Cladding of locomotive

This topic has 8 replies, 7 voices, and was last updated 19 April 2026 at 18:21 by Bruce Voelkerding.

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25 March 2026 at 15:54 #842223
Michael Callaghan
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@michaelcallaghan68621
Hi. I am having a devil of a job working out the hole positions for the various fittings that need to be bolted to the cladding of the 3 1/2 inch gauge Columbia I am trying to complete. The drawing gives you the measurement from what I took to be the central line of the cladding. One measurement shows a measurement of 2 inches down from what I took to be the centre line. However when I place the drawing I made over the boiler shell you can see that the position is way. What am I doing wrong.
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25 March 2026 at 16:33 #842228
Brian Baker 2
Participant
@brianbaker2
Greeting Michael, it is a problem to get the shape and cutouts all lined up and the best way I have found is to make a thin card (cornflake packets?) template chopping that about until it fits.

regards

Brian B
25 March 2026 at 17:47 #842233
Dave Halford
Participant
@davehalford22513
Not tying the cladding on with cotton thread first maybe?. 22/7 x D and all that and sometimes drawing errors.
25 March 2026 at 20:40 #842239
Michael Callaghan
Participant
@michaelcallaghan68621
Thanks chaps. I can position the holes for the safety valves etc ok. However the problem lays with the position of the regulator control brackets which run along the outside of the boiler. So far I have drawn the boiler within solidworks. And then drawn the bracket and handrail positions as per the drawings. However the positions come out wrong. I am wondering if the measurements on the drawings should be read as taken from the top of the boiler along a centre line and not along the diameter. How anyone can make anything from these drawings beats me.
25 March 2026 at 20:43 #842240
JasonB
Moderator
@jasonb
Post an extract from the drawings for us to look at and see how it is dimensioned
25 March 2026 at 20:59 #842242
Paul Lousick
Participant
@paullousick59116
Model engine drawings often contain mistakes and cannot be relied upon. I have worked for 50+ years as a mechanical engineer/draftsman and I never trust what is on the drawings and re-draw everything. My 6″ traction engine was completely modelled in Solidworks and new drawings made before I started manufacture. Much easier and cheaper to fix mistakes in a computer than in the workshop.
25 March 2026 at 21:19 #842243
Julie Ann
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@julieann
On 25 March 2026 at 20:59 Paul Lousick Said:

….easier and cheaper to fix mistakes in a computer than in the workshop.

Amen to that! And currently it is warmer in the office than it is in the workshop.

Julie
17 April 2026 at 14:20 #844893
Michael Callaghan
Participant
@michaelcallaghan68621
Hi chaps. Thanks for replying. Ok, so far I have the bulk of the cladding on. However one more problem comes up. How can I hold the cladding down around the firebox. On the Columbia it’s a long firebox with very little of the cab holding the rear ( firebox end) down in place. I can’t use banding due to position. In the few build notes I have it states that using screws treaded into the boiler can be used. I don’t think this a great idea. Anyone have any better ideas. Thanks
19 April 2026 at 18:21 #845088
Bruce Voelkerding
Participant
@brucevoelkerding91659
Michael, on my 7-1/2″ gauge Atlantic (design by Little Engines, now defunct), the Cladding is all one Piece. The flat Portion over the Firebox is held (retained) in place by the Running Boards and the Cab. It is NOT attached to ANYTHING.

There are no Crinolines under the Cladding – just a Layer of Insulation. The Cladding is held round over the Boiler Barrel with the usual Banding. Do note, on many US Locomotives the Banding was 2-piece with Clamps at both the TOP and the BOTTOM of the Boiler Barrel.

It sounds like you have a separate Sheet for the Firebox. If that is the case, I guess you could make up some inverted “U” shaped Crinolines from, say, 1/4″ square Aluminum Bar. You could attach horizontal Tabs to the front “U” to slip under the Boiler Barrel Wrapper if you deemed that necessary – you could always add the Tabs latter (I would tap them and put clearance Holes in the inverted “U” Crinoline. I would NOT attach either the Crinolines or the bottom Edge of the Cladding it to the Boiler.

The Running Boards on my Locomotive are attached at 4 Locations

1. the Front Steps (not very rigid),

2. the front of the Guide Bar Support,

3. the rear of the Motion Bracket Support

4. the front of the Cab.

The Cladding ends at about 5/8″ below the Running Board. I guess if you need it, you could make L shaped Brackets that attach under the Running Board, pointed downwards, to hold the Cladding in place. US Locomotives have all sorts of Brackets everywhere.

On a Locomotive such as Columbia, in real life, it was not unusual to see a Row of Holes thru the Side of Firebox into the Combustion Chamber just above the Coal Level. These holes where provided with Air Jets to induce more Air to flow over the Fire to help Combustion. There was typically no Cladding from the Level of the Holes to the Mud Ring. This also allowed easy visual Inspection of the Stay Bolts in that Area.

Bruce
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