Farside
Badly Welded Man
- Messages
- 6,223
- Location
- Ireland
I bought this yonks back at an autojumble and sometime soon after that discovered why it was for sale, not that I paid much for it.
It greviously under-reads on the scale, so much that it would be easy to strip threads on 6mm and probably 8mm too, especially on alloy casings. I tossed it in the back of a drawer and forgot about it for years.
Anyway, dug it out again and had a closer look. There's almost nothing in it. The square drive block simply bends a straight beam inside, which is coupled to the meter needle with a tiny brass half-quadrant shape rack and pinion gear. Not much to go wrong with it, I thought. One fault is the needle is loose on the spindle, so I attempted to tighten that up slightly. I succeeded in that by putting a drop of threadlock on it, not so much to lock it, but to restore a bit of the missing friction / drag which time and use had dissipated. The needle is meant to float slightly on the spindle, so that you may zero it before use - the dial rotates to zero it, and providing the needle doesn't bounce around the reading may be taken directly.
Anyway, after that partial success I had another go at seeing how it was behaving.
Nope, still grossly under-reading. I think there's nothing much to be done with it, as when I had it apart I don't see any way of altering the amount the needle turns in response to the amount of beam deflection.
I reckon some ape has used it as a breaker bar at some time, and just stressed the beam beyond tolerance.
It's probably scrap, which is a pity, as it's dated February 1943, so might have been involved in WW2 aircraft production.
It greviously under-reads on the scale, so much that it would be easy to strip threads on 6mm and probably 8mm too, especially on alloy casings. I tossed it in the back of a drawer and forgot about it for years.
Anyway, dug it out again and had a closer look. There's almost nothing in it. The square drive block simply bends a straight beam inside, which is coupled to the meter needle with a tiny brass half-quadrant shape rack and pinion gear. Not much to go wrong with it, I thought. One fault is the needle is loose on the spindle, so I attempted to tighten that up slightly. I succeeded in that by putting a drop of threadlock on it, not so much to lock it, but to restore a bit of the missing friction / drag which time and use had dissipated. The needle is meant to float slightly on the spindle, so that you may zero it before use - the dial rotates to zero it, and providing the needle doesn't bounce around the reading may be taken directly.
Anyway, after that partial success I had another go at seeing how it was behaving.
Nope, still grossly under-reading. I think there's nothing much to be done with it, as when I had it apart I don't see any way of altering the amount the needle turns in response to the amount of beam deflection.
I reckon some ape has used it as a breaker bar at some time, and just stressed the beam beyond tolerance.
It's probably scrap, which is a pity, as it's dated February 1943, so might have been involved in WW2 aircraft production.
. They put new guts in an old ratchet I had, dated back to before ww2. 
