[TowerTalk] Grinding hole in thick steel plate?

[Rich Hallman - N7TR]

I've decided to have another machine shop build me a new plate.  Trying to fix this one was going to be an issue on several fronts.   

Thanks again for all the info and ideas...   Rich

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Rich Hallman - N7TR
Sent: Monday, September 07, 2015 3:38 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Grinding hole in thick steel plate?

Thanks for all the ideas so far.   If I need to I may take the plate to a fabricator and see if they can mill these to the correct locations, but I would rather do this at my house for now.    For those who asked...The plate is 3/4 inch thick steel plate.   The holes are 1 1/4 in diameter for the 1 1/8 inch all-thread anchor bolts.

I have purchased and should be here tomorrow...the below Die Grinder as well as several 1 1/2 inch diameter 1 inch long carbide burr bits.  These are double cut.  Would a single cut be better for this need?
http://www.amazon.com/gp/product/B00FDLB9OC?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s01
http://www.amazon.com/gp/product/B00ECMMOW4?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00

I wonder if I need to get a 3/4 inch or 1 inch diameter carbide burr bit?

Thanks....
Rich

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Rich Hallman - N7TR
Sent: Monday, September 07, 2015 11:33 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Grinding hole in thick steel plate?

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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