holding big stock on lathe

[John Stevenson]

Probably too late now but if it had been me I'd have welded some wheels up from a boss, a plate and a section of thick walled tube.

Quick cheap and good enough for a mower.

[Carld]

mtraven, do you have a three jaw or four jaw? If three jaw there should be two sets of jaws, one set with steps on the outside of center and one set with steps on the inside. One set will hold the ID of a tube and the other set will hold the OD of a tube. The jaws in a four jaw are reversible. That is, they can be removed and turned around so the steps are on the outside or the inside.

A 5" diameter chuck should be able to hold a 6" ID easily.

[tmc_31]

I think I would go ahead and build or acquire a faceplate. Then mount the cylinder between centers with a drive dog (or two) through the faceplate and into the rear face of the work. In this case, the drive dog is simply a bolt that extends through the faceplate and into an appropriately sized hole about 3/8" deep bored into the rear face of the stock.

I did this when I had to reduce the diameter a 6" aluminum cylinder by about .250".

Tim

[mtraven]

Lot of work for going and getting something off the shelf like this:
http://www.harborfreight.com/7-inch-...eel-98951.html

those particular wheels are too large, but I have searched all over & tried a few wheels like these, none have been satisfactory.

you can also use a live centre to press/clamp the disks against the jaws of your chuck to true them up, as long as you are not taking big cuts it works fine

the more you expand the jaws out, the more leverage less slippage you will see

I like this idea, I think I may try it...

If you're going to make bearing cups... you can't use a central mandrel I mean, that would work to true up the outside, but then what? You still can't chuck it. Seems the best way is that multi-bolt clearance hole idea.

I am torn on mandrel vs bolting to faceplate...my mandrel plan was to thread into one face with something smaller than the bearing, but sizable....then bore out the first bearing cup which is almost 2" in diameter...at that point I should be able to chuck it from the inside to hold it to do the other...having picked the stock up today & noting its mass, I am now considering bolting it on...I am concerned about getting it bolted up...wrestling my chuck on and off is difficult due to lack of clearance for the bolts.

So, the need is to turn bearing cups concentric with the outer? And this is an exercise in turning as well as a practical job?

yes & yes

Probably too late now but if it had been me I'd have welded some wheels up from a boss, a plate and a section of thick walled tube.
Quick cheap and good enough for a mower.

I wanted to take this approach, my father(owner of tractor) wanted solid steel, and quite frankly I wasn't going to argue with getting some big hunks of steel to play with

mtraven, do you have a three jaw or four jaw? If three jaw there should be two sets of jaws, one set with steps on the outside of center and one set with steps on the inside. One set will hold the ID of a tube and the other set will hold the OD of a tube. The jaws in a four jaw are reversible. That is, they can be removed and turned around so the steps are on the outside or the inside.
A 5" diameter chuck should be able to hold a 6" ID easily.

the 5" is a 3 jaw, I have a 4" 4jaw as well...I really thought it would be no problem too, but when I tried, I got real close & the jaws dropped out.


thanks again for all the help, its quite nice to hear from those with experience seeing how I have little.