Grooves in brass rolling mill bearings - do I remove?

[emsterv]

Hi all, in the middle of taking my rolling mill apart to clean and hopefully fix it. I see that the brass bearings have grooves worn into them. Should I Polish them out? Keep them there? Does it really matter either way ? (ps using Hans Meevis' tutorial. VERY useful http://hansmeevis.blogspot.ca/2015/0...-mill.html?m=1



First time trying to upload via mobile so I hope this works!!

Sent from my A0001 using Tapatalk

[china]

I would replace them if you polish them out the shaft will most likely be loose they look to be fairly deep scratches, seems like you should use a little more lubrication when using the mill

[ps_bond]

There's a fair chance those are bronze rather than brass; some scoring of soft bearing shells is normal in use, but I'd agree with more lubrication on them (any of the high pressure greases should do OK in that application, but check the manual). You *can* scrape & reshim bearing shells (cf Myford ML7 headstock bearings) but for that application I probably wouldn't. It's a long process involving getting plastered with engineer's blue.

Check there's no debris or burrs on the shafts that could contribute to the scoring before reassembly.

[emsterv]

Ah thanks all. I bought it used and I don't think its had any real TLC for quite some time. I pulled everything apart, cleaned in turpentine and will be putting it back together soon with plenty of grease. I need a new woodruff key made for one of the rollers first. The rollers currently have no debris on the resting ends, but not sure if that was the case before cleaning.

It has no makers marks anywhere but looks just like the Cavallin in Han's instructions. I was told it was a Durston when I bought it and naively just believed the person selling it. I was also told it was over 20 years old (so based on the veracity of the seller its probably closer to 30). Lots of wear and tear.

Taking apart the mill was at the peak of my engineering/mechanical skill, Peter, so I'll think I'll leave the bearings as is!

Ever since buying the mill I've been having issues with the mill not putting enough pressure on the metal to reduce it (annealed copper, no less) so I hoped I could spot a problem while taking it apart or that once its been serviced it will get it's act together! When I bought it, the person I bought it from rolled out an ingot to about 4 mm to prove it worked - which it does, until you actually get into the 1-2 mm range which is where I would use it the most.

[josef1]

It maybe worth getting a digital caliper (they can be picked up really cheaply now) on the bearing and checking the clearance by measuring the internal diameter at a couple of points and the diameter of the roller on the bearing surface. this shouldnt be to big maybe the bearing is worn so much that the roller thread is bottoming before the rollers are closed Im just guessing but it could be a possibility do the rollers close all the way up when its fully wound down ?

[ps_bond]

That's a possibility given the age. I'd be back to checking bearing contact with engineer's blue though... Usually I end up wearing it too.