Re: [CAD_CAM_EDM_DRO] Bar stock

Hi John,

Merry Christmas...

Centreless ground means that it is ground without being supported at each
end by fixed centres. The way they do it is by running the bar between three
grinding wheels arranged in a triangle, so, as it goes through, it is ground
pretty round. Having said this though, it can't be relied on to actually be
round and this is why they specify it as centreless ground. The most common
fault with it is that the steel develops 'lobes' and what should be round is
actually more of a slight triangular shape with very rounded corners. As the
three grinding wheels are fixed, you will always get a constant diameter but
this may not always be exactly concentric with the centreline of the bar -
like the piston in a Wankel engine.

Ian
--
Ian W. Wright
Sheffield UK
www.iw63.freeserve.co.uk

----- Original Message -----
From: "johnhe" <johnhe@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: 26 December 2001 16:58
Subject: [CAD_CAM_EDM_DRO] Bar stock


> Hello,
>
> I was looking at some solid round steel bar earlier and it comes
ground
> centreless. I get the first bit but what does it mean by centreless?
>
> Thanks,
>
> John H.
>
>
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