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LTM 51

Detailing the boiler

Detailing is for me "anything beyond the basic structure". So all appliances, piping, handrails etc. For the most part detailing can be in a rather random order as most appliances parts have little or no logical connection to each other. Therefore the order in which I made things is also rather randomly chosen.

Detailing starts with the chimney. The casting that I have is a NS 3700 chimney from Philotrain. It is 1.2 mm too long for the LTM 51.

The form of a chimney is irregular and vulnerable so simply sticking it in the lathe is out of the question. The only reliable straight surface is the inside hole of the chimney but a look inside revealed that wasn't up to par either.

So I stuck it in the chuck of the lathe protected by a thin sheet of aluminium (from a soda can). I carefully drilled and centered the hole to an acceptable geometry.

I turned a mandrel from steel, originally only on the right hand side. After drilling the chimney as described above this mandrel had become undersize so I turned the left end slightly bigger. This end was glued into the chimney. After the glue had set I stuck the mandrel in the chuck en drilled a 1.6 mm hole from the bottom though the center of the chimney all the way up.

I then parted the chimney base at the lower rim. I filed the chimney base flush with this rim.

I measured its height and calculated how much material I still had to remove from the upper part of the chimney. Just a few tenths of millimeters and these were quickly disposed of on the lathe.

I stuck a M1.6 bolt through the chimney and its base and secured them with a nut.

Then I soldered them together avoiding contamination of the bolt by smearing a bit of grease on the thread. So after soldering I could remove bolt and nut again.

A bit of filing to get it flush on the boiler will do the rest.

Speaking of which, I had two other appliances to fit on the top of the boiler: the dome and the safety valves.

The safety valves I bought where filed down to match the prototype. Easy. The base however took a bit more thinking. Habitually the safety valves were located on top of the firebox and in the Netherlands these were usually Belpaire fireboxes, with a flat top. This flat top was reflected in the casting. The LTM 51 however had a round top firebox. So I had to remove some metal to get it to fit decently on the firebox. After some thinking I took a dive in my old metals and failed parts box and retrieved the number two iteration if my boiler which was rejected because it was undersize. Undersize it still was bit with a piece of emery paper 360 it had just the right diameter. I oiled the paper and rubbed the safety valve carefully until I had a pretty good fit.

The dome received a similar treatment