Lateral location of the cap, perhaps?
When you say bolt heads Howard, I take it you are inserting the bolts from the rod side and putting nuts on the cap side?
I for one wouldn't want to machine the camshaft. One possibility you might consider is helicoiling the 'rod' side and inserting bolts from below? Though I'm not familiar enough with Nippy rods to know if there is 'meat' to enable this. And of course you may not wish to modify them.
Surely the first port of call would be Nippy big end bolts, if only for inspiration.
When you say bolt heads Howard, I take it you are inserting the bolts from the rod side and putting nuts on the cap side?
I for one wouldn't want to machine the camshaft. One possibility you might consider is helicoiling the 'rod' side and inserting bolts from below? Though I'm not familiar enough with Nippy rods to know if there is 'meat' to enable this. And of course you may not wish to modify them.
Surely the first port of call would be Nippy big end bolts, if only for inspiration.