Pin drive bolts splitting Help Please

[Ant]

David brilliant job, I normally look indepth at components to see if they are engineered correctly, but wouldnt have thought to on the pin drive nuts.

We have machined all our hubs from 4140 front being similar to original with press in pins and retaining nuts so not a problem there, but on the rear we made adapters similar to Trigo, I tested the Trigo adapters before I sold them and they are just normal soft free machining steel from memory so I wasnt happy with them even though that type of steel is probably adequate for the job.

I am using Cap screws and the Trigo Pin drive bolts on the rear, but now have major concerns with the small seating ring area, and I have had two of these trigo pins have approx 3/32" chunks of metal break off the inner sharp taper just with assembly maybe the metal is quite hard or brittle!
I will consider machining the correct taper or making new ones, we used to make them with two flats which isnt as nice to work with as the internal 12pt or if anyone is supplying a better product I would be interested.