Kim, this should make it a lot clearer - when I first saw the original plans which just showed the individual parts, I didn't get it either until I found a patent that showed how it works.


Here is a view of the assembled pieces of one drum set, each piece in a different color:

And here it is in exploded view:

The pink drum at the right is what moves the chain. It can freewheel on the shaft unless the pawls are engaged. The yellow disc is fixed to the main shaft, and holds the pawls. This picture doesnt show it, but there is another pivot pin at the end of each pawl, away from the protruding pins, to hold that end of the pawl in place. The light blue disc is the one that the handle can rotate, via the holes in the rim. The slots in that disc fit over the pins at the ends of the pawls, so when the disc is rotated, the pawls are moved in and out. The dark bluw disc at the left is a retaining ring for the light blue ring. It is fastened to the yellow disc to keep the light blue ring from falling off.

So, with the yellow disc fixed to the main shaft, moving the handle on the light blue ring will turn just that ring, moving the pawls. The pink drum can spin unless the pawls are moved out to engage on the crenelations.

Does that help?
 

Quote from: MMan on April 21, 2024, 09:10:32 PM

Hi Kim,

Enjoying this build immensely, if quietly.

For your boiler cutout consider using a hole saw (probably bi-metal for steel) - they are cheap and low on drama if all you want is to remove most of the material and file from there.

All the best,

Martin

Thanks Martin! 

Interesting idea with the hole saw...  It's just enough over a half circle to fit the drill at the center of a hole saw.  But how well does that work to cut a hole where only 60% of it is there?  Would that work OK or cause weird problems with the hole saw?  I've never tried it on a partial hole like that before.

Kim

When over a partial piece, or anytime with thin sheet, clamp the piece between two sheets of plywood to hold it in place and keep it flat. Make the bottom piece of wood thick enough for the  pilot drill of the hole saw to stay in the wood till the saw is done cutting.

This morning was devoted to tappets and tappet guides. The tappets are as per Upshur drawings. I added a 0.050 thick flange to the end of the tappet guides. The guides are pressed and Loctited to the crankcase plates.

Hi Kim,

Enjoying this build immensely, if quietly.

For your boiler cutout consider using a hole saw (probably bi-metal for steel) - they are cheap and low on drama if all you want is to remove most of the material and file from there.

All the best,

Martin

Thanks Martin! 

Interesting idea with the hole saw...  It's just enough over a half circle to fit the drill at the center of a hole saw.  But how well does that work to cut a hole where only 60% of it is there?  Would that work OK or cause weird problems with the hole saw?  I've never tried it on a partial hole like that before.

Kim

The ratchet discs have been pinned to the main shaft, so easier to show how they work. Here is one with the pawls retracted, one shown at the blue arrow. The control lever, marked in red, is in the lower position.

Here, the control lever has been moved upwards, raising all six of the pawls:

Same positions, but with the chain drum in place, shows where the pawls will push on the drum:

Working well! Next step will be to make the bushings for the inside of the chain drums - the center hole in them is larger than the shaft to leave room for them. The bushings will allow the drums to spin freely when the pawls are retracted.