[AT] Drill bits for drilling our old tractor steel and iron.

[Stephen Offiler]

Hey Bob - never really even tried to figure that out, but I I am reasonably
sure the answer is a combination of

(a) they're 1/8" bits which are small enough to be a bit difficult to
resharpen (we have a decent mid-grade Darex drill sharpener)
(b) the guy who tends to resharpen when he feels like it/gets around to it,
is not exactly our very best and brightest.

SO


On Fri, Oct 25, 2019 at 4:02 PM <rbrooks at hvc.rr.com> wrote:

> Steve
>
>
>
> Did you figure out why the resharpened bits did not fair as well?
>
>
>
> Bob
>
>
>
> *From:* AT <at-bounces at lists.antique-tractor.com> *On Behalf Of *Stephen
> Offiler
> *Sent:* Friday, October 25, 2019 8:08 AM
> *To:* Antique Tractor Email Discussion Group <at at lists.antique-tractor.com
> >
> *Subject:* Re: [AT] Drill bits for drilling our old tractor steel and
> iron.
>
>
>
> I've done some work in this area, Dean.  Here's the long version:   my
> company (Central Tools Inc) makes a variety of dial indicator sets.  We
> have some dial indicator mounts based on Vice-Grips.  Here's a link:
>
>
>
> https://www.centraltools.com/6450-brake-rotor-ball-joint-gage.html
>
>
>
> Note in the image a black block pinned to the Vice-Grip.  That is where
> the dial indicator support (our "Flex-Arm" is shown) attaches to the
> Vice-Grip.  We have to drill holes in the Vice-Grip to pin the blocks on.
> And we have drilled a LOT of holes in a LOT of Vice-Grips.  We've offered
> this set for many years.  It was an old established product when I joined
> the company 23 years ago.
>
>
>
> Getting to the drill bits:  we use cobalt.  They don't last terribly long;
> we get somewhere around 50 holes per bit.  Purchased in quantity, the bits
> are only about $1.75 each so about 3.5 cents per hole.  We have a guy who
> likes to resharpen them in his spare time, but it's actually more
> economical for us to toss them.  Resharpened bits only go 15-30 holes and
> his labor costs as much or more than a brand new bit anyway.
>
>
>
> Not long ago we conducted a big experiment to see if we could find better
> drill bits.  Understand that we use a fixture on a drill press; this is not
> a rigid CNC setup; therefore we cannot use carbide.  The best modern
> non-carbide drill bits use powder metallurgy to create alloys with
> properties you can't get with traditional metallurgy.  Vanadium is one of
> the critical factors.  If you Google "powder metal drill bit" you'll find
> them readily available.  The cost is definitely at the "Snap-on" level.
> The ones I experimented with were ballpark 10X the cost of my cobalt
> drills, so I'd need to make 10X the holes to break even.  Results of that
> experiment:  the powder metal drills lasted, at best, only modestly longer
> than the cobalt.
>
>
>
> Steve O.
>
>
>
>
>
>
>
> On Fri, Oct 25, 2019 at 3:12 AM <deanvp at att.net> wrote:
>
> The closest drill bits I have that I would call decent are a set of
> reverse direction drill bits made by Irwin that are Cobalt.  I’ve used them
> for removing broken off bolts, etc. but even those are not worth writing
> home about.  On grade 5 bolts they are ok but on really hard stuff they
> don’t cut the mustard. Cobalt drill bits do have a negative and that is
> they are very brittle. But…  what brand and version of drill bits have you
> guys found that are better than the average bear and work good on our old
> iron which seems harder than the current stuff. I’m fed up with my multiple
> indexes of drill bits that might work in wood if I was patient. On steel a
> nail might work better. :-) I know its going to cost and I’m prepared for
> that. What is the “Snap-On” of drill bits?  What have you had a long and
> successful relationship with.  However, I am convinced that no matter how
> good they are I will break anything less than 1/8”  So a set from 1/8 to ½”
> in 1/64th “  increments is about my style. Or as an alternative. What
> drill bit sharpener do you recommend? I do have a lot of drill bits that
> could be sharpened. Not sure some of them are worth it though.
>
>
>
> Dean VP
>
> Snohomish, WA 98290
>
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