54383fixing 0-8-8-0 Marklin Mallet.
- Nov 1, 2007Here is the text of the message that I placed on the Z-scale forum
early last month.
I do not know if anyone else out there has had problems with this
engine (Marklin 0-8-8-0 Mallet) but Glenn and Sandy Stiska have a fix
and gave me a clue as to the cure. They will do the work for a modest
fee. At least modest in my estimation.
The blind gear that is not pinned in the tower just has to be pinned
in place. No quite so easy as it is said. It appears that over time
with wear that the clearances open up enough to allow the blind gear
to move laterally in the tower and when they do go it grabs the
inside of the casting and looses contact with one of the axle gears
and the whole thing jams up and stops. Classic symptom is side rods
out of alinement.
I used a piece of copper not brass tubing. The tubing was .0635
inches in OD or 1.62 mm and I spun solder onto it to increase the OD
to .0725 inches or 1.84mm after soldered a drill bit shank into the
end of the tube. The drill bit was a slide fit into the tube and it
was soldered in place before the spin soldering of the tube was done.
The drill bit was .032 inches which is a No. 67 bit. When you look at
your engine you will see on one side the hole is bigger than on the
other. So I cut the drill shank so that .070 inches or 1.8 mm are
showing and then pressed it into the hole. It was a tight fit going
through the hole in the wheel wiper and I made sure the shaft did not
protrude very far from the smaller hole on the other side of the
tower. Once I was sure of the fit. I cut the tubing about .08 inches
or 2.0 mm long and result is a stub shaft sticking out of a hub and
the whole assembly is about .15 of an inch long. Once in place I used
a drop of black nail varnish over the hub end only to hold it in the
larger hole. This stub shaft prevents the blind gear in the tower
from moving out of position laterally. The nail varnish will also
prevent a short should it work its way out of position and touch the
pickup strip. This brass tubing is a standard size from KS in my LHS.
Total time to make two of these a fit them about 90 minutes. The
tough part is spinning solder to increase the OD. This is a bit of an
art and if you use a small amount of epoxy or locktite you can fix
the tubing hub in place with out getting it to be a press fit. You
could also fit the drill shank in place in the tubing using the same
products. However when using these products there is a chance of
contaminating the inside of the tower and freezing the gear(s) in
place. To solder the drill shank into the brass tube you will need a
special flux for use in soldering stainless steel to copper and
brass. This hub goes into the chassis far enough to hold gear against
far side of the tower while allowing it to rotate freely it is held
upright and the drill shank becomes the axle for the blind gear and
protrudes slightly from the smaller hole on the opposite side of the
tower. The tower is just under .15 of an inch wide or 3.8mm.
Here is some additional information on my make over.
I used a K36 boiler shell and extended the firebox area a bit and
used a K27 cab for my 2-8-8-2 Mallet and built my front porch from
salvage from a Rivarossi Mallet pilot. My K27's will pull easily 20
cars around my layout and the Mallet will pull 30 cars with the same
ease. There is a picture of my beast under construction on my web
site www.nn3.ca for those interested.
Spin soldering - I chuck the pieces of tubing in a 3 jaw hand crank
drill and clamp the hand drill in a vise with the crank on top and
the tubing extending out horizontally. The tubing has to extend
beyond the chuck by at least 3 inches for my 15 watt iron to do the
job. I heat the end of the tubing and get it coated with solder and
then start the crank and as the tub turns add more solder to it while
keeping the heat to it. Then when it is flowing nicely I with draw
the heat and solder and continue spinning and after the colour
changes I let it sit for a bit and then dress it with a file while
turning it. Then check to OD to see if it is close to what I want. I
learned this trick in a silver smithing class.
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