# Minnie Traction Engine (1" scale)



## CWelkie (Nov 13, 2021)

Now that I've been poking my nose in here more often I guess I better post something what I've actually accomplished in the shop recently.

Just finished a model traction engine of the "Minnie" design  in 1" size (i.e., 1" to the foot).  It is a freelance design of no particular actual engine but does replicate most if not all features an actual engine would have.

Here is a photo before and a couple after paint:












It was a great project to build.  Lots of variety with all the different materials and parts to fabricate.


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## YotaBota (Nov 13, 2021)

That is to cool!!! Now I'll spend the next few days looking this one up.
Did you cast the flywheel and handles?
Is it operational?


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## historicalarms (Nov 13, 2021)

Man I respect folks like you & the fish real guy that can stick to detail & attention on a "many small parts" project ....awesome


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## CWelkie (Nov 13, 2021)

YotaBota said:


> Did you cast the flywheel and handles?


A number of components are castings. Some like the outer wheel rims and chimney stack in aluminium and others in a version of bronze called "gunmetal" (e.g., cylinder, feed pump body, wheel hubs). Castings are available from suppliers in England (e.g., Reeves and Polly).  The flywheel is from a cast iron casting; the handles are gunmetal castings.



YotaBota said:


> Is it operational?


I've only run it on compressed air so far but it has been built and tested to be steamed using coal.  That may never happen - so messy and I don't want to get in trouble with the environmental movement ;o)

Here is a short video of the engine going through the gears; traction engine style:




Please excuse the compressor running in the beginning ... one gets to used to it in the shop that I didn't notice until later.


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## CalgaryPT (Nov 13, 2021)

Wow. That's so far above my pay grade I feel like I should be charged just to gaze at it. Absolutely beautiful work. You're an artist bud.


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## Tom O (Nov 13, 2021)

I’ve always liked Traction engines that’s a beautiful build!


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## DPittman (Nov 13, 2021)

Beautiful, amazing and awesome.  Thanks for sharing


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## PeterT (Nov 13, 2021)

Very Nice! I can only imagine the patient hours that went into the build.
Will it ultimately be 'fired'?


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## 140mower (Nov 13, 2021)

Wow...... That is all I have.... Just wow. Very nice work.


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## 6.5 Fan (Nov 14, 2021)

Very nice, way above my pay grade.


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## CWelkie (Nov 14, 2021)

Thank you everyone for your kind comments.

PeterT - I don't know if I will ever fire it.  Running it on steam would be the ultimate step for completion but does bring its own set of challenges.  To start with, I wouldn't even know where to get appropriate coal (can't pick it up from the tracks anymore ) ). Then I'd have to clean it up afterwards ... Given all my excuses, it'll likely just be a "hanger queen".


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## PeterT (Nov 14, 2021)

I hope you don't feel like I'm judging, it was more for self centered curiosity. I've eyed a few stationary steam engines I'd like to build one day, maybe even through to a functional boiler. I see some guys have designed around or possibly retrofitted gas flame, probably for the reasons you mention around coal. That's where I was coming from. But I'm not up to speed on the details & my simple mind quickly wanders off to other projects. But I sure like the machines of that steam era. IMHO its a hobby so you only have to justify it to yourself. PS- I get asked all the time if my radial will fly a model or be a hangar queen. I don't even have fuel scarcity as reason (although its trending that way). So for now I say 'probably not' LOL. My buddy built two 1/4 scale Kinners simultaneously, one to power a model & one for the trophy shelf. That's too much like work. In the end I think he had ignition reliability issues so I suspect they ultimately became matched bookends.


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## boilerhouse (Nov 14, 2021)

Looks fantastic - hope you keep posting.  Now the pressure is on "us guys" who also poke in here and don't have much of a project to show off.  LOL.


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## YotaBota (Nov 14, 2021)

CWelkie said:


> Then I'd have to clean it up afterwards


Not to mention running it the living room would be a recipe for divorce.
A quick search shows most of the new boilers are using butane or propane to fire the boilers, its virtually smokeless but I still don't think you'd get away with running it in the living room. How you could integrate one of those little butane cans to make it look period correct might be a challenge.


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## CWelkie (Nov 14, 2021)

PeterT - no offence taken by me at all. I got over the notion that a model has to do everything exactly as the full size version to be worthwhile. I too have built a few scale model aero engines that will never get into an airplane even though I'd flown R/C for most of my life. (It seems that the only ones that ask about flying a hand made scale model engine have never built one ... or flown a model <grin>.)

I have considered using a gas burner in the Minnie enough to conclude that although it could work the changes might be terribly inefficient to the point of perhaps not raising adequate steam.  As I understand it, traction engines (and locomotives) were designed to utilize the hot flue gas to heat the boiler more than the radiant heat of the fire. Gas burners really more on radiant heat, especially the ceramic style. On a large enough scale it could be worked out I'm sure but this little engine has a pretty small firebox. If it could be converted to gas, I suppose the supply canister and all the regulating gear could be mounted to a "goods wagon" towed behind.  The entire exercise certainly shows one how much energy can be extracted from a relatively small amount of coal ... one of the reasons it's going to be hard to replace/eliminate.

I have converted a PM Research vertical boiler to use a gas burner from a small backpack camping "stove". It works well but in this case the burner is as large as the bottom of the boiler (i.e., oversized?) and all the heat/exhaust just goes straight up.


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## PeterT (Nov 18, 2021)

CWelkie said:


> Just finished a model traction engine of the "Minnie" design  in 1" size (i.e., 1" to the foot).  It is a freelance design of no particular actual engine but does replicate most if not all features an actual engine would have.



I meant to ask, what was your source of drawings for the Minnie? I seem to recall there was a book available and/or maybe drawings sold separately? Were any castings involved?  
You sure did a nice job. The closer I look, the more details (and work) become apparent. Did you post any build pics on another forum as you progressed along?


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## CWelkie (Nov 19, 2021)

I purchased the drawings and set of castings from AJ Reeves. Castings as also available, I believe, from Polly Engineering (both in England). I was also fortunate enough to acquire a copy of L.C. Mason's book about building the Minnie.  It is out of print, hard to find and pricey as a result but provides a lot of good information about methodology and order of construction.
If I was to do it again, I wouldn't bother with the drawings.  One can easily build from the drawings in the book and it includes so much more information.  The separate drawings are just larger versions of those in the book so there is no issue with them if you can't get the book.

No, I didn't post anything on another forum (until it was completed).  I didn't know what I could have offered that was new given the dozens (hundreds?) of these models that have been built over the years.

Here are a few photos from during the build ...


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## historicalarms (Nov 19, 2021)

"wood knot" just ordinary Kingsford charcoal briquets work as a coal sub, might have to crush them down a bit and experiment a little....coming from a guy that 'spermints" with different gun powders of all sorts in some unconventional circumstances....you'd be surprised some of the results that can be achieved "unexpectedly"....ever here of how a heart drug became a most common ailment that is a long way from the heart.


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## PeterT (Nov 19, 2021)

Again, very nice.
Just wondering, what are your go-to tools for silver soldering - meaning torch type/fuel, solder, flux's etc. These steam/industrial era models seem to necessitate that from what I can tell. Are you able to find what you need in Kanuckistan or have to source from other lands? What about teeny rivets, where do they come from?


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## CWelkie (Nov 19, 2021)

For silver soldering I've been known to use a 1lb bottle-top propane torch, Smith Oxy-Acc torch and/or a Seivert propane torch.  It all depends on how much heat is required and how small the part is.  To do this boiler I needed use the Seivert (7920 nozzle I think) and wrap the parts not being directly heated in an insulating blanket. I find the little jewelry torch ideal for small parts or when concentrated heat is needed.

I get my silver solder from CuPAlloy in England. They have any alloy required, good advice and know what they are doing. I get my flux there too; both "regular" and higher temperature (e.g., stainless steel).

The rivets came from Macc Models as did most of the BA fasteners on this model.  There are numerous British model engineering suppliers for this stuff.

I don't know of any domestic suppliers surely due to the tiny market here for such things.  In my mind, it only makes sense to go to England for such items given the much larger choice of vendor ... have to pay shipping anyway.


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## Tom O (Nov 19, 2021)

I watch a vid a couple days ago of a guy stacking two plates in the vice then drilling a hole between them to the rivet length desired, He placed the rod and a flat washer over it for max length then cut it off, if it’s for a flat rivet counterbore to the head dimensions slip in the rod.and flatten with a hammer or a concave form for round heads.


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## Mcgyver (Nov 19, 2021)

fantastic work!


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## YotaBota (Nov 19, 2021)

Thing of beauty. Is the crank machined from cast or built up?


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## CWelkie (Nov 20, 2021)

Thanks again for all the kind feedback.



YotaBota said:


> Is the crank machined from cast or built up?


The crank is built-up.  The webs were silver soldered to a full length shaft and the connecting rod shaft.  The excess shaft between the webs was then cut away.


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## historicalarms (Nov 20, 2021)

A lot, if not all old gunsmith "how to" books I have, mention an excellent "heat sink" for small parts that are very fragile to change in metallurgy , they all recommend a simple apple as a heat sink, easy to push the part into the mass just the right depth and leaves no unprotected area's.


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