Barometer pointer disassembly

[kinsler33]

This is a cool old Airguide desk barometer whose round glass face is broken. The glass is no problem, nor is the small hole that must be drilled through the center of the glass disk. Into that hole must go a knob that moves a pointer on the inside of the glass in standard barometer fashion.

But the knob and pointer must be disassembled to replace it in the new glass, and I cannot for the life of me get it apart. (It came out because the glass was broken at the hole.)

The three photographs show the heat-blackened brass knob and the equally fried red pointer. Pointer and knob are connected by what seems to be a hollow brass shaft, which I've bunged up quite nicely with various pairs of pliers.

I'd thought that the shaft might have screwed into the knob, but if it does I can't loosen it even with the heat of my little hot-air blower. It's possible that the pointer might be hollow-riveted onto the hollow shaft, in which case the riveting can be drilled out and the pointer glued back onto the shaft after the assembly is placed back in the hole in the glass.

The barometer gods will look with kindness upon anyone who can advise me how to not screw this thing up even worse than I've already done.

Mark Kinsler

 

[bruce linde]

it looks staked/riveted in place... drill out the overhang?

 

[kinsler33]

it looks staked/riveted in place... drill out the overhang?

Thank you. That would seem to be the only alternative aside from prayer. I shall try it and report.

Mark Kinsler

 

[shutterbug]

I agree that it's staked. It's going to be a challenge to get back on in the correct alignment.

 

[kinsler33]

It worked, and no alignment will be necessary, for the outside knob is not calibrated or marked in any way and the rotation is 360 degrees. I used my countersinking bushing reamer and the pointer came right off. I'll glue it back on with something.

Both I and the barometers of the world extend their thanks.

M Kinsler