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-   -   Two general AVO 8 questions (https://www.vintage-radio.net/forum/showthread.php?t=141888)

SeanMcK 3rd Dec 2017 10:33 pm

Two general AVO 8 questions
 
1) Is there a suggested replacement for the red 'rubber' gaiters that go around the cut out and reverse button stalks of the post Mk4 Avo8's?
I have the idea of using slivers of thin 'stiff' plastic in combination with a thin thread wrapped around the outside of those slivers to act as 'piston ring compressor' to guide the deformed gaiter into the underside of the buttons and then letting the assembly sit, compressed' for a month or so.
Has anyone tried anything like this?
The idea being that this could be an in situ fix rather than removing the movement etc. to get to the buttons.
In truth I doubt either method will work since I doubt the rubber will 'unstretch' but, given that I presume these gaiters are unavailable, needs must.

2) Has anyone got a trick for removing the rear Bakelite case of a Panclimatic etc. from its metal surround?
The battery lid screws have been removed as have the nuts from the screws hidden under the instruction plate that pass through the bottom of the Bakelite case, so, as far as I am aware, there are now no mechanical fasteners holding the rear case in the metal outer but the Bakelite case WILL NOT budge.

The Philpott 3rd Dec 2017 10:52 pm

Re: Two general Avo8 questions
 
2) At one point i proposed trying differential expansion by submersing the case in hot water, but in the case of the meter concerned, i understand it didn't work. A hairdryer might deliver more useful localised heat, in conjunction with WD40 or some such release agent. This question has come up before on here so you should be able to find it on a search. The guy in question did manage it eventually but i can't remember how.

Slightly tongue in cheek I also proposed a last resort method of removing the instruction plate to expose the rear, then drilling thro' the steel in strategic places, putting a drift through the holes and tapping the bakelite case free.

The Philpott 3rd Dec 2017 11:13 pm

Re: Two general Avo8 questions
 
Found the previous thread. it was Rob Lines who had this problem a year ago (he has a supermarine spitfire as his avatar so if you search this 'site under:-

'Avo panclimatic case removal' you will find it easily.) He ended up having to cause a bit of damage.. They really can corrode and sieze badly.

SeanMcK 4th Dec 2017 1:06 am

Re: Two general AVO 8 questions
 
1 Attachment(s)
Ta Phil I did wonder about using temperature changes but in my case I was thinking of filling the air gap under the Bakelite (I had one out years ago and recollect that the bottom of the Bakelite is recessed hence the air gap) with water and then bunging the assembly in the freezer but had/have visions of shattering Bakelite.
Which prompts the idea injected expanding foam???
I have also tried the compressed air thing but half a dozen hands are required and I was on my own and the pressing upwards on the inside upper surface of the battery compartment thing.
Another idea that comes to mind is, and excuse the crude diagram, to drill the heads off the two 'hidden screws' through the base so that the remaining threaded portions are free of the outer metal case.
From memory there are nuts and washers on those screws in between the Bakelite and the metal case.
Then rig up some form of bridge puller that attaches to the remaining screw threads and sits on the upper edge of the metal case.
Tightening the grey "puller nut" would tend to pull the Bakelite case.
Of course it could also pull the 'trapped' nuts though the Bakelite

With regard to Rob Lines' problem, since his principal motivation for removing the case was to gain access to the screws holding the battery compartment in place would drilling the metal case in locations corresponding to the battery compartment screws be an alternative solution?
It would expose the screw heads and allow them to be unscrewed or drilled off and the std battery cover would cover the new holes in the metal case.

pmmunro 7th Dec 2017 12:28 am

Re: Two general AVO 8 questions
 
For the first problem of the original post, I think the gaiters came as part of "REV M-C KNOB & SPRING KIT 6120-595". The same parts were used on the Model 8 Mark V, 6 & 7 and might still be available from Megger at Dover.

To change the gaiters, the self-adhesive escutcheon label needs to be carefully peeled back and stuck down with impact adhesive when the new gaiters have been fitted.

What about 3-D elastomer printing?

PMM

SeanMcK 7th Dec 2017 11:40 pm

Re: Two general AVO 8 questions
 
Ta, I will ask them. 3d printing 8-o blimey it must be getting quite well developed!


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