View Full Version : Flange Troubles
I bought a nice Darlot 14 in. Petzval and it came with an ill fitting flange. I would screw on a couple of laps but no more. Obviously not correct, so I took the brass barrel and bad flange to a local machine shop. After a month they came up with a new aluminum flange for me today. The guy screwed it on in front of me and I paid $200. (ouch) Got it home and noticed the flange was put on backwards--that is, the light trap extension was put on first and facing the front of the lens. I took it off, turned it around, and screwed it on the correct way. Except, it only went for a couple of laps and stopped! I didn't try to force it. Took it back off, completely covered the threads of both flange and barrel with white grease, and tried again. Same deal. For $200 I'm not happy. The flange easily screws on "backwards" but not the correct way. Is this fixable? I tried my other large Petzval, a big 12 in. Voigtlander with original brass flange, and it easily screws on from either direction. So do the flanges of several other of my small 8 in. Petzvals. What's the deal with this new flange?
Kent in SD
Keith Pitman
12-Mar-2021, 17:34
Take it back and show the machinist the problem.
Original has right diameter, but wrong pitch...
Old lens makers often had their own unique pitch for their lenses...
Steve K
Original has right diameter, but wrong pitch...
Old lens makers often had their own unique pitch for their lenses...
Steve K
Why does it screw on all the way one direction but not the other?
Kent in SD
Flange thread might have a taper...
Steve K
Tin Can
12-Mar-2021, 23:46
And machinist may not have known which way was what
John Layton
13-Mar-2021, 06:08
Ha! I remember watching the video of an astronaut by the name of...Musgrave? Cory Musgrave? At any rate...there he was, floating in space - fixing some problem, in situ, on the Hubble Telescope...and as he places his wrench on a bolt, he hesitates a bit, as he asks himself (audible on the video) "hmmm - righty-tighty...lefty-loosey?"
Chauncey Walden
13-Mar-2021, 12:06
Put it on the back side of the board??
Conrad . Marvin
13-Mar-2021, 12:52
Could be that the “machinist” didn’t know which way the flange went and only went as far with the thread as he thought was necessary to screw it onto the lens, therefore he needs to finish the thread so that it will start from the other side (not easy to find the thread and continue with it, but possible) or make another part correctly from scratch. If he was in question about which way to put the flange on, he should have asked. If you didn’t make it clear which way...
Ron (Netherlands)
14-Mar-2021, 05:14
Did you or the machinist measure the thread? If you know the thread why not ask here if someone has a matching flange?
some other threads with comparable flange questions/problems:
https://www.largeformatphotography.info/forum/showthread.php?159460-Lens-mounting-flanges-measurements-and-other-info&highlight=mounting+flange
https://www.largeformatphotography.info/forum/showthread.php?159363-Filthy-Flange-possibilities
Drew Bedo
14-Mar-2021, 05:31
I am (potentially) about to face that same issue. I have a nice-ish, but not expensive, No-Name Rapid rectilinear with a machinist. Bought it without a flange and found one that fits in my parts grasb-bag. Only it is a "modern" flange and probably in a metric thread. Only turns twice and jams. . . .so I didn't force it. . . .right size wrong thread.
Will just have to wait and see.
A universal truth of vintage LF gear: There are only three types of mooning flange . . . .
I had the same thing happen to me with a circa 1890 lens. A machinist told me that sometimes threads are "directional". He said that he was not referring to right-hand or left-hand threads but the way the threads were initially cut. Makes no sense to me but I am not a machinist.
Machinists tend to cut threads as tight as they possibly can, this comes from a lifetime of working with engineers giving ridiculous tolerance specifications for everything. Photographers who happen to own a lathe cut threads as loose as possible, because we've had to remove jammed flanges and lens blocks and don't want to deal with galling and seized threads and the like. I would ask the machinist to run another pass on his lathe for you.
Conrad . Marvin
14-Mar-2021, 09:29
I would agree with Jody, being one of those photographers with a lathe and having cut threads to very close tolerances in the past with disastrous result. Threads didn’t really become standardized until the mid 20th century. Even though attempts had been made much earlier, anything that was made in the 19th century is not likely to be standardized beyond an individual maker or country. If I needed to make a flange, I would measure the thread, find a metric or other size that is pretty close in number of TPI and make the thread a bit on the loose side to allow for difference in thread shape. And then hope for the best.
Did you or the machinist measure the thread? If you know the thread why not ask here if someone has a matching flange?
some other threads with comparable flange questions/problems:
This is a large professional shop with many employees and has been around for a number of years. In the past I've found it an exercise in futility trying to match up large 19th C flanges. The new flange is already made, it just needs to be fine tuned.
Kent in SD
Duolab123
14-Mar-2021, 11:01
I would agree with Jody, being one of those photographers with a lathe and having cut threads to very close tolerances in the past with disastrous result. Threads didn’t really become standardized until the mid 20th century. Even though attempts had been made much earlier, anything that was made in the 19th century is not likely to be standardized beyond an individual maker or country. If I needed to make a flange, I would measure the thread, find a metric or other size that is pretty close in number of TPI and make the thread a bit on the loose side to allow for difference in thread shape. And then hope for the best.
Yes, WWI prompted standardization among the Allied powers. I remember, vaguely as a kid at a bicycle shop, an older mechanic said "the English metric and the French metric didn't always agree" not sure exactly what that meant.
William Whitaker
14-Mar-2021, 11:36
Ha! I remember watching the video of an astronaut by the name of...Musgrave? Cory Musgrave? At any rate...there he was, floating in space - fixing some problem, in situ, on the Hubble Telescope...and as he places his wrench on a bolt, he hesitates a bit, as he asks himself (audible on the video) "hmmm - righty-tighty...lefty-loosey?"
Perhaps a bit of schtick?...
Tin Can
14-Mar-2021, 12:11
Depending upon your patience, the range of mismatch, you could try valve lapping compound from an Auto Parts store
Obviously work carefully and mask off ALL with tape and ?
The grit is cheap, in a small can and sold in various grits
I have used this for many things including engine valves
Often in a thin oil already, test it on something else
I would do this while watching a movie, put in the female thread, work slowly, don't get jammed
I REPEAT DON'T GET JAMMED
little by little
My last employer sold Clover out to Loctite (https://www.amazon.com/Loctite-1777012-Grinding-Lapping-Compound/dp/B00O542WDK/ref=sr_1_6?dchild=1&keywords=Valve+Lapping+Compound&qid=1615748745&sr=8-6), but still the same
Tin Can
14-Mar-2021, 12:19
I didn't notice the weapons usage until I read the reviews...
Conrad . Marvin
14-Mar-2021, 12:36
I wanted to say something like “He who has the last lap”...
Drew Bedo
15-Mar-2021, 07:21
No one has mentioned SK Grimes. why is that?
Chauncey Walden
15-Mar-2021, 13:32
Not to mention that hot glue works great;-)
Ron (Netherlands)
16-Mar-2021, 06:45
No one has mentioned SK Grimes. why is that?
Well I guess because they stopped to do that kind of work; thats what I read in another thread
Tin Can
16-Mar-2021, 07:44
Tell us more
in particular are Hot Melt drips removeable from an old uncoated lens glass surface?
and if we use Hot Melt on threads to make a 'flange' will it last
I have a rare lens that is too loose front element to Studio Shutter male threading, from I suppose decades of ... cleaning and polishing
Not to mention that hot glue works great;-)
Tell us more
in particular are Hot Melt drips removeable from an old uncoated lens glass surface?
and if we use Hot Melt on threads to make a 'flange' will it last
I have a rare lens that is too loose front element to Studio Shutter male threading, from I suppose decades of ... cleaning and polishing
I have used STANLEY DUALMELT Dual Temperature Glue Sticks for years now without a single failure. Prep for use on glass is to clean the glass first with lens cleaner. Prep for use on other surfaces is to thoroughly clean the surfaces with soap, rinse, and completely dry. Removal is easy by cutting the hardened glue with an X-ACTO knife and pulling it free. Supposedly low temperature (275 degrees F) for Arts and Crafts and high temperature (410 degrees F) for General Repair. My glue gun is a DEWALT with a ceramic head, which I was told was a high heat gun, but I have never been able to confirm that.
malexand
16-Mar-2021, 09:27
Not to mention that hot glue works great;-)
+1
Another vote for hot glue - I have several older lenses without flanges that I've hot glued to a lensboard. No failures yet.
That is not to say there isn't a learning curve to using hot glue effectively and cleanly. It can be very messy and the burns it can cause are nothing to laugh at...
Tin Can
16-Mar-2021, 10:18
Good answers gentlemen
My primary usage of Hot Melt was my odd sculpture, I have posted here
and plan to again
soon, as selfie
David Lindquist
16-Mar-2021, 10:22
Well I guess because they stopped to do that kind of work; thats what I read in another thread
They no longer do routine repair of leaf shutters, i.e. a CLA. Making custom (threaded) flanges is something they still offer, as well as making and stocking flanges and retaining rings for a number of shutters including the dial-set Compurs.
David
Bernice Loui
16-Mar-2021, 10:28
Tolerances required to make threads function are smaller than most would know or appreciate until they get directly involved with the complexities of how threads work, how they are made and all that can go so very wrong. Tolerances are typically in thousands of an inch or hundreds of a mm. Clearances between internal to external threads are typically in thousands of an inch or hundreds of mm. How much clearance depends on application. Threaded parts used in space flight or aerospace applications are going to be tighter toleranc_ed than common hardware store threaded parts used on the outdoor fence, same with materials.
What is most likely the problem with the threaded flange is thread standards from that era. Thread measurement and standardization did not happen until much post 1900 of the industrial age. Thread measurement and standardization became mandatory to allow for interchangeability. It is very possible the lens barrel threads were made to fit a specific lens flange when these parts were made.
~Solution is to have a flange made specific to this lens barrel's threads by a skilled machinist with the proper machine tools and tooling.
As for mounting the lens with glue.. Not worth the risk. The possibility of the glue becoming un-glued is high. If the lens became un-glued from the lens board, this can and will ruin a lot more than just your day.
Bernice
Machinists tend to cut threads as tight as they possibly can, this comes from a lifetime of working with engineers giving ridiculous tolerance specifications for everything. Photographers who happen to own a lathe cut threads as loose as possible, because we've had to remove jammed flanges and lens blocks and don't want to deal with galling and seized threads and the like. I would ask the machinist to run another pass on his lathe for you.
It is very possible the lens barrel threads were made to fit a specific lens flange when these parts were made.
I have three 'identical' lenses (same model from same manufacturer) from the 1860s, They apprently have identical threads and flanges, only they aren't, or rather the tolerance is such that whilst they are nearly interchangeable, not all combinations of lens and flange fit. Given the difficulties of machining back then I'm not entirely surprised.
Ben Calwell
16-Mar-2021, 11:49
+1
Another vote for hot glue - I have several older lenses without flanges that I've hot glued to a lensboard. No failures yet.
That is not to say there isn't a learning curve to using hot glue effectively and cleanly. It can be very messy and the burns it can cause are nothing to laugh at...
I’ll have to try the glue idea. Currently, I’ve been duct-taping an old Wolensak lens to my Kodak 2D lens board.
No one has mentioned SK Grimes. why is that?
I thought of them, have used them before, but didn't want to wait several months and send a rare lens half way across the country. I also like to support local business when possible.
Kent in SD
Not to mention that hot glue works great;-)
Lens weighs over five pounds. I wanted a more solid connection.
Kent in SD
~Solution is to have a flange made specific to this lens barrel's threads by a skilled machinist with the proper machine tools and tooling.
This machine shop is one of the best in the multi-state region with experienced people and state of art machinery. They've made a couple of flanges and lens parts for me in the past. It wasn't someone working out of a garage. Will take it back for them to look at yet this week.
Tin Can
17-Mar-2021, 01:57
They will make it right
Sometimes apprentices are given an odd job
Age 14 I had a shop class where I was told to make anything on a huge WWII cannon auto taper lathe
I made Slot Car wheels 1/24 Scale
It was a good learning experience
This machine shop is one of the best in the multi-state region with experienced people and state of art machinery. They've made a couple of flanges and lens parts for me in the past. It wasn't someone working out of a garage. Will take it back for them to look at yet this week.
Bernice Loui
17-Mar-2021, 09:37
GOOD! IMO, this is the proper way to get this done. While at the machine shop, ask then to fit this flange to the lens board. Machine tools can do a remarkable job on wood or metal. If possible, remove the lens cells from the barrel before it's trip to the machine shop to limit damage to the lens cells.
As for home garage machine shops, it varies lots. Some are hobbyist tinker types trying to learn how to used their midget sized machine tools. Others, quite serious in every way. Years ago this story in Silly valley was told about a highly skilled and specialized artist who made quartz spheres for space flight gyros in his garage. These quartz spheres must be spherical to the extreme as the performance of these space flight gyros depend on it. Turns out, no "company" was able to produce these quartz spheres are good as this guy in the garage machine shop..
Bernice
This machine shop is one of the best in the multi-state region with experienced people and state of art machinery. They've made a couple of flanges and lens parts for me in the past. It wasn't someone working out of a garage. Will take it back for them to look at yet this week.
Finally got some time today to take the flange in. One of the machinists played with it for about 20 minutes and when he was done it works great! He said they did have it cut to too fine a tolerance. There was some variation in the threads on the barrel. It' goes on and off easily now.
Kent in SD
Tin Can
19-Mar-2021, 16:22
Great news!
I once bought a giant lens from a faraway country, seller said no flange
I asked how much to make one
Glad I did
Cheap
$
Once found and acquired a large Petzval barrel lens in an antiques shop for little money (so wish that I had kept it) in the 1990s. Went to a local machinist shop to have a flange made for the lens. Quoted price was several hundred dollars. Next went to my local High School's machine shop, and was quoted a price of only $20.00. In the end paid the school's machine shop $100.00.
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