Richard.....here you have reasoned a positive case for the adoption of the swivel bearing.
I can just as easily reason a positive case for omitting it.
Now....just open your mind to replacing the fraying string...
No SUPATRAC arm suffers from "fraying string", because I foresaw that problem and always ensured that the hoist was nowhere in contact with sharp edges. The information about hoist longevity is from a manual which was drafted within a year of applying for the patent. We are now four years in and I have not seen any fraying. As far as I'm aware you haven't used a SUPATRAC arm, and I would be grateful if you would refrain from insinuating that they have problems with fraying when in reality they don't. I accept that your arm exhibited fraying, but you should have thought of that and built it properly.
Dont adopt the closed mind attitude of some of our forum members. Try it then comment.
I can imagine a million different ways of making a SUPA, but I'm getting old and will not have time to try them all. I have to concentrate on solving real problems, not imaginary ones, or errors I haven't made.
I can certainly envisage a much simpler & reliable way to string the hoists without using complicated knots
Slip knots and a clove hitch aren't complicated - they are knots that normal people tie every day. We tie them with ease in the workshop, and only a handful of customers has ever needed to do so when maintaining their arms. The overwhelming majority of the hundreds of SUPATRAC customers have not had to tie any knots when installing or using their SUPAs. Again, you seem to be attacking a product you have never used and with which you are unfamiliar.
Making a DIY arm and successfully producing a commercially competitive arm are not exactly the same problem. It may or may not happen that I produce a swivel-apex SUPA in the future, but I will have to develop any commercial version methodically, weighing up whether there are any advantages in sound, set-up, cost, ease of production and ease of maintenance.
