,
That is a beautifully executed jig!!!
I have been turning threads with a EZ Threading Jig, made in England for a few years. The last two years I have been doing Demos of the jig at the local Ontario Woodturning Guilds. (5 Guilds done so far!). Threading is a really fun thing to do.
I really like that you have a multi TPI facility built into your jig, mine was one of the first out of the UK so it is fixed at 10 tpi. The newer models are multi capable. The UK jig is about $250 from Chefware kits.
A suggestion: Try threading the lid inside so it sits down over the tenon on the box, this feels more normal.
Try a threaded Fineal on a Hollow form.
Try a Nut and Bolt like Tim Yoder recently showed in a video.
Remember to always use very dry wood or you will surely get out of round boxes.
Keep having fun.
Well done.
Peter F.

[James Combs]

Hi James,
That is a beautifully executed jig!!! Thanks Peter, really appreciate your comments.
I have been turning threads with a EZ Threading Jig, made in England for a few years. I liked the look of the EZ Threading Pro Jig, it was my inspiration for mine. The last two years I have been doing Demos of the jig at the local Ontario Woodturning Guilds. (5 Guilds done so far!). Congrats, would love to be able to attend one but I don't travel anymore. Threading is a really fun thing to do. Ditto, had a lot of fun with my first piece:D
I really like that you have a multi TPI facility built into your jig, mine was one of the first out of the UK so it is fixed at 10 tpi. The newer models are multi capable. Yes, multiple TPI was always in my plans, the EZ Pro does provided that ability. I definitely want to get to 8tpi. The UK jig is about $250 from Chefware kits.
A suggestion: Try threading the lid inside so it sits down over the tenon on the box, this feels more normal.
Try a threaded Fineal on a Hollow form.
Try a Nut and Bolt like Tim Yoder recently showed in a video.
Remember to always use very dry wood or you will surely get out of round boxes.
Keep having fun.
Well done.
Peter F.
Will definitely follow your suggestions on what to try next. BTW if you turn my box upside down it then has the threading you suggest plus it sits on an elevated leg. Yes as a box it is a little shallow but who's quibbling.:rolleyes::D;) Thanks again.:)

[Fitzhugh Freeman]

I didn't comment the first time I saw this thread because I didn't really feel I had anything particularly interesting to add. I still don't have anything all that interesting to write, but I want to ask that you focus on the sentiment behind the words: awe and appreciation and inspiration. Thank you for posting this.

[James Combs]

I didn't comment the first time I saw this thread because I didn't really feel I had anything particularly interesting to add. I still don't have anything all that interesting to write, but I want to ask that you focus on the sentiment behind the words: awe and appreciation and inspiration. Thank you for posting this.
Thanks Fitzhugh, Appreciate the comment, I think the proper response to it can only be "Awww shucks":o

[James Combs]

Wow. That's quite a job. Well done Sir.
I'm assuming the threads expand/contract with humidity. How to you adjust your jig, and the resulting threads to account for it?
Really nice tool!
Fred
Fredrick, just an update. It has been just a little over a month since I turned and threaded the little Plum wood vessel. It has stayed in my shop screwed together since it was made. So far it has shown no sign of warping or binding of the threads. I am going to check it again in another month but this time I will leave the lid off. The outside has a couple coats of finish but the inside has none. The outside finish may have kept the wood from absorbing moisture so we will see what happens when the bare wood is exposed. Will post again here in 30 days or so.

BTW, if anyone has any first hand knowledge concerning the stability of Plum wood please chime in here. I do know that it checked and split like crazy when it was cut at the wrong time of the year.

[James Combs]

Fredrick, just an update. It has been just a little over a month since I turned and threaded the little Plum wood vessel. It has stayed in my shop screwed together since it was made. So far it has shown no sign of warping or binding of the threads. I am going to check it again in another month but this time I will leave the lid off. The outside has a couple coats of finish but the inside has none. The outside finish may have kept the wood from absorbing moisture so we will see what happens when the bare wood is exposed. Will post again here in 30 days or so.

BTW, if anyone has any first hand knowledge concerning the stability of Plum wood please chime in here. I do know that it checked and split like crazy when it was cut at the wrong time of the year.
I was re-reading a few of my older threads and happen to notice that I said I would report back again in "30 days" on the fit of my little sample screw together plumb box. Well apparently my memory hasn't improved from the last time I forgot something and now it has been more like 360 days. Anyway even though it is a very late report here it is:
The little box is still in my shop and coincidentally I ran across it last month or maybe in February. I picked it up and it was still screwed together from whenever the last time it was that I ran across it. Anyway, I tried to unscrew the lid and it didn't want to budge. Picked up a couple pieces of that rubbery drawer liner stuff and tried again. This time it started turning and I was able to remove the lid without further aid. However, as it rotated I noticed that it would get harder then easier to turn. It would hit two tight spots for every 360 degrees of rotation so something had changed slightly. Taking it off and putting it back on several times though loosened it up to where after about a half dozen cycles it was turning nearly as freely as when I made it. So yes the wood did move some over the past year but it wasn't dramatic.

[Frederick Skelly]

Thanks for the follow up JD. Glad to hear that the threads are pretty much unaffected by changes in humidity. I really didn't know what to expect there, so this cleared me up. I'm still in awe that you were able to make this tool. Threaded lids like this are so classy.

Best regards,
Fred

[Dan Hintz]

Love it, James...

[george wilson]

A very clever jig!! And,I LOVE plum wood. Wish I could get some.

I have been cutting my threads in a metal cutting lathe. For large threads,I use a wood router clamped at a 45 degree angle in my tool holder. It cuts exceedingly clean threads. The 45 degree angle on the router works just fine since proper wood threads have 90 degree angles between them,rather than the 60 degree angle of metal working threads. This more blunt angle makes the wooden threads stronger,and less likely for accidentally knocking the tops off of the threads.

My largest thread with this method is a 12" diameter beechwood log,with 2" wide threads to make 6 threads per inch. This was for a giant cider press for Williamsburg,where I worked for 40 years. I found a small,country machine shop which was willing,for as fee,to take on this strange project. I used the very old lathe seen behind me with the finished thread. There still were two 5" diameter holes to be bored at right angles across the 16" diameter "bulb" at the bottom of the screw. To turn this bulb in the old days,they used a "Sampson",which is a wooden winch firmly affixed to the ground by very DEEP wooden pillars. T rope from the sampson would go around the winches drum,and pull on a long tommy bar of wood that was set into the holes in the screw's bulb.

The apple pulp was wrapped in a bag made of horse tail hair,coarse enough to easily let the apple juice through. This black,woven horse tail hair looked just like the cheap nylon seat covers you could buy for your car back in the 1950's. Maybe it is still available?

When the "senior director" had his job eliminated (a common way of getting rid of someone),the museum seemed to lose interest in the cider press and the cider mill(for crushing the apples into pulp before pressing.) The cider press MAY be seen at Mount Vernon one of these days. There is talk of giving it to them. There is probably about $75,000.00 of work in these large wooden machines.

This is too bad.as cider making and consumption was a VERY important part of 18th. C. life. It was their soft drink,and if fermented,another strongly alcoholic drink.

Sorry,I don't have a picture of the assembled press in my attachments. The size of the screw can be seen. The cider MILL is seen,with a closeup of the large rollers with teeth that chew up the apples. Below these rollers is another roller without teeth,but closer together,to further crush the apple chunks,which then fall into a wooden container bin below.

The trickiest part of the operation was figuring out how to thread the HOLE that the big screw went through. The solution was to chain the large hickory "nut" down across the top of the lathe's carriage,with he cross slide and compound removed. A large hole 8" in diameter was bored through it. The hole was JUST large enough to allow a router with a 1 1/2" diameter cutter in it to start through the hole,taking a test cut as it VERY SLOWLY(10 RPM) was fed through the hole. The router was held at a 45º angle on a jig we welded up. It was mounted on a 20" long piece of 4" pipe. The power cord was allowed to feed around the 4" pipe as the router proceeded through the hole. It took 2 or 3 passes to complete the 2" deep thread. The nut was 10 Feet long,16" thick,and about 3' wide. It had 3 flat sides and one left "in the round" just like the original.

[James Combs]

A very clever jig!! And,I LOVE plum wood. Wish I could get some.

I have been cutting my threads in a metal cutting lathe. For large threads,I use a wood router clamped at a 45 degree angle in my tool holder. It cuts exceedingly clean threads. The 45 degree angle on the router works just fine since proper wood threads have 90 degree angles between them,rather than the 60 degree angle of metal working threads. This more blunt angle makes the wooden threads stronger,and less likely for accidentally knocking the tops off of the threads...
Now that is what I call cutting threads, thanks for the history George.

[Marvin Hasenak]

For those attempting one of these, I would suggest using a "4 way camera macro slide", same as the dovetail but cheaper and you have both sideways and front to back adjustments. I bought mine off of eBay, slow boat from China for less than $30. For the threaded part I used a block of Delrin that I drill and tapped. For my inspiration I used Pat Miller's threading jig from one of his posts on WOW. Sorry no pics of mine, and I am still laid up after triple bypass surgery so pics are out of the question, they won't let me go near the shop.

[Peter Blair]

James I love this threading jig. I bought a commercial one and yours appears to be better!

Any chance you will make more jigs and share your plans? Like a sphere jig, hint hint!

[John K Jordan]

I was re-reading a few of my older threads and happen to notice that I said I would report back again in "30 days" on the fit of my little sample screw together plumb box.

Plum, persimmon, dogwood - some of the woods that warp the most in my experience!

For turned boxes I try to do what I think Richard Raffan recommended, even with very dry wood. I turn it partially, hollowing both the box and the lid, and then let it sit for a while, at least overnight, better longer. Then finish and fit. This is supposed to help relieve the natural stresses in even dry wood. This has worked well for me.

I didn't see your original post so I am glad you brought it up again. Great looking work!! I bought a Baxter jig from Best Wood Tools but If I had my milling machine and metal lathe then I might have tried to make one. I'm sure it wouldn't have looked as good as yours, though!

JKJ