I was working on the cab roof when Dave Lester posted the dimensions of the snifting valve on my thread on RM Web and casually mentioned that I might like to make one since I had most of the details. Now this struck a bit of a chord because I have always been disappointed with the snifting valve castings supplied in kits and to look at the best I have ‘seen’ is the turned example sold by Markits. I say seen in inverted commas because I have no idea if it’s dimensionally accurate it just looks good. The trouble with Markits, is actually getting your hands on anything from the catalogue.
If I had any suitable bar in stock, I might have had a go at turning one but sadly everything I had was far too thin. I did have some brass tube of just the right OD though so this was pressed into service I cut a length off that I could grip and hold safely and soldered a square of scrap etch over the end and snipped/filed it round. Finally finishing it in the lathe chuck. At this point it became a bit “Triggers Broom” because Mike Trice posted a selection of close ups of snifting valves on locos and I realised that I had drilled the holes in the side too big and too many (the hole size was one dimension that Dave didn’t have).
Armed with more info I made a second cover salvaging the end cap and the 14BA hex headed screw that I had fitted to the first attempt. Next came the base plate and five goes later I had something usable, albeit it to my eyes it seems a bit small at the measurements quoted. I may revisit this once I have the chimney fitted.
This is what it looks like.
Finally one with the obligatory 5 pence piece for scale – small ain’t it?
I have to say that I had immense fun making it and learned a few things about my lathe in the process.