There is no definite rule (as is also the case for alumnium). It depends on
the stress levels in the part.

In general MIL-HDBK-5 provides data for e/D = 1.5 and 2.0. Unfortunately the
copy I have handy right now (which is Rev F) does not have any data for e/D
= 1.5 for 4130N. However the data for other steels indicates that you could
have a 20%+ reduction in strength when using e/D = 1.5 cf e/D = 2.0.

I would use 2.0 unless you know what the stresses, can source some
allowables for e/D = 1.5 and have run the numbers to show that you have
adequate margins.



"Ed Wischmeyer" wrote in message
news:2004082215291516807%edwisch@alummitedu...
Folks -

How many diameters of edge distance do you need in steel? I know it's 1.5
in aluminum.

thanks

Ed