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Thread adapter

J

Jonathon Smith

Joined
Dec 17, 2013
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Location
Eunice, LA
I was given a chuck (from Harbor Freight) but the thread is 3/4"x10 TPI. My spindle is 1"x8 TPI. Has anyone seen an adapter that can reduce the threads to the chuck size? I've seen plenty to go from the smaller to the larger size, but not the other way around. Or would I just be better off having one made or try to retap the chuck?
 
Jonathan,

Before you buy another adapter, you should check to see if your chuck's existing thread is actually an adapter that can be removed. Most chucks are made this way so that they can be "adapted" to a number of lathes. Adapters work by reducing the chuck's threaded body to a matching spindle size. I have never seen a chuck adapter that can "increase" the threads as you would be doing moving from 3/4" to 1". If you can remove the 3/4" thread section, you can then measure the original threaded body to get a new adapter to fit. Otherwise, I think you have a conversation piece rather than something that will work on your machine.
 
Changing Chuck thread size

Jonathon if I were you I would just drill the chuck with a 7/8" drill and run a 1"- 8 tpi tap in it. If you are unable to do
it yourself, check out what the local machine shop would charge, may be costly depending on the labor rate. Perhaps
could pay a visit to the local community college, sometimes the instructors are looking for small jobs to give to
their students. GOOD Luck
 
I doubt you could drill and tap and ever get it to run true. If it has a threaded insert you may be able to find one that will fit. If not Bestwoodtools.com can make you an extension adaptor. Is it a wood lathe chuck or a metal lathe chuck. If it has circular set of jaws it's for wood. If it has 3 or 4 small jaws its for metal a d work as well for wood
 
Bruce Smith said:
Jonathon if I were you I would just drill the chuck with a 7/8" drill and run a 1"- 8 tpi tap in it. If you are unable to do
it yourself, check out what the local machine shop would charge, may be costly depending on the labor rate. Perhaps
could pay a visit to the local community college, sometimes the instructors are looking for small jobs to give to
their students. GOOD Luck
Click to expand...

That is a very high precision machining operation and not a DIY project. I am fairly certain that the Harbor Freight chuck doesn't have threaded inserts -- instead the threads are cut in the body of the chuck. First the chuck would need to be perfectly centered and then counter bored and finally the acme threads would need to be cut. That is a milling operation done with a fly cutter and not typically something done by a tap. A chuck needs to run perfectly true otherwise you will just have a heavy out of balance source of vibration hanging on the end of the spindle. A Harbor Freight chuck really isn't worth spending any money trying to make it something that it isn't. I'm sure that you can buy an adapter somewhere, but the price you pay would be a sizable down payment on a proper sized chuck. Seems like I recall somebody on the Wood Online forum looking for a 3/4 X 10 chuck, but it was some time ago so they might no longer be looking for one.
 
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I think that is a knock off of the one offered by Craftsman for their big lathe. You are absolutely CORRECT in pointing this out I have one sitting in a drawer collecting dust because you can't keep the wood in it long enough to turn. In other words it is dangerous.
 
Bill Boehme said:
I just checked what Harbor Freight sells for a woodturning lathe chuck. Click this link: HF Wood Lathe Chuck.

DO NOT under any circumstances use that for turning wood. It is a very very very cheap quality metal turning chuck with independent jaws and completely unfit for wood turning.
Click to expand...

Man-o-man, would I like to be there insurance agent for products liability. I'll bet I could retire on the commissions. That check is one scary POS!

Chuck it, Jonathan, literally!
 
Bill Boehme said:
What is the penalty for unfettered punning? 😀
Click to expand...

Depends:

"How much wood could a woodchuck chuck if a woodchuck could chuck wood?"

We finally have an answer: If it comes from Harbor Freight, an entire dam.

Oh, wait, . . . . that would be for a beaver, right?
 
Jonathon Smith said:
I was given a chuck (from Harbor Freight) but the thread is 3/4"x10 TPI. My spindle is 1"x8 TPI. Has anyone seen an adapter that can reduce the threads to the chuck size? I've seen plenty to go from the smaller to the larger size, but not the other way around. Or would I just be better off having one made or try to retap the chuck?
Click to expand...

I have a spindle adapter that has a 1 1/4 x 8 female thread and 3/4x16 male threads.
The 3/4x16 is a common spindle thread on the first mini lathes 3/4x10 may be harder to find.


Al
 
Check Grrizzly

Jonathon Smith said:
Thanks for the advice. I may just have to invest in a nova
Click to expand...


Nova is nice. I have four of them. If you want cheap though, check out Grizzly; they are nice too.
 
Bill Bulloch said:
Nova is nice. I have four of them. If you want cheap though, check out Grizzly; they are nice too.
Click to expand...

Grizzly chuck quality has gotten worse. The first one I bought was good. Years latter I added a second. The bolts holding the jaws on bottomed out and I could not tighten the jaws to the chuck. The scroll had some rough spots and it was difficult to open and close. They replaced it. The faces of the jaws on the second one did not make a flat surface. A couple of the jaws were slightly taller than the others. I took it to work and machine them flat.
That Harbor Freight might have a use if you want to play around with some small off center turning at lower speeds. The jaws look like they are reversible, but I agree, I wouldn't want to turn bowls with it.
 
You can use the chuck, but maybe not on a lathe.....

If the scroll function of the chuck still works OK, you certainly could use the chuck you have by making (or buying) a carving stand for it, and then use it on a workbench or in a banjo on the lathe to hold a piece for carving, texturing, or other embellishment. I use my Grizzly knock-off of the Vicmarc 100 chuck in my carving stand - it never leaves there.

I doubt you will find a standard adapter for 3/4"-10 to anything else; the 3/4"-16 tpi is the fine thread version of this threading size, and one used on older mini-lathes. As noted above, you could have a machinist work on new threading or making a custom adapter, but that might become really expensive, really fast (...the Harbor Freight chuck might not be worth the extra expense!). BTW - The Oneway Live Center has threading on it for the cone, and other accessories and is 3/4" x 10 tpi (coarse threading) - I have never seen or heard of spindle threading of 3/4" x 10 tpi on any lathes, old or new.

There are a few mini-lathes still around with 3/4"-16, but nearly all new ones have now moved to 1"-8tpi. Adapters for 3/4"-16 sizes can be found from Bestwood Tools (which, BTW, also sells an excellent carving stand adaptable for chucks), Grizzly, Penn State, perhaps Woodcraft, Craft Supplies [ http://www.woodturnerscatalog.com/p/5/-/25/112/-/5837/Turners-Select-Spindle-Adapter?term=spindle%20adapter ], and probably several others.

Even if the Harbor Freight chuck is not used on a lathe it can possibly still be used if you choose to carve, pierce, texture, or do other embellishment methods needing a secure way to hold the piece, but NOT under lathe power. I use my carving stand (Bestwood) all the time, and my Grizzly chuck serves OK in this capacity. Even a home made carving stand would work OK if you can incorporate the HF chuck you have, and maybe get some use out of it without discarding it completely.

I hope this helps!

Rob
 
Rob Wallace said:
If the scroll function of the chuck still works OK, you certainly could use the chuck you have by making (or buying) a carving stand for it, ......
Click to expand...

It does not have a scroll. The jaws operate independently. The chuck could still be used for something like a carving stand, but it has several things going against it -- the lack of a scroll, oddball thread size, and huge six inch diameter makes access for carving close to the chuck a problem. It would make one heck of a paperweight.
 
Bill Boehme said:
It does not have a scroll. The jaws operate independently.
Click to expand...

I didn't realize this.... ....it's not really a woodturning chuck to begin with....

Bill Boehme said:
The chuck could still be used for something like a carving stand, but it has several things going against it -- the lack of a scroll, oddball thread size, and huge six inch diameter makes access for carving close to the chuck a problem. It would make one heck of a paperweight.
Click to expand...

I agree Bill - it sounds like a paperweight!! Too bad these kinds of "tools" exist - a waste of steel.

Just trying to see some redeeming value in what is apparently a device of very low value.

Rob
 
Had to bite my tongue a bit but I went ahead and dropped the dime and ordered the nova. Can't wait to get it in so I can finally get around to turning a few things...
 
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