Make a Thompson Electric Mag Step by Step

[Killbucket]

YES, I know there's off-the-shelf ones now...I guess I'll have to throw away the patterns I worked so hard on...

Yes, there IS a way to fit a servo into a Thommy mag, without it sticking out.
Tamiya Lunchbox diff gears #9115010. Enough to do TWO drum mags, SWEET!!!



Arrowed: An M14 mag winder is cut off, turned smooth, and bevels cut to serve as "indexes" for the Oatey putty to lock into.
We need a new "lug" on the mag winder, that is .315" dia. The putty ball is slightly bigger than this.

Remember my Golden Rule here!

Walk away, just, walk away.
It needs to harden up without being disturbed. I put a lamp on it to warm it, I'll come back in an hour, and turn this down on the 9x20 Harbor Freight lathe.

An electric drill, a file or emery board, and the same op could be done.


The drive lug after turning on the lathe.


A closeup.




Pressed into the gear, and a plug of putty locks it to the hex-shaped recess.


Turning to the drive gear, a shallow slot is cut across the bottom. This allows a keyed lug to be formed into it.


A 3mm screw is wrapped with blue masking tape, and used as a mandrel. A small "snake" of putty is mixed...


And wrapped around the screw, and mashed into place.



A short while later, it can be easily pulled apart, and trimmed up.


Drive parts completed.


Now to mount the servo like this.
The whole assembly is 1.49" thick -less than the servo is deep, measured from the shaft end to case back.

SERVO-MOD DIRECTIONS:
http://www.air-sharp.com/magmod.html

http://www.kapowwe.com/Merchant2/mer...s&Store_Code=R
Thompson lo-cap, Marui-compatible.


And hack the poor thing as shown.


This will hold about 3,000 rounds or so.

Making the drum from scratch, CAD for that and how to make the outer band coming.


To make the outer band for this, the computer says cut a strip 20.82" long, by 1.70" wide.
ASK YOUR MOM FIRST IF YOU ARE UNDER 35.
Preheat over to 325deg, find something "about" 6-7" diameter to use as a form.




Find my forming plastic tutorial, and then, still don't try this yourself:

The main and front cover bands. My uncle said he was in a cover band once.


Mocked up over the CAD at actual size. Approximate locations of components.

Servo Mounts.





The back panel, and the abbreviated Thommy locap.


The Dremel was used to create the "spotwelds" in the front cover.


The locap slides into these slots on the back.


Fully seated.



These were robbed from a Kappowwe springer drum mag- virtually the only parts of it left worth using!


Getting closer!


Some sanding, and a bit of paint, and oh yeah, wiring!

This will get a tracer illumination circuit added next.

I should point out- all the plastic parts for the drum were made with and Exacto knife, a Dremel, and a band saw with a dull blade. Note all pics taken in the kitchen -NO SHOP NEEDED!

[Killbucket]