After the fitting the firebox and checking the fit of the lower firebox sides with the chassis in place I was wondering how to hold them in position while the epoxy set.

After trying and discarding a number of different clamps that I have in the workshop ranging from a small engineers clamp to a pair of 1″ G clamps I decided to make a custom clamp to do the job. On my bench I just happened to have a short length of 14mm dowel which would do perfectly for what I had in mind. The bottoms of the lower firebox sides slope so I reasoned that dowel being round would allow clamping along those slopes.

Next I cut a short piece of 5mm square boxwood to a length that would sit on the footplate inside the firebox and drilled a hole through the middle. I had planned to use a 1″ 10ba screw as I have quite a stock of them. Sadly it wasn’t anywhere near long enough so I decided to turn myself a custom screw and to make it a bit easier to handle a longer length in the lathe, I decided to make it 8ba rather than 10 ba. I started with some 3mm brass rod and turning around 10mm at a time to minimise deflection I kept easing a bit more from the collet until I had a 30mm length that could be threaded 8 ba.

As I started to run the die down it I realised that I didn’t actually need to thread the whole length so I just did about 12mm. As it turned out that wasn’t quite long enough either but rather than start again I worked out that I could just counterbore the dowel to allow for enough thread to tighten the clamp. I created the counterbore with a 6mm 4 flute end mill which allowed enough clearance to use an 8ba nut spinner and for me to add a washer. As it was only to hold the parts in place there was never any need for it to be anything more than gently tightened.

There is a hole in the upper surface of the lower firebox sides which locates over the studs mentioned in the previous post. The clamp then holds down the rear and to be belt and braces I also placed a reel of solder on the on the flat section at the front to be sure that it sat down flush on the studs and stayed there.