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audrey
12-13-2003, 03:16 PM
I have a Large set of rollers to machine for a mix company. The diameter is around 12 inches. They are 12 inches long. Whats the best way to hold them for turning in the lathe?The center roller section has been worn out and welded up. It has a set of bearing races pressed in the center.I need to re machine the roller and keep a very nice finish along with an even diameter for the entire length. I would like some opinions on the best way to do these. Thanx Guys Audrey

Rustybolt
12-13-2003, 03:31 PM
I think between centers would be best. Leave about .015 and have it ground to finish.My.02

Evan
12-13-2003, 03:35 PM
That really sounds like a job for grinding. Probably you will need to make an expanding mandrel to fit the races. Just a good fit at one end and expanding at the other. Center drill the head of the bolt that expands the madrel plug and hold it with a center at that end, chuck at the other end. For a job like this with smooth bearing races there is a product called 3M Traction Lube. This is an unusual oil that only allows rolling contact but strongly resists sliding contact. It works very well for work holding when the work can't take heavy pressure for some reason and it just wipes off.

Grinding would produce low torque loads on the setup. You might have trouble machining the welds normally.

ibewgypsie
12-13-2003, 03:42 PM
We built a belt sander arrangement for a similar project. After passing the grinder across to flatten we would polish it while spinning with sucessive finer belts.

Project was a dye house roller in stainless steel tubing. End shafts pressed in with 2 turned discs to center the shaft.

The six inch by 14 foot roller I think brought $30,000 to the company

Considering we had to build the frame to turn it on, heat it with rosebuds and cool with water to straighten I don't know what we made profit on it.

On the same frame we later made pinned (sharp pins to grab wet carpet, the roller had to be polished and all the pins exactly straight with no fish hooks.

David.

Thrud
12-13-2003, 09:07 PM
Build an expanding mandral or a shaft to mount it between ceters.