View Single Post
  #4   Report Post  
john
 
Posts: n/a
Default drilling 'actual' sized holes with HSS drill bits

bill yohler wrote:

have enough experience to know that a given-size drill bit (hss) won't
neccessarily 'yield' a drilled hole the same size as the drill bit IS,
due to whatever factors. those factors might be: point sides sharpened
at slightly different angles, or sharpened at same angle but different
lengths. also sides of drill edge 'flutes' worn/abraded...there are
'probably' other causes (which I'm unaware of/please detail).

but, other than 'drilling undersize and reaming', what's the best way
to drill a hole in mild steel and get the 'expected' size hole (aka:
have it yield the _same_ hole size as the bit size)?

I'll be using a BRAND new .177 number-sized drill bit, correct RPM,
and lube/fluid cooling, clamped down in a good drill press. anything
I'm overlooking?

thanks for insights :-)


If you have a new drill from a good manufacturer and locate the hole
with a punch it should come out withing a couple of thousandths of the
nominal size. With a resharped drill done by hand or a cheap sharpener
you could get anything.

John