Re: Speed Graphic Ground Glass Repair

[Richard Knoppow <dickburk@ix.netcom.com>]

----- Original Message ----- 
From: "Gordon Cooper" <nwlorax@comcast.net>
To: <alt-photo-process-l@usask.ca>
Sent: Sunday, October 26, 2008 2:39 PM
Subject: Re: Speed Graphic Ground Glass Repair


> I need to replace the ground glass in my spring back 
> Anniversary Speed Graphic in 4x5.
>
> What is the correct procedure? I've removed the screws on 
> the viewing hood to get to the ground glass, but can't get 
> the metal bits on top of the frame that holds the ground 
> glass. Not wanting to break anything, I thought I'd ask 
> here.
>
> Thanks
>
> Gordon Cooper
> Bremerton, WA
    The ground glass is held in place by two strips, one at 
each side. These strips also hold the sides of the viewing 
hood in place. Remove the screws on each side being careful 
not to let the spring loaded cover fly up. Once the screws 
are out the strips will come off and the old glass can be 
removed. The gound glass reference surface is the frame of 
the back so there is no adjustment necessary. The new glass 
just drops in. Replace the strips with the hood edges 
against the glass and fasten the screws. Make sure the new 
ground glass is solidly against the frame surfaces.
    You will need to cut the corners off the ground glass 
for it to fit. The corners are supposed to be cut out to 
allow air to escape while extending the bellows but I think 
the real reason is to allow looking at the back of the lens 
to make sure there is no vignetting. The replacement glass 
may already have the corners trimmed.
    If you need to cut glass precisely use a carbide 
scribe, not a glass cutter. Scribes are not expensive and 
can be gotten at most hardware stores. I got one at Home 
Depot so they are not too arcane a tool:-)

--
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com