Re: [CAD_CAM_EDM_DRO] scraping beds for long tables

Hello Marcus and Jon,
Thank you for the answers.
I will keep it as I made it before. Get as much furface area as possible
as straight as possible.
The idea with the surport on 3 pionts I like and possibly I will apply it
in the future.

> This may not have been intentionally done that way. My aged Bridgeport
> is exactly like that. There is a small bit of sag due to the overhanging
> weight of the table. The center of the table wears more than the ends.
>

Jon here must be something wrong. In all machines I worked on,
It was always that the tips of the bed were worn and some spots
in the table. Only in one ocasion (taiwanese bench mill) the bed was totally
twisted because the casting was machined fresh. (rocked 0,015")

>
> Maybe what this is all about is compensating for sag, as the table is
> scraped upside down. In the Edward F. Connelley book "Machine Tool
> Reconditioning", he shows how you support the table upside down
> on 3 small jack posts, so that the table bows in the same direction
> as when it is hanging over the saddle. Then, you scrape it flat, and it
> should remain just about as flat when put back onto the machine.
>
> Jon

Thank You both
Sven Peter


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