Member postings for chris organ

Hi, I am near the end of the chassis work on a 2-6-2 GWR tank in 5”.
Before I move on to the upper build I would like to put axle lubrication in but I’m scratching my head for the best sites around the loco for the oil boxes. Front of the side tanks looks good for the leading axles but what about for the rear axle, in the cab perhaps ?

Interested in knowing how others have tackled this

Chris

Hi Bruce,

Yes I spotted that. No beam across the back pair. Thanks for pointing it out though, could have saved me a lot of heartache.

Chris.

Thanks all. I reckon I know what to do now.

I have the steam brake already and it's not a big deal to fit so I'll put it on anyway. I can see how the hangers/beams/rods all fit now.

TY

... or maybe they are just carefully linked and adjusted, not compensated at all ?

Hi,

Building Evans' 2-6-2 Firefly. I have the chassis fundamentally finished and would like to finish and fit the brake components, at least temporarily. I have the drawings for the steam and handbrake at the rear of the loco also the linkage below the controls. Also for the brake hangers and blocks which are now in place. What I can't find anywhere is a diagram for a compensated linkage between the controls and the beams.

Does anyone have a diagram or just a couple of good photos of a similar brake set-up ?

Chris.

Thanks for the remarks Jeff. If I had thought ahead I would have arranged for another 1/16 or even 1/8 inch of depth on the bush which would have eliminated the whole concern ! There are several aspects of this design where a little more metal would have helped. Having said that, I’ve never built an engine before and having the whole build in one book was helpful so I’m not complaining. Like many things you learn your own way by doing it wrong on occasion.

.... well I went ahead and tapped blind holes. I used the S/S screws anyway. All held up at 120 psi test so all good.

I'd still like to know people's opinions on this though.

Hi, I am at the point of mounting the regulator to my 3 1/2 inch Rob Roy boiler.
Martin Evans specifies 8BA stainless steel bolts, which suggests to me that he means drilling and tapping right through the bush into the boiler steam cavity.
I was planning to drill and tap only as deep as the bush itself, but that is trickier and means a few less threads to grip. Am I being too cautious, is drilling right through reasonable ?

Thank you to everyone for their replies. On balance, I suspect I have been a little heavy handed and clumsy with a job that needs care and patience to complete successfully. I am going to order a made up and certified boiler (engine is the priority) but as a side-line will have a couple more goes at sealing the homemade one up. If that works then at least I can honestly say I built a whole locomotive, not necessarily assembled in the same locomotive but there you are. Definitely I will a copy of the recommended reading above before starting anything else.

Chris.

..... Nigel ..."you've not been dumping the boiler when it's still very hot into the pickle ... ?"

Oh oh. Schoolboy error ? Some guilt here. Not glowing hot but hot enough to cause some fizzing.

Is there a fix ? perhaps a reheat of the whole area (with plenty of flux on all seams) and a gentle cool down before any pickling.

I have given up on my 3.5" Rob Roy boiler build even though it is outwardly completed. I will order one from someone with greater silver soldering skills than me. My priority is a finished engine I can trust and I feel I can get more from working out what went wrong with this boiler than chasing around more leaks. The point of this thread is to invite suggestions as to what went wrong as I may have another go on another locomotive sometime. I will also show the boiler to the inspectors in my club for their opinion.

This was my first attempt at boiler construction. I have used propane with bigger torches as I've gone along to get the heat into the boiler. I was seemingly on the right track right up to the last fittings ! After I fitted the backplate and foundation ring I did a 20 psi hydraulic test, no problems.

That just left the stays, blowdown valve and top fitting for the water gauge. I silver soldered all of these, using a long neck torch to get heat inside the firebox. All seemed to go reasonably well.

When I repeated the hydraulic test I had water running out at atmospheric pressure from the foundation ring ! I fixed that by a little hammer tapping, a PB screw and then re-soldering. At the next test I had a just weep or two at 20 psi inside the firebox at the seam near the tube ends. I re-soldered that. Now I have weeping at very low pressure somewhere from the tube ends. If the leak was anywhere else I would have another go but I feel every time I put more heat in there I create a new problem.

I have been using SS 55%, pickling and cleaning between every soldering operation and refluxing nearby existing joints when going back in to add the last fittings. Whatever I solder seems to work nicely, it's the surrounding areas that seem to be failing.

Thoughts ?

Well I think that was the right idea and it seems to have made a good repair. I threaded the offending hole 4 BA, screwed in a suitably modified screw and soldered round. Tidied up a little in the vertical slide with an end mill and there is a solid plug in the hole now which I don't think should go anywhere. 30 minutes, better than reaching a whole new cylinder block.

.. thanks BTW.

Tap and plug should be feasible. I can machine off after plugging to get a reasonable finish, these surfaces don't bear on anything else.

Schoolboy error, I drilled through the wall between the steam inlet passage and exhaust passage. This is on a Rob Roy gun metal cylinder. So there is a number 30 hole that should not be there in the 3/32" wall.

Before I put it in the scrap box and start again, is there a reasonable repair ?

Thanks Rex, that sounds like a worthwhile modification. I'll follow that up. If you were able to ping me a snap or sketch of the layout you used that would greatly appreciated ! A couple of elbows then some different bends in the steam and lubricator pipes I'm thinking.

I notice now that the drawings I have (as opposed to the book and drawings within) detail the larger steam chest and valve to match so I'm good with that aspect.

You are right, if I follow the plan to take the centre line to 7/16 then the slide valve would need to be thicker and possibly (depending on how the valve slot is machined) also the nut. There is enough on the cast steam chests to follow this plan.

I'm still pondering the relative merit of doing this (Vs cranked cross head) as it pushes the spindle significantly away from the working surface i.e. the port face. I note that the valve is required to have at least a few thou play from the port face (Evans says MOST important) but my instincts tell me a slide valve works best when the spindle is close to the working surface. Probably a false worry but I could go either way still !

Many thanks Phil, I see it now.

The cylinder diagrams (with steam chest attached) works out correctly at a 7/16 centre from the port face but like yours my book has a 5/16 centre on the later diagram for the steam chest. I'll see how far I can push that centre over with the castings I have, otherwise will step the cross head.

Thanks again. Chris.

Hi, next step on my Rob Roy 3 1/2 inch build is to machine the cylinders so I thought I'd better first clue up on the oft mentioned alignment error in the drawings. Having checked a few times, the drawings I have at least are consistent in having a 1/2 inch centre line through the cylinder, suspension bearing and eccentric, all relative to the frame. The key dimension is the valve centre which is 5/8" from the cylinder mounting flange. Less the frame thickness that's 1/2" again. What am I missing ?

I can see the utility in shifting the whole centre line across to provide more clearance from the horns and axlebox and if the castings allow I will do that.

Thanks for those speedy replies.

Having read and reflected, the right thing to do is remove the wheel with heat and make a proper jig for the refit. Leaving as is would be a compromise.