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Old 7th Oct 2020, 5:48 pm   #1
cernem1alt
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Default Eddystone 740/3 brass panel front removal help

Reluctantly I have to take the front panel off an Eddystone 730/4.

I am at the 4 brass bolt/screw stage, all were stuck fast a common experience as I have read. I soaked with WD40 for 24 hours and have two free currently repeating the stubborn two again for 24 hours but not looking hopeful any other advice for getting these devils free?

Many thanks
Mike M1ALT
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Old 7th Oct 2020, 6:59 pm   #2
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Default Re: Eddystone 740/3 brass panel front removal help

Using a quarter inch pin punch give them a sharp tap with a light hammer. Get a squarely and accurately ground screwdriver and you should get them free. Don’t let the screwdriver slip.

Jim
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Old 7th Oct 2020, 7:05 pm   #3
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Default Re: Eddystone 740/3 brass panel front removal help

Cheered me up no end,as I have the same model with no tuning drive and I guess that will be similar.

There is an excellent article on this models restoration on the Eddystone users group by O,Hara.
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Old 7th Oct 2020, 7:19 pm   #4
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Default Re: Eddystone 740/3 brass panel front removal help

I will try the punch method carefully, but it has not happend yet ~I feel the inevitable is going to happen and the screwdriver will slip and shear off the brass head worse case scenario what then??
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Old 7th Oct 2020, 7:34 pm   #5
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Default Re: Eddystone 740/3 brass panel front removal help

Try heating up the area with a powerful hair dryer beforehand, it's amazing what a little thermal action can achieve.
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Old 7th Oct 2020, 7:59 pm   #6
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Default Re: Eddystone 740/3 brass panel front removal help

WD40 doesn't really penetrate. Have you tried Plus-Gas?
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Old 7th Oct 2020, 9:06 pm   #7
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Default Re: Eddystone 740/3 brass panel front removal help

get everything on your side, you want a screwdriver bit which is a precision fit in the slot, preferably 'hollow-ground' so it doesn't try to wedge out and that peak force is at the root of the slot.

Turn it with a socket set with a tommy bar sticking equally out of each side, so you apply a pure twist to the screw and no offset force.

It's one of those Delia-boiling-an-egg in 200 moves things. You set everything up to perfection and give it the twist and it still might shear off on you, but at least you know you gave it everything. It keeps your cool while you're searching for where you put yout BA tap set.
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Old 7th Oct 2020, 9:37 pm   #8
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Default Re: Eddystone 740/3 brass panel front removal help

I had exactly the same problem with my 888A front panel. Everything I did failed and just caused more damage to the four screw heads. This is not advice, it's only saying what I did. I used a small drill to make a 3.2mm hole about half inch deep in the centre of each screw head for centring purposes. Then I used another drill close to the minimum thread diameter and drilled about three quarters of an inch deep. Then I jammed a slightly oversize screw driver down the hole and used a mole wrench on it for torque. One twist and a loud crack and out they came. Sweet. Then I bought equivalent brass bolts off the internet (easy), cut them to length and tested them - ready to refit later. Also sweet. pete
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Old 7th Oct 2020, 9:51 pm   #9
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Default Re: Eddystone 740/3 brass panel front removal help

Quote:
Originally Posted by carnivalpete View Post
I had exactly the same problem with my 888A front panel. Everything I did failed and just caused more damage to the four screw heads. This is not advice, it's only saying what I did. I used a small drill to make a 3.2mm hole about half inch deep in the centre of each screw head for centring purposes. Then I used another drill close to the minimum thread diameter and drilled about three quarters of an inch deep. Then I jammed a slightly oversize screw driver down the hole and used a mole wrench on it for torque. One twist and a loud crack and out they came. Sweet. Then I bought equivalent brass bolts off the internet (easy), cut them to length and tested them - ready to refit later. Also sweet. pete
I am thinking this may be the way on inspection of the two bolts I removed I would suspect thread lock has been used anyhow I know Eddystone built these for the military/government so they are bombproof but clearly back in the day the KISS method was not employed
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Old 7th Oct 2020, 10:11 pm   #10
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Default Re: Eddystone 740/3 brass panel front removal help

You may be able to apply heat on the part of the casting holding the screws from the inside of the case. A soldering iron tip perhaps.
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Old 8th Oct 2020, 2:28 pm   #11
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Default Re: Eddystone 740/3 brass panel front removal help

The coefficient of thermal expansion for aluminium is about 20% greater than that for brass.

A hot air gun on the case and an ice cube on the screw might be worth trying.
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Old 8th Oct 2020, 4:07 pm   #12
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Default Re: Eddystone 740/3 brass panel front removal help

On mine a used a impact driver but removed the valves and display bulbs first . They came out no problem but as already stated make sure the screwdriver blade is a good fit .
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Old 8th Oct 2020, 4:30 pm   #13
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Default Re: Eddystone 740/3 brass panel front removal help

As two of the screws are out, that'll emphasise stress on the remaining two- try knocking around the edge of the front bezel with something like a gash bit of softwood- don't go mad, don't harm the paintwork! As mentioned above, look out your best suitable screwdriver and try the screws. If no go, and the other two screws and their tappings in the coil-box bosses are in good condition, try replacing them and do them up sensibly tight, then try the stubborn two again, putting the others in may just ease the tension on them.

My Eddystone 750 (a near-immaculate and obviously previously dry stored specimen) gave in easily here, the decade-younger but less cared-for 670A took a bit more grunt but all four screws yielded with a satisfying snick once "appreciable" torque was applied.

At least no goon has glued the finger-plate on- something I have heard as being a right pain on other sets (and why would someone do that anyway?) Good luck with it.

Does anyone know the screw type?- the ones on mine were of about 0BA size but with a noticeably coarser and deeper thread. I didn't investigate further as they were fine but wondered if they were maybe a Unified or a more "traditional British" type.
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Old 12th Oct 2020, 3:13 pm   #14
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Default Re: Eddystone 740/3 brass panel front removal help

Success heated the bolts soak in WD 40 drill and repeat process several times over 2 days. I would not like to have to do it again but to get to the next problem it had to be done and so was revealed a mangled dial cord/wire and a snapped white plastic disk attached to two star shape bearings on the VFO dial control, I wonder how much stress this takes? I am attempting to Araldite it together it snapped in 3 places and clearly was an old break so I suspect someone before me took the front panel off to see decided against repairing and managed somehow to bodge the brass screws back in place , there was a glue type substance around these two screws so who knows?? any how onward and upwards with it

Last edited by cernem1alt; 12th Oct 2020 at 3:16 pm. Reason: spelling D- must do better
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