Provincial
Well-known member
I had a project that needed 1/2" NC bolts to thread into a 1/8" tread plate floor of a flat bed. I didn't want to use nuts on the back side because I wanted the bolts to be easy to remove from the top side only. I keep an assortment of unplated NC square nuts on hand for just this sort of project, but I didn't want to be laying on my back welding them overhead onto the bottom of the bed.
I decided to weld the nuts to 1/2" plate washers and plug weld them from above. I made a drill jig from one washer, and since the washers have 9/16" holes, I used a drill that size to make the hole in the tread plate and a 9/16" NC bolt for alignment. I drilled two 5/16" holes for the plug welds.
To locate the square nuts centered on the hole in the washer I machined a taper on one face of a nut. Using a short bolt and this nut I draw the washer tight to the square nut and tack weld it is place. After removing the bolt, I welded all four sides of the nut to the washer.
I had my son hold my blind nuts up from the bottom and held them in position with the short NC bolt and tapered nut. I then plug welded the washer through the 5/16" holes.
I decided to weld the nuts to 1/2" plate washers and plug weld them from above. I made a drill jig from one washer, and since the washers have 9/16" holes, I used a drill that size to make the hole in the tread plate and a 9/16" NC bolt for alignment. I drilled two 5/16" holes for the plug welds.
To locate the square nuts centered on the hole in the washer I machined a taper on one face of a nut. Using a short bolt and this nut I draw the washer tight to the square nut and tack weld it is place. After removing the bolt, I welded all four sides of the nut to the washer.
I had my son hold my blind nuts up from the bottom and held them in position with the short NC bolt and tapered nut. I then plug welded the washer through the 5/16" holes.
