Rich,
FYI...I used a bi-metal circular hole saw that uses a 1/4"
pilot hole to cut some holes that were over an inch in
diam through some 5/8" hot-rolled steel. I also cut some
holes that were 7/8" Dia.
I used plenty of oil and kept the drill press at a reasonably
low speed. I stopped and cleaned out the chips once in
a while with a shop vac. I drilled from the other size of
the steel plate when I was about 1/2 way through with the
hole saw.
No problems at all and the hole saw is still sharp after
4 of the larger holes were cut....same for the smaller hole
saw.
NO EXCUSE for your machine shop to get it wrong. They
need to buy you a new plate and start over.
73,
Charlie, N0TT
On Mon, 7 Sep 2015 18:33:22 +0000 Rich Hallman - N7TR <rich@n7tr.com>
writes:
> I had a ¾ inch steel plate made up that will be used to retrofit a
> HDX589 base foundation to a HDX572 base. After giving both bases
> to the machine shop and asking them to make sure all of the holes
> are exactly the same location as the base, some of the holes are 1/8
> to ¼ inch off. I had a major issue with this machine shop so I
> will not take it back for now.
>
> I wanted to see what others have done to grind out holes in thick
> steel plate.
>
> I was looking at the Carbide Burr bits and getting a ¾ inch burr bit
> to see if that would grid enough from the hole so it would then fit
> the bases.
>
> The holes are pretty close....so I thought grinding them out would
> be the best solution for now.
>
> Any thoughts?
>
> Thanks....Rich
>
> Rich N7TR
> ex KI3V, N3AMK, WB3JOV
> www.n7tr.com<http://www.n7tr.com>
> http://www.qrz.com/db/N7TR
> Telnet: dxc.n7tr.com N7TR DXCluster
>
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