Lathe chuck adapters

[Mark Burnette]

OK now I'm confused. I thought most small wood lathe chucks has the body threaded 1"x8tpi and would accept various spindle adapters with that OD thread.
Then I get a reply from Grizzly that such adapters won't fit their chucks and they don't have anything to fit my Shop Smith with 5/8 plain spindle.
I was looking to buy their T10810 kit that fits 1"x8tpi spindles.

In the picture it "looks like" a normal thread-in adapter.

[Leo Van Der Loo]

Oneway makes an adapter for the Shop Smith, it has a plain 5/8” opening and fits their Oneway and Talon chuck, if/when you change to a better lathe, all you need is an adapter to fit the new lathe and you are all set.

[William C Rogers]

Nova also has an adapter for their chucks.

[Mark Burnette]

What about the dozens of similar chucks? Do I have to buy each to verify one way or the other whether those adapters will fit?

[Mark Burnette]

About those Nova chucks... Their website claims their chuck bodies have a proprietary thread and only THEIR adapters fit. I've NEVER seen this mentioned anywhere else and suspect it's a flat lie.

[Roger Chandler]

There was a generic adaptor sold by WoodCraft for the Nova chucks under the "Wood River" brand. Lots of folks had problems with them making the chuck not run true. I think you would be well served with a genuine Nova insert if you want to use Nova chucks.

[Brice Rogers]

This doesn't make a lot of sense. There are several adapters out there to convert from 5/8 straight to 1x8 TPI. If you screw in a 1x8 male into a 1x8 chuck, it will fit. There could be an issue of runout, but because these adapters don't add length, it reduces the amount of runout. I own two of those kits and they are fairly decent.
OK now I'm confused. I thought most small wood lathe chucks has the body threaded 1"x8tpi and would accept various spindle adapters with that OD thread.
Then I get a reply from Grizzly that such adapters won't fit their chucks and they don't have anything to fit my Shop Smith with 5/8 plain spindle.
I was looking to buy their T10810 kit that fits 1"x8tpi spindles.

In the picture it "looks like" a normal thread-in adapter.

[Bill Blasic]

Your getting confused by the words insert and adapter. In the case of Nova if the chuck has their proprietary thread you need an insert that will fit your lathe and as Roger stated their insert is to my knowledge the only ones that will make the chuck run true. Oneway has different inserts to fit different sizes also. These make the chuck a direct fit for your lathe. Grizzly does not make inserts for a whole bunch of threads so if you wanted to use the Grizzly 1" X 8 chuck on your Shopsmith you need a spindle adapter that is 5/8" on one end and 1" X 8 on the other. This adapter would then let you use any 1" X 8 chuck. Your best bet is to get a Nova or Oneway with the 5/8" insert and not have to use an adapter which puts the weight of the chuck further out the end of the spindle.

[Michael Mills]

I agree with Roger and Bill in that it is probably best to use an insert made by the oem.
IIRC with the Nova line the end of the insert and the interior of the body are milled to mate. That is why, as Roger pointed out, the insert by Woodcraft will thread in but will probably cause runout.
Some other chucks may use a taper instead of thread but the taper in the chuck and the taper of the insert must match in the same way. I also have a Hurricane chuck with a taper and it is no better or worse than my Novas which threads in. It is the final mating of the two surfaces, not the threads, that give proper alignment.

[Thomas Canfield]

PSI also has the 5/8" to 1" adapter. Using the 5/8 to 1" adapter and the 1" insert in chuck, does add length and a possibility of added vibration and run out.

[Mark Burnette]

Brice,
Ok as the only responder who has this Grizzly chuck, does the kind of insert that everyone shows online (about 1-1/4" long with 1"x8tpi threads at one end and a thicker collar about 3/8” long sticking out of the chuck backplate) fit? Or do I need TWO threaded adapters as has been suggested here?
I'm still confused exactly what the difference is between chucks that claim to fit 1"x8tpi inserts and those that fit 1"x8tpi spindles.

A picture of the back of the Grizzly chuck with no adapter installed would probably make it obvious to me, but I haven't found such a picture.

[Mark Burnette]

Here are 2 pictures. One is the Robert Sorby Patriot chuck with insert, the other a Grizzly with... Whatever they call it.
Looks identical to me. It's Grizzly saying nobody's insert will fit.

Sorby chuck back:

http://www.robert-sorby.co.uk/media/catalog/product/cache/1/thumbnail/600x/9df78eab33525d08d6e5fb8d27136e95/i/o/LRSPC_RSPC_Patriot_Chuck_Back.jpg

Grizzly chuck back:

https://images-na.ssl-images-amazon.com/images/I/51vwbuo7bdL.jpg

[David Delo]

Mark,
What you need is what's called a taper-lock adapter. No threads on the inside or outside. 5/8" inside hole for your Shopsmith and then you compress the taper (evenly) into the chuck body. Here's a couple pics of an adapter for a Stronghold chuck to fit on a SS. If it helps, the collar is 2.360"D, the taper next to the collar is 1.720"D tapered down to 1.663"D. The socket depth is a heavy 1". Not sure if this helps but hope you get it figured out.
349539349540349541

[Michael Mills]

Maybe this will help.
Some chucks come direct threaded and some come to accept an insert.
Here is a short clip of the Patriot showing the insert style about 2:45 and the direct threaded about 3:15

https://www.youtube.com/watch?v=O78LNPr5G40#t=177

Here is one retailer who shows five different inserts for the Patriot but they do not show a 5/8" so
Sorby may not make one to fit your lathe.
http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=chuck-fourjaw-sorpat

Here is listing of Nova chucks by another retailer. Note in the G3 ($99) they offer a direct threaded and an insert style.
http://www.tools-plus.com/nova-chucks.html Nova and other brands do off an insert for your 5/8" but these only fit the insert style chuck.

As far as I know the Grizzly is a good chuck but it appears to be direct threaded.
So instead of a chuck insert you would need a spindle adapter. This would convert your spindle from 5/8 to 1X and allow you to use any chuck or attachment with a 1X8 thread. This is the PSI spindle adapter for the Shopsmith.
https://www.pennstateind.com/store/L5818.html

[Mark Burnette]

The Grizzly catalog page for the T10810 chuck shows 2 optional adapters--one that could be described as an "insert" that's 3/4” x 16tpi ID INSIDE 1"x 8tpi OD, and a different one that fits the description of an "adapter" that's 1-1/4” x 8tpi ID INLINE with male thread 1"x 8tpi OD.

A 5/8" bore will easily fit inside a 1"x 8tpi OD plug and these are available from several sources.

[David Dockstader]

The PSI 5/8" x 1" x 8 adapter fits my two Shopsmiths perfectly and the PSI Barracuda chuck runs true on it. If Grizzly's chuck has a 1" x 8 thread, I can't see why it wouldn't run on this. If it doesn't, send it back and buy a Barracuda.

[Brice Rogers]

Yes, Mark, I saw that. For some reason most of the 5/8" shopsmith to 1" x 8 adapters are not made that way. If they were made more like an insert, as the one you reference, it would shorten the overall length and would also help with potential runout.

If you cannot find one of the shorter insert-like adapters, then plan B would make sense. Just buy one of the several conventional 5/8 to 1" x 8 adapters. They are fairly inexpensive and are intended for exactly your intended use.

[Mark Burnette]

Seems like I could also make an adapter bushing out of a short 1"-8 hex bolt, with a 5/8 bore through it. Add a grub screw through one of the flats to lock it on the spindle.
Turning a nice shoulder on the back of the head should reduce run-out.

I'm not a machinist but I work with some.

[Brice Rogers]

Mark, I machined my own adapter (5/8 x 16 M to 1 x8 FM) and there were some challenges to getting really low runout. I would NOT recommend starting with a bolt. The threads on a bolt are rolled rather than cut, the head is probably stamped/forged and nothing may or may not be perfectly concentric or perpendicular with the axis or the head of the bolt.

But, what the heck, give it a try and report back how it works. Also, perhaps your personal requirements for run-out are more relaxed than mine.

[Bill Blasic]

The easiest thing to tell you is this: Buy a Nova Chuck with insert INFS Insert F 5/8 Plain Bore RH or a Oneway Chuck with their 5/8 insert, either of these you stand the best chance of running the best and true and it makes them a direct fit to your machine.

[Clint Bach]

It's a no brainier.... Buy the psi Shopsmith adapter... The Shopsmith spindle doesn't run all that true no matter what you put on it. Nothing runs true on my Shopsmith. I like the Shopsmith anyway. You don't need no stinking new chuck.

C

[Clint Bach]

I reread the thread. You haven't purchased the grizzly chuck yet? Anyway, even though I haven't used my grizzly chuck on my Shopsmith, the chuck is more rigid and better machined than the Shopsmith. Don't expect great performance from your Shopsmith with any chuck. Almost any cheap lathe will probably out perform your Shopsmith as a wood lathe.

[Mark Burnette]

I bought a Nova G3 but on examination it looks weak and I don't like the open back. So I started looking again.
The Grizzly T10810 chuck kit looks to be a good value. IMHO they're limiting the appeal by threading the body so it only directly fits 1"-8 lathes. They should make it to accept the array of inserts already available that fit 1-1/2”-8 bodies.