A couple of weeks ago I decided to make a lock that would be able to lock from the inside. I wanted it to not look jack leg, not be able to vibrate locked while driving and lock me out, be able to unlock reasonably quick, and not too completed. I had some brass 1/4″X 1 1/2″ a little less than a foot long and figured it would be enough for one lock. It was and than I went on EBay and ordered another foot to do the other door. I was able to cut the soft brass on my bandsaw to shape and used a jig saw for the sq hole after drilling it out. I cut some scrap nylon down to 1/8″ and made a 1/16″ cavity in opposite sides of the two pieces of brass that would have a taped 5/16″X 18 threaded hole that accepted a knob from Rockler that came with a threaded rod. I joined the two pieces of brass with 6/32 ss screws to sandwich the nylon. Then I drilled out with a bit size needed to tap all three pieces with a 5/16″X 18 tap, I accomplished this after I fastened all 3 together to assure alignment. The nylon providedin enough friction to stop any vibration that would lock it in travel and the cavity the nylon sat in was shallow enough to squeeze it enough to prevent it from spinning. Of course you will need to reposition the latch and if needed it can be bent some. I used a small bench sander to make all the pieces appear even with each other and Give them a brushed look as well as bevel in all sharp edges. The threaded part of the knob extends into the pre drilled hole brass piece mounted on the door when locked. The most critical part is correctly aligning the sq brass hole with the shoulder of the door latch, I was aiming to have the brass parallel with the teardrop floor. It also helps to have the sq brass hole fit as tight as you can and avoid a loose sloppy handle feel. I have more pictures but this site and me don’t agree on more than two it appears, if you need more let me know and I’ll post them in another, meanwhile I’ll try and reduce My pix resolution and see if that helps.