|HM303 Universal Cross: The crosses are
made from two pieces of 3/4" diameter brass rods silver soldered
together. I started with two rods each at least a fool
long and drilled/bored holes about 1 3/8" deep in the ends of each
rod. The holes were about 23/64" diameter --- slight undersize
for the 3/8" pins.
The mill was set up so that center was 5/8" from the end of the
vise and 3/16" off the center of the 3/4" diameter rod.
The photo shows using a wiggler to locate the side of the rod.
|The next step was to plunge a 3/8" diameter
end mill thorough the rod. Note that the hole is 3/16" off the
center of the rod. This will be the hole for the
intersecting pin. A 1 1/4" length was then cut off the end of
the rod. This is one side of the cross ---- 1/16" too long on
each side. The ends will be finished later.
|The is a setup just like the previous one only this
time after the 3/8" diameter hole was cut the end mill was changed to
a 3/4" diameter cutter and the hole is enlarged to 3/4"
|This is the finished 3/4" diameter hole.
The mill works slick,
just make sure everything is tightened down.
|These are the two pieces of a cross.
The long end is left on the second piece to ease the soldering
|Next, the parts were cleaned. In the past I used a pickling
solution. The new shop has a bead blaster setup which I now
use to clean the parts.
The areas where the
two pieces are joined were fluxed, the parts put together and then
the little lip in the long piece center punched to prevent the
smaller piece from sliding during soldering.
|A setup like this was used to make sure the two rods
were perpendicular to each other.
(I forgot to take a photo doing this operation --- this photo was
taken after the last piece was soldered.)
|The long end was secured in the vise and a couple
pieces of silver solder were laid on the top of the joint
|This shows the red hot joint just after the solder
The pieces were blasted again, and the part put back in the vise
with the little piece on the top. Flux was applied to the
joint and, pieces of solder places on the joint and the whole piece
heated again to the point where the solder flowed.
The resulting joint is very strong.
|It is nearly impossible to keep the two shaft holes
perfectly aligned during the soldering operation. The
hole in the long piece is the one which might be slightly obstructed
by the small piece.
The photo shows boring the hole in the long piece
again to get grid of
|The two holes for the pins were then reamed to 3/8"
diameter. The brass tends to grab a drill so a drill should not
be used to finish the holes --- use a reamer.
A 3/8" rod was
inserted though the hole for the pin as shown in the photo.
The pin is resting on little blocks one each side of the cross.
This setup was used to finish each end on the cross to the correct
The last operation on the cross is to drill and tap the setscrew