Linear Bearing mat’l?

[mxtras]

Come on - anybody else?

Scott

[DareBee]

I also have had experience (bad) of trying to use CR TGP shaft with linear BALL bearings. It was a fairly heavy load (not exceeding bearing capacity though) and I couldn't even get I stroke out of it.
The bearing balls just dug into the shaft and it was scrap (had a row of large grooves down the length).
The system probably would have worked for awhile with Oilite's or Frelon bearings due to there improved weight distribution.

[Halfnutz]

What is "Cr TGP" ?

[mxtras]

I am pretty sure it stands for Cold Rolled, Tempered, Ground and Polished.

Nice material - but it has been my dreadful, expensive experience that it is not compatible with ball bushings/bearings unless the loads and speeds are rediculously slow - even then I would suggest a different method or a hardened and chromed shaft.

Scott

[Halfnutz]

Wow, I had no idea. I just figured all the shiny stuff was , well, shiny. And shiny is good right? I geusse not, necessarily. But seriously, I did know Thompson's real specific about what to use, and suggests not deviating. I wonder what the cheap, well, cheaper anyway, knock off rails are. So the main difference is polished vs chromed and hardened. Thats what I love about this site. So much knoweledge.

[mxtras]

Turned, Ground and Polished - not Tempered. - sorry guys! I gave the material TOO much credit!

The rails made by Thompson are case hardened, ground and chromed - yes. Carbide tooling can drill them, contrary to popular opinion. Been there.

The typical "TGP" material may be shiny, but it's not hardened. It's either 1018 or 1048 steel in a normalized condition which is about 18-20C hardness. In comparison, Thompson's shafts are 60C surface hardness. The case hardened shafts from McMaster can be as high as 65C(Rockwell C scale)...not too bad in my book.

I don't know what diameter you guys use, but you may investigate these links if you haven't seen them before -

http://www.smi4motion.com/shafting.htm
http://www.metalsdepot.com/products/...dround&LimAcc=

Scott

[DareBee]

Good research Mxtras was about to give a correction untill I read on. ;-)
IMO TGP is very reasonably priced for precision shafting - as long as soft suits your application.

damn - Paul you getting anywhere with adding a spell checker here

[mxtras]

I am not knocking the TGP material - not at all. It has it's place. Just passing along info, opinion and relavant experience if any. I agree that it is reasonably priced!

I vote for the spell checker, too!! or better yet - how about speech to text instead?

Scott