[Public-List] Public-List Digest, Vol 3148, Issue 2

[Glenn Brooks via Public-List]

Gordon,

Ideal would be to use tungsten or carbide tipped bits.  Depending on what grade stainless, you have, you might get by with a high quality high speed steel (HSS) bit, if you drill slowly, say 250 to 400 RPM or thereabouts.  these will dull quickly, but might work for enlarging existing 1/4" holes.    Other wise look for a tungsten or carbide bit.

It's Critical that you clamp the chain plate to a drill press table to control the work as you drill through it, particularly the last little bit.  preferably use a drill press so you can turn down the speed (RPM) of the bit.  A hand drill just won't do it.  They turn to fast.  If bit speed is to fast, for example, over 800 -900 RPM, the bit will likely heat   up quickly and loose its hardness. If the tip turns bright red then  it won't cut and will work harden the Stainless by grinding/rubbing against the hole.  Work hardened stainless can almost never be drilled thereafter. So be careful not to work harden your work surface.

Also, always use some cutting oil - even 3in 1oil if nothing else is at hand.  The cutting oil will help dissipate heat and make all the difference in the world getting through the chainplate.

Regards
Glenn 

Sent from my iPad

> On Nov 8, 2015, at 3:16 PM, gordon white via Public-List <public-list at lists.alberg30.org> wrote:
> 
> what drill is good for use on the stainless chainplates?
> 
> - Gordon White
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