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View Full Version : How do you use a Key way broach??



randyjaco
01-18-2010, 09:47 PM
I recently purchased a key way broach set and it came with no directions. Yesterday I needed to cut a key way in an aluminum pulley I made. I technique I thought was correct was quite cumbersome. I did get the key way cut, but I suspect there is a better way. What is the proper way to broach a key way?

TIA
Randy

Jim Hubbell
01-18-2010, 09:56 PM
I simply start the broach into the bore to be cut using the correct bore adapter and press it through with lots of oil. Twice if a shim is used.

SpyGuy
01-18-2010, 09:58 PM
I technique I thought was correct was quite cumbersome. I did get the key way cut, but I suspect there is a better way.

Why don't you tell us the technique you used?

Mcgyver
01-18-2010, 09:59 PM
bushing in hole in arbor press, press through, shim appropriately and repeat as necessary....short of expanding that to a chapter....how did you go about it and what was cumbersome? might help identify the problem

daveo
01-18-2010, 10:06 PM
Here ya go... http://www.youtube.com/user/mrpete222#p/u/8/8tAz5YDFtAs

oldtiffie
01-18-2010, 10:23 PM
Better still - use an arbor press in a hydraulic press:
http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hydraulics1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hydraulics2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hydraulics3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hydraulics4.jpg

All powered by Porta-Power

Mcgyver
01-18-2010, 10:26 PM
Better still - use an arbor press in a hydraulic press:



Not imo, you want the feel of it that the arbor press gives. I wont jinx my self by saying I've never broken a broach, but you get the idea

oldtiffie
01-18-2010, 11:15 PM
Quite right macgyver.

Thanks for the "heads up".

I have one hand on the pump and other on the arbor press handle.

The "feel" you correctly refer to is still there.

Edit:

I wouldn't use just the press ram and frame as I can't be sure of a "straight/aligned" "push".

Having the arbour press ram do the job pretty well solves that problem.

Same for pressing bearings etc.

End edit.

Big T
01-18-2010, 11:20 PM
Here ya go... http://www.youtube.com/user/mrpete222#p/u/8/8tAz5YDFtAs

He has a lot of good video's.

daveo
01-18-2010, 11:31 PM
Yes he does! I learned a lot from them....

John Stevenson
01-19-2010, 03:49 AM
Go to DuMonts website http://www.dumont.com/
Brilliant website for all broaching info and very accurate, they tell you the pressures needed for each size and my hydraulic broaching press is graduated in pounds and it's always very close to what Dumont says.

I arbor press up to 12mm, 1/2" and hydraulic broach over that, mainly because of the pressure needed but the bigger broaches need a lot of daylight especially if you have a thick gear or pulley to do.

Carld
01-19-2010, 08:52 AM
I'm sure that we all would like to know how Randy used his broach and found it did not work well.

Perhaps he had a good idea but something just didn't work right. Hope he tells us what he did.

miker
01-19-2010, 03:04 PM
Randy. one thing that may not have been clear from the video.
The little shim with the right angle hook at the top end is placed behind/on the NON toothed side of the broach. It effectively pushes the toothed side deeper into the cut for the next pass.

Sometimes you may have to add more shims and more passes to achieve the depth of slot required.

A bucket/garbage bin with rags/paper in it can be placed under the press to catch the Broach as it falls through. Better than letting it hit the floor.:o

whitis
01-19-2010, 04:32 PM
The easy way is to turn a 7-year old girl loose on a hydraulic press. She can broach 150 parts (with shims) in 2 hours and shows how it is done in this youtube video I ran across a while back:
http://www.youtube.com/watch?v=BMDafZ23LXs
No arbor press with 2 microinches of daylight for the part and broach. She is using a pretty big broach, though.

John Stevenson
01-19-2010, 04:38 PM
Whitis,
I think the sums are wrong, 150 in two hours, that's less than a minute per piece on a handdraulic press ? One or two passes ?

.

oldtiffie
01-19-2010, 06:03 PM
I do hope that young lady has taught some of the old women a thing ot two.

randyjaco
01-21-2010, 09:26 PM
Thanks all,
Sorry to be so slow getting back.
I was broaching a 5/8í ID shaft in an aluminum pulley. I put the proper insert into the hole and selected the appropriate broach and shim. I lubed everything liberally with oil. I first took it to a 2 ton arbor press. That didnít work. I then took it to my 12 ton hydraulic. This time I removed the shim thinking that I would do it in 2 passes. First pass required what I thought was too much force. I removed the assembly from the press. The broach was really jammed. I backed it out with the arbor press and cleaned the teeth. I then put in the shim and tried the hydraulic press again. The shim straightened out and slipped out of the insert. I heated up the shim and re-bent it. I backed out the broach, reassembled the broach shim and insert and added lots of oil. It finally went through. I then turned everything around and broached from the other side. The job got done, but I suspect there is a better way.

Randy

doctor demo
01-21-2010, 10:53 PM
Randy, different broach makers make broaches differently . Some broaches require multiple shims and passes. It is important to NOT put the required shims in on the first pass, that is like trying to drive up a curb without a ramp. Usualy this will result in broken peices and possible injury.
It sounds like You got lucky this time.

Steve

whitis
01-21-2010, 10:54 PM
Whitis,
I think the sums are wrong, 150 in two hours, that's less than a minute per piece on a handdraulic press ? One or two passes ?

.
Never underestimate a kid, they can work pretty hard until they realize it is work :). I suspect the "2 hours" wasn't exactly NIST traceable or even wall clock traceable. In the video, while she is talking, it takes her about 2 minutes for the first pass and 1-1/2 for the second just to drive the press, though I think she was under pumping. But she was broaching a fistful (literally) of parts at one time. "We have to have at least five of these because if we had one by one it would take forever". So she might indeed have cranked them out at about a minute each.

oldtiffie
01-22-2010, 01:08 AM
I recently purchased a key way broach set and it came with no directions. Yesterday I needed to cut a key way in an aluminum pulley I made. I technique I thought was correct was quite cumbersome. I did get the key way cut, but I suspect there is a better way. What is the proper way to broach a key way?

TIA
Randy

Randy.

As it came with no directions, I have to ask if it was new or if used, was-it sharp?

If it was not sharp - really sharp as they are HSS - they have a habit of "losing" a corner or front edge or two which will cause galling in some aluminiums - which in turn can cause the problems you seem to have had.

randyjaco
01-22-2010, 05:33 PM
It was a new import set from Enco.
Randy

randyjaco
01-22-2010, 06:35 PM
Here is that broached pulley in action. It now turns my newly restored Logan 820. Thanks again everybody. :D

Randy

http://i640.photobucket.com/albums/uu124/randyjaco/Logan%20820/P1010013.jpg

Carld
01-23-2010, 01:40 AM
Really nice looking lathe Randy. Logan is a good lathe, I had one.

When broaching the first pass is always without the shims. If one shim is in the kit use it on the second pass. If more than one keep adding shims on each pass until you used all of them.

Aluminum can be hard to broach and pushing a broach out backwards can break the teeth off the broach. Your lucky it was aluminum.