For years I've been machining 1" diameter tube using steady rest and live center because the 3/4"ish spindle bore was too small to allow a "short stock projection" from the chuck jaws when machining springer piston shells so I bored out the spindle bore to about 1.09 diameter. This did wipe out the #3 morse taper, but since I never "machined between centers" anyway it really wasn't an issue to me...........
I didn't bore out the whole length of the spindle bore, it was bored only deep enough that I could machine the end of a 6" long piston shell blank without the need for a steady rest (like this) when machining an oring sealed piston cap while mounted to the piston...............
My chucks are all inexpensive Chinese 5" chucks. I have a 5" 3 jaw, a 5" 6 jaw, and 5" 4 independent jaw chuck.
I seldom use the 3 jaw because there is about .010 total runout with it. After making a new back plate for the 5" 6 jaw chuck the tir is about .003 which is acceptable. If I must machine a part with and need a perfectly repeatable part centering I use the independent 4 jaw chuck. The original 4" chuck that came with the lathely had a 7/8"ish "thru hole", however the 5" chuck had a 1 3/16"ish "thru hole".
The 4" chuck was mounted to a rotary table clamped to my small milling machine for milling equally spaced pockets when installing "piston buttons"..........
As a side note, the lathe chuck was originally mounted with 3 bolts, however it was a bit of a pain to fish the bolts between the head stock and spindle flange so I replaced the bolts with 8mm studs. The studs help hold the chuck in place till I can thread 8mm "flange nuts" on the protruding studs..............
@EdCanoles I appreciate that info bud!
I did the stud thing on my chucks too, you're right on those bolts. The nuts are still a fumblesome affair but less so than the bolts lol.
I have a bigger 4 jaw for mine but I'll have to pull it out and measure it. I seem to remember the hole not being that big in mine. But the Chinese stuff is all over the place, you know how that goes.
Was the spindle fairly easy to machine? I have a boring bar with a carbide insert that I think will work.
Yep, my carbide insert tool worked well. I did take care however to check the spindle OD to be sure I could bore it to the size needed without weakening the spindle under the bearings.
