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John Phillips
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 19, 2005 - 11:09 am: | 
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In trying to remove a dinged top cover for repair, I found the back two retaining screws held fast for no obvious reason. Nothing worked. I broke the heads off. I got the top cover off ok, but now the brass screws are sheared off in the frame. Advice on how to remove them without buggering the the threads in the frame? Any thoughts appreciated. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 19, 2005 - 01:11 pm: |
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Place a drop of Naphtha onto each of the stubs and leave to penetrate, repeat this 3/4 times.Using a small slothead screwdriver with a sharp blade, press into the brass stub and try to unscrew. Note; the screwdriver blade must be of good quality tempered steel, also sometimes it is preferable to turn the stub clockwise first to break it free.
If the stubs are corroded in, a drop of kettle descaler will penetrate and loosen the corrosion products. Here in UK I have used a limescale remover/shower cleaner called Cillit-Bang to free up a number of corroded screws on various Russian lenses.
As it appears that your problem may be caused by bi-metallic corrosion, some means of removing the corrosion products may be your only way of freeing up the stubs.Otherwise you are left with the prospect of carefully drilling out and running a tap through. |
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