Re: [CAD_CAM_EDM_DRO] Alternative shafts for linear bearings

On Sun, 18 May 2003 21:43:59 -0500, you wrote:

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>JanRwl@... wrote:
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>(snip)
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>>I have found even that "expensive" case-hardened shafting will develop
>>"grooves" where the ball-lines roll, over years, so the use of softer than
>>RC-60 steel simply won't last useable over a few hundred inches of travel, at
>>least if your LOADING is within a practical realm!


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>I have just looked at an application where I had a FRELON lined bearing
>doing daily duty. Unknown how many cycles, but I'm here to tell you way
>more than I can count. Very impressive actually.

I've got some ceramic bearings working on a home-built piece of
equipment.

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>I wonder if using Frelon lined bearings would make those lesser hardened
>shafts last longer. They are slightly less money than Ball Units and
>claim to have much more load capability because of the surface contact
>patch available rather than just a little "line" of balls.

They probably do, but they need more force to make them move, which
might be a problem depending on your application. There is also this:
You might have a problem with alignment. I found that I had
difficulties with alignment (to the point of lockup) because of the
angles between two of the bearing carriers. Switching to linear ball
bearings (very light pressure needed to move) and self aligning
bearings (more pressure needed to move), "solved" the problem.

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>I've got some sections of the "coated" aluminum rail for Frelon bearing
>applications.... Even that rail is lots cheaper than the typical case
>hardened steel.
>I just didn't build anything with it yet.

That's what I'm using, or at least, the ceramic coated aluminum rail.
Be advised that it can bend...

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>Has Anyone used this aluminum "coated rail from Pacific on an
>application yet ??

Possibly, but the main comment I would have is to spend a little more
money and probably go with the steel rod, I would expect it to be more
rigid. I tried to save a bit of money, and ended up with four ceramic
coated aluminum bearings that I can use on another project, just not
this one. The rod seems to be OK, so far. I do not expect much
stress on it, but then again, there might be.

Harvey

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>I could easily see using Frelon on my next Plasma Project, maybe even a
>Router/Engraver the way this takeout looks and feels.....
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>Chris L
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