Thread: When to use coach screws vs carriage/coach bolts?

Coach screw threads connects timber to timber, or metal to timber.... where as the bolts thread holds on to a nut and clamps the timbers together

Originally Posted by wolften

Coach screw threads connects timber to timber, or metal to timber.... where as the bolts thread holds on to a nut and clamps the timbers together

I do understand this part, but when would you actually opt for one over the other?

The only time I have used a coach bolt in the last 15 odd years, is screwing step treads to the metal stringers from underneath. No metal bits on top of the tread.
I always advocate using a bolt at all times and so would all engineers.
I cant think of any other time you would use a coachy.

We sometimes use coach bolts at work to clamp the top and bottom of large table pedestals when regular clamping methods are too awkward or won't reach far enough and leave the bolts in for extra strength. Also use them on extension tables to fix the box/frame with the running gear to pedestal legs.

Originally Posted by hellofellow

Hi everyone,

Just a few newbie questions:

1. When would you use a carriage bolt rather than a normal hex bolt? Is there any reason other than aesthetics?
2. When would you use a coach screw rather than carriage bolt? Other than not sticking out one end, it seems as if they are similar- Will either be stronger?

cheers

I use coach bolts when it is awkard to access a bolt head during tightening, or for a neater appearance.

I wonder if they are less prone to vibrate loose, which would be an advantage on a shaky coach.

I use coach screws when there is no access to the other side, or the timber is so thick there is no standard bolt of the required diameter.

So ironically,

If I applied this to building a workbench... Would you use screws or bolts or either? Many people seem tO go for carriage bolts, and a few go screws or Coach screws?

...a bit of commmmmmonnn sense does apply as to what fits when how where and why.
Go bolts as one can always tighten them up.

Originally Posted by hellofellow

So ironically,

If I applied this to building a workbench... Would you use screws or bolts or either? Many people seem tO go for carriage bolts, and a few go screws or Coach screws?

Neither. 70x70mm legs, 150x35mm side rails, 70x35mm stretcher rails, 70mmx1/2 inch dowels (70x10mm will also do just fine) and glue. Glue and screw in some decent size corner blocks and it'll never go anywhere.