I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.

thanks

Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.

thanks



try cutting a scrap piece of metal. There are many variables involved
including the stiffness of your machine, the quality of the tool
holder, run out of the cutter and shank itself. I don't remember what
tool holder you are using in your mill but the shank should slide up
into the tool holder, Put it up as far as possible, shorter is better.
Don't try to climb mill unless your machine is very rigid.

good luck with your machining education.

John

On 11/28/2010 06:28 PM, Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.
Yikes. If you mean the gear cutter is 8" away from the spindle nose,
then yes, I think that is too long. I have made a stub milling arbor,
and also bought one that gets the cutter down to about 1" from the
spindle nose. You may actually need more, depending on the arbor the
gear is mounted on and the rest of the setup. But, I would want the
cutter no more than 3" away from the spindle, unless it is really heavy
up to where the cutter sits. I have done some of this with 1" and 1.25"
arbors, the 7/8" arbor is even more flexible than mine.

Jon

Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.

It's basically the same situation as turning with stock held in a lathe
chuck. Stickout shouldn't be more than 3X diam. I don't think that
Young's modulus is going to be much different for your arbor.

Bob

On 2010-11-29, Jon Elson wrote:
On 11/28/2010 06:28 PM, Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.
Yikes. If you mean the gear cutter is 8" away from the spindle nose,
then yes, I think that is too long. I have made a stub milling arbor,
and also bought one that gets the cutter down to about 1" from the
spindle nose. You may actually need more, depending on the arbor the
gear is mounted on and the rest of the setup. But, I would want the
cutter no more than 3" away from the spindle, unless it is really heavy
up to where the cutter sits. I have done some of this with 1" and 1.25"
arbors, the 7/8" arbor is even more flexible than mine.

Jon

I agree. I will just cut it off.

i

On Nov 29, 6:34*pm, Ignoramus32174 ignoramus32...@NOSPAM.
32174.invalid wrote:
...
I agree. I will just cut it off.
i-

You could make a shorter one, index it to the spindle and turn the
cutter seat on the mill with a lathe bit in the vize. Then the cutter
should run as true as possible and not leave revolution marks.

jsw

On 2010-11-29, Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Is that 8" the overall length -- or just the length of the 7/8"
diameter part? My following answer assumes that it is just the 7/8"
diameter part.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.

Well ... the diameter of the stack of spacer rings will help
somewhat. (What do those wind up at -- perhaps 1-1/4" for 7/8" bore?)

But mount the cutter as close as possible to the NMTB 30 taper
end. For the 40-taper ones on my Nichols mill -- the other (free) end
is supported in a needle roller bearing to more than double the
stiffness.

Good Luck,
DoN.

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On 2010-12-01, DoN. Nichols wrote:
On 2010-11-29, Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Is that 8" the overall length -- or just the length of the 7/8"
diameter part? My following answer assumes that it is just the 7/8"
diameter part.

Overall

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.

Well ... the diameter of the stack of spacer rings will help
somewhat. (What do those wind up at -- perhaps 1-1/4" for 7/8" bore?)

This tool has a shank, and no spacer rings. It is called "slitting
saw arbor".

But mount the cutter as close as possible to the NMTB 30 taper
end. For the 40-taper ones on my Nichols mill -- the other (free) end
is supported in a needle roller bearing to more than double the
stiffness.

Yes, I do not have that support.

i

On 2010-12-01, Ignoramus9343 wrote:
On 2010-12-01, DoN. Nichols wrote:
On 2010-11-29, Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Is that 8" the overall length -- or just the length of the 7/8"
diameter part? My following answer assumes that it is just the 7/8"
diameter part.

Overall

O.K. Not that bad, then.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.

Well ... the diameter of the stack of spacer rings will help
somewhat. (What do those wind up at -- perhaps 1-1/4" for 7/8" bore?)

This tool has a shank, and no spacer rings. It is called "slitting
saw arbor".

Oh -- one of those. Does it have a key to prevent the gear
milling cutter from slipping? The normal arbor for a horizontal mill
has a keyway running its length and a key goes into it and the keyway in
the holes in the cutters and spacers. Beyond that there is a threaded
length and a big nut (typically two flats milled into a cylinder,
instead of the usual hex nut) to clamp the whole stack firmly. Beyond
the nut is the reduced diameter for the needle roller bearing described
below -- supported by at least an overarm, and likely some diagonal
braces as well to allow heavy cuts with minimal deflection. Really long
horizontal milling cutters have an extra bearing spacer which goes
between cutters (there are often many cutters stacked on there to do
multiple parts of the job in a single pass -- such as cutting the two
flats, the edges, and the two inverted V ways on a cast iron lathe bed
in a single pass.

But mount the cutter as close as possible to the NMTB 30 taper
end. For the 40-taper ones on my Nichols mill -- the other (free) end
is supported in a needle roller bearing to more than double the
stiffness.

Yes, I do not have that support.

O.K. I was thinking in terms of a horizontal milling arbor. I
know that I have several in various sizes for the NMTB 40 taper, and
assumed that you found a smaller one in NMTB 30 taper designed for a
benchtop horizontal mill.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2010-12-02, DoN. Nichols wrote:
On 2010-12-01, Ignoramus9343 wrote:
On 2010-12-01, DoN. Nichols wrote:
On 2010-11-29, Ignoramus8040 wrote:
I have a shank to hold slitting saws, gear cutters etc. It is on a
7/8" shank and is appx. 8" long.

Is that 8" the overall length -- or just the length of the 7/8"
diameter part? My following answer assumes that it is just the 7/8"
diameter part.

Overall

O.K. Not that bad, then.

No. I misled you. The arbor is 7/8" thick, it is not thicker than that
in any of its parts.

Having never cut gears etc, I am concerned if, perhaps, this is too
long and would generate chatter. Is there any kind of a guideline on
this.

Well ... the diameter of the stack of spacer rings will help
somewhat. (What do those wind up at -- perhaps 1-1/4" for 7/8" bore?)

This tool has a shank, and no spacer rings. It is called "slitting
saw arbor".

Oh -- one of those. Does it have a key to prevent the gear
milling cutter from slipping? The normal arbor for a horizontal mill
has a keyway running its length and a key goes into it and the keyway in
the holes in the cutters and spacers. Beyond that there is a threaded
length and a big nut (typically two flats milled into a cylinder,
instead of the usual hex nut) to clamp the whole stack firmly. Beyond
the nut is the reduced diameter for the needle roller bearing described
below -- supported by at least an overarm, and likely some diagonal
braces as well to allow heavy cuts with minimal deflection. Really long
horizontal milling cutters have an extra bearing spacer which goes
between cutters (there are often many cutters stacked on there to do
multiple parts of the job in a single pass -- such as cutting the two
flats, the edges, and the two inverted V ways on a cast iron lathe bed
in a single pass.


No key, unfortunately.

But mount the cutter as close as possible to the NMTB 30 taper
end. For the 40-taper ones on my Nichols mill -- the other (free) end
is supported in a needle roller bearing to more than double the
stiffness.

Yes, I do not have that support.

O.K. I was thinking in terms of a horizontal milling arbor. I
know that I have several in various sizes for the NMTB 40 taper, and
assumed that you found a smaller one in NMTB 30 taper designed for a
benchtop horizontal mill.

I just missed an ebay auction for a nice cutter arbor in the size that
I needed, dang!