As you can see this is made mostly with printer
but am sure could be made with wood or plastic. The base has a slot 8mm wide by 5mm thick a hole 1.8mm goes through it and the sliding motor mount 1.5mm wire is used as guide and holds the mount in place the wire is also held in position with the small keeper block. The mount must be able to slide freely with no tight spots. Pictures show wire in base and on mount.
Next chain drum and drive disc have 2.1mm hole all the way through for 2mm brass shaft the 3mm hole drill 10mm deep in drive drum at motor end. The motor then gets fitted on sliding platform. On drive drum face drill 2 holes 6mm Dia and 3mm deep, 180 degs apart for magnets. These are then glued in with a bed of epoxy adhesive
as in photo, where the 2mm shaft goes through drill a recess 5mm Dia and 2mm deep for cable drum retaining ring. Also drill a hole 1.5mm Dia about 5mm from end of motor side of drum and tap for M2 grub screw for holding motor shaft. Now fix drum on to motor.
At chain drum side cut a thin piece of tin and glue to face of drum this I used super glue and a mall brass nail fitted for a bit of extra security as in photo. Two 1mm holes drilled through the centre length of the drum very close to the outside diameter and clear of centre shaft. A piece of copper wire can be fed through one hole the chain link fed through the copper wire and the wire is fed through the other hole then the two twisted together or soldered to hold chain in centre of drum.
Now 2mm brass rod is pushed through the drum ( I fitted 2 x 2mm flat washers
at this point between mounting bracket and chain drum to ensure the drum did not rub on bracket) making sure sure the drum spins very freely the rod is pushed through the hole in the motor drum until it meets the motor shaft then push hard to slide the motor to end stop. Now slowly push motor forward towards the chain drum (fully open gap between drum 7-10mm) when fully home fit holding sleeve on brass rod at outside of bracket and tighten grub screw this should give the correct length for rod. Now push motor back to end and make sure shaft is still in motor drum. If not adjust until it is still in shaft Next push chain drum back against washers
and shaft pushed towards motor make a saw cut in brass rod to mark drum position now remove shaft and make a brass ring to fit tightly on saw cut on shaft and solder then clean all solder from chain drum side of shaft refit and check drum still runs freely adjust as required when sure cut off brass rod as photo
The base I made is 120 x 50mm x 5mm, chain drum 30mm x 25mm Dia, mountings were 28mm high x20mm wide. Will continue with linkage setup next. Any questions or ideas please feel free to let me know.