Spider setup for china lathe

Hello
I am looking to drill and tap the rear of the spindle to setup for though the spindle chambering of barrels. Grizzly currently sells their gunsmith lathe setup like this. I have a 13X40 Birmingham lathe the spindle appears to be very similar to that of the grizzly lathe. Should I be aware of anything that would prevent me from drilling and tapping the spindle like this?
Bottom right of the page link below.

http://www.grizzly.com/catalog/2008/Main/562

muley said:

Hello
I am looking to drill and tap the rear of the spindle to setup for though the spindle chambering of barrels. Grizzly currently sells their gunsmith lathe setup like this. I have a 13X40 Birmingham lathe the spindle appears to be very similar to that of the grizzly lathe. Should I be aware of anything that would prevent me from drilling and tapping the spindle like this?
Bottom right of the page link below.

http://www.grizzly.com/catalog/2008/Main/562

Click to expand...

Uh-h-h, if I were to do it (spider) I would certainly make it as a slip on piece and leave the drilling and tapping of the spindle alone.
If there is enough room to drill and tap, then there is plenty of room to attach a separate spider. You're going to indicate in the barrel anyway so being separate is not going to be any problem as far as I can tell. I would turn a piece of 6061 with 4 set screws at each end to make the spider...........pg

Well, you might be able to thread it in.

The inside of my 12x36 lathe spindle is threaded which is how I'd attach a spider. In fact, a lot of chinese lathes are threaded. Are you sure that the grizzly isn't just an attachment that threads into the back of the spindle?

This the one I did for my lathe, attaches with three set screws.

Rolland said:

This the one I did for my lathe, attaches with three set screws.

Click to expand...

Looks good. Just what I would do......if I could get a barrel through my skimpy little 10K.......pg

drill it get er done!

Ive drilled and tapped 3 spindles no problem. I use fine thread cap head scres. I like having 4 screws instead of three, IMHO it makes it easier to center up

Its easy to drill and tap them, but as already said, its better (for resale of the machine anyway) to make a sleeve to fit over that and drill and tap that. If its the 1340 I am thinking of, its not threaded on the inside. Make it a tight fit with set screws. The only problem is that the spider then may be too far from the chuck end, making the barrel not reach it.
The spindles are balanced too, I doubt it will make much difference on the back end there, but anything is possible. Probably would make a difference only on a larger machine with a thicker spindle. And 2000 RPM is not all that fast if its not perfectly balanced.
I have seen them strip out after a while though when tapped right in the spindle, its not all that thick in the back there, so you may only have 2-3 threads in it so that may or may not become an issue.