To do some repairs and restoration I need to get the lower plate off of an early Speed Graphic - actually a couple of them. These are the ones with a separate curtain aperture plate and a curtain tension plate.
( Pre Pacemaker) It is the tension setting knob that I'm asking about.
Is it: grip the knob tightly and use a spanner to turn the slotted nut inside the knob?
Will a spanner work?
Is it a regular right hand thread?
Your experience and advice is appreciated!!
Robert Newcomb

No one has ever taken the tension knob off of a Speed Graphic or removed the lower curtain roller?
Help

Why REMOVE the lower plate? It will release spring tension in the lower roller. The lower roller is like a window blind, with an internal spring. Winding it back up is a royal pain.
Do what everyone at Graflex.org does-ask Bert Saunders for help. Bert has rebuilt every Graflex/Graphic ever made.
Determined to DIY? Loosen the 4 screws that hold the lower plate, clean under it, try not to release tension on main spring.
Did you check that auction site, for a repair manual or a parts list with an exploded shutter view for Speed Graphics? Rear shutter stayed the same from 1912 to '46. There should be something in print out there.

I've restored a few Graflex SLR's over the years, including putting in new mirrors and curtains. And for one reason or another on some I have removed the lower plate, but they are different. Putting the spring tension back in a SLR is no big deal because I know how.
I do not have this experience on the Speeds.
I was looking for some help to hedge the bets against me tearing up something.
I emailed Bert.
thanks though.

It's been a while since I've taken one apart but one of the nuts is left hand thread and the other is right hand thread. I believe the inner lock nut is the left hand thread, but don't hold me to it. My memory used to work. Honest, it did.
Many of these get broken off by people who don't ask.

You've re-wound lower roller tension springs on Graflex SLRs, and find it no big deal? Then the Speed Graphic won't pose any problems, it's very similar.
Glennfromwyoming is right about the nuts. Don't force anything, the shaft's only brass, it breaks easy.
For me it's a pain, since I'm only guestimating the correct amount of re-tensioning needed to get accurate speeds without the benfit of electronics.
Personally, I try to avoid it, but when I'm repairing a torn curtain, it's innevitable. Consequently, I've got a bunch of old Graflexes with working, but hopelessly innacurate, shutters.

DHF845 wrote:

For me it's a pain, since I'm only guestimating the correct amount of re-tensioning needed to get accurate speeds without the benfit of electronics. Personally, I try to avoid it, but when I'm repairing a torn curtain, it's innevitable. Consequently, I've got a bunch of old Graflexes with working, but hopelessly innacurate, shutters.

Personally I don't attempt tuning these essentially friction controlled shutters to original speeds, unless I have to do a full rebuild - with all the aging in materials, bringing them up to old spec by mere cleaning, lubing and increased tension often is impossible, and even where it works it will make the mechanism more vulnerable.

In any case, it is quite irrelevant whether you have to use your own measured settings/timings table or the original Graflex one. But a electronic timer makes it tremenduously more easy to establish what the real speeds on a repaired shutter are.

Sevo

How much does an electronic shutter timer cost (or how much does it cost where you are)? I'll see if I can find one over here, if price fits my budget.

BTW, the three Graflex SLR's I do all my shooting with (2x3 RB Ser. B w/ Graflex 23 holder; National Graflex Ser. II; RB Ser. D w/Graflex 23 holder) have good, un-repaired shutters. They fire smoothly at all speeds.

Accurate? Don't know for sure. The exposures come out good, excellent negative density range. You've got me curious, though. If I can afford one of those gizmos, I'll try it.

When re-assembling one f these shutters, if you give it 6 turns of initial tension you'll be very close. It actually takes more speed difference, one way or the other compared to ideal, to see a visible difference on the film than you might think. One of the nice things about roller blind shutters. A lot of the old Press photographers that worked the sports beat would crank it up a bit to be sure the 1000 speed was going to stop even the fastest action. I've gotten hold of a couple that made me think the thing was going to launch itself right out of the box.
Robert, did you get the knob off okay?

DHF845 wrote:

How much does an electronic shutter timer cost (or how much does it cost where you are)?

These cheap Chinese black plastic ones are occasionally on ebay for about $100, and do the job. You can also cobble up one from a µsec timer, switch module and photo sensor from a lab electronics supplier, if you want something heavy-duty, but that would run up to a much higher price unless you manage to know and spot the right parts in some surplus store.

Regular photo repair shop testers do sometimes crop up on ebay as well, but those I've seen so far were strictly built for small format SLRs or unmounted leaf shutters - you won't get a Graflex into the 5-10cm space between their light source and sensor.

Sevo

http://graflex.org/helpboard/viewtopic.php?t=5345

Home Brew Shutter Speed Tester

Hi,
I haven't gotten the lower knob off yet. The tips on my spanner are too big to fit well into the slots in the knob. As soon as I get a smaller tip spanner I will try. Thank you for all the good help from all of you.
I'll let you know how it goes.
Robert newcomb