I use mostly levy's straps and Schaller strap locks.I always have to take a pair of side cutters and trim some of the leather away from around the hole so the threaded part goes
thru. If the strap is real thick I use a pair of channel locks
and or pliers to smush down the washer enough to get the threads started. If you have a small vice grip you can clamp one side down and hold the other side down with the channel locks or pliers. If you have someone to help and dont have the vice grips you can squeeze the washer down from both sides while your helper gets the nut threaded on. then I hold the bottom part with the channel locks while tightening the nut with a wrench 13mm I think. Be sure not to squeeze the
bottom part with the channel locks when tightening the nut.
If you do it may bind or not slip over the pin end that goes in the Bass.
