Metal Plate/Wood Connection Hole Clearance?

[StructuralEd]

I have never come across a reference for what oversize to make screw and bolt holes through Steel side plates in a steel side plate to wood member connection.

I think it might be more critical in a multi-fastener connection to get them to all be making contact and work together.

I found that metal connectors for Simpson 1/4" SDS screws use 1/64" oversized holes.

That is relatively small compared to the +1/16" we use for standard steel bolt holes, but then again those connectors can work in a different manner.

Any thoughts on larger wood connectors like 1/2" - 3/4" lag bolts?

 

[StructuralEd]

I should add, at the moment I am considering one sideplate so the bolts do not have to hit any target on the opposite of the wood member.

 

[Ron]

Keep in mind that the larger the tolerance, the less contact area you'll have within the radius and thus the higher the shear stress. For thinner plates, the tolerance has to be much tighter.

For protected applications, not subject to large temperature fluctuations, keep the tolerance as tight as possible...in the 1/64" range. If more temperature fluctuation, you might stretch it just a bit, but not much.

As a rule of thumb, I would make sure that at least 1/3 of the bolt diameter is in contact with the plate.

 

[dhengr]

Structural Ed:
The hole size should be tight, and it can be since the plate and hole are the template through which you drive the screws. Watch out for the fact that in some cases the major thread dia. is larger than the shank dia., know what. Ideally you would like all the screws to come into bearing at the same time and your plates screwed or nailed from both sides have a chance of coming fairly close to that. This is less true in steel connections due to tolerances btwn. hole centers and hole sizes, quite a different animal, but still accounted for in our design methods. Look up Timber Rivets, the NDS covers them. As for larger bolts and plates; have the plates punched or drilled in pairs, and use one of them as a wood drilling template, along with a drill which is held perpendicular to the plate.