Thread: Coach Screws and RHS

Coach screws are for timber. More info needed on how the RHS/SHS will be fitted together.

Nev

Hi DMC,
you might possibly mean cup-head bolts as in pic below.

Attachment 128187

I don't know if these are suitable for rhs either though

Cheers, Greg

Cup-head bolts as pictured above will be perfect as the cup-head is obviously on the inside of the rails to protect the horses. Just keep in mind that the steel used in cup-heads is not as strong as other "normal" bolts. The steel used is only as strong as the shiny plated bolts sold in Bunnings. For greatest strength, use a large diameter bolt, I would suggest 1/2" dia. These bolts are actually very strong in shear as the shear force is taken by the full diamater of the solid part of the bolt. Where the shear forces are taken by the threads is where a failure may occur. You will need a nominal size hole for the bolt in one side of the RHS and a bigger hole in the other side to clear the size of the square section under the cuphead.
If you are concerned about the end of the threads on the outside of the rails, you could use an "Acorn" style of nut. These nuts stop all the sharp threads from protruding out.

Kody

Thankyou for your replies. I'll have a look at these cuphead bolts.