[Jamie]

I've finished the chassis on my 37-650 and I'm trying to fine tune my shadowmeter. It is the later style. The meter is working and the vane is moving freely, however, the coil is difficult to move. I can rotate it about 20 degrees, and it does move forward and back, but it's sorta stuck, so when I try to adjust it, it jumps from one extreme to the other.

Would it be okay to spray some wd-40 on it to lubricate it?

Also, there is a metal disc in the rear of the meter housing that is a bit loose. I believe it is the magnet. If I move the coil forward, the disc slips out of the rear. I can press it back in place and it stays, but any vibration will cause it to slip.

Should I try to glue it in place, or leave it be?

I don't have much experience with shadowmeters, so I don't know what is considered normal.