Grub screws can provide insane amounts of clamping pressure if done right. The diameter, thread engagement, orientation, and driven torque all contribute. If used properly they hold on tight forever.
I am glad they work for you, they caused me nothing but grief.
Welding my motor mounts on to the trucks has solved all my vibration related issues.
I don’t have to use locktite on everything anymore.
I can feel the ends of my fingers for the first time in years 
The problem with welding motor mounts on aluminum trucks is that it weakens the truck hanger and could wind up causing it to bend or break unless the hanger is annealed after welding.
I have a single motor Liftboard and the whole motor bracket is loose too. Apparently the set screws backed out at some point and stripped out the holes to where I can’t tighten the three set screws. The whole assembly is shot. Besides welding this to the truck itself, can I just put a new truck under there? I was thinking about a Caliber II truck with 44⁰ angle and then putting after market motor bracket and using existing motor and pulleys. Any ideas?
Loctite 638, cure it for 24 hrs (that means leave it alone, do not even touch it)…Also…you can DIY almost everything in this world…
Ok. If Loctite doesn’t work, do you think putting a new truck and motor mount would work? It looks to me that by putting a new truck and motor mount, I can just bolt up the existing board and motor to this set up and not have this problem again.