Linhof Technika V - Ground Glass is Dim.

[stephenmcateer]

Years ago the GG on my 11x14 Burke & James view camera was also "dim". Took the GG out and very, very lightly scrubbed it with a very soft brush in a diluted Ivory soap solution. Rinsed it several times under the tap, and then finally a few times with distilled water. Dried it slowly using a hand held drier. I swear after doing this, the GG was X2 times brighter. Used the same posted procedure for cleaning a front surfaced telescope's mirror... Google it.

Thanks Greg. I suppose I should have tried cleaning the glass before I bought the new one. Live and learn…

[Bob Salomon]

Okay thanks. I looked at the hardware that secures the glass — 6 screws, a couple of plates and I think some shims. Hopefully fitting the new one won't be too difficult. I may put the old one on eBay to recoup some of the cost of the new one.

The way I do it is to remove the three screws and the plate at one end, note that sometimes the center,screw may be longer.
Loosen the 3 screws on the other end.
Lift the gg up and slide it out from the other end.
Place the new gg in place on the shims.
Replace the plate and tighten all screws.

[stephenmcateer]

The way I do it is to remove the three screws and the plate at one end, note that sometimes the center,screw may be longer.
Loosen the 3 screws on the other end.
Lift the gg up and slide it out from the other end.
Place the new gg in place on the shims.
Replace the plate and tighten all screws.

Thanks Bob. The glass should be here in a few days. Looking forward to more brightness.

[stephenmcateer]

UPDATE: I have the ground glass now. It looks nice.
However, I couldn't loosen the screws that are holding the original glass in place: the screwheads are about 5mm wide but the slot is very narrow — less than a millimetre I think, so a normal screwdriver won't do.
I purchased a 3mm precision screwdriver, thinking it ought to be wide enough to let me exert enough force to undo the screws but I'm wondering if they're a little seized in the threads: the 3mm driver cammed out on the first screw I tried, so I stopped there.
[I couldn't see a suitable screwdriver online despite searching for quite a while, so if anyone can recommend one suitable for this task I'd be obliged.]

[Conrad . Marvin]

A proper screwdriver should be the same width as the screw head and the same thickness as the slot width. If it is too wedge shaped, it will push up out of the slot and and make the screw useless. Time to get a machinist to make you a correct size screwdriver out of something a bit too big. It should be worth the cost.

[LabRat]

A screw can freeze in a hole as many changes of weather force moisture into threads causing local corrosion in hole... Getting a tiny drop of thread penetrating oil near base of threads, let sit a couple of days, repeat, taking a hot soldering iron and heating up head with tip a few times and allowing it to cool, then try...

A good screwdriver to try is made by Wiha, good tip that should fit exactly, and has a larger handle that has good torque, and not expensive for a single... Don't use a cheap driver, as you are more likely to damage screw head with one...

Good luck!!!

Steve K

[stephenmcateer]

A proper screwdriver should be the same width as the screw head and the same thickness as the slot width. If it is too wedge shaped, it will push up out of the slot and and make the screw useless. Time to get a machinist to make you a correct size screwdriver out of something a bit too big. It should be worth the cost.

Thanks. The drivers I have are too narrow / too thick in the blade. I don't know if there's a machine shop near here or not but I'll look.

[stephenmcateer]

A screw can freeze in a hole as many changes of weather force moisture into threads causing local corrosion in hole... Getting a tiny drop of thread penetrating oil near base of threads, let sit a couple of days, repeat, taking a hot soldering iron and heating up head with tip a few times and allowing it to cool, then try...

A good screwdriver to try is made by Wiha, good tip that should fit exactly, and has a larger handle that has good torque, and not expensive for a single... Don't use a cheap driver, as you are more likely to damage screw head with one...

Good luck!!!

Steve K

Thanks. Some good tips there. I'll look for Wiha.

[David Lindquist]

I got these to deal with those large diameter narrow slotted screws with which to my mind European makers of view cameras seem to be enamored: https://www.brownells.com/gunsmith-t...s-prod425.aspx

They are even described as being for "European style slots." These are hollow ground, in the US anyway this pattern of screwdriver tip is often called a "gunsmith's screwdriver". I don't know if Brownells ships to the UK, I expect that is some where in the fine print on their website.

I got the full set largely because I'm a tool weenie. You could scroll through the selection for the blade width(s) that you want, note that they say "blade diameter" instead of "blade width". As far as thickness, these come in .020 and .025 inch (.51 and .63 mm) thickness. I find the thicker ones are a very close fit bordering on a push fit in the screws holding the ground glass on my Master Technika 3000; the thinner goes in easily. If it were me, I'd get both thicknesses. But then I'm a tool weenie and I got the full set.

I have to wonder where Linhof and Linhof repair people get their screwdrivers.

Stand by while I track down the handle for these.

David

[David Lindquist]

Here are handles: https://www.brownells.com/gunsmith-t...s-prod400.aspx

I use the #81, the #84 is hollow and holds up to to four bits.

Let us know if these work for you.

David