Wireless Set No. 52 Canadian - Project

[David Dunlop]

A small bit of work done on the Sender this passed weekend, but highly productive.

I was able to successfully remove the two tubular rivets securing what was left of the TERMINALS, Aerial, No. C1 mounting plate to the Sender front panel. If you refer back to Post # 302, you will see the three mount fragments and the back end of the two rivets. The second photo in Post # 308 shows the two truss heads of the rivets from the front of the panel.

I lined the table of the drill press with an old face cloth to protect the front panel paint and went with a 3/16-inch drill bit to cut back the cinch ring on the back of the rivet, being sure to stop the cutting before the centre of the bit got too close the brown phenolic mounting plate.

It was important to be able to identify these rivets to source proper replacements, so once the ends were cut back sufficiently, I switched to a 7/64-inch drill bit to use on the drill press as a punch pin to try and press the rivets out of the front panel. I was a bit wary of this, as generally speaking, drill press spindles are not built to handle that kind of excessive load, unlike a milling machine spindle. But with some gentle increase in pressure, out they both popped.

Before I had started this work, I had assumed these two rivets were plated brass. As the drilling phase progressed, however, the shavings kept coming up bright, shiny, silver. Once the rivets were free, a quick check with a magnet showed they were actually steel. That was a bit of a surprise as I was expecting aluminum.

In any event, they spec’d out to be truss head tubular rivets, with a 7/32 –inch diameter head. Shank diameter is 1/8-inch. Original length was no less than 3/16 –inch and no longer than 7/32-inch. From what I have read on this style of rivets, length is critical to get the job done without damaging parts being held together.

I am going to go with aluminum replacements, as they are the easiest to work with. Particularly when holding thin brown, phenolic board without crushing it to pieces and I only have one replacement available to work with. As it turns out, I can source sizes at both ends of the possible range I came up with exactly, as well as a 7/32-inch length in the middle of the range. I will order in a selection of each.

Now I just have to find an inexpensive hand tool for setting these rivets. The most promising I have seen so far is a C-Clamp style to tool with several interchangeable heads. I will likely only ever use it a half dozen times or so, so don’t need to break the bank There are some countersunk head tubular rivets I need to replace in this 52-Set Project as well, so I need to look into those next.

David