Re: [CAD_CAM_EDM_DRO] Alum. Extrusion Manufacturers

It would be very nice to create or purchase that simple liner or bushing to
hold the bearing centered.

I looked at your link and it sure would be a handy method ! But,

All of the extrusions I have looked at, have a hole that is a hair too small
which makes it a challenge for Mr. "doithimself" to bore it out *properly*.
If you can't bore it perfectly straight, it will not work. It can be bored
straight with the right stuff, but, here too we are back at square one with
Mr. Hobbiest.

Even then, the ones that come close would just not leave much material behind
if they were machined open. So, those types just need a bigger hole, plain
and simple.

The other popular technique is the "kinda Square but not really" hole in the
center. This too makes it a very challenging problem. Remember that my goal
here was to finally find that Miracle linear slide technique for the hobby
guys. Having to make a custom kiddywumpas square liner takes my concept out
of the gameplan.

I am pretty sure the answer to this technique has to be be found in some
ready to go extrusion somewhere, one that there is enough made of it to keep
costs in check. One really nice thing is you would not need very much
material!

Ant extrusion that may work for this would need a round hole in the extrusion
and it does not necessarilly need to be smack dab in the middle. But it will
need to be big enough that similar methods like your tolerance ring could
fill the gap while allowing a properly sized Linearshaft to be applied.

As you may guess, We can find a way to use a 1/2" linear rail in some of
these extrusions but 1/2" does not let us get very far. It has to be at least
capable of using 3/4".

On each end of a typical unsupported 3/4" rail, I was amazed at how much more
rigid the rail became when using 2 thomson stands on each end. This in effect
creates a "bridge". Here again, the extra length possible by using extrusion
as rail stands on each end, will be stronger than the typical thomson style
stand.

I wouldn't doubt that the Thomson Style bearing blocks are made from an
extrusion, cut to length then cleaned up to spec. I need to find an
affordable, off the shelf extrusion that would work.

I don't think it would ever be feasable to get involved in a custom order
situation with an extrusion company for this. This only makes real good sense
for a company who makes them now and could easily modify their production
line to handle linear bearing insert capability.

Thats what I wish we could get........You read it here first !

Chris L

Jon Anderson wrote:

> Chris,
>
> There is a product that just might help, called a "Tolerance Ring".
> Picture a miniature version of aluminum siding, but with a very short
> pitch and height. Make it out of springy stainless and roll into a
> circle.
> Some of the applications include fixing bearings in low tolerance bores.
> http://www.usatolerancerings.com/ is the site, there just might be one
> that will fill a gap for you allowing you to do what you want.
> I think you have a clever idea, Tolerance Rings might help make it
> happen.
>
> Jon
>
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