Brian’s 1″ Minnie Traction Engine

[CotswoldsPhilParticipant @cotswoldsphil]

Bump: So that Brian's last post is not lost in the festivities. Happy New Year everyone.

Brian,

It looks like you find yourself in the same situation as I was about 40 years ago when I was attempting to make a Minnie boiler. No matter how I tried, I did not seem able to get the work up to temperature before I exhausted the flux, which was the correct high temperature type for C24, as it was then.

I still have the shell – throat-plate, barrel, thickening plates, and pump pad, which I managed to assemble and silver solder OK with some help at night-school using oxy / acetalene – (very scary – for me) – which gas do you turn off first?.

The firebox did not, however, want to be silver soldered by me with my propane set-up which was a Bullfinch 1250 / 38mm dia / 12.6 kw / consuming 907 grams of gas per hour and which also kept blowing out! I had a makeshift hearth with lots of coke (as suggested by Mr Mason in his book) to surround the work and conserve the heat.

I gave in and bought a boiler which may not be an option for you as the prices have increased quite a lot since I paid £25 at Reeves in the early 70's.

I did some research last year (Sievert and Bullfinch websites) into propane torches, hearths and methods in preparation for a second attempt. Apart from a lot of successful small test pieces, some more Sievert burners and remade firebox plates – no further progress.

Your Sievert 2941 / 28mm / 7.7 kw output is quite a bit smaller than I was trying to use. I'm not saying that this is not enough – I just don't know, those more skilled at this may say – why are you wasting so much gas.

Another bit of information to bear in mind is the maximum off-take possible from different sized bottles:
A 3.9kg bottle – 25000 btu or 7.3 kw :: 11kg bottle 50000btu or 14.6 kw. etc.

Silver soldering a boiler, even a small one, is a difficult and potentially costly skill to learn.

I hope someone will be along soon to offer some practical advice, which I will also gladly welcome.

Regards

Phil

[pgk pgkParticipant @pgkpgk17461]

I have a vague recollection of someone telling me about improving gas flow by placng the cylinder in a barrel of warm water.

Perhaps having the job of a gas BBQ might also help?

[Andy HoldawayParticipant @andyholdaway]

I use a Rothenberger torch with MAPP gas – you will never have a problem soldering / brazing again!

The heat output of these things is phenomenal, and while they're not cheap they make the job so much easier.

There are other makes available, usually described as a Turbo Torch, but the MAPP gas makes all the difference.

[Brian AbbottParticipant @brianabbott67793]

Hello all, thank you for your reply's.

Phil, interesting information about the gas bottles take off.

I have ordered a 43.5kw burner which will be connected to a 19Kg bottle of gas.

I have had a couple of quotations to have the boiler made, not cheap but knowing the amount of work that is involved i am not surprised.

I would really like to crack this so fingers crossed this will get me a little closer, and if nothing else i am getting quick at making flanged plates for the fire box..

[CotswoldsPhilParticipant @cotswoldsphil]

Hello Brian,

That's quite a flame you will have there, based on what I remember of the Bullfinch torch I used.  It's going to consume about 3.5kg per hour.

Boiler making is I fear, a difficult and costly skill to acquire.

Phil

Edited By CotswoldsPhil on 05/01/2016 11:49:34

[Brian AbbottParticipant @brianabbott67793]

Hello Phil,

That’s what worries me, bottom line is that working with such equipment is dangerous and maybe I should be leaving this to the professionals!

I am going to have a go with this new torch, but not going to push it, if I am any doubt I will have to bite the bullet and invest.

[Brian AbbottParticipant @brianabbott67793]

Well it's beaten me….all I can do is console myself that silver soldering and boiler making is a skill that must be learnt over many years.

I have seen much improvement with my efforts, but they will never be at a level I would be happy with.

Is there anything I should be looking out for when getting a boiler commercially made ?

[CotswoldsPhilParticipant @cotswoldsphil]

Hi Brian,

You are in exactly the same place as I was a good few years ago. I'm now pondering whether I should try and complete the Minnie boiler I started in the 70's.

With this in mind, some good advice has just appeared in another thread on silver soldering which may be of interest:

**LINK**

Regards

Phil

Edited By CotswoldsPhil on 13/01/2016 09:48:03

[Brian AbbottParticipant @brianabbott67793]

Thanks Phil, some good advice in there.

I have resigned myself to having one made, either GB boilers or Chedder valley.

Would have liked to go to western steam but my budget will not allow it.

Must say, all the worry about ending up with something i am not happy with is making think i should put the lot in a box and have a break for a while..

not to worry,

Brian

[Neil WyattModerator @neilwyatt]

Posted by pgk pgk on 05/01/2016 09:34:49:

I have a vague recollection of someone telling me about improving gas flow by placng the cylinder in a barrel of warm water.

Perhaps having the job of a gas BBQ might also help?

I read the story of someone who used warmer and then warmer water on a small cylinder until… it made their parents quite cross…

Neil

[CotswoldsPhilParticipant @cotswoldsphil]

Hi Brian,

My engine, for what it's worth, took the best part of 40 years to complete (it still needs painting) between work and family commitments, slow-downs in the manner which you describe and other diversions. The last slow-down was caused by commercially available steering chains which kept on breaking, until I bit the bullet and came up with a method to manufacture and silver solder each link of the 18 inches of steering chain required for the engine.

Keep smiling it is just a hobby after all.

Regards

Phil

 

Edited By CotswoldsPhil on 13/01/2016 19:12:51

[Brian AbbottParticipant @brianabbott67793]

Thanks Phil, very true, need to keep this in mind…

Dropped all the parts from my boiler in on Saturday for someone else to solder it for me..very greatfull I am to them to.

Whilst it's away I am going to make a start on the horn plates and bearings, am I best to follow the book with regards to marking out the correct gear spacing, mark the position of the crank on both plates whilst they are attached to the boiler ( when it's back ) then set the spacing using the gear tool?

Thanks,

Edited By Brian Abbott on 17/01/2016 22:37:45

Edited By Brian Abbott on 17/01/2016 22:42:51

[CotswoldsPhilParticipant @cotswoldsphil]

Hi Brian,

I apologise in advance if any of the following smacks of "teaching granny to suck eggs", it is just my experience of building a Minnie in my workshop .

Glad you have found a solution to your boiler construction issues, can't do much to a TE without the boiler.

The horn-plates should be bolted to the completed boiler before marking out the horn-plates. So this may give you an enforced break.

When I did the setting-out on the horn-plates, I did use the book's description (facing pg. 48) of a gear depthing tool, (not much else available to ME's at the time – DRO's 1970's?). The alternative being toolmakers buttons.

Once I had the crank-centre marked on both plates, I removed the horn-plates, aligned them and riveted them together using rivets in the waste area before marking out the rest. The pair of plates were then treated as a single item for marking-out / machining.

Make sure that the centre-points on the pins of your depthing tool are as accurate as possible (a job for the collet chuck?), and that the holes for the pins are perpendicular to the arms and that the pins are as short as practically possible, one pin projecting more that the other to compensate for the thickness of one arm. They do look a little long in the illustration.

You will need a spacer, to bring the pair of gears being meshed onto the same plane. It does test your marking out skills. I first drilled / reamed 1/4" holes to test the mesh of the gears on the actual horn-plates. You can then dial-in each 1/4" hole and finally drill / ream to size. Tool-makers buttons or DRO's make much of this procedure unnecessary of course.

Regards

Phil H

Edited By CotswoldsPhil on 18/01/2016 10:54:59

[Brian AbbottParticipant @brianabbott67793]

Hi Phil, thank you for the reply,

Must say I was going to try and stick to the book, but as I have used drilled and tapped bushes in the boiler I can spot through from the inside.

Plan was to clamp one plate to the boiler and mark from the inside of the smoke box, drill and re attached, then mark out as described using the gear tool.

Clamp both plates together as you describe and drill, once all assembled with bearings and shafts, bolt the drilled plate to the boiler, and clamp the opposite side ensuring all shafts spin as they should, then back spot again from the inside.

[Brian AbbottParticipant @brianabbott67793]

Hello all.

Need some advice on my Minnie please.

Is there any reason why I could not fix the crank and second shaft bearing by fixing them through the horn plates into the bearing, if I understand the book correctly it is suggested I tap the horn plates, don't really fancy that idea.

Thanks,

[JasonBModerator @jasonb]

I tapped all my bearings so yes its OK to do it that way

[Brian AbbottParticipant @brianabbott67793]

Hello all.

Could i ask a question regarding the gear selector lever, should the 1/8" pins that run in the groove on the second gear shaft be on the center of the gear,

Thanks,

Brian

[JasonBModerator @jasonb]

Eyeballing mine when in neutral I would say they are on ctr or just a fraction behind , the later seems to tie in with your red line

Edited By JasonB on 25/05/2016 18:02:05

[Brian AbbottParticipant @brianabbott67793]

Thanks Jason, will work on the center line.

[Brian AbbottParticipant @brianabbott67793]

Hello all.

About to start making the water gauge for my Minnie, not sure if to use brass or bronze.

Any advise ?

[JasonBModerator @jasonb]

Bottom fitting comes into contact with boiler water so best in Bronze. You could leave the nuts that seal the tube in brass as they don't get wet and barss hex is easily available.

[Brian AbbottParticipant @brianabbott67793]

Ok,

Thanks Jason.

[Brian AbbottParticipant @brianabbott67793]

Hello.

1" Minnie water gauge issues

I have been looking for a piece of 3/16 water gauge tube but only seem to be able to get 5mm

If I drill through the top fitting to clear the 5mm tube, say 5.1mm this will be to big for the 7/32×40 tapped hole for the blanking plug, should I look at using a 1/4×40 instead ?

Thanks for any thoughts.

[JasonBModerator @jasonb]

I think thats about all that can be done, should be enough meat there to take the 1/4" thread

[Brian AbbottParticipant @brianabbott67793]

Hello all.

Jason, did you happen to take any in progress photos when you where machining your cylinder casting on the 1" minnie ?

I am after some inspiration on how to go about machining it.

Thanks.

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