[AT] drill bits

[jtchall at nc.rr.com]

I've been buying all the cutting tools for the machine where I work for the 
last 20 years.  First off, never seen a drill that wasn't HSS or carbide. 
Coatings are just that. They are intended to help disperse heat but to 
primarily keep from the cutting edge wearing down and to prevent chip 
galling in  the flutes when drilling aluminum. You most likely aren't going 
to find any decent drills locally--if you do the price will be pretty high 
most likely. Never seen a decent cutting tool from China or India. There is 
a good line of endmills from Korea. The drills I use come from USA, Japan, 
Canada, Germany and Mexico. We are a job shop so we need good quality 
tooling but don't do large production runs to justify using the extreme 
stuff. I keep the shop stocked with Nachi drills up to 1/2", Viking up to 
1", whatever is cheapest beyond that. Take a look at MSC, Travers or Enco 
and you should be able to find some made in USA drills at a reasonable 
price. You'll want jobbers length, most likely 118 deg point, 135 split 
points are nice as well but generally found on screw machine length drills. 
Get either a bright or black oxide finish. The other coatings are eye candy 
on cheap tools to drive the cost up by making you think they will last 
longer. Coatings on production grade tooling are a different story all 
together. We use black oxide coating on our drills and we cut anything from 
plastic to 4140 pre-hard. We actually cut way more tool steel than all other 
materials combined. PTD, CLeveland, Chicago Latrobe, Dormer, Ghuring, 
Titex--all are great tools, but are going to get expensive quick.

Keep this in mind next time you are drilling. I run a general purpose 1/4" 
drill at around 1400 RPM in a rigid setup under flood coolant when drilling 
cold rolled steel. With no coolant (cutting oil keeps it lubed but not 
really cool), and using a hand drill or drill press (neither of which is 
very rigid or runs the tool true), 1400 RPM is too fast.  We can and do push 
beyond those limits if the quantity of drilling warrants speeding things up.

John Hall

-----Original Message----- 
From: k7jdj at aol.com
Sent: Thursday, April 30, 2015 2:58 PM
To: at at lists.antique-tractor.com
Subject: [AT] drill bits

I wonder what type of drill bits work for antique tractor bolt removal and 
repairs?  I have been buying cheap throw away Harbor Freight titanium 
nitride coated bits but have gone back to using high speed steel bits.  Even 
the higher quality coated bits don't seem to work as good as the high speed 
steel bits.

The coated bits don't drill as well and are much easier to catch and break. 
It is getting harder to find high speed steel bits. I have a drill doctor 
but it doesn't do a good job on the really small sizes.

Would be interested in what others are using or doing that I might be 
missing.

Gary

Renton, WA

JD B
2 Cletrac model F's
1 Cletrac model W

and lots of other old iron
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