I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4". The
problem is that the holder seems to be hardened throughout. A small file
won't scratch the bore of the holder. It seems that my options would be to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas barbecue, a
propane torch, or a 1-hour round trip to a friend with a small heat treating
oven. If scale is likely to be a problem with annealing, what is the best
way to deal with that? I don't much care about the appearance of the end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?

"Mike Henry" wrote in message
...
I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4".
The
problem is that the holder seems to be hardened throughout. A small file
won't scratch the bore of the holder. It seems that my options would be
to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas barbecue, a
propane torch, or a 1-hour round trip to a friend with a small heat
treating
oven. If scale is likely to be a problem with annealing, what is the
best
way to deal with that? I don't much care about the appearance of the end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?


I'm not familiar with that particular holder, Mike, but I'd be cautious
about opening it up for a larger shank unless the exterior is fairly large
diameter. If it compares favorably with the typical 3/4" holder, I
wouldn't hesitate, but it could prove a mistake if you put it to work with a
slender body. Screws may not hold, and it may offer chatter that a more
robust one wouldn't. I'm assuming it looks similar to a cat 30,40 or 50
holder.

Assuming there's no good reason to not open it up, the first thing you need
to determine is if it is hardened through. It may be induction hardened,
which often controls heat treat depth. If that be the case, you may get
through the hard layer and it will machine better, although you would then
be faced with a soft interior when finished. Regardless of how hard it
may be, I think I'd hesitate to anneal it in any way, not being able to
control where to stop, and scaling.

Grinding the size larger would be the ideal way to go, assuming it is
hardened, and it wouldn't be much of a job on a proper internal grinder,
where you have more power and rigidity and can keep the thing cool while
grinding. If push gets to shove and you can't do it otherwise, you may be
able to bore near finish size, then grind for size and finish. Carbide
should cut it, even if it's in the low 60's, Rc scale. I'm not suggesting
it would be easy, just possible. One thought could be using a carbide end
mill held in your toolpost, not the tailstock. Just a thought.

Luck. Tell us how it turns out.

Harold

End mill holders cost about 15.00 depending on the shank- why not just buy
one.
"Harold and Susan Vordos" wrote in message
...

"Mike Henry" wrote in message
...
I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4".
The
problem is that the holder seems to be hardened throughout. A small
file
won't scratch the bore of the holder. It seems that my options would be
to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas barbecue,
a
propane torch, or a 1-hour round trip to a friend with a small heat
treating
oven. If scale is likely to be a problem with annealing, what is the
best
way to deal with that? I don't much care about the appearance of the
end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?


I'm not familiar with that particular holder, Mike, but I'd be cautious
about opening it up for a larger shank unless the exterior is fairly large
diameter. If it compares favorably with the typical 3/4" holder, I
wouldn't hesitate, but it could prove a mistake if you put it to work with
a
slender body. Screws may not hold, and it may offer chatter that a more
robust one wouldn't. I'm assuming it looks similar to a cat 30,40 or 50
holder.

Assuming there's no good reason to not open it up, the first thing you
need
to determine is if it is hardened through. It may be induction hardened,
which often controls heat treat depth. If that be the case, you may get
through the hard layer and it will machine better, although you would then
be faced with a soft interior when finished. Regardless of how hard
it
may be, I think I'd hesitate to anneal it in any way, not being able to
control where to stop, and scaling.

Grinding the size larger would be the ideal way to go, assuming it is
hardened, and it wouldn't be much of a job on a proper internal grinder,
where you have more power and rigidity and can keep the thing cool while
grinding. If push gets to shove and you can't do it otherwise, you may
be
able to bore near finish size, then grind for size and finish. Carbide
should cut it, even if it's in the low 60's, Rc scale. I'm not suggesting
it would be easy, just possible. One thought could be using a carbide
end
mill held in your toolpost, not the tailstock. Just a thought.

Luck. Tell us how it turns out.

Harold

I'll gladly buy one, but no one seems to make Morse Taper 2 end mill holders
for 3/4" shanks any more. Someone (the VersaMill guy?) once offered to make
a few specials in that size but ISTR that he needed to get around $200 each
in small quantities just to break even. That's a bit over my tool budget.

"EdFielder" wrote in message
ink.net...
End mill holders cost about 15.00 depending on the shank- why not just buy
one.
"Harold and Susan Vordos" wrote in message
...

"Mike Henry" wrote in message
...
I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4".
The
problem is that the holder seems to be hardened throughout. A small
file
won't scratch the bore of the holder. It seems that my options would
be
to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas
barbecue,
a
propane torch, or a 1-hour round trip to a friend with a small heat
treating
oven. If scale is likely to be a problem with annealing, what is the
best
way to deal with that? I don't much care about the appearance of the
end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?


I'm not familiar with that particular holder, Mike, but I'd be cautious
about opening it up for a larger shank unless the exterior is fairly
large
diameter. If it compares favorably with the typical 3/4" holder, I
wouldn't hesitate, but it could prove a mistake if you put it to work
with
a
slender body. Screws may not hold, and it may offer chatter that a more
robust one wouldn't. I'm assuming it looks similar to a cat 30,40 or
50
holder.

Assuming there's no good reason to not open it up, the first thing you
need
to determine is if it is hardened through. It may be induction hardened,
which often controls heat treat depth. If that be the case, you may
get
through the hard layer and it will machine better, although you would
then
be faced with a soft interior when finished. Regardless of how hard
it
may be, I think I'd hesitate to anneal it in any way, not being able to
control where to stop, and scaling.

Grinding the size larger would be the ideal way to go, assuming it is
hardened, and it wouldn't be much of a job on a proper internal grinder,
where you have more power and rigidity and can keep the thing cool while
grinding. If push gets to shove and you can't do it otherwise, you may
be
able to bore near finish size, then grind for size and finish. Carbide
should cut it, even if it's in the low 60's, Rc scale. I'm not
suggesting
it would be easy, just possible. One thought could be using a carbide
end
mill held in your toolpost, not the tailstock. Just a thought.

Luck. Tell us how it turns out.

Harold

On Fri, 25 Feb 2005 00:25:41 -0600, "Mike Henry"
wrote:

I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4". The
problem is that the holder seems to be hardened throughout. A small file
won't scratch the bore of the holder. It seems that my options would be to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas barbecue, a
propane torch, or a 1-hour round trip to a friend with a small heat treating
oven. If scale is likely to be a problem with annealing, what is the best
way to deal with that? I don't much care about the appearance of the end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?



Mike,
I can only speak to the annealing question, Harold gives
excellent advise as to the other considerations. He and others also
cautioned me about annealing a MT2/J33 adapter so that I could remove
the tang and drill and tap for a drawbar for use on my Clausing 8520
mill. I never heat treated the adapter after finishing it and it seems
to be holding up well under my light use. I annealed as follows:

I put the adapter in a piece of copper pipe with one end pinched off
and the other sealed with a
brass plug. Put the whole thing into a charcoal fire and let it burn
until the coarcoal was gone. Perhaps an hour total burn time as I
added charcoal at one point. Fished it out when cool and it had turned
a nice blue-grey color and was well annealed. There was virtually no
scale except where air had leaked in a little at the crimped end of
the pipe. I finished drilling and tapping and can now use my new Rohm
chuck. I haven't tried to reharden and temper it as it seems to work
well as it is. For my hobby use I doubt it will matter. YMMV. If I had
thought of it at the time I'd have put some paper in the pipe with the
adapter to burn up the oxygen in the pipe. Better yet would have been
to seal the pipe better in the first place.

Mike Henry wrote:
I've a used 1/2" MT2 end mill holder that I'd like to bore out to
3/4". The
problem is that the holder seems to be hardened throughout. A small
file
won't scratch the bore of the holder. It seems that my options would
be to
bore it out as-is with carbide or anneal it and bore. I suspect that

grinding would take forever and am not real thrilled with the idea of

grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 =B0F) or gas
barbecue, a
propane torch, or a 1-hour round trip to a friend with a small heat
treating
oven. If scale is likely to be a problem with annealing, what is
the best
way to deal with that? I don't much care about the appearance of the
end
mill holder end, but don't want to screw up the MT2 end.
=20
Does anyone have any thoughts on the best approach?

Mike Henry wrote:
I've a used 1/2" MT2 end mill holder that I'd like to bore out to
3/4". The
problem is that the holder seems to be hardened throughout. A small
file
won't scratch the bore of the holder. It seems that my options would
be to
bore it out as-is with carbide or anneal it and bore. I suspect that

grinding would take forever and am not real thrilled with the idea of

grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 =B0F) or gas
barbecue, a
propane torch, or a 1-hour round trip to a friend with a small heat
treating
oven. If scale is likely to be a problem with annealing, what is
the best
way to deal with that? I don't much care about the appearance of the
end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?

I would avoid annealing and the potential of scale ruining the MT2. My
approach would be to try tempering it back to about 600 degrees F (pale
blue) and then bore it out with a carbide tool. If you try this, let us
know if this works.

"Harold and Susan Vordos" wrote in message
...

"Mike Henry" wrote in message
...
I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4".
The
problem is that the holder seems to be hardened throughout. A small file
won't scratch the bore of the holder. It seems that my options would be
to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas barbecue,
a
propane torch, or a 1-hour round trip to a friend with a small heat
treating
oven. If scale is likely to be a problem with annealing, what is the
best
way to deal with that? I don't much care about the appearance of the end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?


I'm not familiar with that particular holder, Mike, but I'd be cautious
about opening it up for a larger shank unless the exterior is fairly large
diameter. If it compares favorably with the typical 3/4" holder, I
wouldn't hesitate, but it could prove a mistake if you put it to work with
a
slender body. Screws may not hold, and it may offer chatter that a more
robust one wouldn't. I'm assuming it looks similar to a cat 30,40 or 50
holder.

Assuming there's no good reason to not open it up, the first thing you
need
to determine is if it is hardened through. It may be induction hardened,
which often controls heat treat depth. If that be the case, you may get
through the hard layer and it will machine better, although you would then
be faced with a soft interior when finished. Regardless of how hard
it
may be, I think I'd hesitate to anneal it in any way, not being able to
control where to stop, and scaling.

Grinding the size larger would be the ideal way to go, assuming it is
hardened, and it wouldn't be much of a job on a proper internal grinder,
where you have more power and rigidity and can keep the thing cool while
grinding. If push gets to shove and you can't do it otherwise, you may
be
able to bore near finish size, then grind for size and finish. Carbide
should cut it, even if it's in the low 60's, Rc scale. I'm not suggesting
it would be easy, just possible. One thought could be using a carbide
end
mill held in your toolpost, not the tailstock. Just a thought.

Luck. Tell us how it turns out.

Harold



The MT2 is Morse Taper #2, which is the spindle taper on my Clausing 8520
mill. You probably know what that is, but if not the shank that fits into
the spindle tapers from around 0.7" to 0.59" over a length of about 2.5" and
is internally threaded for a 3/8-16 drawbar.

The tool shank end of the holder is 1-1/4" OD by 2", so the OD would leave a
1/4" wall for the set screw after boring it out to 3/4" ID. Possible
applications include a Rotary Tech carbide insert flycutter and a Tree
boring head, both of which have 3/4" shanks. The mill is a bit beefier than
the import benchtop mills, but no where near as stout as a Bridgeport, so I
figure that fairly light cuts would be required in any case and that 1/4"
wall for the set screw won't be a problem in that sort of duty. That could
be wrong but I'll only be out the cost of the EM holder and the time to
"adjust" it. Please let me know if that analysis is likely to cause
problems to the mill.

Is there an easy way to tell if the hardening is through the part or not?
Annealing doesn't really appeal to me. The holder end has a lot more mass
than the spindle arbor end so I suspect that it would be tough to use a
torch to anneal just the EM end without affect the spindle end. A Clausing
5914 (12" lathe) would be used to bore it out with the MT2 arbor inside a
MT2-MT3 sleeve and that inside an MT4-1/2 to MT3 sleeve. All of the
adapters are in good shape with no corrosion, dings, or galling. I'd rig up
a drawbar to help prevent any of that from slipping. The number of adapters
needed does have me a little concerned though.

What sort of cut(s) should be taken if boring with carbide? The 1/2" ID of
the holder has about a 0.050" chamfer so I assume that a first pass should
have at least that much DOC to get it started properly. I also seem to
recall that carbide likes healthy cuts and that sneaking up on a dimension
doesn't work very well.

Grinding it out myself with a tool post grinder really doesn't appeal to me
as I don't like the idea of all that grinding diust flying around, even with
proper precaustions. If that's the best choice it might be better to find a
local shop that can do it.

Mike

"Mike Henry" wrote in message
...
I'll gladly buy one, but no one seems to make Morse Taper 2 end mill
holders
for 3/4" shanks any more.


That has to do with the ability of an MT2 (a small taper) to resist spinning
at the torque a 3/4" shank bit might put on the holder. Even with a tanged
holder it might spin a few degrees before the tang stops it; you're likely
to nasty-up the socket with too small a holder. It's not NICE to bugger up
a taper socket! (bad machine operator! BAD machine operator!)

MSC lists 3/4" holders in MT3. Their MT2s go up to 5/8 shank, only.

LLoyd

"Mike Henry" wrote in message
...

I'll gladly buy one, but no one seems to make Morse Taper 2 end mill
holders
for 3/4" shanks any more.



Nobody makes 4 inch dia x 1/2 in shank silver & deming drills either, go
figure....

--

SVL

"PrecisionMachinisT" wrote in message
...

"Mike Henry" wrote in message
...

I'll gladly buy one, but no one seems to make Morse Taper 2 end mill
holders
for 3/4" shanks any more.



Nobody makes 4 inch dia x 1/2 in shank silver & deming drills either, go
figure....

I gather that you think a 3/4" end mill holder will put too much torque on
the MT2 spindle. My primary application would be for occassional fly
cutting of aluminum with a 3" insert fly cutter with modest DOC. Is that
too much to expect?.

"Mike Henry" wrote in message
...
snip---

The tool shank end of the holder is 1-1/4" OD by 2", so the OD would leave
a
1/4" wall for the set screw after boring it out to 3/4" ID.

That's what I wondered about. That's a relatively thin wall, and is likely
the fly in the ointment, but that doesn't mean you can't do it. Possible
future problems would include thread failure because of the thin wall and
the amount of torque you may need to prevent end mill slipping, but on a
light duty machine as you've described, it may not be a problem. Assuming
there are no 3/4" adapters available, I'd think that's an indicator that
you're bordering on a bad setup, but Bridgeport also stopped at 3/4" for R8
collets, but the aftermarket supplied the size. With care, they work
fine, as would your modified adapter.

Please let me know if that analysis is likely to cause
problems to the mill.

I'm having a hard time thinking of how it could affect the mill, the only
scenario being that the less than rigid enough adapter might spring enough
to cause a crash, but that's a risk we take anyway, especially on light duty
machines. In my opinion, so long as you worked within the capacity of the
machine and didn't crowd it, there's no reason it wouldn't work It's just a
matter of how long it might last once modified, and how much chatter you're
willing to tolerate. We all have to accept some on these small machines,
Bridgeport included. I hear the smart guys talking about the fact that
steel is the same where deflection is concerned, heat treated or not, but
the fact that tensile increases with heat treat tells me that hard is better
than soft, requiring more effort to deflect. Maybe I don't understand how
it works.


Is there an easy way to tell if the hardening is through the part or not?

I'm not aware of any simple indicator, Mike, but reading the response about
annealing an adapter, plus thinking about my post after making it, I can't
help but wonder if you might have success annealing only the end. If you
submerse the shank in water, securely, and heat the end with a torch, it
would prevent scaling and annealing the part you'd like to protect, and
soften the part that needs modifying. The transition zone could be
trouble, but you maybe could have that just behind the area needing
modification. Overall I don't like the idea, but that doesn't mean it
wouldn't work. I'd also consider the idea of drawing it back at 600°,
which, if it's high carbon steel, should make it soft enough to machine, and
still retain a trace of hardness, with no scaling. It's not anything I've
tried before, but sounds good.

I recommended the use of an end mill to start opening the bore because it
could be a real bitch with a boring tool, if nothing else, because of the
interrupted cut. The starting diameter limits the size of a bar so much
that it would be quite slender, so I'm not convinced you'd have great luck
while it's still in the heat treated state. Once you had it roughed and the
bore was considerably larger, you may be able to change to a boring bar and
achieve size, but if it's hard through, it isn't likely to cut well enough.
All depends on how hard it is. If it's 50Rc or under, no big deal.

I share your concern where the multiple adapters get involved. You're at
the mercy of several things beyond your control. Could turn out fine, maybe
not. If I had the job to grind, I'd want to be able to dial it in instead
of trust multiple adapters.


What sort of cut(s) should be taken if boring with carbide? The 1/2" ID
of
the holder has about a 0.050" chamfer so I assume that a first pass should
have at least that much DOC to get it started properly. I also seem to
recall that carbide likes healthy cuts and that sneaking up on a dimension
doesn't work very well.

If you haven't ever tried machining something hard, I suggest you tackle a
dowel pin. Once you see how they respond, it will snap right into focus.
Hard stuff often will cut OK for a moment, but tip failure usually causes a
rapid cascade to the point your tool goes from cutting to broken in a very
short interval. When material is (very) hard, you have to rule out healthy
cuts, too. The material doesn't cooperate, it breaks your tool instead.
I'm assuming you have nothing at your disposal than typical carbide. Iscar
sells tools that are capable of machining hard things, but it's a real good
idea to have rigid machines with proper spindle speeds. Light duty machines
are likely to disappoint.


Grinding it out myself with a tool post grinder really doesn't appeal to
me
as I don't like the idea of all that grinding diust flying around, even
with
proper precaustions. If that's the best choice it might be better to find
a
local shop that can do it.

I'd probably feel the same way, Mike. That's a lot of grinding to do dry,
and I'm not convinced you'd have good luck, anyway. Internal grinding on a
blind hole takes a little skill if you expect a straight bore. Grinders are
adjustable, lathes are not. Grinders run coolant, on a lathe it would be a
mistake, even though it would help tremendously....

Chuckle! Just had a thought, Mike. What a great excuse to buy a nice Heald
internal grinder! g

Keep us advised~

Harold

You could ask a machine shop to make an adapter for you ;-)

Seriously, MT2 is too small for a 3/4 end mill. As others mentioned,
torque will likely spin the holder in the taper, and then you'll be
looking for some very expensive repair parts.

Mike Henry wrote:
I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4". The
problem is that the holder seems to be hardened throughout. A small file
won't scratch the bore of the holder. It seems that my options would be to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas barbecue, a
propane torch, or a 1-hour round trip to a friend with a small heat treating
oven. If scale is likely to be a problem with annealing, what is the best
way to deal with that? I don't much care about the appearance of the end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?

In article , Mike Henry says...

I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4".

Another option would be to purchase a soft MT2 arbor with enough
meat on the working end, and simply bore it to fit your tooling.

This would be easier than trying to grind it open I suspect.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"Mike Henry" wrote in message
...

"PrecisionMachinisT" wrote in message
...

"Mike Henry" wrote in message
...

I'll gladly buy one, but no one seems to make Morse Taper 2 end mill
holders
for 3/4" shanks any more.



Nobody makes 4 inch dia x 1/2 in shank silver & deming drills either, go
figure....

I gather that you think a 3/4" end mill holder will put too much torque on
the MT2 spindle. My primary application would be for occassional fly
cutting of aluminum with a 3" insert fly cutter with modest DOC. Is that
too much to expect?.


For the tool manufacturers, apparently yes.........'modest cuts"
no......"very light".....perhaps......realize that many shops would fire
your butt due to the hazard and possible liability....

But since you seem so determined, why not just turn the shank down on your
flycutter, or maybe even make up a new flycutter--one that actually 'fits'
the holder you already got ???

--

SVL

"Harold and Susan Vordos" wrote in message
...

Grinding it out myself with a tool post grinder really doesn't appeal to
me
as I don't like the idea of all that grinding diust flying around, even
with
proper precaustions. If that's the best choice it might be better to
find
a
local shop that can do it.

I'd probably feel the same way, Mike. That's a lot of grinding to do
dry,
and I'm not convinced you'd have good luck, anyway. Internal grinding on
a
blind hole takes a little skill if you expect a straight bore. Grinders
are
adjustable, lathes are not. Grinders run coolant, on a lathe it would be
a
mistake, even though it would help tremendously....

Chuckle! Just had a thought, Mike. What a great excuse to buy a nice
Heald
internal grinder! g

My budget (financial and space) is a little tighter than that would allow.

Keep us advised~

I wimped out and ordered a 3/4" EM holder from JTS following email from a
kind lurker. I'd be inclined to try carbide on the 1/2" holder anyway, just
for the experience, but there is a full weekend of work planned anyway.

Thanks for all of the suggestions!

Mike

On Fri, 25 Feb 2005 00:25:41 -0600, "Mike Henry" wrote:

I've a used 1/2" MT2 end mill holder that I'd like to bore out to 3/4". The
problem is that the holder seems to be hardened throughout. A small file
won't scratch the bore of the holder. It seems that my options would be to
bore it out as-is with carbide or anneal it and bore. I suspect that
grinding would take forever and am not real thrilled with the idea of
grinding on the lathe, though I do have a decent toolpost grinder.

For annealing, I have available a toaster oven (500 °F) or gas barbecue, a
propane torch, or a 1-hour round trip to a friend with a small heat treating
oven. If scale is likely to be a problem with annealing, what is the best
way to deal with that? I don't much care about the appearance of the end
mill holder end, but don't want to screw up the MT2 end.

Does anyone have any thoughts on the best approach?


I would buy a blank MT2 arbour (actually I keep a stock of them for similar
emergencies). The I would turn the end down to 1/2", bore a bit of 1 1/4" bar
1/2" and braze or Loctite 603 it onto the arbour. Then I would bore the
resulting assembly to 3/4" and fit the lock screw. I'd keep the 1/2" holder,
or sell it if it was a spare.


Mark Rand
RTFM

Mike Henry wrote:

I'll gladly buy one, but no one seems to make Morse Taper 2 end mill holders
for 3/4" shanks any more. Someone (the VersaMill guy?) once offered to make
a few specials in that size but ISTR that he needed to get around $200 each
in small quantities just to break even. That's a bit over my tool budget.



Mike,

You can order one from JTS Machinery in Ohio for $20.00, and take 10%
off every
Tuesday for a final cost of $18.00. The part number is MT2-34, their
phone
number is (800) 321-3566. I'm picking up an MT-3 end mill holder for a
1"
shank, they are the only source for them also. Be sure and get their
catalog.

Dennis

Tim Killian wrote:

You could ask a machine shop to make an adapter for you ;-)

Seriously, MT2 is too small for a 3/4 end mill. As others mentioned,
torque will likely spin the holder in the taper, and then you'll be
looking for some very expensive repair parts.


I don't know, Tim, my Shoptask's milling spindle is MT3 and I run 1 1/4"
multi-flute end mills and 1 1/2" indexable carbide end mills in mild
steel without any trace of a problem. They have 5/8" and 3/4" shanks
respectively. Lovely cuts. I would think a 3/4" cutter width would work
in an MT2 holder. I did manage to stop the 1 1/4" once, but that was
because I didn't snug it up enough.

I now do most of my heavy cutting with M-42 cobalt roughing/finishing
cutters from Production Tool (page 182 of their 2005 catalog). The
staggered teeth give low chip loads and the wide flats in between the
teeth produce a nice smooth finish. Man, they just run through steel and
iron with a neat buzzing sound.

Dennis

"Mike Henry" wrote in message
...


I wimped out and ordered a 3/4" EM holder from JTS following email from a
kind lurker. I'd be inclined to try carbide on the 1/2" holder anyway,
just
for the experience, but there is a full weekend of work planned anyway.

Thanks for all of the suggestions!


A wise decision, IMO--still, light cuts should be the order of the day when
using that arrangement.

--

SVL

"Mike Henry" wrote in message
...

"Harold and Susan Vordos" wrote in message
...
snip----

Keep us advised~

I wimped out and ordered a 3/4" EM holder from JTS following email from a
kind lurker. I'd be inclined to try carbide on the 1/2" holder anyway,
just
for the experience, but there is a full weekend of work planned anyway.

Thanks for all of the suggestions!

Mike

Very cool, Mike. That means the idea is manageable, and the purchased one
is likely to have thicker walls, which was one of my concerns. Great
solution.

Harold

"PrecisionMachinisT" wrote in message
...

"Mike Henry" wrote in message
...

"PrecisionMachinisT" wrote in message
...

"Mike Henry" wrote in message
...

I'll gladly buy one, but no one seems to make Morse Taper 2 end mill
holders
for 3/4" shanks any more.



Nobody makes 4 inch dia x 1/2 in shank silver & deming drills either,
go
figure....

I gather that you think a 3/4" end mill holder will put too much torque
on
the MT2 spindle. My primary application would be for occassional fly
cutting of aluminum with a 3" insert fly cutter with modest DOC. Is that
too much to expect?.


For the tool manufacturers, apparently yes.........'modest cuts"
no......"very light".....perhaps......realize that many shops would fire
your butt due to the hazard and possible liability....

I'd have been fired long ago if I did this for a living. It's mostly just a
hobby for me, though some parts are made for work in an R&D environment.

But since you seem so determined, why not just turn the shank down on your
flycutter, or maybe even make up a new flycutter--one that actually 'fits'
the holder you already got ???

The flycutter can be seen here, in the second picture down from the top:

http://www.rotarytech.com/products.php

It's got center holes on each end, so I suppose it could be turned between
centers. Getting a dog leg on the flycutter end might be a problem given
the radius on that end, so it might be better to hold it in a 4-jaw chuck.
From an engineering standpoint, though, it seems that a 3/4" EM holder is
simpler and at least as cheap a solution if machining time is considered.
Then too, I'd also like to use (or at least try out) the Tree boring head
and I'm not about to try turning it's 3/4" shank down to 1/2".

Mike

"Dennis Thompson" wrote in message
...


Mike Henry wrote:

I'll gladly buy one, but no one seems to make Morse Taper 2 end mill
holders
for 3/4" shanks any more. Someone (the VersaMill guy?) once offered to
make
a few specials in that size but ISTR that he needed to get around $200
each
in small quantities just to break even. That's a bit over my tool
budget.



Mike,

You can order one from JTS Machinery in Ohio for $20.00, and take 10%
off every
Tuesday for a final cost of $18.00. The part number is MT2-34, their
phone
number is (800) 321-3566. I'm picking up an MT-3 end mill holder for a
1"
shank, they are the only source for them also. Be sure and get their
catalog.

Thanks - that's just what I did. They are out of stock, but this is has
been a long-standing need so waiting a little longer is not an issue.

Mike