How to prevent McWire Z stage from dropping?

I have my McWire ready to go, all stages operational, but I'm worried about my Z stage and how easily the tubing slips off the motor. I didn't see anything that prevented this in the original design. What has people done to prevent a catastrophic drop?

-Lars

I had the same issue.

A smear of epoxy on the very end of the motor axle and a smear along the studding before the tubing was pushed on fixed the problem. I've now run my mcwire with a heavy dremel on the z axis for a couple of 4 hour sessions and have had no slippage.

When you want to remove the tubing you can slit it with a sharp knife and the epoxy will fall off the studding and the motor axle.

ro

zip ties. I drilled a hole through a long nut(can't remember what it's called ) The kind that holds two all thread rods together. Used a bolt through the stepper motor shaft and threaded the nut on to the all thread rod and used a double nut there(one would be enough). Be careful with the metal shavings. Stepper motor magnets are very strong. I used blue tack to keep them out.

After that description I decided to just take a picture.

I tied the gasoline tubing that I used as the motor coupling on using a bit of bailing wire (tie wire). Kinda the same sort of thing as a pipe clamp, but cheaper. That worked great, but does have the disadvantage that it won't come apart even if the Z stage hits the end (hard) and so it may lead to damaging the MDF that I built it out of. Someday I'll post pictures...

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I'm building it with Baling Wire

I had a problem with the other end of the Z-axis, where the coupling nut is wrapped in duct tape. There was so much load on the duct tape that is began to telescope and would actually drift enough during small prints that I lost all z-height.

I used some metal plumber strap http://www.google.com/search?hl=en&q=metal+plumber+tape&aq=f&aqi=&aql=&oq=&gs_rfai=, bent and cut so that the 1/4-20 rod went through the big hole and it mounted to the z-stage just above the coupling nut. Now the metal strap prevents the duct tape from telescoping.

I used some shrink wrap tubing, the type with the adhesive, to attach the Z-axis once I realized that problem. It works very well.