Machining A Bolt Head
Machining A Bolt Head
(OP)
I am in a situation where we need to machine down the head of a 3/4" A325 bolt from 1/2" to roughly 3/8" in order to attach a pipe clamp to a steel tube. I was wondering if anyone has done this before and if so how do you determine the new capacity of the bolt. There is not a lot of load on the bolt, should be less than 2 kips, but I was looking for a way to have accurate calculations. Any help would be great. Thanks.





RE: Machining A Bolt Head
Since the design of the bolts shear/tensile strength is primarily based on the cross-sectional area of the bolt. I don't think you can calculate a change in the shear/tensile strength based on the head thickness.
Is there a washer under the bolt head? For standard or OVS holes, a washer is only needed under the turned side. Removing the washer may provide the clearance you seek.
Is the bolt snug-tight or pre-tensioned?
http://www.FerrellEngineering.com
RE: Machining A Bolt Head
The shank tensile area is .442 in.^2
The .5 in. head shear area is 7.4 in.^2
The .375 in. head shear area is 5.6 in.^2
Min tensile strength 120ksi. Min shear strength 60ksi. Shear capacity of .375 head is still greater than shank tensile capacity.
Ted
RE: Machining A Bolt Head
The .5 in. head shear area is 1.18 in.^2
The .375 in. head shear area is .88 in.^2
The reduced head shear capacity is about equal to the shank tensile capacity.
Sorry.
Ted
RE: Machining A Bolt Head
RE: Machining A Bolt Head