[TowerTalk] [Bulk] Re: [Bulk] Re: Grinding hole in thick steel plate?

Roger (K8RI) on TT K8RI-on-TowerTalk at tm.net
Thu Sep 10 13:00:43 EDT 2015


They cut the deadbolt holes in our steel doors too small. I was able to 
cut a plug that just fit. The center hole worked for the larger hole as 
well although I'd use aluminum for the plug in solid steel.  Cut one a 
bit over size and trim on a lathe if possible.  I think the hole saw in 
3/4" steel will be slow going.  Lots of lube!

73

Roger (K8RI)

On 9/9/2015 12:19 PM, Grant Saviers wrote:
> Charlie,
>
> The proposed "move the hole 0.25"" application of a hole saw would 
> have it cutting only on one circular segment of the work, so the 
> center stub on the hole saw is undergoing a +/- something stress 
> reversal of bending every rotation.  In my segment sawing try the hub 
> fatigued and broke, which was a very logical result in retrospect.  I 
> was using a high quality US brand bi-metal saw about 3" in diameter.  
> For a smaller diameter saw the peak to peak stress cycle would be less 
> so the saw hub might not fail from fatigue.  For a full circle cut, 
> there should be no bending of the hub when using a drill press.
>
> Another way to manage the chip buildup in a 360 degree hole saw slot 
> is to drill 2 to 4 thru holes just inside the od of the saw kerf so 
> the chips can be pushed out to the backside of the work, so it needs 
> to be clear.  For sawing a segment that is not needed as the swarf 
> will mostly clear itself.
>
> Grant KZ1W 
<snip>

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