Re: Rivets


Dennis Storzek <destorzek@...>
 

--- In STMFC@..., "ed_mines" <ed_mines@...> wrote:


Do you really need 1/2" diameter rivets to hold sheet metal (or thin
metal plates) to a frame? And so many of them? With sheet metal in
particular freight would break through the side before a 1/2 bolt would
break.

Ed,

As a rule, the size of the rivets is chosen based on the material
thickness to be joined. Bridges can use big rivets on wide spacing
because that material fastened is so thick. Freightcars use smaller
rivets on closer spacing because the material is thinner. Airplanes
use tiny rivets on really close spacing because the material is
thinner yet.

Machinery's Handbook gives this general rule for selecting rivet
sizes, and I quote:

"The rivet diameter D commonly falls between D=1.2 X &#8730;T and D=1.4 X &#8730;T
where T is the thickness of the plate."

The steel side sheets of the AAR standard boxcars I'm looking at the
drawings of are specified as .1". Using the extremes of the range
above, the calculated diameter of the rivet shanks should be between
.379", slightly over 3/8", and .443", slightly over 7/16". Therefore,
I would suppose that at least some cars could have been built using
3/8" rivets having 11/16" diameter heads. These would scale out to
.008 dia. in HO. However, as I said, the drawings I was looking at had
the side rivets drawn the same as the door post gusset rivets; they
just weren't specified. The ones that were had 7/8" dia. heads, which
scale to .010".

I just looked at a Standard Railway Equipment Co. drawing for an
Improved Dreadnaught end. It specifies "9/16" holes unless otherwise
specified." That's the clearance hole for a 1/2" rivet, which will be
covered with a 7/8" diameter head. Certain holes, where ladders,
grabs, and brackets will be attached are specified 11/16" for 5/8"
rivets. This makes sense, as IIRC all safety appliances must be
attached with either 5/8" bolts or rivets. The top flange of this end,
which is designed for a car with "ZU" eaves and overhanging roof
panels, is specified to have 7/16" holes, which would be the size for
3/8" rivets with 11/16" diameter heads. I also looked a the
fabrication drawing for a YSDCo. steel side, but it STILL doesn't
specify the rivet diameters; just the Part No. and Drg. No. for each
panel and post. I'd need those drawings to see what size rivet holes
are specified.

Dennis

Join main@RealSTMFC.groups.io to automatically receive all group messages.