I cant exactly remember the brand of risers I have but they were made for SAE 1/2" thread. I wasn,t gonna drill the tree so I bought a couple of of 1/2" studs had them turned down at work and used a 10mm die and cut new threads on the other side. Work great, had them on about 2 yrs now. Probably would have been faster and cheaper to have just ordered the adaptors that Ian mentioned but I wanted to do it myself.
