:yikes:My team has recently run into a problem. We looked at our drill motors and found that the hex-shaped shafts that were designed to work with the flexible couplings are moving in and out when we drive our motors forward, and back when we drive backward. 
Can someone please help us out
Dave:cool:
How much movement? Do you have proper retainers outboard of the bearings on each end of the main shaft containing the small worm gear? Do you have the motor securely fastened?
Basically what is happening is the hex coupling is moving back and forth. We are not using a worm gear. and the movement is only on one side. A member of our team described the movement as “unscrewing itself”
Dave:cool:
I think you need to put in the left hand screw which came with the kit to keep the drill motors from unscrewing themselves.
*Originally posted by DaveG702 *
**:yikes:My team has recently run into a problem. We looked at our drill motors and found that the hex-shaped shafts that were designed to work with the flexible couplings are moving in and out when we drive our motors forward, and back when we drive backward.
**
We noticed the same problem. We have thought of several ways to correct this. Here is what we are trying right now: Tap a hole for a 4-40 machine screw into the Aluminum hex piece. Drill a clearance hole in the plastic coupler. Then fasten the two pieces together with a screw. This, admittedly, is a bad hack. However it was quick and cheap. If this fails, our backup plan is to remake the Aluminum hex pieces ourselves, except out of 1" round stock instead of hex stock. Then, we’ll go to the MSC catalog and buy a standard off the shelf shaft coupler to replace that goofy plastic one.
/* Daniel */
We noticed that the palstic couplings are tapered inside, proably was done to make them more moldable, but makes them less than ideal for transmitting high torques.
Hence we are making steel couplings made to our own design to go on the end of the motor shaft, and putting a 5/8’ pinned shaft ito the end of it eliminating the plastic stuff.
As mentioned before make shure the lefthand screw is in place and is the right length, the standard drill screws sold for chucks is shorter than the ones form FIRST. also I would recomend high srength loc tight on the motor and screw thread also. Let it cure over night before using it. Also tighten the coupling and screw by putting the drill motor in low and holding the fan in the motor with a small screw driver while clamping the motor mount down.
This worked well for the older drill motors and should work again.