Well, I guess that rules out my intended suggestion of using inserted
There should be many companies offering coolant through drills in
11/32" and 21/32" sizes. Although, .2264 might have to be a special grind.
I wish I had through the tool coolant, but I don't. The 3-flute
carbides at YG1 are in fraction sizes, or I'd be all over those. My
tool vendor is doing the family funeral thing so I can't complain
about him being awol.
I guess that trashes my through coolant drill suggestions as well.
Get a chunk of hot-rolled and practice drilling with some 135 degree
split point stub length Cobalt drills. For the .2264 size, they make
reamers in increments of every thousandth.
Tell me more about this coolant inducing collar, John.
And I wish I had time to poke holes in a plate, but I'm far so behind
the 8 ball right now I wish I could just curl up and be the shape of
the soccer ball I feel like I am right now.
Not to go into terminal thread drift, but look at this HSK tool holder
chainsaw near the bottom of this page. I'd sure hate to be reaching in
the machine when that puppy was running and have it's locating pins
so my wife has been bugging me to do some intricate chainsawing, on our
trees, actually. and there you go, with just the tool to do it.
so now i am trying to figure out how I can get my mill on a lift up into
the tree canopy, with these babies in the spindle <G>
I've used a "through coolant collar" when doing a series of holes using
a large power feed manual machine with an inserted drill, (what a messy
situation though - even with a makeshift tube guard around the drill).
Thinking about it now, that no-doubt qualifies as one of those "World's
How would a "through coolant collar" work with the need for frequent
multiple tool changes?
They make tool changeable units Bob.
The coolant connection is made when the draw bar seats the holder to a block
mounted just off to one side of the spindle. You have to make sure the drive
key is properly oriented in the tool carousel or the coupler ends up 180
degrees out of position but you probably do that with boring bars already.
On Thu, 6 Mar 2008 15:19:58 -0800 (PST), Charlie Gary
Just about any twist drill ought to go through 1/2" plate in one peck.
Stub split point, if you're not spotting.
I was going to suggest using Master Drills. They're a straight fluted
carbide drill. I use a 3.1mm (.122") to cross drill through a 7/16
round SS part on the Swiss. No spot, almost 4x dia. in one peck.
I buy them from Goddard Rotary Tool, here in Escondido. 760-740-6717
They stock them in fractions and numbers, but can get them in metric
Sounds like you need them right away, though. Guhring probably is the
best source. Did you call them, or try to contact them online? I'd
call them. Someone always answers the phone. 800-877-7202
On Thu, 6 Mar 2008 11:05:08 -0800 (PST), Charlie Gary
============As usual, very good replies/suggestions in this thread.
If this is for a high volume production operation, the following
observations may be helpful (but these are from an American
manufacturing plant, long, long ago in a land now far, far away).
Based on my observations [I was the SPC study guy] of a very high
volume operation drilling forged [and some cast] slack adjuster
bodies [big-rig air brake truck part] the drill manufacturer is
not the critical factor, but the point [re] grind is, from a
total consumable tooling cost perspective. The machine was a PLC
controlled rotary index center, with drill bushing fixtures,
flood coolant, and gear drive/gear feed [non operator adjustable]
Because of production considerations [piece work] there was
continual problems with the operators not changing tools on
schedule to the point that we had to install a counter that
locked the machine, and required supervisor key reset to resume
after verification of tool change. The problems caused were not
only excessive tool consumption because of extensive rather than
touch-up re grind required [to the extent that it was frequently
cheaper to scrap the drill rather than take the time to re
grind], but the huge burrs generated required extensive/expensive
As I recall, the Peugeot drill point was selected as optimal for
this use, but the Bickford and Relcon points were very close and
may be better for your application. For what ever reason, we had
to discharge several operators for attempting to resharpen their
own drills by hand rather than using the supplied Peugeot
re-pointed drills from the grind shop (even though we supplied a
"kit" to each shift with the required number of sharp prills and
a spare or two for the scheduled production). They seemed to
feel the points didn't "look right," and indeed the Relcon looks
We used the Guhring parabolic flute drills with great success.
These drills did indeed seem to clear the chips better than other
drills. for one source see