Building a Whistle Sign
My whistle sign
Written by Laurence
Johnson
Ever 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 design.
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
from warping.
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
scribe.
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
Johnson
