Information needed for construction of flanges

[akfreak]

Well I grow tired of searching for flanges. I plan to buy a small lathe and start making my own flanges. I know there are thread pitch gauges but how does one know what size lip on the mounting side of the flange need to be. All of the flanges I have are not flat on the bottom, the have a indexing lip that centers in the hole of a lens board. Does it matter how thick that indexing lip is?

To those who do this already what are the tools I need to buy in order to build these flanges. I assume a nice parting tool, a set of inside and out side jaws, various tips for thread cutting. A indexing table to drill the holes in the flange lip itself.

It seems flanges are scarce for certain lenses. Also The prices for these rare flanges are ridiculousness IMO.

I am also planning to be converting some DSLR lens mounts so the investment in a lathe was already in the cards so to speak. If you guys have any ideas that I may need to consider, as well as flanges that always seem to be in short supply, please let me know so I can add them to the development list.

I know SK grimes already does this type of work, I also know they are awesome at all they do. I am just a glutton for punishment and like to do one off stuff to help further drive myself insane:)

[Leigh]

Cutting threads in the size and pitch of mounting flanges is a non-trivial task, requiring a good lathe and mastery of its use.

I would strongly recommend leaving this to someone who has the tools and skills to do it right.

- Leigh

[goamules]

And to counter the above, go for it! Everyone starts somewhere when learning a skill (such as LF photography). They were making screw flanges in 1840 with primitive lathes. I don't recall reading about a long, multi-year apprenticeship for becoming a "LatheSmith".

[Leigh]

They were making screw flanges in 1840 with primitive lathes. I don't recall reading about a long, multi-year apprenticeship for becoming a "LatheSmith".
There's nothing "primitive" about an 1840's lathe.
Machines of that era were quite capable of holding close tolerances and doing excellent work.

Machinist apprenticeships are multi-year, like the one I completed.

- Leigh

[ic-racer]

I have seen Chinese lathes with thread-chasing carriage for a little over $1200. However, that amount of money would supply a lifetime's worth of SK Grimes flanges for me.

[Leigh]

Learning how to use it will cost a lot more than $1200 in scrapped parts, time, and aggravation.

- Leigh

[Steven Tribe]

I do many wood and brass working activities. But I have too much respect for the size of machine required, the specialised tooling needed and the need for an experienced machinist, to ever think about cutting these very different threads.
Just think about the stock you would use? Would this rough cast brass form or cut out from a 5mm thick plate of brass?
I think most of the threads we admire in early flanges - and in even earlier telscopes - were hand cut using specially made taps - rather like the way that threads were cut in wood for table legs before IKEA. The entry rate was controlled by the tap having at the other end the same thread pitch that was turned in a female thread.

[Jim Jones]

http://www.harborfreight.com/ sells a $1000 Chinese-made lathe that might suffice. It might not cut all the threads one will encounter. It cost less than that to get my ancient Craftsman lathe outfitted. A few years ago I saw a nice 6" Craftsman outfit bring only $400 at a live auction.

The indexing lip on many flanges is not necessary. Material, brass and otherwise, might be found in a plumbing supply store. A lens flange doesn't have to be metal. Enlarger lens adaptors were sometimes plastic. A couple of aluminum drip pans might end up as flanges or flat lens boards someday. An indexing table shouldn't be necessary. One can do the layout on a computer and transfer it to the flange.

I agree with Leigh that DIY flanges will be expensive. However, there may be enough satisfaction in learning a new art to make it worth while. It is indeed an art.

[Jay DeFehr]

I would recommend designing a kind of universal flange that can be printed by a 3D printer. Imagine something kind of like one bracelet of a handcuff, closed by an allen screw. Just thinking out loud.

[winterclock]

Lindsay publications http://www.lindsaybks.com/ carries several lathe manuals as well as old course books on lathe operation. You might want to do some research on this before you buy the lathe, cutting threads can be tricky, it takes some math to return the lathe bit to the correct location to start multiple passes. And remember: never part all the way through!

[Leigh]

I would recommend designing a kind of universal flange that can be printed by a 3D printer.
Regarding 3D printers...

The mounting threads for a Copal #0 shutter are M32,5 P0,5.
So the distance from one thread peak to the adjacent peak is 0,5mm or .020".
For any kind of reasonable engagement you would need a form accuracy at least 10 times better, or 0.002".

The 3D Touch printer from Alibre ($4K) has a minimum features size of 0.80", positioning accuracy of 0.004", and layer thickness 0.012"...
Nowhere close to what's required for the flange.

Their V-Vlash printer ($15K) has the same specs.

You can find 3D printers with the required accuracy, but you're talking major $$$.

- Leigh

[eddie]

Why. NOt just buy lenses with flanges?!?!? Spend a bit extra for a complete lens .... Far cheaper than a lathe.

[c.d.ewen]

Interesting thread; not much to disagree with here, to be sure.

I certainly agree, and can attest to personally, that buying a lathe for personal use is not an economical solution. Tooling for the lathe is an endless expense, and the search for a magic bullet is not exclusive to photography. In an effort at speed and efficiency, for example, I wound up buying a second lathe, to be used exclusively for threading.

Material costs are another drag. I recall standing in front of Grimes' shelves of round and flat stock and thinking how many thousands of dollars was tied up there. Priced brass lately?

If $$$'s don't matter, you're not in a hurry, and you enjoy turning nothing into something, though, I'm with Garrett: go for it. Turning on a lathe is often art, but not necessarily brain surgery - only your wallet will care if it takes you 6 or 8 tries to get it right. Take a community college course, if you can, if only for the safety lectures. Playing around with unfamiliar machinery is dangerous! Protect your eyes and ears, don't wear jewelry or loose clothing, and learn not to catch things that fall off the bench (hard to do). Do I have to tell you not to drink alcohol?

There are too many ways of getting hurt to list; start small and slow. Cut plastic (watch the fumes!) before you try titanium. Keep in mind that those little chips (swarf; start learning the language) are very hot and razor sharp. Have fun. Be productive.

PM me if you have any questions.

Charley

[c.d.ewen]

...how does one know what size lip on the mounting side of the flange need to be. All of the flanges I have are not flat on the bottom, the have a indexing lip that centers in the hole of a lens board. Does it matter how thick that indexing lip is?

It just occurred to me that no one answered your question about the shape of mounting flanges.

The only critical dimension, obviously, is the size of the hole the lens screws into. The other dimensions are generally arbitrary. How thick should the flange be? Usually depends more on what size scrap you've got laying around than anything. Got a lens that's two inches in diameter? Look around for a 1/4" sheet that you can cut a 3"x3" piece out of. That's a lot easier than parting off a chunk from a round. Ever see a flange that's flat on two sizes? If all you had at hand was a 2 1/2"x 12" sheet, you'd cut a rectangular piece out and put the mounting holes on the long sides. I've been lazy enough to just leave the roughcut flange square.

You asked about sizing the flange to fit into the lensboard hole. It needs to go deep enough into the lensboard so as to not move (but not be jammed in). That doesn't need to be much, but how much flange do you want to leave above the lensboard? Aesthetics often count more than engineering: once you're sure everything will be secure, how massive do you want the flange to appear? Same concept for the diameter of the flange needed to allow for the mounting screws.

On first read, I though you were asking about the size of the flange that rises above the level of the screwholes. The top of flanges isn't always completely flat. If there's a lot of contact area between the lens/shutter and the flange, there's a higher likelihood that dirt and corrosion will increase the friction between the two, to the point that it becomes impossible to separate them. Leaving a small area of the flange above the screw level aleviates the problem.

Charley

[akfreak]

Cutting threads in the size and pitch of mounting flanges is a non-trivial task, requiring a good lathe and mastery of its use.

I would strongly recommend leaving this to someone who has the tools and skills to do it right.

- Leigh

Oh I see, being able to set pins (the gears) in the proper position to cut a thread is an exact science. I have run a lathe and cut many threads. I guess my question is is there a reference book of sorts to the known common thread counts, pitches and flange od, as well as step dimensions. I hate the trial and error method.

I know hoe to use a parting tool, I know how to use inside and outside 3 and 4 jaw heads. I suppose I should just leave it to the experts so I can pay 100 bucks a pop for flanges that dont exist.

[akfreak]

It just occurred to me that no one answered your question about the shape of mounting flanges.

The only critical dimension, obviously, is the size of the hole the lens screws into. The other dimensions are generally arbitrary. How thick should the flange be? Usually depends more on what size scrap you've got laying around than anything. Got a lens that's two inches in diameter? Look around for a 1/4" sheet that you can cut a 3"x3" piece out of. That's a lot easier than parting off a chunk from a round. Ever see a flange that's flat on two sizes? If all you had at hand was a 2 1/2"x 12" sheet, you'd cut a rectangular piece out and put the mounting holes on the long sides. I've been lazy enough to just leave the roughcut flange square.

You asked about sizing the flange to fit into the lensboard hole. It needs to go deep enough into the lensboard so as to not move (but not be jammed in). That doesn't need to be much, but how much flange do you want to leave above the lensboard? Aesthetics often count more than engineering: once you're sure everything will be secure, how massive do you want the flange to appear? Same concept for the diameter of the flange needed to allow for the mounting screws.

On first read, I though you were asking about the size of the flange that rises above the level of the screwholes. The top of flanges isn't always completely flat. If there's a lot of contact area between the lens/shutter and the flange, there's a higher likelihood that dirt and corrosion will increase the friction between the two, to the point that it becomes impossible to separate them. Leaving a small area of the flange above the screw level aleviates the problem.

Charley
No I was speaking to the inside lip where the flange passes thru the lens board.

If one knows the thread info, cutting them is easy! I also think thick wall aluminum tubing is the way to go to make flanges

[c.d.ewen]

No I was speaking to the inside lip where the flange passes thru the lens board.

If you're starting with a lens, then you know the major diameter (outside dimension of the male threads). That lip has to be big enough to contain those threads, plus a certain amount extra for support. An extra 0.100" is a good starting point. Remember that you need that extra all around, i.e., if the lens' OD is X and you want 0.100" support, then the OD of that portion of the flange should be X+0.200".



If one knows the thread info, cutting them is easy! I also think thick wall aluminum tubing is the way to go to make flanges.

Holobar. Makes sense to not have to cut away the insides. Depending on how many different sized flanges you're going to make, though, you could wind up with a lot of different sized rounds.

For big flanges, I'll go to the metal merchants on eBay and order a couple of pieces of 0.500" thick 6061 AL in diameters of 5" or 6". I find it cheaper and easier than having a lot of big stock laying around.

Now, when you start thinking like a thrifty Yankee (or a canny Scot!), you'll start with a solid round and cut the center out with a hole saw. You make one flange out of the outer ring, and another out of the center disk. ;) I've only bothered to do this when cutting brass, though. :rolleyes:

Charley

[winterclock]

You don't even really need to have an index lip on the board side. I didn't bother with it
for the flange I made for an Alphax #4. I just measured the diameter of the threads with a caliper, checked the pitch with a thread gauge, and cut the flange from a piece of 1/4"
6061 plate. With no glass in the shutter it was easy enough to check the fit without pulling the piece from the lathe, I did have to make one extra .003" pass to get the fit.
If you're OK with running the lathe stop over-thinking and just cut the part.
P. S. Charley s method is what we use to cut titanium tubes: the size we use only comes in solid billets!

[Jody_S]

I've cut dozens of flanges on an old engine lathe from the 60s, it wasn't hard. Threads: don't worry too much about pitch, look at the threads on the lens using a cheapo thread pitch measuring gauge, set the dial to that on the lathe, and stop worrying. Over the 2-3 threads on your flange, this just isn't that critical. Dimensions? Well, if you've got the lens in front of you and your thread is too tight, cut it a bit deeper. Too loose? Start over. Scrap metal is cheap. I bought all the tooling I needed for less than $100 (I had the lathe itself). In a good evening, I could knock off 4 or 5 of these, usually wasting 1 or 2 pieces.

[c.d.ewen]

...your thread is too tight, cut it a bit deeper. Too loose? Start over.

Jody: What? Are you out of teflon tape? :D

Charley

[c.d.ewen]

P. S. Charley s method is what we use to cut titanium tubes: the size we use only comes in solid billets!

:eek:

Note to woodworkers: ever work with lignum vitae? :o

Charley

[Jody_S]

Jody: What? Are you out of teflon tape? :D

Charley

Actually, I use a type of putty called 'Duct Seal'. Can be found at Home Depot or any of the major hardware 'big box' stores in the electrical department (used to seal the inside of electrical conduit by pressing in around the wires, to prevent air and moisture movement). Sold in 1lb boxes for under $10. Like plumber's putty but sticky and a bit harder.

In a pinch, I can mount any smooth-barrel lens (like a projection lens in a simple tube) directly into a lensboard using this, so long as it's a reasonably tight-fitting hole. I discovered that Dremel makes a circle-cutting adapter that threads to the front of a rotary Dremel tool, and using a 1/8" router bit I can make perfect circles (+/- 1/64" or so) and mount these lenses in masonite lensboards in just a few minutes. As a plus, the putty comes off without leaving residue, but it does harden quite a bit over the years so it's a semi-permanent thing once it's dried out a bit.

[Tim Meisburger]

I have successfully cut tight holes in plywood lensboards and screwed lenses directly into the hole. Flanges for some smaller lenses could be made the same way, if enough of the lens is threaded to give good purchase. Cabinet-grade plywood would be preferable to ordinary wood as it would not split if the fit is tight, and would be dimensionally stable when mounted. Wooden flanges can be made with a $30 expansion bit and a few other simple tools.

Tim

[Jay DeFehr]

Regarding 3D printers...

The mounting threads for a Copal #0 shutter are M32,5 P0,5.
So the distance from one thread peak to the adjacent peak is 0,5mm or .020".
For any kind of reasonable engagement you would need a form accuracy at least 10 times better, or 0.002".

The 3D Touch printer from Alibre ($4K) has a minimum features size of 0.80", positioning accuracy of 0.004", and layer thickness 0.012"...
Nowhere close to what's required for the flange.

Their V-Vlash printer ($15K) has the same specs.

You can find 3D printers with the required accuracy, but you're talking major $$$.

- Leigh

I was thinking of a friction Fastener. I use something similar for my 14-1/2" Verito, and it works perfectly. Plastic won't damage the threads, and will hold the lens quite securely.

[Henry Ambrose]

I have some suggestions and thoughts you might consider:

Do a survey of the range of the thread pitches you want to cut first, before you buy a lathe that won't do what you want.

You can find most of the size and pitch information on the internet if you look for it. You'll find metric and American sizes. But you need pretty good measuring tools and the knowledge to use them to be able to make your parts. Its gonna be a cut and try procedure for most old photographic parts. You're not making a part to a print or specification most of the time.

You can also figure out dimensions for yourself if you're something of a mechanic. This assumes you have the parts in hand and good measuring tools.

Most of the threads you need to cut are pretty fine and you'll find you need good tooling and skills to cut them and make a nice job of it.

Different materials may require different tooling.

Brass is expensive. Shockingly expensive. You'll notice this right away when you shop for raw material to make even a moderate sized flange. Aluminum is cheaper but it might be harder to cut nice smooth threads depending on the particular alloy you choose. And big chunks still cost more than you think, when you buy them a smallish piece at at time.

$100 flanges will not look so outrageous after you consider all the above.

And I'm not trying to discourage you but its not quite as simple as it seems at first glance.

Here's some stuff I made for a member:

http://www.largeformatphotography.info/forum/showthread.php?t=77199

[E. von Hoegh]

:eek:

Note to woodworkers: ever work with lignum vitae? :o

Charley

Yes. From bearings for water turbines to bushings for wooden works clocks.:)

Edit. Lathes can often be had for very little cash, or sometimes just the trouble of hauling one off. In this CNC CAD/CAM world, the skills to use an engine lathe are disappearing fast. Of course, the tooling is the most expensive part. I would avoid a Chinese lathe, unless I wanted to spend a week or two aligning the piece of $h!t.

[akfreak]

Thanks fella's. I just wanted to ask a few questions to see if there was something obvious or not so obvious I was missing. Sometimes one will overlook little details that can really come back to bite you in the A$$ (I mean wallet) when going to get started doing a project. This post was an exercise in information gathering. I think I have enough to make an educated decision.

I used to one a machine shop full of tooling, I had a Cadillac lathe, a Bridgeport. a screw machine, a turret lathe, and several cold saws. I am planning on tooling to to start doing lens mount conversions so while I was at it. I thought about cutting flanges,

I know one can use all sorts of home brews to get a lens to hold on a board, my favorite is a soaked black shoelace , with some Elmer's white glue then wrap the gluey shoelace tightly around the shutter thread after the shutter is mounted to the board, five or six turns around. Put a rubber band on it til dry. Also I hear a wet rawhide bootlace, they shrink as they dry. Heck it used to work for stone axe heads.

I am going to be on the hut for a new lathe and mill. I will most likely end up back in KCMO where I know everyone and can get a lathe for the price of moving it. The Bridgeport will be a little more expensive, but I need one anyway.

I am tired of having to wait to use a shop, I guess I was spoiled when I had my own custom chopper shop