"Christopher Tidy" wrote in message
...
Glenn Ashmore wrote:
I need to make a couple of adapter plates for the new 56HP Yanmar to fit
the CV
joint to the prop shaft. The gear box flange has four M10x1.5 threaded
holes on a 78mm
pitch circle and the CV joint has six M10x1.5 holes on a 93mm pitch
circle.

At anything other than a 15 degree offset between the two circles the
holes interfere. At 15 degrees I have 3mm between the holes. I am
limited to 22mm in thickness so I can't drill blind holes on either side.
Is 3mm between holes sufficient or is there another way to lay out the
bolt circles?

Hi Glenn,

Surely the least metal you can have between the holes is 5 mm? The outer
edge of the holes on the 78 mm circle will be at a radius of 83 mm, and
the inner edge of those on the 93 mm circle will be at a radius of 88 mm.
So I figure there's a minimum of 5 mm between them. Someone correct me if
I'm wrong here...

It's customary to specify bolt circles as the diameter, not radius. It's a
tight fit.

I have no answers for the OP, but I will say this. It might be better to use
only four of the six mount holes rather than compromise all four of the
other set.