Photo is of a low voltage dc motor replacing a 125 V ac one on a gearbox
.I Tend to like to use angle rod because it is easier to replace your motor
and if you mount it with a little extra distance it allows you to use a larger
motor if needed. Its possible that I may be a bit fussy but I chose to do
this by placing a piece of angle rod aligned to match up with the gearbox
by placing the whole thing on a sheet of glass, and using small pieces of
metal or blocks with all the same heights to bring up the angle rod to
approximately the height that I need and a small carpenters square or similar
to align it while it stays flat to the glass surface, it may be best to be
a little farther out so that one can build up the surface with shims and
for this lots of materials will work such as pieces of tire tube rubber .
After everything is fastened down with tape or other method , you can then
start to weave the fiberglass strands to hold the angle rod in place . For
best stability you need to use at least 3 screws or other areas to attach
to
This is the top illustration of a woven gearbox . I made mine with the gears,
I also molded myself and it dose work reasonably well . One of the main
advantages of weaving the whole gearbox is that it takes less material ,
than individually mounted bearings , but is at a disadvantage for reusing
any of the parts and the extra trouble making the reusable jigs. Permanent
or semi permanent jigs can be advisable for making many of the same .
Another reason for this type of gearbox is that it can take advantage of
the strength of using triangles to hold your gears in place and this is most
obvious from the top view
Below is a side view of the jig in use showing with the clamps holding
the shafting at right angles to the plate below , it also shows washers
and the clamps used to hold the washers in place . For washer holding clamps
I used old electrical connectors and they seamed to work well . This gearbox
x is made by weaving more than one layer . After the first layer is
done the clamps to hold the washers are removed so extra bearings, and washers
are added " note no gears are added yet" and then the small clamps
are put back on , of course lots of grease on everything , you don't want
it to stick . It turns out that by weaving 2 layers you can remove one layer
to make the opposite side of your gearbox , just remember that the this second
layer dose not need a motor mount , turns out even if you do a poor job of
keeping everything at the same height it will still work . The motor is attached
to a piece of angle rod that is also held by the bottom clamps to assure
it at right angles to the plate also .The angle rod is unfortunately, to
become part of the gearbox unless you can find other places to wrap onto
to hold the motor in place . It also turns out that to make your gearbox
mount on whatever you want , you only need provide an extra set of shafting
and just wrap them extra heavily , when it comes time to mount it all , you
just put the 2 shafts back in and mount it the whole thing from them
.
When weaving this , remember the importance of not pulling
on the fibers, as this can really pull even the strongest jig out of precision,
Kevlar is good in that it takes much less effort to pull it around the bearings
. Its worth considering sometimes to try using a few fibers to start with
and let harden to give a little extra strength to whole thing wile weaving
on the extra fibers , or you could also consider making this as a separate
and reusable strengthener for other gearboxes if they are the same
. Try Kevlar in crazy glue if you want strong and fast . Its interesting
that I made mine without any extra reinforcement and with just electrical
tape holding on my shafting to the clamps , however I did mean to try putting
such materials as cigarette paper between the gears to see if it helps preserve
a little extra space between the gears to prevent binding , of course
remove the paper when done .Its also a good idea to keep all the work as
low on the shafts as practical as this lessens the strain on the ends
of the shafts to lessen the chance of pulling them out of place .
These 2 drawings are of the type of shaft clamps I chose to use and
the part I used to make them , actually old 8 track flywheels as the shafts
are precisely placed just right for this use . In the lower part it shows
the semi finished setup .I didn't bother to show the dike or surrounding
container to hold the epoxy in place so it can harden and embed all the pieces
together as this can be modeling clay or small greased blocks or etc. As
usual I recommend enough fillers into the resins such as micro spheres and
or milled fiberglass so it will not so easily flow through small cracks and
maybe with extra clay or other crack sealant if needed . The piece shown
taped onto the shaft itself is made by a method shown below to give strips
of fiberglass with a triangular grove down its length. you could make these
, like the ones I made extra long so that they can be cut into shorter
pieces as needed
Finished clamp and it doesn't really mater
about how the bottom is shaped as long as the poured resin surrounds the
pieces or something that is attached to the piece that is to be held
together . The long rod you use can be just about anything with a screw
or some other piece of metal to grip itself into the epoxy . A round shaft
is not so good for clamping in place when you go to use it You can also you
might use metal rods that have threaded holes so you can use screws
to clamp it onto flat metal plates as I have chose to do .The second drawing
is one with a much longer rod but I never got to try this yet , but it only
makes since to use a longer rod that can be clamped at both ends as it probably
will not need to be so ruggedly fastened down . I have tried just using number
of lab clamps to make shaft holding jigs for making gearboxes
but the ones I tried seamed to be off by quite a bit , when the last shaft
was added but its possible if you could get them precise enough they could
actually be quite easy to use
.
This is an extra way of clamping that I didn't get the chance to try yet
. This additional idea that I never got the chance to test and should
.A longer rod that could be
clamed at both ends should be more stable and require less effort to clamp
securely..
Shown is the type of mold I made to mold my strips of fiberglass with the
v type grove for the above clamp .This can have some other uses also but
for them you also need to keep the opening where you pour in the resin, very
flat and smooth . You can do this by using the same type of angle rod on
both sides , or some other strips of metal that are exactly the same height
so that a top strip of metal can be used to cover the mold and force out
excess resin leaving it flat and smooth . For the above clamps it dose need
to be rather small or thin so if you do not have very tiny angle rod you
can try building up the surface with strips of metal so that when the two
sides are put in place to contain the resin , only the tip of a larger
angle rod is actually used to mold the strips . As usual I prefer to use
grease to hold the aluminum foil on as a mold release, and add the usual
fillers in my epoxy so it will not continue to leak out of the fine
cracks . This use of assorted coarse fillers works so well for me , that
I never need to use modeling clay except on lager holes .
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