Spindle adapter for threading jig

[Mark Greenbaum]

I am in the process of another jig for the G0766. I am making a threading jig for urns and screw on lidded boxes. I am starting with 3/4-10 UNC x 12" lg all thread rod as the lead screw. I will need an adapter to fit the chucks that have 1-1/4"-8 threads (female). So I need an adapter that is 3/4"-10 unc (female) x 1-1/4-8 (male). I have gone through a few searches on Google, and have gone to local Woodcraft store and no luck yet. Anyone have a source?

[John K Jordan]

Could you make one with a threaded adapter and mount an MT2 socket on your rod? For example, https://www.amazon.com/5016-Tailstoc.../dp/B0064JJ49Y

Another option might be to have one machined. Any good machine shop (or an amateur with a metal lathe) could make one with the chuck threads on one end and a threaded socket to match your 3/4-10 rod.

The guy at Best Wood Tools has a lot of experience in building such things. He has 1-1/4x8 adapters for his Baxter threading jig I suspect could be adapted to your threaded rod. In fact, he might even sell a just the 10 tpi rod and chuck adapter from the threading head (or just buy the threading head). http://bestwoodtools.stores.yahoo.net/bathma.html

JKJ

[Bert Delisle]

I am in the process of another jig for the G0766. I am making a threading jig for urns and screw on lidded boxes. I am starting with 3/4-10 UNC x 12" lg all thread rod as the lead screw. I will need an adapter to fit the chucks that have 1-1/4"-8 threads (female). So I need an adapter that is 3/4"-10 unc (female) x 1-1/4-8 (male). I have gone through a few searches on Google, and have gone to local Woodcraft store and no luck yet. Anyone have a source?

Check with Oneway they have these adaptors in stock. Good luck with your build, you may find the accuracy of concentricty a challenge, the accuracy of all-thread is fine for nuts and holding things in tension but my experience with my jig build was less than acceptable for my urns, so I finally bit the bullet and bought a purpose built threading jig. Now I do threads up to six inches in diameter on urns up to eight inches tall. Could never do that on my home built jig.

[Brice Rogers]

Hi Mark,

There are adapters that go from 3/4 x 16 to 1" x 8, and adapters that go between 1 x 8 and 1-1/4 x 8. But for adapters going from 3/4 x 10 to either 1 x 8 or 1-1/4 x 8 seem elusive - - as you have found.

You might want to consider buying a 1" x 8 tpi threaded rod. They are available from places like McMaster-Carr, and perhaps MSC, etc. . Visually it doesn't look all that much different than 10 tpi. This would allow you to use the 1 x 8 tpi rod for both advancing the chuck and screwing into the back of the chuck. Also, you can buy "jam-nuts" pretty easily. 1" x8 is a common chuck size. I'm not positive but I think that you can get adapters to go to 1-1/4 x8.

Finding 1-1/4 x 8 threaded rod and matching nuts might be a bit challenging. The 1-1/4 x 7 is more common for some reason.

Another alternative would be to take two threaded rods of the desired thread/pitch and turn down one end to a common diameter and stick the two ends into an unthreaded coupler (like a piece of brass rod the you drilled from one end to the other (co-axial). You could either silver solder them together or used setscrews. But alignment and run-out might be a challenge. The threads need to be protected during the turning process. I've used both dual jamb nuts or a coupler and jamb nut to hold threaded rod. I have also held it with copper tubing, etc.

John's advice to find a machinist might make sense. The machinist could turn a shoulder for the chuck end that would be virtually guaranteed to be perpendicular to the axis of the threads.

There is a Youtube video by Mike Peace where he builds his own threading fixture, and it might be of interest. He addressed making a nut with a shoulder to help register the back of the chuck. https://www.youtube.com/watch?v=RIGS-fcl2LM&t=669s

I will be following this thread because I too am thinking of making a threading fixture. But I might just go to chefwarekits.

Good luck, Mark

[Paul Gilbert]

I am speaking off my head here, (I won't quote exact sizes and TPI unless you request that I go out into the shop and look) but what I did was buy the lead rod of the same thread size as my Robust style (PM knock off) live center. Then I use the same adapter that I use to hold my Chuck onto the live center.

[Mark Greenbaum]

I just sent an email to Oneway to see if maybe they have a suitable spindle adapter available.

I also have a couple of Nova adapters for the Shopsmith, that possibly could be re-bored and tapped for 3/4-10 UNC (currently 5/8" straight bore), and re-threaded to 1-1/4-8 (currently whatever size the Nova G3 chuck has for internal threads). Not sure who can be found to do that.

[Mark Greenbaum]

Oneway responded with this selection:
https://oneway.ca/index.php?route=pr...earch=3941-222

A little pricey for my tastes, so I may see if I can get my Shopsmith adapter modified here at work. If not, I may have to go that route.

[Brice Rogers]

Mark, I rewatched the Mike Peace video and heard where he mentioned getting the spindle adapter from Pennstate. So, I looked on Penn State and find that they have the adapter from 3/4 x 10 to 1" x 8 for around $17. Hurricane tools also has a similar one for a couple bucks less. On my G0766, I ended up with three 1" chucks so I had originally bought the $9 adapter from Griz. If you have a 1" chuck, then this adapter should work for you. But if you are heavily invested in 1-1/4" chucks, then this might be a costly direction.

[Mark Greenbaum]

Brice:

Thanks for the leads. I've already seen these adapters, and they are not suitable for my chucks. I too have the 1-1/4"-8 TPI threads and adapter in both of my chucks (Grizzly 5.5" and Nove G3). Nova has nothing to offer. And I just sent an email to sales@bestwoodtools.com to see what their custom piece price would be. Another option is for me to have a machine shop grind the end of the all-thread rod down to 5/8" diameter and either remove the adapter from my Nova as I currently use it, and use the Shopsmith 5/8" straight bore adapter I already have. I am not to keen on this idea as it involves removing the adapter for every threading operation. I am still in the fabrication stages, so I have time.

[Mark Greenbaum]

I have been designing this jig in Rhino v.4 to make sure I have all the dimensions correct.

[Brice Rogers]

Thanks for posting and giving me some more ideas. I have wondered if it would be of value to have a lock on the cross feed to remove any slop when making the final pass? I'm looking forward to seeing how you device progresses.

[Mark Greenbaum]

That's good idea. I'll incorporate that one. In fact last night, I added locking wheel to the lateral adjuster in 3D CAD.

I tried to add some details to the above submission such as:
1) The shafts will be turned down to 5/8" diameter x 1" long to fit the NOVA adapter for the Shopsmith.
2) The NVA Adapter will have the male threads machined off, and new threads cut for 1-1/4"-10 TPI to fit my 2 chucks.
3) If I decide to get different thread pitches I can get the shafts ground down to 5/8" diameter x 1" long, and keep using the rest of the assembly.

I did get the collet and cutter ordered this AM and it should be here in about 3 days.
Too busy this weekend to get the assembly cut and assembled. I hired my 13 year old son to help me clear out my side of the garage and get it more organized. We threw away a bunch of stuff, but after moving everything back in - I still have too much stuff.

[Mark Greenbaum]

After studying the design of y threading jig, and seeing inputs from many others, I've decided to have removable side plates so I can accommodate a different lathe in the future. Perhaps at some point I'll get a midi or mini lathe for smalls, and the threading jig may live there. So the horizontal members that the side plates attach to will have threaded inserts to all for quick change overs.

I did get the machinist at work to make the threaded adapter from an old Nova adapter for the Shopsmith. 5/8" bore thru and 1-1/4-8 TPI male out. It fits the inside of the Nova G# chuck like a glove. The collet should be here tonight, and the cutter should arrive next Thursday. I'll post pictures as I build. This weekend is "Honey-Do" time.

[Mike Peace]

I agree with Bert on the problems with using coarse rod. After making one and publishing an article on it, I hate to admit it but I was never happy with it and wound up buying one. I am not a machinist and approached the project trying to get by without any machining and buying off the shelf items. It was a fun project though so if your primary goal is the challenge and fun of making one, go for it.

[Mark Greenbaum]

I agree with Bert on the problems with using coarse rod. After making one and publishing an article on it, I hate to admit it but I was never happy with it and wound up buying one. I am not a machinist and approached the project trying to get by without any machining and buying off the shelf items. It was a fun project though so if your primary goal is the challenge and fun of making one, go for it.

I can purchase other 3/4" diameter thread rod configurations from McMaster Carr and get the hex nuts to fit. So it is adaptable. I'll see it I can make it work, then decide if I can afford to go further. The collet has been delayed 'til Monday.
Mike Peace - your article and videos are really inspiring and if this works, all the better. If it doesn't, maybe post an addendum to your video and make a disclaimer?