Monitor High Speed Picnic travelling cap/snuffer

Discussion in 'Fettling Forum' started by Twoberth, Nov 12, 2019.

  1. Twoberth

    Twoberth Spain Subscriber

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    Some of you will know by now that I like to make stove parts out of brass plumbing fittings. They are cheap and strong - ideal for fettling. Here is how to make a Monitor HSP snuffer from a 15mm compression/1/2 inch BSPT (British Standard Pipe Taper) fitting. The taper fitting is better than the parallel fitting as it is longer.

    The dimensions for the snuffer are already on this site if you scroll down on the link here, and this is what the fitting looks like.

    DSC08976.JPG DSC08977.JPG

    The taper end on the left will be the top of the 'snuffer', and the 15mm compression end will have the internal thread.

    First, I have to say that you don't need a lathe for this as you can smooth the outside into a cylinder with a hacksaw, file, sandpaper and a drill. You can leave the hexagonal in place to aid screwing and unscrewing in use. If you do it by hand, you will need to buy a 5/8" x 26 tpi tap to cut the correct thread inside the compression end to match the male thread on the burner. These (BSB) taps are available on-line for a little as £5 for a carbon steel version, which is good enough to cut into brass. This is how it will fit when finished, with the compression end downwards

    DSC08979.JPG

    The inside of the compression end already has the correct inside diameter to cut the thread down to the lip where the wall thickens.

    DSC08978.JPG

    I used a lathe, first turning the outside to a cylinder.

    DSC08980.JPG

    I don't have a knurling device, so I left the top part roughly machined.

    Next turn the inside thread. I couldn't do exactly 26 tpi, so I set the lathe to cut a 1mm pitch which is good enough (for me). The correct angle to match the male thread on the burner is 55 degrees, but if you buy a tap you don't need to worry about this.

    DSC08981.JPG

    Then solder a cap on the other end and smooth round

    DSC08982.JPG DSC08985.JPG

    9mm countersunk hole, and a suitable thickness washer (in this case cut from a rubber shoe heel) completes the job.

    DSC08988.JPG DSC08989.JPG DSC08990.JPG DSC08991.JPG DSC08992.JPG DSC08986.JPG

    Fitting costs about £3 and the tap £5.

    Have fun!!
     
  2. presscall

    presscall United Kingdom SotM Winner Subscriber

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  3. Ed Winskill

    Ed Winskill United States Subscriber

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    Awesome.
     
  4. ROBBO55

    ROBBO55 Subscriber

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    Thanks @Twoberth for another practical project. :clap:
    Now all I need is the Monitor stove :cry: