Any machinists - pro or hobby -- interested in making mounts/adapters?

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brusby

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Wondering if there are any people on the forum with experience machining small parts and who might be interested in making lens mount adapters or parts for them.

I've got a few ideas I'd like to see made both for personal use and there might be a small market. So it could both provide a service for the community plus make some spare change.

Anyone?
 
There are several things that are not readily available that I'd like to explore whether they'd be economically feasible.

For instance, no one seems to be making an adapter for Canon 50mm f0.95 lens to Canon R mirrorless with close focus capabilities. It's available for Sony, but very few other mounts.

Rather than try to make the entire mount with helicoid, which I'd love to do but which might be complex and costly, a simple adapter that couples the native lens mount to a Leica M mount would work nicely. Then that could be used to mount the lens to any number of inexpensive M to EOS-R macro adapters that are already on the market. It would allow that lens to be used on mirrorless without having to butcher the lens by attaching an M mount adapter.

As far as machining goes, would need a thin, flat,circular piece of brass or steel with 3 "wings" that fit into the lens mount, then a spacer that fits on top of it so the lens' attachment mechanism could rotate and be functional, and then a traditional M mount adapter on the camera side.

Could be made with 3 pieces, even using a cheap, existing LTM to M adapter. Or, better yet, machine in one or two pieces. Much more elegant solution if practical.


If the idea works, maybe make a few dozen and sell them to recoup costs and possibly even make a small profit.
 
I worked in a machine shop (airplane landing gear parts) over 50 years ago. They had a tape (computer) machine there. So it should be much easier to do it today.

I want a LTM screw mount to a Pentax K mount.

Here is hoping.
 
I know the tolerances on M mounts are pretty critical for a good fit. Lot of M mount adapters on the market. Some are not good and wobble or are too tight.

I'm guessing it might be a pain to set up because of the many facets and different shapes used in the M mount, but with current computer automation might not be too tough to actually make after the initial measurements are done.

On the lens side, I think it would be very simple and straight forward. Just need good measurements to get sizes right. If I had a flat piece of brass the right thickness, I could fashion the lens side with a file, although it would be super crude.

But this wouldn't be the first time I've been mistaken. That's why I'm hoping to get input from someone with actual knowledge of today's technology.

I was thinking of taking to a local machine shop, but it would be so much nicer to have someone who is a photographer be a part.
 
I don't use anything more complex than a drill or dremel when hand fitting my own personal projects, so sitting with a set of micrometers and a few good files is how I would personally take on this mount. The problem is that you're looking at a lot of work for a low amount of return, if any. There are so few of these lenses available because they were just too expensive when originally sold, they were low volume sellers. For the few out there that haven't been "converted" to M mount, there isn't much of a larket for this particular adapter. If you do 3 pieces, you're looking at a specialized mount at no less than a few hundred US dollars per adapter, along the lines of what Amedeo has done with the Contax/Nikon adapter line. He'd actually be the guy to talk to but there is a much bigger market with a wide variety of glass to stick on an LTM or M mount than there is interest in the 50/.95, solely due to lens availability and price. You might be able to find a TV mount version of the lens that hasn't been butchered to make an adapter off that as well. Either way, with only about 27,000 samples of this lens ever being produced, it's pretty rare. It's not 2.1cm f/4 Nikkor in Nikon S mount rare, but it's certainly uncommon enough that one has to be nearly obsessed to find one. One way might be to find a trashed Canon 7 and scavenge the flange from it, you're going to need it out of the camera regardless, to get precise measurements.
As for an LTM to Pentax K mount adapter, that's easy, you might be able to find an M39x1 adapter for Zenit to original Contax. You could always just find the Zenit camera and rip the flange off then add the K adapter. The only problem you would have is it won't focus to infinity without a negative element. You'd be pushing the infinity focus of the LTM lens to maybe an inch or two since the Zenit registration is 45.2mm. It could easily be fudged for Pentax since the registration is 45.46mm.
Have fun and post photos if you get to it.
Phil Forrest
 
Phil_F_NM said:
I don't use anything more complex than a drill or dremel when hand fitting my own personal projects, so sitting with a set of micrometers and a few good files is how I would personally take on this mount. The problem is that you're looking at a lot of work for a low amount of return, if any. There are so few of these lenses available because they were just too expensive when originally sold, they were low volume sellers. For the few out there that haven't been "converted" to M mount, there isn't much of a larket for this particular adapter. If you do 3 pieces, you're looking at a specialized mount at no less than a few hundred US dollars per adapter, along the lines of what Amedeo has done with the Contax/Nikon adapter line. He'd actually be the guy to talk to but there is a much bigger market with a wide variety of glass to stick on an LTM or M mount than there is interest in the 50/.95, solely due to lens availability and price. You might be able to find a TV mount version of the lens that hasn't been butchered to make an adapter off that as well. Either way, with only about 27,000 samples of this lens ever being produced, it's pretty rare. It's not 2.1cm f/4 Nikkor in Nikon S mount rare, but it's certainly uncommon enough that one has to be nearly obsessed to find one. One way might be to find a trashed Canon 7 and scavenge the flange from it, you're going to need it out of the camera regardless, to get precise measurements.
As for an LTM to Pentax K mount adapter, that's easy, you might be able to find an M39x1 adapter for Zenit to original Contax. You could always just find the Zenit camera and rip the flange off then add the K adapter. The only problem you would have is it won't focus to infinity without a negative element. You'd be pushing the infinity focus of the LTM lens to maybe an inch or two since the Zenit registration is 45.2mm. It could easily be fudged for Pentax since the registration is 45.46mm.
Have fun and post photos if you get to it.
Phil Forrest
Click to expand...

I've done the LTM to M42 with a LTM to Pentax m42 adaptor and the a Pentax number 1 extension tube (with the wisdom of Pentax those two adapters add just enough to make the 45.46mm). It works great, but I'd like to use my 20mm K mount so I need a M42 to K mount number 1 extension tube. But it is not to be.
 
Thanks Phil, that's exactly what I suspected regarding costs for any one-off or small run fabrication of a complex item like the M mount. That's why I may just buy a cheap M mount adapter off eBay and use it. The rest of the device I have in mind is very simple and I could probably make by hand.

But, I was hoping someone would have experience with modern laser measuring devices and would know a very accurate way to measure an original Leica M mount and be able to cut a duplicate of the tricky parts at a reasonable price. Still hoping
 
I wonder if recent advances in 3d printing might not be a way forward. There are some pretty exotic materials out there I believe that might be more robust than plastics. It may even be possible to use a hybrid approach such that a standard metal mount adapter can be incorporated in the design to make it more robust and prevent wear much as Brusby seems to be suggesting. Just a thought. That would make the whole task much more feasible as most of the cost would be in design not build. So it is replicatible at even lower incremental cost.
 
Unless you have access to a 3-d design/cad person and/or quality milling machines, I'd think about this from another approach. There are thousands, millions, of the parts you need already machined and within factory spec because they came from the factories that developed the specs in the first place. Old lenses and old camera bodies have all the parts you need.

When I had a Tele-Rollei with a missing Bay III mount, I took the part from a junker body, made a few mods, and installed in on the camera. When I wanted a helical for a 47mm Ilex Acugon, I took an old Pentax 50mm f/2 lens, stripped out the interior, made a front insert with #0 shutter mount, and off I went.

So think about how to scab together assorted parts that are already out there?


Two resources- watch Craigs List or such for someone selling old machinist tools. The odds are that they either are, or know someone who is, a retiring/unemployed machinist. Many machinists are problem solving type of people, so ask them if they can help.

Second resource is to look for 'maker spaces' in your area. These will have a variety of machines and a variety of people who, like retired machinists, enjoy tracking down solutions to weird problems.
 
S. K. Grimes (website under that name) is a specialist in photographic machine work.

They are the gold standard for this kind of work.
 
Graybeard said:
S. K. Grimes (website under that name) is a specialist in photographic machine work.

They are the gold standard for this kind of work.
Click to expand...
Exactly. And they already have a lot of the dimensions you would need to know in order to make such adaptors work.
 
I was prompted by this thread to have a look on Google and found this pic of an adapted Canon 50mm f0.95. It looks relatively straightforward (comparatively speaking that is). Of course preservation of rangefinder focusing requires fine tolerances. The image below is from this video.

https://www.youtube.com/watch?v=v7ebhYtm31A
maxresdefault.jpg
 
Thanks Peter, Dan, Pentode, Graybeard and everyone for your input.

Regarding the video above, it would be very simple to remove the stock mount and slap an M mount adapter on the lens like they did. The only minor difficulty with that method would be getting depth correct, probably requiring a shim or spacer, if you'd want rangefinder coupling to be accurate. That's a pretty simple matter.

But I don't want to butcher or modify the lens in any way and that type of mounting requires drilling into the lens which I don't want to do.

I want to fabricate a mount that couples to the existing Canon one on the lens side as it was designed to be used, and converts to either a Leica M or Canon EOS R mount on the camera side. I can envision the mount I want. 'Just don't have the precise measurement and machine tools needed to make it yet.

May be giving Grimes a shout.
 
brusby said:
Thanks Peter, Dan, Pentode, Graybeard and everyone for your input.

Regarding the video above, it would be very simple to remove the stock mount and slap an M mount adapter on the lens like they did. The only minor difficulty with that method would be getting depth correct, probably requiring a shim or spacer, if you'd want rangefinder coupling to be accurate. That's a pretty simple matter.

But I don't want to butcher or modify the lens in any way and that type of mounting requires drilling into the lens which I don't want to do.

I want to fabricate a mount that couples to the existing Canon one on the lens side as it was designed to be used, and converts to either a Leica M or Canon EOS R mount on the camera side. I can envision the mount I want. 'Just don't have the precise measurement and machine tools needed to make it yet.

May be giving Grimes a shout.
Click to expand...

It looked to me as if the standard external mount was affixed with screws through the plate holding the external mount flanges. I may be wrong. But if I am not wrong it had already occurred to me that it could be possible to use the same screw holes and threads so the conversion is reversible. Needs more investigation but it may be worth looking into. And you are right - some shimming would be required to correct the flange distance. But while requiring care - this is quite trivial technically. The Canon LTM 50mm f1.2 for example is shimmed internally to achieve proper focus as were many other lenses of the era. It is simply a "donut" spacer of aluminium or brass of the required thickness placed in the lens to move it forward by the correct amount.

Some ideas here:

https://www.rangefinderforum.com/forums/showthread.php?t=62992

And here:

https://www.photo.net/discuss/threa...-rangefinder-lenses-to-leica-m-mounts.123108/
 
That one had the "wings" removed which are used to operate the native mount. It may work just fine. And that's definitely something to consider. But I'd prefer to leave the native mount entirely intact if possible, and just use it as it was designed.

Regarding shimming, I think it's best to get the flange distance set to factory specs first by adding any shim or flange to the mount. Once that distance is correct, the lens should focus perfectly. If it's off a bit it could be shimmed internally. But on a mirrorless camera it wouldn't be necessary unless you'd want infinity focus to be a hard stop.
 
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