View Full Version : How do you remove motor shaft key?


walter
10-07-2007, 07:46 PM
_
And how did they make it stuck so well?

http://i233.photobucket.com/albums/ee298/mineral-casting/th_IMG_3058-1.jpg (http://i233.photobucket.com/albums/ee298/mineral-casting/IMG_3058-1.jpg)

Your help will be appreciated.

Geof
10-07-2007, 08:03 PM
You can do it the butcher's way with a small chisel at the front tapped with a hammer. With care you only get a groove in the front radius and it does not affect the refitting of the keyway and hub.

Or you can do it the real butcher's way and grip the sides with Visegrips and just rip it out. The Visegrips may slip off but whther they do or not you will probably wreck the key.

Or you can do it the careful, elegant way: Drill tapping holes for 8-32 thread near each end just through the key and a little bit into the shaft. Tap carefully and sometimes the tap lifts the key out when it hits the bottom of the hole. If this doesn't happen and you feel the tap may break just tap as deep as possible.

Now you have two options: Take the first two or three threads of a couple of screws so they can reach the bottom of the hole before running out of thread and carefully screw them down to the bottom so they lift the key out. Again if you feel the screw is going to strip or break don't get carried away go to option two.

Get a length of steel longer than the key and drill clearance holes for the screws. Put nuts on fully threaded screws and screw them into the key through the holes in the steel. Now put packing either end of the key to space the steel out and tighten the nuts to pull the key up.

And if you still cannot get it out I give up.

307startup
10-07-2007, 10:53 PM
Go for the butchers way. Keystock is cheap and you can cut it with a cutoff wheel or abrasive saw. Grinding a radius on your new key is pretty simple if you have a bench grinder, and not terribly hard if you put the key in a vice and use a grinding wheel on a die grinder or electric grinder. Drilling and tapping keystock isn't exactly fun, because it's usually harder than the back of god's head. Just my $.02 as I have to do this at work all the time...usually 2-3 times a day.

chipsinpan
10-07-2007, 10:55 PM
Keys are cheaper than time .. weld a slide hammer to the top , and pop that sucker out .

walter
10-07-2007, 11:37 PM
Butcher way it is, then!

I thank you, gentlemen.

Kiwi
10-08-2007, 06:46 AM
Pinch end of key and lever out with side cutting pliers.
May leave nicks in key which can be smoothed with a flat file.

widgitmaster
10-08-2007, 07:08 AM
I wouldn't want a sloppy fitting key in a stepper motor, as it could show up as lost steps!

The key can be removed by any of the methods mentioned above, but remember if the shaft is soft steel it can be damaged or bent. If you use a vise grip plier's, make sure they are new and have a sharp jaws or they will slip off. I have removed tight keys with them, and usually work one end out first!

My 2 cents.
Widgit

Geof
10-08-2007, 12:42 PM
Butcher way it is, then!

I thank you, gentlemen.

Butcher or Real Butcher?:)

pixpop
10-08-2007, 02:42 PM
Let me preface this by saying I have no clue about this... sorry if this sounds stupid.

But.. I worry about any method that involves a hammer. Isn't it going to transfer shock to the motor bearings? Isn't that likely to damage the bearings?

I guess it would be OK if you could support the far end of the shaft, so the bearings don't see the impact. I don't know how you would do this for the slide hammer method though.