Brake for a 5 ton Cannon

by John

Well, actually, it is a 1:10 scale model of a 5 ton cannon. The model weighs around 5-10kg at a guess.

The brake is to control the descent of the barrel/ carriage down the 4º slope of the 5 meter long chassis.

On the original, the brake was a steel band on a steel drum which was attached to the big gear.

The drum is approx 600mm/2′ diameter.

This is how it appears on the scale model..

From the other direction. The stainless steel band winds around the drum, and is attached to a small lever which is operated through the shaft by a much larger lever on the outside of the chassis.

I was a bit apprehensive about this job. The lever is very close to 2 gears. the steel belt has to be properly tensioned, because the degree of movement of the control lever is quite restricted. And the width of the band has to be slightly less than the 5mm groove on the drum.

But, I found these…..

Stainless steel cable/plumbing ties. 4.75mm width, and in various lengths. And quite inexpensive.
The cable ties are sharp and springy. Feeding them into position was tricky. But after bending them around the pins on the shaft I was reasonably confident about silver soldering them with a loop at each end. The soldering was straight forward. Stainless steel silver solders well.
The handle is almost 1 meter long. 96mm brass on the model. It will be pinned to the shaft.
I will adjust the shaft length in the next workshop session.

So, for once, my apprehension was not warranted. The job was fiddly, but no major mistakes!