RCA cable help

I figured I'd post this here incase someone knows of something I'm missing..I make custom locking RCA cords. When I wire them up, I use my machines as reference and I wire the polarity so that the DC motors spin in a clockwise direction (except the dan kubin which spins counterclockwise)..I just recently had a customer write to me and said that the cord works fine on all his machines except his bishop and stigma hyper. he says neither machine will work with my cord. At first i thought this might be a polarity issue, however, if I reverse the polarity on the cord, most machines will run counterclockwise. I've read on some posts that most DC motors are made to run clockwise and running them in reverse will shorten the lifespan of the motor..

Is there something I don't know about these 2 particular machines or is there something else I'm missing?

They have polarity protection (the stigmas do anyway) so will only run one direction. Not sure which direction that is though.

I would wire one with tip positive and wire one tip negative and offer both for sale? I'd also try to build a polarity list of machines to help people with selection. As long as a machine always runs in the same direction the motor life and polarity are virtually nil, its when people keep flip flopping polarity with clip cords that hurt motors especially the bushed motors, because the brush wears higher on one side than the other, when the polarity flips its like a chisel edge grabbing the motor core making it work against itself. Polarity protection was intended to prevent the polarity flip flopping and protect the motor by forcing it to only work in one direction. I'd just offer both and have them color coded based on tip positive or tip negative.
I hope this helps

Also people need to test their power supplies. Some Chinese ones and some older ones are not consistent with the polarity.

or the correct display of volts.

you could just make a polarity flip phono adapter. Plug it in to the power supply then plug the rca cord in to that. Have 1 made. I'll post pics of it when I get to the shop. I made it back when no one knew anything about rotaries. I just used a plastic tube with male on 1 side and female on the other. Just cross the wires in the tube.

Don't know if this link will offer any insight. Maybe the Bishop and Stigma are meant to spin the other direction as well?

Then again, some rotaries are better counter clockwise - I forget who mentioned it - but it had to do with hit of the direct drive being more efficient if you are a righty and the machine is turning counterclockwise. Maybe counterclockwise isn't a bad thing, just so long as the machine is ALWAYS going counterclockwise and not flip flopping as others mentioned.

I posted a thank you to all who helped out the other day..for some reason it didn't make its way to this thread so I will repeat..thankyou all who helped out your invaluable information..I'm taking the advice and should have this sorted out..

You're welcome, I wish you much success in working out the solution you have in mind.