Author Topic: Square headed 'plugs'.  (Read 215 times)

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Offline Jon Nazareth

Square headed 'plugs'.
« on: Sep 02 2019 14:15 »
Does anyone know where I can get square headed plugs 1/16" a/f?  There are six on the back head of my Lion boiler.  I suppose it wouldn't hurt if they were a tad bigger.


Offline IanT

Re: Square headed 'plugs'.
« Reply #1 on: Sep 03 2019 09:38 »
Probably not Jon - but they could be simply made from brass rod.

Assuming A/F on original Lion 'plugs' was 1.5" (the square within a circle) the diameter of the containing circle can be found by Pythagoras, the squares' diagonal being the circles diameter. I make that diameter to be 2.121" full size - so scaling it at 22.6 would give 0.094" - and 3/32" is 0.09375" ( near enough?  :) )

I'd drill a piece of square material centrally 3/32", add a small grub screw to hold the material and then have it protrude a bit more than you actually need. Gently file the square on the rod (using the 'safe-edge' of the file against the jig face) by turning the jig as required. A few strokes per side should do it - then file the square end to required length. A small 'roller' about the same diameter as half the height of the jig will help you keep the file flat.

I use a similar set-up when filing squares on the end of regulator rods for instance. It's quicker to do than to explain. I generally use a collet block and published this as a 'tip' in the G3S NL a few years ago. I'll dig out the photo used for that and attach it





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