Jet 1221VS spindle threadform?

[John Snow]

I have a Jet 1221VS midi-lathe, and I just bought a Supernova2 chuck for it, which needs a spindle thread insert/adaptor. Most of the import lathes with use spindles with 1"x8TPI UNC threads, but apparently the Jet has a "different" 1"x8TPI threadform (per Teknatool). I have been using an insert that fits 1"x8TPI UNC for years with no apparent problems with my Nova G3 chuck, and that insert seems to fit the Supernova2 chuck just fine. I can't find the Jet-specific insert anywhere (even the Teknatool site seems to not allow its purchase).

Does anyone know what spindle threadform Jet uses on the spindle? And if it would be a problem to just use the 1"x8TPI UNC insert?

 

[Bill Blasic]

Any of my chucks from various manufacturers with a 1" X 8 thread fit every one of my different manufacturers lathes including the 1221VS with a 1" X 8 spindle. All you need is a 1" X 8 nova adapter. I think the Supernova II is slightly overkill for the Jet 1221. I use G3s or the smaller chucks from various manufactures on my midis. That's not to say you can't use a Supernova that's just me.

 

[John Snow]

Any of my chucks from various manufacturers with a 1" X 8 thread fit every one of my different manufacturers lathes including the 1221VS with a 1" X 8 spindle. All you need is a 1" X 8 nova adapter. I think the Supernova II is slightly overkill for the Jet 1221. I use G3s or the smaller chucks from various manufactures on my midis. That's not to say you can't use a Supernova that's just me.

Bought the Supernova for two reasons: 1) the bundle came with both the 4" and 5" jaw sets, which I was looking for, and b) I bought it with an eye toward a future larger-capacity lathe.

 

[Bill Blasic]

That is a good reason to by a chuck that is not direct threaded. I have G3s that I use on the bigger 1 1/4" X 8 lathes.

 

[john lucas]

All threads spindles and inserts should fit. However there are tolerances. I had a student who had a Nova lathe and a Nova chuck that would not go together. I ran a tap through the chuck. Still didn't fit. Filed the spindle with a triangle file for just a few passes and the fit. When I talked to my friend Vic at Bestwoodtools about this he showed me some master gauges that are used to check his spindle adaptors and he told me if you get a spindle that is on the gat side of the tolerance and an insert that is on the skinny side it could easily not fit.

 

[Joe Kaufman]

I have a Jet 1220. The issue may be a lack of area to secure the chuck to the spindle with a locking screw w/o distorting the threads. If you want to operate in reverse and change chucks frequently, keeping track of the little leather or composit puck could be a big problem. I remember reading questions as how to restore spindle threads that were distorted by the set screw.

 

[John Snow]

I have a Jet 1220. The issue may be a lack of area to secure the chuck to the spindle with a locking screw w/o distorting the threads. If you want to operate in reverse and change chucks frequently, keeping track of the little leather or composit puck could be a big problem. I remember reading questions as how to restore spindle threads that were distorted by the set screw.

I wondered about that. What I usually do with grub screws that bear on surfaces that shouldn't be deformed is to put a small washer made from a bit of copper wire. It's nice and soft copper, and holds well.