Hey guys, I'm looking to force a bunch of old camera parts together for a wonky purpose. I'd like to consult someone who knows what they're doing on how I go about measuring what I need. I've got an old Goerz Red Dot Artar f/9.5 10 3/4 focal length lens, and I can't seem to determine the front and rear thread sizes. What tools do I need? I'm afraid to hand this directly a local machine shop in town, because I don't know if most of them will be able to do much either. From what I can tell a lot of the local industry is geared towards work on a much larger scale, involving large factory machines. My intent is to get the measurements myself, and then if necessary, purchase the taps and dies to mate everything, because it seems like the hourly rates for a lot of machine shops around here are so high that it'll be cheaper to do myself at a makerspace.
Would making an inside-threaded m56x0.75 to whatever the rear barrel thread is on this, and an outside-threaded lens filter adapter for the front from whatever it is to 43mm be the job of a mill, or a lathe? I suppose I will need aluminium blanks. What grade is most appropriate?
Included here is an imperial measurement of the rear thread.
I've looked all over at old Goerz lense brochures, and unfortunately none of them carry information about the threading. I do know with certainty that towards the demise of the company in the late 60's, they did switch to metric threading. Now, I'm not sure if that means that they did so while continuing to label the focal lengths in Imperial.
A thread pitch guage can be had for $10-15 or a set with metric and imperial for like $20 then you will know the thread pitch for sure then model it up and print it, if it doesn't work change the dimensions slightly, and print again.
Here are pictures of the adapter I currently use to front-mount lenses to the Copal 3S shutter.
It is important that when I clone this, I make a slightly recessed seat for the lens, as you want its rear to be relatively close to the shutter, for the greatest image circle possible on the other side. I'd love to get these lenses in-shutter, but the cost of such copies of the same lenses, as well as the alternative cost of having a skilled photographic machine shop like S.K. Grimes do it for you are both prohibitive for me. I'm broke as frick.
>inb4 find a cheaper hobby
This would require a metal lathe with threading capabilities.
Standard 6061 aluminum would be fine
You will not be using taps and dies, they dont exist for odd sizes, you will need to thread with the lathe itself
You need to buy some pitch gauges to find the pitch of the threads
Its a pretty easy part to make, if you know what you are doing and have the lathe.
You just need to know the basics of lathework, and the basics of threading.
>>inb4 find a cheaper hobby
Well machining is not any cheaper than photography is.
>You need to buy some pitch gauges to find the pitch of the threads
The ones I've seen online come in 5 degree increments. How much of a complement of gauges should I buy? Is there any foolproof way to get a rough idea of what I'm looking at? I have a loupe.
>you will need to thread with the lathe itself
How is this achieved? I'll need someone to hold my hand, eh?
Thanks for the help.
All the metric gauges come in 5 degree increments for the upper half of the spectrum, and get smaller on the shorter half of the spectrum. The pitch will be on there.
How do I determine that it is metric?
Buy a set of both SAE and Metric pitch gages, itll only match one or the other. There is no crossover.
I'll need to buy several of each, to account for not knowing the thread angle?
A single gage has all the different pitches you might want to check
Yes, I understand this. When I was shopping for gauges before making the this thread, I discovered that each gauge is targeted for a certain thread angle range, usually 5 degrees. e.g. 55-60 degrees for all that I saw on Amazon
How do I make an educated guess on the thread angle, in order to choose the appropriate pitch gauge? Or is it reasonable to assume that a 60-70 year old lens will likely have 60 degree threads, as seems to be the standard elsewhere when I looked it up?
The thread angles dont change, they are nominal. They are all 60deg
I had to look it up, and what you are talking about at 55deg is fricking British Standard Whitworth which was never widely adopted and is now completely dead. The chinks are just throwing the leafs on there because they have them I guess.
Oh, I didn't know this. Thanks for telling me.
It probably ain't because
. The ones they sold that are compatible with Alphax #3 are of a slightly different make.
Sorry, to expand on this, they assembled lenses in different barrels with different threading and slightly altered housing. The shape of the barrel on lenses designed for shutters will be such that they allow for focusing when the front and rear sell are slightly separate (across the blades of the shutter). Barrel lenses have an internal iris and the front and rear cells are conjoined. A lens made to be used with a shutter cannot be used without, because it will lack the iris (and thus be always wide-open, an aperture they seldom perform best at nor were they usually designed for) and will not be appropriately spaced unless you create your own ring.
So a barrel lens is more like a lens for a focal plane shutter camera, which means your large format rig is going to be slightly squished if you adapt it to a shutter at the back.
Yeah, you're basically stuck reverse-engineering this lens's mount. I'm guessing you won't even be able to find flange mounting distance.
It's a large format lens and I'm front-mounting it to a Copal 3S shutter and then a large format camera. It'll be fine. I don't have to worry about flange focal distance because it moves on a rail. I get some vignetting of the image circle, but I still have more than enough for movements on the comparable lens I also front-mount to the Copal 3S.
>I don't trust expert machinists to do this for me
It's more that I've called around a small sampling of shops and none said they could do it. I'm also afraid of paying someone an hourly wage in the high tens, only for them to tell me they've determined they don't have the right stuff. I live in a very corrupt country where this is not entirely out of the question.
The purpose isn't secret, I've said it multiple times: front mounting this lens to a shutter for making images on 4x5 negatives.
Manufacturing's a b***h, most people won't quote if you can't give them a drawing showing exactly what you want them to do.
Is there software for that or will a hand drawing suffice?
Fusion 360 and Onshape are most accessible if you want to solid model, but there are competent free 2D CAD packages like QCAD.
OK, well, if this is legit (I thought you were making secret ghost or alien detector equipment), I suggest you look for small one or two person machine shop in your area. the type that does custom work for military / govt customers. if there is such in your area. in my area there are 2 or 3, still not cheap but maybe if you are friendly and get them interested in the project or offer to trade services / skills they might help. as a last resort if you have no money but are very determined... perhaps get a job or internship with a place that does such work and make one in your spare time... or perhaps a local technical school offers a course your could take in machining, often if your are a good student and make friends with the teacher they might not care if you work extra hours on a special project.
>secret ghost or alien detector equipment
Not quite. I do, in the long term, want to gain access to a local makerspace and turn my own lens adapters because I do a very non-standard sort of photography that requires combining a lot of disparate equipment not meant to be used together.
Whitworth thread form (the 55 degree) is in use commonly in Europe and bongstan for pipe threads. The BSP/BSPT are whitworth.
>This would require a metal lathe with threading capabilities.
Not necessarily. You can rig up a pattern following setup and use the original parts as the pattern. Quite a common procedure for people with Taig lathes, since they have no leadscrew. This way you don't even need to know what the thread pitch is.
In what I've seen online, the general standard is that metric threads of whole numbers tend to be x.7mm, where x is the noted number minus one. So it's curious to me that from and rear thread are in the .2-3mm range. If the rear thread was M46x1, I cannot find any standard for M46 and the matched tolerances online. Otherwise, it would seem that for many other metric standards x.3mm may still match the x+1mm thread diameter. Pitch or TPI has also been difficult to determine, and I discovered that in order to purchase the tool to measure it, I'd need to have some idea of the thread angle, which I'm not sure how to measure.
Here's some documentation:
https://static.pacificrimcamera.com/rl/00259/00259.pdf
>https://static.pacificrimcamera.com/rl/00259/00259.pdf
I wonder if those shutters have documented specs for flange distance and thread size. You might find a match.
Oh, fricking hell.
>We supply all lenses in barrels or Rapax and Acme Shutters. Alphax Shutters on special order. See price list.
Here's a site that lists common large format shutters and their thread specs:
https://www.lensn2shutter.com/shutters.html
This might be an Alpax #3.
>https://static.pacificrimcamera.com/rl/00259/00259.pdf
There's a master list on LFPF which links to dozens of brochures and catalogues. I looked through all of them. The problem is that this copy I have is a "barrel lens", meaning that it has slightly different measurements, since it wasn't meant to be mounted to a shutter (probably because many of these were used in process cameras, where you might've been just turning lights on and off in an enclosed space). I know that S.K. Grimes has previously machined an adaptor for a shutter for this specific lens and a similar shutter to mine. The question is whether they'd freely hand over their measurements. I can't hack the 180$ USD + shipping to my country to get them to make me one themselves, especially because I'd like to make a second adapter to mount it to a Nikon F ring for measuring the focus shift in a non-design-accommodated wavelength.
>I want to do some detailed fine work for a secret purpose
>I don't trust expert machinists to do this for me
>yet I don;t even know the threads myself
>oh yeah haha guys I don;t have any money either
just stop. how many days have you skipped your meds?
Two of them asked for a consulting fee without promising they would do the job. I'm not paying 120$ a pop for someone to turn me around. It's not about whether I think that's fair or not, I understand they need to see it first. I just can't afford to waste several hundred dollars on getting no work done.
>Two of them asked for a consulting fee without promising they would do the job. I'm not paying 120$ a pop for someone to turn me around.
Those fees dont actually exist, they only throw them around when they know you as a customer arent worth their time.
No machine shop is going to make this for a price you can afford.
Not going to deal with you when they could be making 40 parts in a row for someone else.
Find some guy in their garage with a lathe that would do it for you.
That or just buy a lathe
>Those fees dont actually exist, they only throw them around when they know you as a customer arent worth their time.
I figured as much.
They tend to direct me to the one place in Rhode Island that does work like this. I'm not very close, and the shop in question prefers to work with the lens in hand, meaning that I'll pay a second run of shipping back and forth at an exorbitant price thanks to my country of residence's fun policy of charging sales tax on the insured value of an item. I've spent the past week looking at every photographic forum, I checked every digitized sales catalogue and brochure I could find for Goerz, and exhausted all of the search results on google for any combination of "goerz" "lens" and "thread", "diameter", "measurement", "dimensions", etc. S.K. Grimes has done this exact job for a customer on one of the forums before, only adapting it to a different shutter. I'm going to email them tomorrow when they get back from vacation and see if they're willing to give me those measurements.
Ask around astronomy and telescope forums. They're hard into DIY for cameras and fittings. They of anyone would probably be able to make what you need, or know where to source something that works. Stop bothering businesses for one-off parts, they don't care.
What do professional photography forums suggest you do and on which have you asked?
Taps and dies won't do it. All that stuff is machined not least because workholding (make all the cuts then part the part off parent bar stock).
3d print with a resin 3d printer, grab a elegoo for like $200 and learn to cad.
Can a structure like that in resin hold on to a 2.7kg lens? I thought most printed plastic was flimsy.
It's for prototyping
>inb4 expensive machined adapter don't fit