How to Mount Wood Chuck on Insert

[Steve H Graham]

I am still tooling up for turning. I don't have my tool rest set up yet, but the spur and chuck arrived.

Wondering if someone can confirm that I'm doing this right. I asked for a Shopsmith insert for the chuck, because I thought that would be a straight 5/8" shank which could be held in my lathe's 3-jaw. Instead I received an insert with a 5/8" bore and a set screw to hold a shank.

I machined a shank for the spur the other day, so I stuck it in the chuck, and I chucked the shank in my metal lathe. I realize this is a little strange, and I am not asking for input about using the big lathe chuck. I just want to know if the Supernova chuck is supposed to go on a 5/8" shank with a set screw.

One problem that jumps out at me is that if I use the brake on my lathe, this thing is going to spin right off the insert and kill me. Maybe I should put a screw into the side of the chuck and into the insert to prevent it from turning? I hate to cut into the threads, but it sounds better than being crushed by a flying chuck.

A shank held in by a set screw does not seem like a brilliant way to do this, since it's not really symmetrical. I get around 15 thousandths of runout that way, which is a lot even for woodworking. If I chuck the hex-shaped body of the insert and bypass the shank, I get more like 4 thousandths. The insert body will get marred up over time, but I guess they're cheap.

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[Mark Greenbaum]

My Nova G3 chuck with insert for Shopsmith has a setscrew with nylon face to lock against the threads and keep it from spinning off.

[Leo Van Der Loo]

That is one of the reasons I have bought the Oneway chucks, as it has the adaptor fitted with a taper into the chuck body and held with 3 screws, so I’m able to turn in both directions without the possibility of the chuck unscrewing.

I did a heat shrink of the shaft into the adaptor, and have turned very large pieces that way and for better than 20 years by now, no setscrew is going to hold a large blanks weight from spinning the chuck body right out of your Nova chuck if you slow the lathe down fast.

[Matt Radtke]

Wondering if someone can confirm that I'm doing this right. I asked for a Shopsmith insert for the chuck, because I thought that would be a straight 5/8" shank which could be held in my lathe's 3-jaw. Instead I received an insert with a 5/8" bore and a set screw to hold a shank.

I machined a shank for the spur the other day, so I stuck it in the chuck, and I chucked the shank in my metal lathe. I realize this is a little strange, and I am not asking for input about using the big lathe chuck. I just want to know if the Supernova chuck is supposed to go on a 5/8" shank with a set screw.


Um, what three-jaw chuck? You don't mean the drill chuck, do you?!

I also have a Shopsmith. Yes, it is supposed to be a 5/8" plain bore. You received the correct insert.

All Shopsmiths, from the original 10e to the modern Mark VII (or is it 7?) have a 5/8" shaft. Remove the "three jaw chuck" and put the Supernova on the 5/8" spindle. Line up the set screw with the flat on the shaft to lock it down.

[Michael Mills]

because I thought that would be a straight 5/8" shank which could be held in my lathe's 3-jaw.

It is made to go directly onto the spindle, not into another chuck.

One problem that jumps out at me is that if I use the brake on my lathe, this thing is going to spin right off the insert and kill me. Maybe I should put a screw into the side of the chuck and into the insert to prevent it from turning?

Looking at your picture you see a small hole in the body of the chuck. This is to insert an allen wrench into to tighten a set screw in the chuck body down onto the insert locking it in place. Make sure the insert is seated fully before tightening the screw as the transfer of power is from the end of the insert to the interior of the chuck body.

The set screw in the chuck body locks it to the insert, then a set screw on the insert locks it to the spindle. I have never had a chuck come loose from the insert in 6-7 years and with seven different Nova chucks.

I have one Hurricane chuck with an insert that works like the Oneway Leo described. If this is better at keeping the insert in the chuck then, by default, you also need three mechanical screws to keep the insert mounted to the spindle. Chucks that I am familiar with only have one set screw to lock to the spindle.

Your setup with the three jaws chuck will probably cause more run out because you have the fit of the chuck to the spindle, the "shaft" into the 3 jaw chuck, then the shaft into the insert, then the insert into the chuck body. Going direct eliminates three potential runout areas.

[Steve H Graham]

I knew someone would think I had a Shopsmith. It's a regular engine lathe, but thanks. The lathe has an MT7 taper in the spindle with a 3-jaw chuck that weighs as much as a small child, so I am working on a solution that avoids removing the metal chuck.

I know about the hole for the set screw, but I didn't understand why they sent me a tiny red circle of soft material. Going over the instructions again, I see that this goes between the set screw and the threads, so I think I get it now. I assume it won't hold well enough to let me turn wood with the lathe reversed. Is that correct?

I am thinking the easiest thing would be to chuck the hex-shaped body of the insert instead of using a 5/8" shaft. If that fails I'll just make my own insert.

I appreciate the replies. I will report if I get it working.

[Michael Mills]

I assume it won't hold well enough to let me turn wood with the lathe reversed. Is that correct?

I'm not sure why you would turn in reverse. You may sand in reverse as most do but there should not be enough pressure for the insert to back out, especially with the set screw. I have never had one come loose.

[Matt Radtke]

Oops. Sorry, I found your old post. This suddenly makes more sense...

It should be safe to reverse the SuperNova. I have a G3 with a a Shopsmith insert. IIRC, there are two set screws. One to secure the chuck to the spindle, one to secure the insert to the chuck. The chuck to insert set screw has allowed me to reverse without issue.

[Leo Van Der Loo]

because I thought that would be a straight 5/8" shank which could be held in my lathe's 3-jaw.

It is made to go directly onto the spindle, not into another chuck.

/snip/snip/

I have one Hurricane chuck with an insert that works like the Oneway Leo described. If this is better at keeping the insert in the chuck then, by default, you also need three mechanical screws to keep the insert mounted to the spindle. Chucks that I am familiar with only have one set screw to lock to the spindle.

Your setup with the three jaws chuck will probably cause more run out because you have the fit of the chuck to the spindle, the "shaft" into the 3 jaw chuck, then the shaft into the insert, then the insert into the chuck body. Going direct eliminates three potential runout areas.

My Oneway chucks have 2 threaded setscrew holes to hold the chuck to the spindle, that if used on a Oneway lathe, they would go into a groove in the spindle, and not with a soft plastic tip on the thread of the spindle.

On my setup, the shaft goes into the taperlock adaptor of the chuck and with a taper into my lathe spindle, using tapers is as close as one can get to zero runout as anything, something you can not achieve with treaded parts fitted together.

Since my lathe spindle has a #5 MT, I had to step down to get the Oneway Stronghold chucks to be able to use those on my lathe, and when turning large pieces I do turn in either direction as maybe working the best with the particular piece.

Shown here are the pieces I do turn on my large metal lathe with the outboard setup I build and the accessories I made for it, and no I would not trust a setscrew to keep my chuck from un-screwing with a large chunk of wood held in it and stopping fast or turning in reverse direction.

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