Re: [CAD_CAM_EDM_DRO] Re: Ball screw cost and sources - Moglice - Phillycast - concrete

Hi Chris;

Thanks for the response.

Chris L wrote:

>David A. Frantz wrote:
>
>(snip)
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>
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>>I was considering casting the rails in place, but I can't possibly
>>imagine getting the parallel and level. Anyone with experience here?
>>
>>
>>
>Don't cast them in place "Raw"...... Assemble the gantry portion,
>bearings and all, THEN carefully cast them in place. With the right
>temporary fixtures, you should be able to "slide" the axis back and
>forth to help align things.
>
>However, I think I would build a simple "cage" first, mount the rails on
>the "Cage", THEN pour it full of concrete. All you really want is the
>"Mass" it provides anyhow. I'm not sure how much concrete moves around
>when drying. It must move some as water evaporates.
>

Yes the mass is important but even more so I was looking at this as a
way to fabricate a resonably large machine with little welding or
fabricating. Lets just say that my shop has tools but many of them
are for woodworking. So fabricating forms and such should not be a
problem.

I was also worried about concrete asorbing what ever fluids are to be
found. I found a site on the web where this company makes machine
frames out of epoxy and granite. Sounds like a very approachable
process for the do it yourselfer. The trick of course is finding the
right Epoxy components and mixing them.

>
>Last ditch effort... place fixtures in the concrete that the rails
>simply bolt to. Then align the rails in typical fashion after concrete
>is hard.
>
>If it truly is a first effort though, forget the concrete.... Just get
>something running. The first attempt usually leaves much to be
>re-engineered on "the next one".
>

I agree that I want to get something running, but unless i find some
used mill somewhere cheap; the thought was that molding my own might be
the way to go. At this moment I'm trying to score some extruded
aluminum framing cheap that might be a good alternative.

>
>Chris L
>
>
>

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