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View Full Version : BP Arbors & Key Dimensions ???



JoeLee
02-25-2015, 12:09 PM
I recently had an issue with a new side milling cutter that I bought. This cutter is ToolMex brand..... Poland. I have dozens of them and never had an issue until now.
This one wouldn't fit on my 1" BP stub arbor or my long arbor. The reason is the key slot is just a bit too shallow. I checked some of my other cutters and found that all of them are slightly deeper, some by as much as .006.
So what I'm wondering here is what is the height of the key supposed to be on a 1" arbor. My stub arbor measures 1.1035. My long arbor is about 1.110.
I measured a few different cutters and found that the key slots in all of them were slightly deeper than the ToolMex cutter I just bought, they all vary a little but all fit both of my arbors. So perhaps some of you guys can measure your 1" arbor and give me an idea of what this dimension should be before I grind the key's down.

JL....................

http://i911.photobucket.com/albums/ac317/JoeLee09/Telescopic%20Sq%20Tube/Image001_zpsdqcmf8rv.jpg (http://s911.photobucket.com/user/JoeLee09/media/Telescopic%20Sq%20Tube/Image001_zpsdqcmf8rv.jpg.html)
http://i911.photobucket.com/albums/ac317/JoeLee09/BP%20Arbors%20and%20Key%20Slot%20Dimensions/Image002_zpsknoyhbvk.jpg (http://s911.photobucket.com/user/JoeLee09/media/BP%20Arbors%20and%20Key%20Slot%20Dimensions/Image002_zpsknoyhbvk.jpg.html)
http://i911.photobucket.com/albums/ac317/JoeLee09/BP%20Arbors%20and%20Key%20Slot%20Dimensions/Image003_zpsnvqmkjk6.jpg (http://s911.photobucket.com/user/JoeLee09/media/BP%20Arbors%20and%20Key%20Slot%20Dimensions/Image003_zpsnvqmkjk6.jpg.html)

sarge41
02-25-2015, 01:51 PM
Joe: Better to mill the offending arbor another .010" deeper.

Sarge

duckman
02-25-2015, 01:52 PM
I don't use a key would rather it spin than blow up a cutter.

Doozer
02-25-2015, 02:34 PM
It is common to run without a key with slot cutters.
Safer that way.

If you must have keyway and keyseat dimensions
they are in the Machinery Handbook.

-D

oldtiffie
02-25-2015, 06:27 PM
Grind the key to measure 1.100" over the key and arbor.

Its best to have a number of spare keys.

I always use a key as if the cutter spins on the arbor it will either loosen the arbor nut (further freeing the cutter) or further tightening the arbor nut which in the worst case will make the nut very hard to undo/release.

John Stevenson
02-25-2015, 07:05 PM
Grind the key to measure 1.100" over the key and arbor.

Its best to have a number of spare keys.

I always use a key as if the cutter spins on the arbor it will either loosen the arbor nut (further freeing the cutter) or further tightening the arbor nut which in the worst case will make the nut very hard to undo/release.

If a slitting saw spins on an arbor with a key fitted it shatters, no argument, it shatters and those bits are not just like razors they ARE razors.

Anyone who has used one as opposed to taking pretty pictures of one knows this and leaves the key out of that section of the arbor. By all means leave a key in the bushes next to the nut to prevent it loosening or tightening.

oldtiffie
02-25-2015, 07:55 PM
The OP's post/question was with regard to a side and face cutter which is considerably larger/wider than a slitting saw.

http://s911.photobucket.com/user/JoeLee09/media/BP%20Arbors%20and%20Key%20Slot%20Dimensions/Image002_zpsknoyhbvk.jpg.html

JoeLee
02-25-2015, 10:24 PM
I think OldTiff has the right idea. Have a few extra keys or grind the key down a few thou. If you guys are afraid of shattering a cutter like that then your hogging way too much material, I never have that fear. I would never run one without a key. If it spins and galls up your arbor and spacers, then what???
But my question here was what should the height of the key be on a 1" arbor??? This is the first cutter I've had an issue with so I'm assuming the key height is OK, it's the slot in this one cutter that is the problem.

JL.............

Ohio Mike
02-25-2015, 10:58 PM
Another reason to have Machinery's Handbook. From the bottom of the key to the opposite side of the bore of the cutter should be 1.1040, tolerance +.010 inch. The arbor with key should be 1.0940 inch max and 1.0880 min.

oldtiffie
02-26-2015, 02:46 AM
The OP's problem is to do with the key slot in that cutter not being broached deep enough.

The OP didn't seem to have any problems with any other cutter on that arbor so it seems that by a process of elimination (and logic) that the problem is (was?) solely to do with that single cutter keyway depth.

JoeLee
02-26-2015, 07:32 AM
Another reason to have Machinery's Handbook. From the bottom of the key to the opposite side of the bore of the cutter should be 1.1040, tolerance +.010 inch. The arbor with key should be 1.0940 inch max and 1.0880 min. I do have a machinery's hand book, try finding stuff in it, and what doe's the book call it???? What page or section did you find that info on???

JL................

Ohio Mike
02-26-2015, 07:44 AM
Started at "Keys and Keyseats" and then wen down the list and saw "milling cutters & arbors". I have a couple, the one I grabbed is 19th Ed.

sawlog
02-26-2015, 10:52 AM
I second the idea just cut down the key to fit. Simple quick and probably the easiest method.

RichR
02-26-2015, 11:31 AM
The first picture in the original post shows a measurement of 1.1035 while the Machinery's Handbook states it should be 1.0940 max. Either the key is
too long or it is not seated all the way into the arbor, possibly due to a burr or debris.

Doozer
02-26-2015, 12:57 PM
We gave you a fishing pole and a fish.
What kind of answers would you like to receive?

-D

PixMan
02-26-2015, 01:06 PM
I've seen keys not seating because they have fairly sharp corners yet the keyways have a healthy radius in their corners from a dull or chamfered cutter.

If worried about mashing an arbor because the cutter jammed, make keys out of aluminum or brass and get the happy medium between enough holding power and something that will shear off of too much force is encountered.