Last attempt at plain bearing

[uute]

Still wondering if I could run an 1 1/2" or 1 5/8" shaft in plain bearings at 2100 max.

Already convinced me to go with harder shaft, at least 4140 at 35C

planned on split bearing w/ shimmed cap & oil cups - this will be a mill spindle running mostly 200 - 800 rpm, but top speed is 2100.

Regular bearing bronze was mentioned, are there other/better bearing materials I could use?

I think flanged sleeve bearings would save space, take good radial load w/ closer support (no seals). Of course none of that matters if they sieze!

Gotta commit soon.

TIA for your help

[Leigh]

Search for "bronze bearings" on the McMaster-Carr site http://www.mcmaster.com

They have a good discussion of maximum load and speed, and rate the different bearings according to these criteria.

------------------
Leigh W3NLB

[torker]

uute, I'm curious as to why you can't run some type of roller bearing? You mentioned space contraints?
I also think this was mentioned before..base line (as in cheap) model airplane engines have and still do run their crankshafts in the aluminum housings or a plain sleeve bearing. Some of these run for years at over 10,000 rpm (K+B is a good example).
Auto engines use plain bearings....some don't even use bearings for the cams, they just run in the alu head (older Toyotas etc). Granted, they run pressurised oil and "fairly" loose tolerances but are subject to some pretty harsh loads and high sustained rpm.
Automatic transmissions also use bushings for the rear bearing.
Just some thoughts..
Russ

[uute]

I'm just about commited now to the taper roller bearings, barring a short fill on the casting when I pour it.

Sleeve bearing would have been 2" dia or less, roller is 2 5/8", requiring a larger housing and at least 3/8 more overhang (mill head runs horiz. on a vert. collum - Lincoln type, Gingery style). Other big concern is it will be much tougher job to bore the bearing seats in the housing. Plus seals.

Still think there may be something out there that would be adiquate. Seen some Vespel ?? bearins at McMaster, but they were a bit pricey!

Motors run at 1800, but less load, and as you say engines go 4-6k.

If I get through this, next nightmare will be spindle warp!

[This message has been edited by uute (edited 03-09-2006).]