Building a Whistle Sign
My whistle sign
Written by Laurence
since I saw this picture of this whistle sign I’ve thought I would like to have
two beside my home track. Within the past week my gravel pile froze and snow
has closed me down for the winter and I have move indoors to do some serious
modeling till next spring.
Looking at this picture I cannot decide how it was fabricated but the first
thing that pops into my mind for me to build it is to use two rings of quarter
inch steel rod welded together with sheet steel between them.
With this fabrication technique in mind I drew the attached blueprint on a
8-1/2 x 11 sheet of paper:
The first step is to cut two lengths of 1/4” rod a 14-5/8 long. I took them
to a local welding shop that has a set of rolling wheel with grooves to roll
the rods into circles — almost touching. Remember each end will have a straight
portion that is not bent. This is no problem and I’ll tell you below what to do
with them. Your two circles will not be perfectly symmetrical as mine were not
also. No problem. You’ll also find the circles will not be flat.
I did some minor bending and
flattening using the bench vice anvil and hammering. I used a small bar clamp
to bring the circle to a touch for welding; pinching them on the long side of
the short radii of the curve. After both circles were welded into rings I had
to do some more minor adjustments making them flat and equal in roundness. Much
to my surprise, the straight portions of each ring were very close in size and
shape; hay, we’re not making a grand piano here.
Using the smallest of rings I marked the outside diameter using a felt tip
pen on a sheet of 20 gage steel and cut my disk with a pneumatic nibbler. You
can use a sabre saw, jig saw or scroll saw with a metal cutting blade to
achieve the same results. The picture on the right shows my layout and the left
shows just how close I was after the first cut. I did mark a few high spots and
cut again in a few places.
Using c-clamps and bench vice to hold the rings
and disk “sandwich” in place spot weld several times around the circumference.
(This is the time to align the straight portions of the rings on opposite sides
of the disk.) I ended up tack welding six times; but just by luck and not by
After tack welding I ground off the sheet steel sticking out beyond the
rings and then I did a full weld; skipping around the outside to prevent things
What I hadn’t planed on was the warp in the sheet steel, but more about that
later.* After welding, I ground the outside to a flatter shape giving it a
“professional look.” Cover one side of the disk with layout dye.
Next I drew the “W” on a
piece of scrap paper, cut it out and tapped it in place. Yea, I used electrical
tape but you could use masking tape just as easily. And, the straight portion
of the rings, if you can find them, are at the bottom of the sign.
Using a small hammer and punch, mark each corner of the “W” and then remove
the paper template. Mark a line between punch marks using a straight edge and
Make sure your letter width is greater than the platens of you nibbler or
you’ll not get the job done! I had some problems here because of the warp in
the sheet steel* — I would have been better off if I had used the pop down side
rather then the up side as shown here.
I had a piece of 3/4 x 3/4
steel stock in my junk box so I cut a 1/2 length off the end and cut a 5/8 slot
in one side. Drilled a 1/4 diameter hole in it and tack welded a short length
of 1/4-20 threaded rod into the bottom. This bracket piece I welded onto the
bottom of the sign, wire brushed everything up and you can see the results on
the right. The next step is sandblasting and painting.
I cut a five foot length of 3/4” diameter steel rod, drilled
it with a #7 bit and tapped a 1/4-20 hole in the end. This’ll make the mounting
post and I’ll drive them beside my track when the ground isn’t frozen.
* When I made the second sign and after I cut the round disk I changed my
fabrication a bit; instead of welding it in between the rings and then marking
and cutting the letter “W”, I first marked and cut the “W” and then welded up
the sandwiched sign.
This was a smart thing to do: everything stayed flat. And, it was easer to
cut the letter out also. By the way, if you do not have a pneumatic nibbler you
can drill small holes at the corners and cut straight sides with cold chisel
while the sign is laying on a heavy steel plate.
See the blue print for this project.
Written by Laurence