I recently did a small project that required multiple hole that I
drilled with a Forstner Bit. The holes were about a half inch in
diameter and about and inch deep.
Until this project I would use the Forstner Bit to recess bolts and
other simple projects that required on or two shallow holes.
I had a lot of trouble with heat. After I noticed there was a burning
problem, I was very carefully to control the feed rate but this did not
seem to resolve the problem.
Is this problem cause by my poor techniques or would better bits solve
Entirely possible but I have a 1-3/8" Forstner bit that I have literally
drilled hundreds of holes with in hard woods and MDF for probably 10 or 12
complete kitchen hinge jobs and the bit still cuts respectably. Then again
there are many different qualities of bits.
The quality differences I have seen with some of my
Forstners is amazing.
I have some cheapos that are about shot after very few uses.
Others, clearly of much higher quality seem to last forever.
Somehow, more than with other types of bits, it seems you
get what you pay for.
All the best,
Here are a couple of tables of speeds for Forstner bits
Note that they differ somewhat on speeds. Note also that they agree
that one should use lower speeds on "hardwoods" than on "softwoods".
Yours may have come with a table of recommended speeds--if it did then
follow that unless you get burning at the recommended speeds, if so
then reduce the RPM until you don't anymore and make a note of the
Carbon steel Forstners you can ruin easily with excessive
speed--examine the bits for any blue discoloration and if you find it
then the bit is shot.
Also make sure the bit is sharp--steel Forstners are actually pretty
easy to sharpen if you have one of these
http://www.woodcraft.com/family.aspx?familyidC40 (I keep it in my
wallet, it's handy when the Swiss Army Knife decides it doesn't want
I guess the answer to my question is both my technique and drill bits.
I set the drill up for standard twist drills and used that speed, so it
was probably much faster than it should have been The next time I need
to slow it down quit a bit. (I don't remember the exact speed since I
have had the drill press for sometime and have not changed it since I
got it. )
As I said I don't use the Forstner often, so had picked up a quite cheap
set to see what they would do and learn to use them. I will have to get
a better set before I start a real project.
I was drilling a piece of clear soft pine.
I will read up on the use of the Forstner bits
A set of really high quality Forstners will set you back a
But, as I mentioned earlier in the thread, the differences
in quality will make a significant difference.
You might consider buying 'em individually as you need a
particular size. Over time, you would assemble a high
quality set without having to sell your home. <g>
All the best,
Dull bit or poor relief. Something's rubbing, probably the
sides of the bit or the undersides of the lifters. Sharpening
is possible (file or slip, do NOT file the outside of the bit
or the undersides of the lifters), but a pain. Replacement is
best. Freuds are cheap and work well. Brad points might
work better for your application.
My last project required over a hundred 3/8 holes a half inch deep. I
went with a brad point bit. They last longer and it's easier to hit
That said, I had a bunch of 3/4 holes to drill a while back and all I
had was a cheap set of forstners my sister gave me for Christmas. The
3/4 bit burned up after ten holes and I had it on slow speed and feed.
I'm pretty sure the bit I bought at Woodcraft cost as much as that
whole BigBox set but it cut many dozens of holes clean and fast with
no burn and it's still cutting.
Now I have a set of cheap forstners with two expensive ones in the
set. (I, uh, dropped one and chipped it...) The others have done fine
for what I've had to do. When I need a better one for a specific job,
I'll go get it.
Stanley Powerbores were great, cheap, *easy* to resharpen with a
triangular file, and cut smooth, crisp holes in no time flat.
Try to find a set locally, short of the flea market. Stanley quit
making them. It's either pay $60 for what used to sell for about
$20 per set, or hire a machinist.
Half and pocket holes come to mind. Forstners don't take
abuse well, and like I said, Powerbores are a LOT easier
to sharpen when you blunt the edges. You wouldn't use a
Norris A-1 to plane a door slab, would you?
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