This picture is from the outside of the frame. The nylock nut is bigger than the stock one. It also shows how the larger bolt fits on the inside of the frame. It is flush with the inside of the frame lug.
This shot shows the stock parts (smaller, 10mm bolt/nut) and the ones I modified and used 1/2x20 (fine thread). The bushing has been narrowed and it is threaded inside so that it bolts up firmly, squeezing the frame and locked by the big nylock nut. The holes in the bushing provide me with a way to hold the bushing so I can tighten the bolt. A bicycle pin spanner fits the holes.
This shot shows the narrower bushing.
Chuey, somethin' just doesn't sound right to me. Is the stock bushing hole threaded? Why would one want to bind up the bushing with the bolt? To me, it makes more sense that the bushing hole should not be threaded, so the bushing could do its job. The amount of "squeeze" force exerted on the ass'y can be regulated with the nylock nut.
The bushing does not turn. Even in the stock format, it is pinched by the bolt/nut. The stand has holes that are a snug fit on the bushings but not so snug that it cannot pivot on them. The difference, and the reason I threaded mine is that on the other bikes I have, the frame has a step bore, or recess for the bushing. This stepped recess indexes the bushing and adds support. The bushing sits partly in the frame. In other words, on frames with a step, the step makes it so the bushing/step take the load of the weight of the bike. That relieves the bolt of that job. It is only there to hold the bushing tightly into the recess. This frame has no recess for the bushing.
This frame has a bigger hole and a bigger counter sunk recess than any others that I have. They were just right for the 1/2x20 bolts that I used. The stock bolts kind of swum around in the hole and sat too deep in the recess. If I'd just bolted it up with the stock bolt/nut, it wouldn't have given me confidence.
The bushing is narrowed so that it approximates the width of the center stand at the holes. That way, the stand won't swim around on the bushings. That is how it is made to work on the other bikes I have. In other words, without the recess in the frame, the bushings would have been wider than necessary. The lip on the outside of the bushing makes it so the stand can't slip off to the side. By threading the bushings, I hoped to replace the locater function of the recess with compression of the bushing to the frame. I think it is stronger than if I had simply pinched the bushing between the bolt and nut. It is an attempt to take some of the load off the bolt.
