Trimming ground glass/fresnel

[Scott Davis]

I just got a groundglass/fresnel set to put in my old Century Master studio camera. The fresnel and glass are about 4mm too long and 2mm too wide to fit. How should I go about trimming them? Is this something the glass cutter at a frame shop could do, or do I need to take it somewhere that specializes in glass work? Or does this need to be filed down with a grinder of some kind? Of course, the fresnel is plastic.

[Eric Woodbury]

Glass shops have a belt sander and they could sand it down. Or maybe open the camera up a bit.

[Rob_5419]

I used a glass-cutter (circular razor on a wheel which rotates) and tried to score the glass before cutting it - the glass was a few mm too long.

It didn't work, so I took it to a glass specialist who did the same thing, except clamping the glass onto the worksurface. He then used a pair of plier clips and started biting off the glass in millimetres. I was a little shocked and too stunned to say anything.

Then he presented me with a completely jagged edged ground glass and smiled and said: "there!". I asked him how much the charge was. He said there was no charge.

On second thoughts, I should have asked him if he had done this before. He said that I just needed to use sandpaper to file down the crimped edge. True enough, it worked once behind the ground glass screen, but it certainly wasn't beautiful.

[Dave Parker]

I would recommend taking it to a glass shop, they will be able to trim or clip the glass for you, the fresnel can be sanded down to the correct dimension, be very careful in cutting, when dealing with this small a cut it is very important to make sure you get a good score line so the glass breaks correctly, I know I can cut down to about 1mm, but it is difficult and I use carbide glass cutters with oil baths, the most important thing is to make your score with about 15lbs of pressure on the cutter. But again, the best way, is take it to a glass shop and have someone who is experienced with glass make the cuts and the breaks for you, to finish the glass, you need someone who uses a glass grinding machine with about a 600 grit diamond stone that knows what they are doing, the wet belt sander is great for roughing in the glass, but you need a bit more control to actually fit the screen correctly.

If for some reason, you can't find someone to do it for you, please feel free to let me know, you can send it to me and I will be happy to take the required amount off and not charge, your only charges would be postage to me and postage back to you, but doing the glass work would be free. Cutting at these tolerances is not that common now a days, but see what your local glass hop has to say. Of course, if that don't work, I cut all of my screens to specification of the customer, but tolerances in the glass industry now a days on average is 1/8 inch, but we cut to size as long as you can provide them..

Dave Parker
Satin Snow Ground Glass

[Rob_5419]

That's really kind of you Dave - great to know you're on this forum ;)

Now about my car windscreen......

[Dave Parker]

That's really kind of you Dave - great to know you're on this forum ;)

Now about my car windscreen......

Rob,

Actually I thought about doing windscreens for a while, but where I live, I would be working on cars from sun up to sun down 365 a year...even I don't want to work that much!

LOL

:eek:

:o

Dave

[Scott Davis]

Dave- many thanks for the offer. I might take you up on it. I'll ask around here first and see if I can find someone who would do it. If not, it may well find itself on the way to Montana shortly.

[Rob_5419]

Rob,

Actually I thought about doing windscreens for a while, but where I live, I would be working on cars from sun up to sun down 365 a year...even I don't want to work that much!

LOL

:eek:

:o

Dave


Yeah...strange enough - I think of "A river runs through it" when I think of Montana - not 4x4 car owners wiping flies off their windscreens!

Maybe one day when my eyesight starts diminishing I'll need to upgrade my half-plate ground glass and will be knocking on your windscreen ;)

[riooso]

Hey Scott. You ought to order one from Dave as a backup. You will have it before you are done with yours, I would bet. I am sure that you will be suprised about the charge for a new piece of glass.

Richard