Have to convert from idea to reality first. maybe this afternoon if it warms up enough.

I think I have it. Found a 1" nylon strap to demonstrate the idea. See this album:

Split work glove leather should be more than adequate and easy to obtain in the necessary lengths. As it is relatively thin and soft just about any antique Singer machines will sew it up or any commercial machine. The Velcro will provide a smooth palm rest and the pressure of the palm and index finger will keep the leather from slipping while grinding and the Velcro from separating. The thumb will no longer to be doing any heavy gripping of the grinder body which is the point of this device. The actual grinding force will cause the band to tighten and pull the base of the thumb and palm into a tighter contact or grip with the grinder body.

Great to see it, thank you very much. Exactly as I thought. The leather version would have a pretty nice feeling, I am quite sure, and should be very easy to contruct. My original vision had the same type of loop connected to sleave all made up of the transparent silicone. I think it should work too, I will mabe try to simulate it with a similar band construction as the leather one. I use silicone bands for slingshots, and they have way more springiness than leather for sure, but I am really confident the forces created while grinding can not make it break. I will post pictures when I succeed

Thank you once again

Pavel

Leather will avoid the stretch that other materials will have, that was my thought anyway.

Thats true, but I am not sure if that bit of a stretch is any problem at all. I will try both anyway:)
Thinking about it.... maybe it would be fine to not make the loop by laying the material across, but bending the loop and laying it along, sewing the edges together, That way there would be only one layer everywhere, cleaner visually. Nice little project to play with

It is on the list. I may have some heavy nylon webbing to experiment with. Will look and see what I have here now.

I have tested both the options yesterday, with a silicon flat band I have ready for some slingshots . It seems to me that the paralel layout is also more ergonomical, but it needs the sew to start cca under the center of the palm. I will have a look today if I could find some leather to make it for real (the bands were too short to call it usable, but it worked anyway

I have to make a trip across the river and it will be Thursday or Friday befor I get over there to the real leather store as this will take a piece of at least 18" (50 cm) long, which I do not have.

Tested yesterday with a leather strip, confusing a bit since with the leather it seemed more natural to have it across and not in paralel, but anyway still only a strip of leather and it worked very nicely, so today I hope to get the leather cut a bit more nicely and do some glueing or sewing ... so far its very pleasing.