This is my first time broaching.

I am broaching a keyway slot in a pulley bushing. The hole is 1 3/8
and the slot is 5/16". The reason for needing to broach is that I had
to bore this pulley from 1.25" to 1 3/8", to accommodate a larger
motor shaft.

I am finding it difficult to do with a 3 ton press. It does work, but
I feel at the edge of this press's capability. I am concerned
that, perhaps, I am doing something wrong, or the broach is dull. So,
my question is, what would be a normal force required for broaching
iron bushings with a 5/16 broach. The bushing is about 2 inch deep.

I am using tapmagic cutting fluid.

i

We normally do 1/4" slots in a 12 ton hydraulic press.

Ignoramus17181 wrote:
This is my first time broaching.

I am broaching a keyway slot in a pulley bushing. The hole is 1 3/8
and the slot is 5/16". The reason for needing to broach is that I had
to bore this pulley from 1.25" to 1 3/8", to accommodate a larger
motor shaft.

I am finding it difficult to do with a 3 ton press. It does work, but
I feel at the edge of this press's capability. I am concerned
that, perhaps, I am doing something wrong, or the broach is dull. So,
my question is, what would be a normal force required for broaching
iron bushings with a 5/16 broach. The bushing is about 2 inch deep.

I am using tapmagic cutting fluid.

i

On Tue, 23 Jun 2009 21:39:51 -0500, Ignoramus17181
wrote:

This is my first time broaching.

I am broaching a keyway slot in a pulley bushing. The hole is 1 3/8
and the slot is 5/16". The reason for needing to broach is that I had
to bore this pulley from 1.25" to 1 3/8", to accommodate a larger
motor shaft.

I am finding it difficult to do with a 3 ton press. It does work, but
I feel at the edge of this press's capability. I am concerned
that, perhaps, I am doing something wrong, or the broach is dull. So,
my question is, what would be a normal force required for broaching
iron bushings with a 5/16 broach. The bushing is about 2 inch deep.

I am using tapmagic cutting fluid.

i

Nothing you've described sounds wrong. You might have a dull broach.
I've never worried about force aside from breaking broach or failing
to get the job done, using a 12-ton press because that's what I have
handy.

On 2009-06-24, RoyJ wrote:
We normally do 1/4" slots in a 12 ton hydraulic press.

OK, that's a useful data point.

I am done with this particular broaching task. It turns out that using
a different lubricant ("heavy threading oil with sulphur and
chlorine") helps somewhat.

The pulley is nicely sitting on the new motor's shaft with the proper
key between them.

The reason for all this is that I got a 7.5 HP single phase motor,
which will replace the current three phase motor on my compressor.
As I mentioned before, I had a three phase motor on this compressor
before.

i

Ignoramus17181 wrote:
This is my first time broaching.

I am broaching a keyway slot in a pulley bushing. The hole is 1 3/8
and the slot is 5/16". The reason for needing to broach is that I had
to bore this pulley from 1.25" to 1 3/8", to accommodate a larger
motor shaft.

I am finding it difficult to do with a 3 ton press. It does work, but
I feel at the edge of this press's capability. I am concerned
that, perhaps, I am doing something wrong, or the broach is dull. So,
my question is, what would be a normal force required for broaching
iron bushings with a 5/16 broach. The bushing is about 2 inch deep.

I am using tapmagic cutting fluid.

i

Iggy,
I do it all the time with a 3 ton arbor press and experience no problem. You
do have to use the shims and make multiple passes though. However, 2" is
quite long. I hope your quide bushing is the same length. It also helps to
oil the guide. I also have Tapmagic, but never had the need to use it for
broaching.
Steve

"Ignoramus17181" wrote in message
...
This is my first time broaching.

I am broaching a keyway slot in a pulley bushing. The hole is 1 3/8
and the slot is 5/16". The reason for needing to broach is that I had
to bore this pulley from 1.25" to 1 3/8", to accommodate a larger
motor shaft.

I am finding it difficult to do with a 3 ton press. It does work, but
I feel at the edge of this press's capability. I am concerned
that, perhaps, I am doing something wrong, or the broach is dull. So,
my question is, what would be a normal force required for broaching
iron bushings with a 5/16 broach. The bushing is about 2 inch deep.

I am using tapmagic cutting fluid.

i

On Tue, 23 Jun 2009 21:39:51 -0500, Ignoramus17181
wrote:

This is my first time broaching.

I am broaching a keyway slot in a pulley bushing. The hole is 1 3/8
and the slot is 5/16". The reason for needing to broach is that I had
to bore this pulley from 1.25" to 1 3/8", to accommodate a larger
motor shaft.

I am finding it difficult to do with a 3 ton press. It does work, but
I feel at the edge of this press's capability. I am concerned
that, perhaps, I am doing something wrong, or the broach is dull. So,
my question is, what would be a normal force required for broaching
iron bushings with a 5/16 broach. The bushing is about 2 inch deep.

I am using tapmagic cutting fluid.

i

Check here

http://www.dumont.com/prodc.html

a 5/16C broach at a 2.5" loc will need 3960 pounds to push it through.

At 2" LOC you're most likely at 3000 or so......


Thank You,
Randy

Remove 333 from email address to reply.

On 2009-06-24, Randy wrote:
On Tue, 23 Jun 2009 21:39:51 -0500, Ignoramus17181
wrote:

This is my first time broaching.

I am broaching a keyway slot in a pulley bushing. The hole is 1 3/8
and the slot is 5/16". The reason for needing to broach is that I had
to bore this pulley from 1.25" to 1 3/8", to accommodate a larger
motor shaft.

I am finding it difficult to do with a 3 ton press. It does work, but
I feel at the edge of this press's capability. I am concerned
that, perhaps, I am doing something wrong, or the broach is dull. So,
my question is, what would be a normal force required for broaching
iron bushings with a 5/16 broach. The bushing is about 2 inch deep.

I am using tapmagic cutting fluid.

i

Check here

http://www.dumont.com/prodc.html

a 5/16C broach at a 2.5" loc will need 3960 pounds to push it through.

At 2" LOC you're most likely at 3000 or so......


Thanks. It would seem, then, that the broach is a little dull.

DuMont sent me a document on broach sharpening and I will try to
sharpen this broach.

In any case, as I said, I broached the bushing from that Browning
pulley, and it sits securely on the motor's shaft.

i

"Steve Lusardi" wrote:

Iggy,
I do it all the time with a 3 ton arbor press and experience no problem. You
do have to use the shims and make multiple passes though. However, 2" is
quite long. I hope your quide bushing is the same length. It also helps to
oil the guide. I also have Tapmagic, but never had the need to use it for
broaching.
Steve

I also use an arbor press. A dull broach lets you know it. I'm thinking since a broach
is a tapered cutter, the loads scale linearly as length increases.

The first broach I broke I did it on a hydraulic press. I tried to do the job in one
shot. Best to ease up and let the broach recenter or relieve deflection if there is any.

That is the nice thing about an arbor press, easy to let up, fast to shove though for
reasonable sizes.

Wes
--

When in trouble or in doubt, run in circles, scream and shout.

On 2009-06-24, Wes wrote:
I also use an arbor press. A dull broach lets you know it. I'm thinking since a broach
is a tapered cutter, the loads scale linearly as length increases.

The first broach I broke I did it on a hydraulic press. I tried to do the job in one
shot. Best to ease up and let the broach recenter or relieve deflection if there is any.

That is the nice thing about an arbor press, easy to let up, fast to shove though for
reasonable sizes.

Yes, the nice thing about an arbor press is the "feel" of the handle,
which tells me a lot about what is going on.

i

Ignoramus28618 wrote:

Yes, the nice thing about an arbor press is the "feel" of the handle,
which tells me a lot about what is going on.

Same for those manual feed handles on lathes and mills.