Rear Spectacle Plate fouling boiler

Evening,

Having aligned the crank alignment tool to the rear of the piston cover plate, which was dead on, another problem appeared.

As I want to drop the crank in I thought it would be easier to align the Hobbs elbows first and seal them in as once the crank drops in my hands are not going to fit in there.

So I popped the rear spectacle plate in, on which is assemble the steam turret, regulator lever and pressure gauge, but the bottom two bolts of the steam turret foul the top of the firebox, this in turn makes the spectacle plate misalign.

I took the two bottom bolts out, checked the hornplate alignment (spot on still) and the plate still needs around 3 to 4mm to allow the bottom to align. I then drew a line on the spectacle plate with a chalk pencil following the firebox radius to see how much metal was in the way. I would have to remove a 20mm arc of steel right across the existing arc, which also cuts through both the holes where the turret bolts come through.

Am I alone with this problem, or has somebody had the same issue please?

It seems either the boiler is too long by about 8mm, or the spectacle plate is too deep, something flipping obvious I simply don't know.

I'll try and take a photo tomorrow when it is light.

Thanks.

Richard

Morning,

With the lack of replies I assumed I must have been the only one, but just in case somebody else has the same problem at a later date. below is how I fixed it.

The rear spectacle plate would not line up with the holes in the horn plates. The top bolt lined up but by bolt 3/4 there was no hole visible and the plate was canted.

1) The bottom steam turret bolt nuts were fouling the fire box top, so I countersunk the spectacle plate and inserted countersunk bolts, Loctite on the heads.

2) I noticed two very large blobs of weld spatter, they were around 4mm more proud than the rest of the welding and very rough, so I dressed with a file the weld spatter until smooth and at same profile of the other welds. This did not compromise any of the welding of the boiler, it was spatter not weld and was very sharp so now I have insulation tape around my left thumb.

3) As a cosmetic addition, I countersunk the three holes at the bottom and inserted countersunk bolts so it looks as if the plate was bolted to the firebox like on a full size engine.

4) Finally I opened the holes out in the hornplate and spectacle plate bolt holes by 1mm.

The above just about gave me enough room to fasten the rear spectacle plate square to the hornplate, I just need to repaint where I countersunk the holes. I now have around 2mm between the plate and the boiler.

Finally I can now fit the crank, hopefully without problems.

Hard work but looks nice and neat.

Richard.