7/8 Forstner, in drill press at lowest speed (350 RPM). Carbon steel.
Bit sharp (how do I know? Worked it over with a fine grit diamond file
las time I used it. This time I managed to slice myself taking it out
of the box--it didn't hurt until I saw the blood).

By the time it's maybe a quarter inch into the ash, much smoke. Tried a
piece of poplar and a piece of Douglas Fir, no smoke. Shavings coming
out are fine, continuous, hole is clean other than looking burned.
Continue on--cut a quarter inch, pull the bit out, repeat. By the time
I'm 3 inches in the bit is hot enough to burn me, overall yellow (not
just the edge, all the way up to the shank--not yellow-hot but the
straw-yellow discoloration you get when drawing the temper).

Does the same thing on the lathe at lowest RPM (500).

Drilled a dozen pieces 3 inches deep, drill continues to cut fine, so am
assuming that yellow is something coming out of the Ash and not
indicative of the bit losing temper.

Now, obvious thing to do is get a carbide bit for this job (it's going
to be continuing I hope). But was wondering if anybody had any other
sage advice.

"J. Clarke" wrote

7/8 Forstner, in drill press at lowest speed (350 RPM). Carbon steel. Bit
sharp (how do I know? Worked it over with a fine grit diamond file las
time I used it. This time I managed to slice myself taking it out of the
box--it didn't hurt until I saw the blood).

Could be you got it too hot before you sharpened it, and it lost its temper.

Though I would remind you that the larger the bit, the slower the speed is
required. 250 RPM might be slow enough to do the job.
--
Jim in NC

"J. Clarke" wrote in message
...
7/8 Forstner, in drill press at lowest speed (350 RPM). Carbon steel.
Bit sharp (how do I know? Worked it over with a fine grit diamond file
las time I used it. This time I managed to slice myself taking it out
of the box--it didn't hurt until I saw the blood).

By the time it's maybe a quarter inch into the ash, much smoke. Tried a
piece of poplar and a piece of Douglas Fir, no smoke. Shavings coming
out are fine, continuous, hole is clean other than looking burned.
Continue on--cut a quarter inch, pull the bit out, repeat. By the time
I'm 3 inches in the bit is hot enough to burn me, overall yellow (not
just the edge, all the way up to the shank--not yellow-hot but the
straw-yellow discoloration you get when drawing the temper).

Does the same thing on the lathe at lowest RPM (500).

Drilled a dozen pieces 3 inches deep, drill continues to cut fine, so am
assuming that yellow is something coming out of the Ash and not
indicative of the bit losing temper.

Now, obvious thing to do is get a carbide bit for this job (it's going
to be continuing I hope). But was wondering if anybody had any other
sage advice.

I can sharpen pretty well, but I am thinking of the times when things didn't
get as sharp as I thought they were and were just dull enough to make a
difference. The sharpenss or dullness can usually be experimentally
determined by the volume of blood a cut on your finger produces :-)

I'd have to say it's a resin or something in the ash, since everything else you
drilled was ok..


mac

Please remove splinters before emailing

"J. Clarke" wrote

This particular bit is clearly marked "Max 870 RPM".

If you know of such a chart online I'd like to see it. All the generics I
find say 500 RPM for hardwood.

I still think that the bit has lost temper, if it was getting as hot as
straw temperature, as you were saying. Straw temp is for making steel soft.
Bad for bits. You now must get the bit up a bit hotter than straw and oil
quench it to get hardness back.

Another question, about how you sharpened it. I hope this is not insulting,
but I have seen bits sharpened very wrong, before.

The leading edge angle of the cutting edge is critical. If you sharpen the
leading edge, it must be sharpened all of the way up the face, to maintain
the angle of the leading edge of the cutting surface. The angle of the bit
behind the cutting edge is critical, too. If it does not go upwards rapidly
enough, the bit will not be allowed to cut as thick of a chip as necessary
to cut without burning. The chips coming out of the cut should be thick,
and long, not too unlike a sharp bit cutting steel. It will not be a
curly-cue as steel would be, of course, but the chips should be much thicker
than dust from a circular saw. Even if it is not sharpened correctly, it
will still cut fairly well in softer woods.
--
Jim in NC

On 9/4/2010 11:01 AM, Morgans wrote:
"J. wrote

This particular bit is clearly marked "Max 870 RPM".

If you know of such a chart online I'd like to see it. All the generics I
find say 500 RPM for hardwood.

I still think that the bit has lost temper, if it was getting as hot as
straw temperature, as you were saying. Straw temp is for making steel soft.

I'd be inclined to agree with you if it wasn't yellow all the way up the
shank. I'd expect some blue somewhere around the edge if it got hot
enough to go yellow all the way up, but there's no blue on it.

Bad for bits. You now must get the bit up a bit hotter than straw and oil
quench it to get hardness back.

Assuming it's an oil-hardening steel.

Another question, about how you sharpened it. I hope this is not insulting,
but I have seen bits sharpened very wrong, before.

The leading edge angle of the cutting edge is critical. If you sharpen the
leading edge, it must be sharpened all of the way up the face, to maintain
the angle of the leading edge of the cutting surface.

Yep. Diamond file places in contact with full face and full face
sharpened. Sharpening Forstners is easy. And it cuts fine in
everything but ash.

The angle of the bit
behind the cutting edge is critical, too. If it does not go upwards rapidly
enough, the bit will not be allowed to cut as thick of a chip as necessary
to cut without burning. The chips coming out of the cut should be thick,
and long, not too unlike a sharp bit cutting steel. It will not be a
curly-cue as steel would be, of course, but the chips should be much thicker
than dust from a circular saw. Even if it is not sharpened correctly, it
will still cut fairly well in softer woods.

What comes out of it is the same quality of chip that I get from a block
plane.

On Fri, 03 Sep 2010 22:55:27 -0400, "J. Clarke"
wrote:

7/8 Forstner, in drill press at lowest speed (350 RPM). Carbon steel.
Bit sharp (how do I know? Worked it over with a fine grit diamond file
las time I used it. This time I managed to slice myself taking it out
of the box--it didn't hurt until I saw the blood).

By the time it's maybe a quarter inch into the ash, much smoke. Tried a
piece of poplar and a piece of Douglas Fir, no smoke. Shavings coming
out are fine, continuous, hole is clean other than looking burned.
Continue on--cut a quarter inch, pull the bit out, repeat. By the time
I'm 3 inches in the bit is hot enough to burn me, overall yellow (not
just the edge, all the way up to the shank--not yellow-hot but the
straw-yellow discoloration you get when drawing the temper).

Does the same thing on the lathe at lowest RPM (500).

Drilled a dozen pieces 3 inches deep, drill continues to cut fine, so am
assuming that yellow is something coming out of the Ash and not
indicative of the bit losing temper.

Now, obvious thing to do is get a carbide bit for this job (it's going
to be continuing I hope). But was wondering if anybody had any other
sage advice.

Nope. I have a boat-load of Ash (probably 300bf left of 600) and have never
had that problem with drill bits. Sometimes I'll see a burn mark from a saw
blade but never smoking drills. It is hard stuff, though.

"J. Clarke" wrote

What comes out of it is the same quality of chip that I get from a block
plane.

That sounds great.

Yet it burns? Strange.

Where on the hole is it burning? The sides, or the bottom of the hole? If
it is the bottom of the hole, and it is a through hole, don't worry about
it. (easy to say) If it isn't a through hole, then put some stain on the
burn and go with it. g

I think the only thing left to try is slower speed. From machining
philosophy, if it is too hot, slow the tool speed, or cool the workpiece and
bit. Since cooling them is impossible, that remains slowing the tool.

How about increasing the relief angle on the bit. Making it steeper? How
about letting the bit be cooled by drilling and waiting, and so forth? How
about blowing a stream of high volume, high pressure air onto the bit to
help keep it cool?

It seems like you have everyone baffled. You need to experiment, figure it
out, and come and tell us the results, me thinks.
--
Jim in NC

"J. Clarke" wrote

Drilled a dozen pieces 3 inches deep, drill continues to cut fine, so am
assuming that yellow is something coming out of the Ash and not indicative
of the bit losing temper.

Wow, I just realized how deep you are drilling. Drilling that deep in hard
stuff would be bound to heat the bit.

Try a closely directed stream of compressed air on the bit. Cool that
sucker with air, and slow down the drilling process if the burning is
objectionable.
--
Jim in NC

On 9/4/2010 12:40 PM, Morgans wrote:
"J. wrote

What comes out of it is the same quality of chip that I get from a block
plane.

That sounds great.

Yet it burns? Strange.

Where on the hole is it burning? The sides, or the bottom of the hole? If
it is the bottom of the hole, and it is a through hole, don't worry about
it. (easy to say) If it isn't a through hole, then put some stain on the
burn and go with it.g

Good question. It appears to be the sides. The bottom is pretty much
the same color as the rest of the piece.

I think the only thing left to try is slower speed. From machining
philosophy, if it is too hot, slow the tool speed, or cool the workpiece and
bit. Since cooling them is impossible, that remains slowing the tool.

And the drill press is on its lowest speed now, so without reworking it
somehow that's out.

How about increasing the relief angle on the bit. Making it steeper?

That's a possibility.

How
about letting the bit be cooled by drilling and waiting, and so forth?

When I gotta do 70 of these at a time without an NC machine that's not
all that workable.

How
about blowing a stream of high volume, high pressure air onto the bit to
help keep it cool?

Another good possibility.

It seems like you have everyone baffled. You need to experiment, figure it
out, and come and tell us the results, me thinks.

I think I'm just going to say to Hell with it and spend the 25 bucks for
a carbide bit.

On Sat, 04 Sep 2010 13:46:41 -0400, "J. Clarke"
wrote:

On 9/4/2010 12:40 PM, Morgans wrote:
"J. wrote

What comes out of it is the same quality of chip that I get from a block
plane.

That sounds great.

Yet it burns? Strange.

Where on the hole is it burning? The sides, or the bottom of the hole? If
it is the bottom of the hole, and it is a through hole, don't worry about
it. (easy to say) If it isn't a through hole, then put some stain on the
burn and go with it.g

Good question. It appears to be the sides. The bottom is pretty much
the same color as the rest of the piece.

The fact that it's burning on the sides indicates to me that the side of the
bit is rubbing on the wood, like there is excessive runout on your drill or
bit.

I think the only thing left to try is slower speed. From machining
philosophy, if it is too hot, slow the tool speed, or cool the workpiece and
bit. Since cooling them is impossible, that remains slowing the tool.

And the drill press is on its lowest speed now, so without reworking it
somehow that's out.

How about increasing the relief angle on the bit. Making it steeper?

That's a possibility.

How
about letting the bit be cooled by drilling and waiting, and so forth?

When I gotta do 70 of these at a time without an NC machine that's not
all that workable.

How
about blowing a stream of high volume, high pressure air onto the bit to
help keep it cool?

Another good possibility.

It seems like you have everyone baffled. You need to experiment, figure it
out, and come and tell us the results, me thinks.

I think I'm just going to say to Hell with it and spend the 25 bucks for
a carbide bit.

If the problem is the bit, that should solve it.

wrote

The fact that it's burning on the sides indicates to me that the side of
the
bit is rubbing on the wood, like there is excessive runout on your drill
or
bit.

Runout could be the problem, but I think it is more likely that the burning
is because the outer teeth have lost their "set."

When this type of bit is new, (for new woodworkers in the group) the row of
small teeth around the outside are slightly further out than the main
diameter of the bit. When they wear and get sharpened, the outer point is
what wears down. The only way to fix a bit like that is to knock the teeth
back out a little, or reduce the diameter of the sides of the bit a bit.
--
Jim in NC

On 9/4/2010 4:19 PM, Morgans wrote:
wrote

The fact that it's burning on the sides indicates to me that the side of
the
bit is rubbing on the wood, like there is excessive runout on your drill
or
bit.

Runout could be the problem, but I think it is more likely that the burning
is because the outer teeth have lost their "set."

When this type of bit is new, (for new woodworkers in the group) the row of
small teeth around the outside are slightly further out than the main
diameter of the bit. When they wear and get sharpened, the outer point is
what wears down. The only way to fix a bit like that is to knock the teeth
back out a little, or reduce the diameter of the sides of the bit a bit.

This is a classic Forstner--no teeth.

"J. Clarke" wrote

This is a classic Forstner--no teeth.

Now it all makes sense.

I have always liked the type with teeth. Faster cutting, easier to turn,
and clean holes.

I would bet you could use one of those with teeth, and it would do just
fine, without having to go to an expensive carbide model.

That has been my experience, anyway. I have a couple sets with teeth. I
have one (1 1/8th, I think) without teeth. It usually goes unused.
--
Jim in NC

On 9/4/2010 7:18 PM, Morgans wrote:
"J. wrote

This is a classic Forstner--no teeth.

Now it all makes sense.

I have always liked the type with teeth. Faster cutting, easier to turn,
and clean holes.

I would bet you could use one of those with teeth, and it would do just
fine, without having to go to an expensive carbide model.

That has been my experience, anyway. I have a couple sets with teeth. I
have one (1 1/8th, I think) without teeth. It usually goes unused.

Have to give one a try.

On Sep 4, 1:19*pm, "Morgans" wrote:

Runout could be the problem, but I think it is more likely that the burning
is because the outer teeth have lost their "set."

There's one other possibility: if there is a buildup of sap on the
bit,
a bit of cleaning (brass wire brush or chemical) can remove the
material that is rubbing and causing the heat.

In article ,
J. Clarke wrote:
On 9/4/2010 9:01 AM, Larry W wrote:
...snipped...
I've read that too. And perhaps worth trying, use a HIGHER speed. Various
drill speed charts I've seen for forstners recommend something around
1200 or 1500 RPM for a 7/8" bit in hardwood.

This particular bit is clearly marked "Max 870 RPM".

If you know of such a chart online I'd like to see it. All the generics
I find say 500 RPM for hardwood.


Sure, here's a couple:

www.ibiblio.org/twa/info/drillSpeedChart.pdf (pdf warning)


http://www.woodcraft.com/Articles/Ar...?articleid=380 (chart in
right sidebar about 1/2 way down the page)


--
Often wrong, never in doubt.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

On Sat, 04 Sep 2010 13:46:41 -0400, "J. Clarke" wrote:


I think I'm just going to say to Hell with it and spend the 25 bucks for a carbide bit.

Yep.. that was going to be my recommendation..
For production work, carbide is the way to go..


mac

Please remove splinters before emailing

On Sat, 4 Sep 2010 16:19:36 -0400, "Morgans" wrote:


wrote

The fact that it's burning on the sides indicates to me that the side of
the
bit is rubbing on the wood, like there is excessive runout on your drill
or
bit.

Runout could be the problem, but I think it is more likely that the burning
is because the outer teeth have lost their "set."

When this type of bit is new, (for new woodworkers in the group) the row of
small teeth around the outside are slightly further out than the main
diameter of the bit. When they wear and get sharpened, the outer point is
what wears down. The only way to fix a bit like that is to knock the teeth
back out a little, or reduce the diameter of the sides of the bit a bit.

That still doesn't explain why it only burns the ash, not other woods that he's
drilled..


mac

Please remove splinters before emailing

On 9/4/2010 11:18 PM, Larry W wrote:
In ,
J. wrote:
On 9/4/2010 9:01 AM, Larry W wrote:
...snipped...
I've read that too. And perhaps worth trying, use a HIGHER speed. Various
drill speed charts I've seen for forstners recommend something around
1200 or 1500 RPM for a 7/8" bit in hardwood.

This particular bit is clearly marked "Max 870 RPM".

If you know of such a chart online I'd like to see it. All the generics
I find say 500 RPM for hardwood.


Sure, here's a couple:

www.ibiblio.org/twa/info/drillSpeedChart.pdf (pdf warning)

And it says 500 RPM for hardwood.

http://www.woodcraft.com/Articles/Ar...?articleid=380 (chart in
right sidebar about 1/2 way down the page)

That article also discusses carbide and high speed steel bits and is not
at all clear whether that chart is safe speeds for carbon steel bits or
best cutting speeds for carbide or what.

mac davis wrote:
On Sat, 4 Sep 2010 16:19:36 -0400, "Morgans" wrote:
wrote
....
bit is rubbing on the wood, like there is excessive runout on your drill
or bit.

Runout could be the problem, but I think it is more likely that the burning
is because the outer teeth have lost their "set."

....

That still doesn't explain why it only burns the ash, not other woods that he's
drilled..
....

Nor that OP said it doesn't have teeth...

--

On Fri, 03 Sep 2010 22:55:27 -0400, "J. Clarke"
wrote:

7/8 Forstner, in drill press at lowest speed (350 RPM). Carbon steel.
Bit sharp (how do I know? Worked it over with a fine grit diamond file
las time I used it. This time I managed to slice myself taking it out
of the box--it didn't hurt until I saw the blood).

By the time it's maybe a quarter inch into the ash, much smoke. Tried a
piece of poplar and a piece of Douglas Fir, no smoke. Shavings coming
out are fine, continuous, hole is clean other than looking burned.
Continue on--cut a quarter inch, pull the bit out, repeat. By the time
I'm 3 inches in the bit is hot enough to burn me, overall yellow (not
just the edge, all the way up to the shank--not yellow-hot but the
straw-yellow discoloration you get when drawing the temper).

Does the same thing on the lathe at lowest RPM (500).

Drilled a dozen pieces 3 inches deep, drill continues to cut fine, so am
assuming that yellow is something coming out of the Ash and not
indicative of the bit losing temper.

Now, obvious thing to do is get a carbide bit for this job (it's going
to be continuing I hope). But was wondering if anybody had any other
sage advice.
What an Ash hole!!!
Sorry - couldn't resist.

Seriously - I'd try a carbide bit

On Sat, 4 Sep 2010 01:01:18 -0500, "woodstuff"
wrote:

"J. Clarke" wrote in message
...
7/8 Forstner, in drill press at lowest speed (350 RPM). Carbon steel.
Bit sharp (how do I know? Worked it over with a fine grit diamond file
las time I used it. This time I managed to slice myself taking it out
of the box--it didn't hurt until I saw the blood).

By the time it's maybe a quarter inch into the ash, much smoke. Tried a
piece of poplar and a piece of Douglas Fir, no smoke. Shavings coming
out are fine, continuous, hole is clean other than looking burned.
Continue on--cut a quarter inch, pull the bit out, repeat. By the time
I'm 3 inches in the bit is hot enough to burn me, overall yellow (not
just the edge, all the way up to the shank--not yellow-hot but the
straw-yellow discoloration you get when drawing the temper).

Does the same thing on the lathe at lowest RPM (500).

Drilled a dozen pieces 3 inches deep, drill continues to cut fine, so am
assuming that yellow is something coming out of the Ash and not
indicative of the bit losing temper.

Now, obvious thing to do is get a carbide bit for this job (it's going
to be continuing I hope). But was wondering if anybody had any other
sage advice.

I can sharpen pretty well, but I am thinking of the times when things didn't
get as sharp as I thought they were and were just dull enough to make a
difference. The sharpenss or dullness can usually be experimentally
determined by the volume of blood a cut on your finger produces :-)


It might be very sharp, but not a steep enough angle - or two wide a
cutting area.