I have always tried for a minimum of 50% contact, while making sure the shim is equal around the periphery of the bolt. In other words, there should be an equal amount of shim all the way around the bolt, except for the slot.
It is both possible, and desirable, to minimize the negative effects of soft foot. While it may be difficult to completely get rid of soft foot, it can typically be reduced to a few mils, if the following techniques are used.
We recently received a customer request about shim safety. An employee at the customer site had experienced a “near miss” safety issue due to walking too closely to a machine, and getting their clothes caught against a shim. Since I have a scar on my right thumb caused by a 3 mil shim, I thought a discussion on shim safety might be in order!
Shims do three things:
Change the elevation of