Brian's Donkey Engine

[Brian Rupnow]

My remaining short piece of brass isn't long enough to build an entire winch drum out of, so I will build the two end sections out of brass and fill in the center with some form of pipe. Trouble is I don't know exactly what pipe yet, so that is an unknown dimension at this time. I can live with that---make the end bells now and figure the pipe out later. Brass would be nice, but I'm way over budget on this build.

 

[ozzie46]

Brian, How about a brass sink drain thingy?


Ron

 

[Brian Rupnow]

Brian, How about a brass sink drain thingy?


Ron

Good idea Ron---I'll check at the plumbing supply house tomorrow.

 

[Brian Rupnow]

Another drawing to add to the ever growing pile----I made these today, but didn't take any picture of them before I installed them.

 

[Brian Rupnow]

However----This did let me assemble all the bits and pieces I've been working on. I've been too busy to hunt down a suitable piece of brass tube to connect the two ends of the winch, although I did stop at a couple of plumbing stores and check out the brass sink drain tubes---they were too small. So far, everything is working out well, and I will probably spend some time working on clutch parts and finishing the winch drum this week.----Brian

 

[chuck foster]

looking good as always brian, what diameter of brass tubing do you need ?
i have some pieces here at home and some at work let me know the o.d and the length and i will see what i can find.

chuck

 

[Brian Rupnow]

looking good as always brian, what diameter of brass tubing do you need ?
i have some pieces here at home and some at work let me know the o.d and the length and i will see what i can find.

chuck

Well, in a perfect world, I'd like a peice 2.30" outer diameter by about 1/16" to 1/8" wall x 2 1/2" long. I can live with a bit smaller o.d., but can't go any larger.----Brian

 

[kcmillin]

Well, in a perfect world, I'd like a peice 2.30" outer diameter by about 1/16" to 1/8" wall x 2 1/2" long. I can live with a bit smaller o.d., but can't go any larger.----Brian

Could you make it out of sheet brass, formed and soldered?

Kel

 

[Brian Rupnow]

Kel---I probably could, but I don't have a set of slip rolls, and brass thick enough to do the job would be really difficult to roll. I just haven't had time to persue this issue, and brass is far too expensive to make it from solid. I'll figure out something this week. I have a ton of other things to address yet, so I'm not in a time crunch for the pipe.

 

[tel]

Once the drum is laid with cable the bit of pipe will be invisible anyway - steel would be fine - even a bit of exhaust pipe tubing.

 

[Captain Jerry]

Brian

Use any kind of pipe and cover it oak lagging. Very authentic. Oak lagging had two benefits on the historical donkeys. To increase the drum diameter and line speed and to reduce cable wear.

Jerry

 

[Brian Rupnow]

This afternoon I built the clutch.---At least the wooden part that will become the expanding "clutch shoes". In the foreground is the piece of 3/4" thick oak flooring that it was made from. (A left over from when I had hardwood floors installed 5 years ago.) The process??---Well, first I drew a 3" diameter circle on the wood with an old drafting compass and "rough cut" it out on my bandsaw----And its darn rough, because my bandsaw has a 1" wide blade that is far more into cutting straight lines than curves. Then out to my big ancient drill press where I drilled and reamed a 5/8" hole in the center of the circle. I had bought a piece of 3/4" brass rod to make the winch shaft bushings from yesterday, and about 3/4" of length was turned to 5/8". I mixed up a small batch of 2 part epoxy and gobbed it on the turned down section, slid the wood over the shaft, then went and eat my supper. Came back downstairs after supper and turned the o.d. to an exact 2.8" diameter. Faced the end farthest from the chuck. Then came in from the back side and took repetitive cuts untill it measured exactly 1/4" thick. There is a 3/8" hole about 1/2" deep in the end of the brass rod. Tomorrow I will bore the brass rod away in small incrememts utill I am left with the hardwood disc with a 5/8" hole in the center. The solid model shows what this wood will eventually look like. (The solid model of course shows only one clutch shoe---there will be two of them both made from this single wooden disc)----I hope!!!

 

[Brian Rupnow]

Well of course I'm going to give you a drawing of it!! You thought I forgot, didn't you-----------EDIT EDIT--Drawing has been revised. Center radius was originally .313"

 

[miner49r]

Brian,
I have been following your build since the beginning and I am at a loss for words. I hope that some day my skills would come somewhere close to the exacting work that you are doing.
Any thoughts as to how much horse power (or watts) your engine puts out?
Alan

 

[Captain Jerry]

Brian

I have been looking at your drawings and if I haven't made an error, something is not
fitting. Looking at the slider in the clutch mechanism, the bottom of the shoe that fits into the
slot in the wooden clutch shoe is .375" off of the face of the gear plate.

Total height .400"
Slot Width - .125"
Top Flange - .080"
---------
Total .375"

And the wooden shoe, after subtracting the depth of the slot adds .100" for a total of .475"

The internal depth of the drum is only .375" which means that there must be a gap between the
face of the gear and the lip of the drum of at least .100" and that is if the face of the wooden
shoe bears against the face of the drum, which it definitely should not do. The only contact
between the drum and the shoe should be the outer edge of the shoe.

I dont see anything that will maintain the relative position of the gear and the drum on the shaft.
What is there to keep the face of the clutch shoes clear of the drum face?

In my design, the inner face of the clutch drum bears on the end of the gear hub, with a bronze
thrust bushing between. The depth of the hub and the bushing keeps the gear and clutch drum
separated by about .015" and also maintains a clearance of about .015" between the shoe face and
the drum.

In this post, where I mention the shoe face, I am talking about the flat face of the disc, not the
edge of the shoe.

It is entirely possible that I have misinterpreted your drawings or added the numbers wrong.

Jerry

 

[Brian Rupnow]

Jerry---maybe this will help. In the picture the slider you see on the smooth face of the gear sticks out a total distance of 0.275---that is .125 plus .150 In the drawing of the clutch shoe, the remaining amount of material below the 0.150 recess is 0.100 If you add .275 of metal plus .100 of wood, that is a total of 0.375, which is the depth of the counterbore in the end of the winch drum. Shouldn't in theory be any gap. However---Where the drawing shows a 0.013 clearance between the end of the gear hub and the inside face of the winch drum, I will probably make up an 0.025" brass spacer to fill that gap and give me 0.012 clearance where there is now no clearance at all between the back side of the gear and the end of the winch drum. Another thing I just noticed is that the wooden disc can't be "size on size" with the 2.8" bore in the winch drum AND the 0.625" hub on the back of the gear. I will open that hole in the wood to 11/16" thus giving a possible movement of 0.031" to each clutch shoe as it engages and disengages. ----Brian

 

[Jasonb]

But without a gap you will get a lot of friction between the side of the winch drum and the sides of the wooden clutch parts, I think that is wat Jerry is saying and I agree.

J

 

[Brian Rupnow]

Jason---That is a theoretical, mathematically possible "zero gap". In reality there will be a gap, but it will be very small.---I control that.

 

[Brian Rupnow]

Yes Virginia, you can bore wood with a carbide tool-----If thats the only kind of boring tool you have!!!

 

[Brian Rupnow]

And here's what the finished wooden bits look like laying in the cavity in the end of the winch housing.