Ask the Mechanic

Gib Key Removal

(Steve Thompson)

Last month (in September 2022…), I talked about how to align two sprockets by adjusting the alignment of one of the sprockets that was held in place by a gib (wedge) key.

This month, we will look at gib key removal. The gib key removal is a little different process than most in order to loosen a sprocket or bearing on a shaft. That's because the shaft is secured directly to the sprocket rather than the shaft turning inside a bearing with a lock collar locking the shaft to a bearing.

To remove the sprocket and gib key, the sprocket must be driven in away from the tapered gib key. There should be enough room between the back of the sprocket and the support bearing to drive the sprocket far enough back to remove the gib key.

Some techs use a big punch and an adjusting tool (hammer) to drive the sprocket off its seat between the sprocket and the shaft. I prefer to use a pipe with a notch cut in the pipe the size of the gib key (see photo accompanying this article). The pipe with the notch allows the full surface of the pipe to mate with the sprocket. If the key is rusted in place, you may need to soak it with penetrating oil, and sometimes a little heat helps.


-- Write Steve Thompson at Ask The Mechanic, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email, and be sure to include your phone number.