Dave Hinz wrote:

On 22 Mar 2005 17:15:08 -0800, mike wrote:
1 Why is it that the thread on carriage bolts goes the entire length of
the bolt but not on hex bolts?

Carriage bolts are always going to have a nut on them, I think.
Since you don't know where that'll end up, it's threaded all the
way.

Well, it's no harder to measure/calculate the length for the bolted
pieces for a carriage bolt than a machine bolt...

A hex bolt usually goes through a drilled hole, and having
a non-threaded section gives you more strength and positive
location in the axial direction.

And a machine bolt goes through a non-drilled hole?

Just a thought, kinda winging it, but it makes sense. Annoying
sometimes, though.

My observation is that it's a way for the cheaper
manufacturers/distributors to minimize the number of sizes kept in stock
-- carriage bolts are a lesser quantity item in general and so it's the
first to minimize.

The only thing in stock locally now except at the farmers' equity is
cheap (and I'm really talking cheap, but not inexpensive) imported pos
stuff...there are sizes in 1" increments and best...

I suppose there's also some reason that the fabrication process makes it
cheaper, too, but I don't know precisely how...can't imagine it's done
for anything other than cost, however.