Any solutions to my problem?

[jcdammeyer]

"sliding (vertical) rack in a channel and pinion on the pot shaft"

My plan B, above.

Should still support the other end of the pinion shaft. Don't use the pot bushing to handle any load.

 

[DPittman]

Should still support the other end of the pinion shaft. Don't use the pot bushing to handle any load.

Yes that was one of my fatal mistakes

 

[jcdammeyer]

It's like software. Sometime you have crumple up the page and toss it in the trash and start fresh.

 

[DPittman]

It's like software. Sometime you have crumple up the page and toss it in the trash and start fresh.

Thank goodness I will never have to worry about having that scenario also.

 

[mickeyf]

 

[jcdammeyer]

View attachment 26343

The word "software" should be replaced with "Microsoft Windows"

 

[Ian Moss]

I am almost embarrassed to show you this, but it has worked so well for many hours over many years that I guess it is worth having a look at. The cord from the spring, around the pot knob to the foot pedal is a very fine nylon covered? multi-strand cable, but lots of other things should work. I cobbled it together for a job winding magnetic coils with the intention of improving it if the whole winder worked, but it worked so well I never had a reason to change it. Occasionally the cable may slip a bit and off is not off, but you just draw the spring down to take the tension off, reset the pot and good to go.

 

[jcdammeyer]

I am almost embarrassed to show you this, but it has worked so well for many hours over many years that I guess it is worth having a look at. The cord from the spring, around the pot knob to the foot pedal is a very fine nylon covered? multi-strand cable, but lots of other things should work. I cobbled it together for a job winding magnetic coils with the intention of improving it if the whole winder worked, but it worked so well I never had a reason to change it. Occasionally the cable may slip a bit and off is not off, but you just draw the spring down to take the tension off, reset the pot and good to go.

There's nothing wrong with your solution and the mechanical characteristics of the 1/4" shaft pot are what make it work so well! Change that to an 1/8" shaft and it's not really meant for that sort of load. But again, all it takes is a bearing support on the other end.

 

[DPittman]

I am almost embarrassed to show you this, but it has worked so well for many hours over many years that I guess it is worth having a look at. The cord from the spring, around the pot knob to the foot pedal is a very fine nylon covered? multi-strand cable, but lots of other things should work. I cobbled it together for a job winding magnetic coils with the intention of improving it if the whole winder worked, but it worked so well I never had a reason to change it. Occasionally the cable may slip a bit and off is not off, but you just draw the spring down to take the tension off, reset the pot and good to go.

Ha ha I love it! Often simple is best. I seem to start with a simple idea and it grows unnecessarily complex often times.

I'm giving my #3 version attempt at this thing mostly because I'm learning alot and need practice at some things. I'm going to attempt to cut my own nylon gears using a new dividing head and I'll likely screw up using that once or twice also. Despite my frustrations, I am kind of enjoying myself .

 

[Ian Moss]

There's nothing wrong with your solution and the mechanical characteristics of the 1/4" shaft pot are what make it work so well! Change that to an 1/8" shaft and it's not really meant for that sort of load. But again, all it takes is a bearing support on the other end.

The 1/4 shaft is better, no doubt, but notice that the cable is in a straight line, and the tension above and below is balanced when not in motion, adding no bending moment to the shaft. When travelling, the difference between the top and bottom segments of the cable are only the small torque of the pot. Pots are cheap, can you substitute a more robust pot if you are worried?

 

[mickeyf]

occasionally the cable may slip a bit and off is not off,

That could probably be dealt with by anchoring the cable to the knob at one point. I like this. Yes, "Often simple is best".

 

[VicHobbyGuy]

Should still support the other end of the pinion shaft. Don't use the pot bushing to handle any load.

Here's one (of many) Pfaff pedal mechanisms: