Ian
Notorious member
So I had this original idea to make a part for my mini-lathe so I could thread the muzzles of rifle barrels too long to fit between chuck and tailstock center and too large in diameter to pass into the spindle bore. After doing some research, if appears that my idea was a long way from original but still a solution to the problem: An inboard spider which acts like a cathead in a steady rest, but instead of having fingers riding the OD of the cathead, it has a bearing positioned precisely on the spindle/tailstock centerline, square to the bed, and has a spider hub pressed into its center. Four clamping screws instead of eight, and ball bearing support so no wear, chatter, fighting to get the steady fingers exactly on center, or tendency to fret out of the chuck. Very clever. Not so easy to make without a mill, but my lathe came with a steady rest suitable for mounting a flanged bearing with a couple of bolts, so I got a bearing and started engineering the cathead/ spider/steady rest thingy.
Pictures speak better....
Setting up on bullnose live center after aligning bearing in the housing square and plumb to lathe bed:
After drilling and tapping the steady rest base and bearing housing. Due to lack of material on top of the steady, I had to put the bolts through from opposite sides and d/t the bearing housing. I made the bolt holes oversized so that slight alignment corrections can be made to center the bearing bore.
Now to make the spider part. The bearing bore is only 1.25" and I plan to make the spider ring press on the OD of the bearing race so I can use most of the bearing hole diameter.
Pictures speak better....
Setting up on bullnose live center after aligning bearing in the housing square and plumb to lathe bed:
After drilling and tapping the steady rest base and bearing housing. Due to lack of material on top of the steady, I had to put the bolts through from opposite sides and d/t the bearing housing. I made the bolt holes oversized so that slight alignment corrections can be made to center the bearing bore.
Now to make the spider part. The bearing bore is only 1.25" and I plan to make the spider ring press on the OD of the bearing race so I can use most of the bearing hole diameter.