On Sat, 08 Mar 2008 08:12:03 -0800, Mechanical Magic wrote:

I'm planning on either using Rulon bearing inserts from McMaster, or
just running the shaft against the aluminum.

Dunno about the adjustable bearing idea -- I've considered it, but if
I'm paying to have it assembled it may be worth a bit of time on a
milling machine to avoid having to find someone who's capable of doing
the bearing adjustment right. The whole bearing adjustment issue is
being driven by the sensor, so I'm going to look into that part
independently.

It's important that it look reasonably professional, but bare aluminum
may be good enough -- I may ask for another quote without the
anodizing.

--
Tim Wescott


Tim,
I believe there are several expensive areas in your design. First off,
expecting .001" tolerance means it must be milled or wire EDM.
Can you tell me why the tight tolerance? Does the mating part have the
same tolerance? What size holes in the mating part?

I knew I should have erased parts of that damn drawing and re-scanned it.

At this point I'm just trying to understand the cost drivers for the part
without the holes -- I'll either have the cost to have the holes put in
at a machine shop as a second operation, or I'll see if I can eliminate
the need for such accuracy altogether.

Next, I don't understand the bracket. Is this a purchased item, or is
it formed into the sheetmetal?
Or, is it to be fab'd separately and attached, if so how?

Fabbed separately, screwed on.

Material thickness?

The bearings I'm contemplating require moderately thick material -- it
works out to 14 gauge, but I'm damned if I can remember exactly what the
bearing spec is at the moment.

Anodize is not a big cost. Here, it's about $50 run charge, plus $1/
part. IIRC.
Dave

That's good to know, and a reasonable price.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html