[simpits-tech] High speed steel drill

[Marv De Beque]

Look at the chips you make.  If they are long clean spirals, then it should
be fine.  If they are blue and fracture easy, then it's too fast and hot.

You are making too much of this in my opinion.
-- 


> From: mysticz28@swbell.net
> Reply-To: simpits-tech@simpits.org
> Date: Thu, 19 Sep 2002 01:44:12 -0500
> To: simpits-tech@simpits.org
> Subject: Re: [simpits-tech] High speed steel drill
> 
> kelly Mclaren wrote:
>> 
>> Thanks Steve, I'm drilling steel tubing, <finding the
>> speed of the edge of the bit in feet per minute at a given RPM >Now how do
>> I calculate that?
> 
> It's easiest with a SFM chart, but it's just:
> 
> (Pi * bit dia. * RPM)/12
> 
> if I remember right. Somewhere I have a chart that makes it easy. First
> find the bit diameter row and material column. Where the two intersect
> is the spindle speed. I had a spreadsheet that I modified with the
> specific spindle speeds I have available on the big drill press (wish it
> had a quick change gearbox, but it's only a dual belt/3 pulley system)
> so it was a piece of cake. I also printed it in color so that if the
> material is drilled dry the RPM is black, cutting fluid is green, and
> wax is red. I had pages for HSS, cobalt, bimetal (hole saws, mainly),
> and carbide.
> 
> Unfortunately I can't find the bloody charts ANYWHERE.
> AAAAAAAAHHHHHHH!!!!
> -- 
> Steve
> mysticz28@swbell.net
> Jesus saves, Budda enlightens, Cthulhu thinks you'll make a nice
> sandwich.
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