Countersunk Bolts and Connection Strength
Countersunk Bolts and Connection Strength
(OP)
Hi All,
Where I am, it is common for contractors to countersink bolts and fill the hole in with automotive body filler. In such a case, would you consider the timber member thickness to be limited by the length of the bolt (inclusive of nut and head) or limit it to just the shank of the bolt that is in direct contact with the wood.
Alternatively, is it plausible to deduce that countersinking has not impact on connection strength since full thickness of the wood comes into play very quickly.
Having said that, would you countersink in a 2x??? timber member which is only 1.5" thick?
Thanks
Where I am, it is common for contractors to countersink bolts and fill the hole in with automotive body filler. In such a case, would you consider the timber member thickness to be limited by the length of the bolt (inclusive of nut and head) or limit it to just the shank of the bolt that is in direct contact with the wood.
Alternatively, is it plausible to deduce that countersinking has not impact on connection strength since full thickness of the wood comes into play very quickly.
Having said that, would you countersink in a 2x??? timber member which is only 1.5" thick?
Thanks






RE: Countersunk Bolts and Connection Strength
RE: Countersunk Bolts and Connection Strength
The connection is in shear. I agree with you in the sense that for shear, the bolt head and nut will bear onto the bondo which is stronger than the wood. So there should be no reduction is shear capacity for countersinking.
Thanks
RE: Countersunk Bolts and Connection Strength
I would design the shear connection for the reduce length of the side member, due the the countersinking. Plus a overcut (ever though I would note "Do not overcut the countersink depth") safety factor.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.