Originally posted by c.a.m
I just happen to have a KX and a K1000 on my repair bench.
Here is a picture of the two rewind assemblies - the knobs and shafts.
The two shafts have the same diameter but slightly different construction at the base. The screw threads are identical.
The winder knobs are identical (same dimensions, identical winder arm, action, etc) and seem interchangeable on the two shafts.
I tried the K1000 shaft on the KX. It fits. It secures a film canister properly, and it unlatches the door.
However, you'll notice in the image that the grooves on the shafts are not identical - they're placed at different locations along the shaft. The main effect is that the K1000 shaft doesn't provide the designed positive engagement when pushed fully into the camera's film compartment. It may be pulled upwards easily without resistance, so there would be a risk of disengaging the film-canister sprocket when in use. If you've used a film camera, you probably know that a slight tug or force is required to pull the re-winder shaft up to unlatch the door -- this resistance is not present with the K1000 shaft on the KX. Other than that issue, I'd say the K1000 shaft may be used on a KX camera. There is enough play designed between the film canister and shaft to accommodate the K1000 shaft.
Hope this long-ish description helps. Sorry I can't offer the set from my K1000 - I'm in the process of restoring it.
- Craig
Brilliant, Craig. Thank you for that. Sounds like a K1000's will work since that's the direction I'm going and they're easier to track down for certain. I suspected this but was hoping for an answer just like this.
Also, *just* prior to reading this, the same was confirmed to me by Eric H. via email, though his response was typically far less verbose.

He wrote:
Quote: "K1000 the old style"
Hahaha. Between that and your response I think that's settled.