Roller material to run on aluminium

[Ronthewood]

Hi,


My job is not in engineering, I'm actually a furniture maker and I'm stuck, and I hope you knowledgeable folk can help me out.

All the wood I use comes from within a 5 mile radius, I buy the trunks from local landowners/forestry, sawmill it, dry it and then make domestic furniture.

My sawmill is a "Swivel Saw". A head unit with engine and circular saw blade runs fore/aft on a pair of aluminium beams (250mm deep) with a rise/fall mechanism.

The head unit frame has 4 slotted rollers at its extremities and these rollers run on the aluminium beams. It's basic but has worked well for 20 years.

There's quite a load on the rollers and a couple need replacing. Needless to say the spares are no longer available and I can't find any substitutes.

My plan now is to buy some plain rollers and machine slots in these rollers to match up with the original design. I had one made a few years ago at a local machine shop, he only had nylon in stock, it was ok but this is already showing signs of wear.

So, my question to all you knowledgeable materials engineers is: What material would be best for the outer of the roller so that it will last ok but doesn't wear out the aluminium beam. I've seen these rollers at about the right size (60mm x 20mm) in a range of different materials (urethane, nylon, Vulkollan, phenol and so on...I'm a wood man!) but I'm not sure which has the right properties for my application.

Any advice very much appreciated.

Thanks

Ron

 

[btrueblood]

Polyurethane would work pretty well. Cheap too. You could likely make (or have made) a mold and cast the tires directly onto a roller bearing yourself. Or just go buy roller skate wheels and adapt them to your machine.

 

[Ronthewood]

Hi and thanks,

Ok, I'll go with polyurethane, but I think I'll leave the casting method up to you experts for the time being, I've seen a few rollers online which are about the right size. Does it machine on a lathe OK?

Skate wheel, good idea, presumably these are also made from polyurethane? One of my concerns is that I don't wear the aluminium beam down by using the wrong material.

Thanks for your help

Cheers

Ron

 

[btrueblood]

Most skate wheels are polyurethane, yes.

PU can be machined, with sharp tooling. Harder durometers are easier. Sometimes getting a finish dimension is easier by sanding/grinding or other abrasive methods.

 

[Teardrop]

Did you look at Delrin?