Originally Posted by
dddd
I've never heard of or seen an example of a 3-degree taper. Do you know what brand or country that one of these came from?
I can not say for sure I have a crank arm with 3 degree, but I have been told it might have. It is a drive side crank I bought on ebay that is presumably made by SR (the photo below looks very similar but there is no SR markings). The square taper is considerably larger than JIS, as you can bottom out a JIS spindle in the crank and it still rattles around. I know it's an early Japanese square taper size that didn't last very long and it may be a 3 degree taper. Strangely enough it has the old JIS symbol on the back.