Breech Block Handles

by John

I am glad that I had no visitors to my workshop in the past 2 days.

The language in the workshop has been a touch foul.

Because I have been making handles for the previously made bronze breech blocks.

The handles are very small, very exacting, and difficult. In a word, I struggled.

End result photo….

1. Those little handles were used to lift out the 130lb breech block by 2 gunners. The handles swivel, and push down on the barrel, to lever the block out of the gas tight seal the block makes with the end of the bore of the barrel. As you can see from the scale of of my finger tips, they ARE very small.

I was not enthusiastic about this job. I had a feeling that it would be a bugger. And so it was.

2. First task to cut out the top of the handle bracket. Piece of cake with CNC.

3. Next, drill a hole into the bronze block and silver solder it into permanent position. Also, straightforward. The top was Loctited into position with Loctite 620, so the silver solder was not disturbed. So far so good.

4. Next job, make the actual handles. I milled a round rod with appropriately sized flats, then annealed some brass rod, and wound it around the shaped steel. Total failure. Did not take the shape accurately, and sprung outwards. So I tried it in copper. That worked better…

5. The copper wire was out of the scrap bin. 2.4mm diameter.

6. Then milled some brass rectangular section (6x4mm) and silver soldered the copper pieces to it.

7. Then cut the brass approximately to length.

8. Slit the brass to 2mm width on the mill.

9. Drilled the fastener holes and attached to the breech block with BA10 bolts and nuts.

10. And ended up with a breech block which can be levered out, and replaced into position reasonably accurately and consistently.

All straightforward.

So why all of the bad language?

Well, I needed 2 of these, so 4 handles. I made 2 spare.

I dropped one. Could not find it, despite hours of searching, including using a fibre optic 5mm diameter device to look under the milling machine and sweeping the floor. (no snakes in this cold weather. I hope). But no luck, so I made another.

Another handle jammed in the Dremel drill. I hear it hit the tin wall 7 meters away. I did look for a minute or 2, then succumbed to common sense and made another. The language really was foul.

Anyway. You have seen the final result. not too bad. Another bit of brass bling.