"Fred" wrote in message
...
Drilling 1/4" holes on a 1/8" thick mild steel plate on a floor drill
press
but a few of the holes were off. Try to corrected it on my drill press to
widen the holes with the same 1/4" drill bit the bid just deflected from
side pressure. I do not want to use a larger bit since it will make the
holes too large. I then try to corrected it with a Dremel with one of
those
small cylindrical grinding stone attached to a 1/8" shaft to get in the
1/4"
hole but the grinding stone only lasted about 10 seconds before
disintegrated. So what is the right tool/method just to widen those holes
on
one side?



When you are drilling holes that you intend to match other holes, one of the
best things you can do to help yourself is not use a center punch. Even
with a drill press, if you clamp your work and use a wiggler to locate the
cross hairs from your carefully scribed locations, you should be able to
work to less than .005" consistently, avoiding those flyers.

For what it's worth, and many will choose to argue------a center punch has
no place in the tool box of one that is considered a precision
machinist-----not unless they work with hand tools. There are other methods
that insure proper location and reduce unacceptable results-----although at
the cost of speed. Still, applying such methods are faster than doing a
project twice----or more.

I'm sure it comes as no surprise to any of us when mention is made of the
fact that drills are circular ground and relieved to minimize the amount of
metal in contact with the hole. The circular grind acts as a guide in the
hole, but lacking proper relief for side cutting, they are not well suited
for such cuts.

Harold