[MLC] Timbers, Lumber and more

Since the donkey engine itself is finished, it’s time to start the wood working part.

I found plans for typical donkey sleds in my books and magazines. The timbers are cut from spruce on my table saw. The square holes for the cross timbers are made in traditional way with a router and chisel. Like on the real thing, the sled is hold together by truss rods and nuts only.

To avoid getting stuck in the woods, the nuts are countersunk on all surfaces. The portion below the donkey engine keeps free, while the front portion got decking installed. This was often used to hold and transport all the rigging equipment and other clutter.

A first ” come together” in gives a good overview of the final dimensions and look of the engine. The sled meassuers round about 4×1′. At the front and back is a chain installed, lead though the sled timbers ending in metal rings. Those were used to anchor the donkey in the woods, or to attach ropes and blockes to move the donkey under its own power.

Back in the shop, I gave speed to get the donkey ready for first service. I added a bulkhead for the haulback. To protect the sled timbers around the pull chains, I ordered laser cut eye-plates.

A rather uncommen view is shown above with the donkey on it’s side. The engine itself is hold in place by 4 bolts. To extend the walk way for the donkey puncher (operator), I added another bord with some more hardware, just as seen on protoype engines.

Next to add is the water tank, which is of course, made ouf of wood. To ensure the water tightness, I installed a plastic box inside.

Since the water tank will hold the gas tank as well, I needed good access. I decided to make the whole top removeable, which needed some tricks in scope of the truss rods.

In an early state, I spend thoughts on adding a roof to my donkey. I discarded the idea, as an open cab donkey gives more insights and is easier to operate. Anyway, when I looked at my model, I began to miss the roof. Back on the table saw, I cut some more lumber and build a typical backwood style roof, which is completely removeable. It’s hold in place by steel rods in the uprights, pushed into matching holes in the sled.

The roof will be covered with boards as I couldn’t find corraguated sheet metal of a matching size.

Last challenge were the typical logging blocks for all the cable rigging. Instead of using simple stock from the DIY-store, I decieded to make them as scale-models as well. I choosed prototypes made by Skookum, recreated them as 3D-model and ordered the housing parts 3D-printed in stainless steel. Not cheap, but worth every cent.

I made 6 of them in 3 different types. Those are enough for nearly any operation with my little donkey.

So next time, I’ll present my steam donkey model in detail and in operation. Stay tuned.

[MLC] Clutches, brakes and more

Hi folks and welcome to another Donkey update.

A real challenge was the construction of the drum chlutch mechanics. I choosee the system named Wern-Patent, which was widle used by Orr&Sembower as well.

To attach the drum to the drive gear, the drum is pushed sidewise on the main shaft. This is done by a threaded part, which pushes the drum over by use of some other small parts. The problem has been the pitch of the thread and the fact that I needed two, but one in lefthand and the other in righthand thread.

The solution I used to manufacture these parts is simple. I mounted the vise on the mill to the correct angle and milled vertical slots into a piece of brass tubing. Once done, I soldered them to a core piece and finished them to shape.

The other part is a U shaped bow. I silversoldered two pieces of steel togetherand finished them with more milling and filing. The larger hole will take the brass pieces above and allow them to turn. A 3mm pin is pressfitted  into the small hole on top and grabs into the grove on the brass parts. Pin and grove will transmit the turn into a sideways movement.

The brass part will than push a steel pin inside the hollow main shaft and by another link and bushing, its transfered to the drum. The levers are also hand milled from mild steel.

Last parts missing were the band brakess which are riding on the wider side of the drums, bear the bull gears. They are operated by foot pedals below the clutch levers. With those parts added, the engine itself is nearly compete. Last photo gives a sneak preview to the next update. It will feature the wooden sleed, logging blocks and much more finishing work.

See you next time,

GerdHi folks and welcome to another Donkey update.

A real challenge was the construction of the drum chlutch mechanics. I choosee the system named Wern-Patent, which was widle used by Orr&Sembower as well.

To attach the drum to the drive gear, the drum is pushed sidewise on the main shaft. This is done by a threaded part, which pushes the drum over by use of some other small parts. The problem has been the pitch of the thread and the fact that I needed two, but one in lefthand and the other in righthand thread.

The solution I used to manufacture these parts is simple. I mounted the vise on the mill to the correct angle and milled vertical slots into a piece of brass tubing. Once done, I soldered them to a core piece and finished them to shape.

The other part is a U shaped bow. I silversoldered two pieces of steel togetherand finished them with more milling and filing. The larger hole will take the brass pieces above and allow them to turn. A 3mm pin is pressfitted  into the small hole on top and grabs into the grove on the brass parts. Pin and grove will transmit the turn into a sideways movement.

The brass part will than push a steel pin inside the hollow main shaft and by another link and bushing, its transfered to the drum. The levers are also hand milled from mild steel.

Last parts missing were the band brakess which are riding on the wider side of the drums, bear the bull gears. They are operated by foot pedals below the clutch levers. With those parts added, the engine itself is nearly compete. Last photo gives a sneak preview to the next update. It will feature the wooden sleed, logging blocks and much more finishing work.

See you next time,

Gerd