Hole Saw For Commercial Ektar Lens

[pendennis]

I just found a very nice Commercial Ektar Lens, 8.5" f/6.3, set into the standard Ilex Acme #3 Shutter. I've drilled lens boards before, mostly for Copals, etc., and I found the specs on the lens. It calls for a hole size of 1.985" (50.42mm). I have hole saws of 1.875" and 2". However, I would have future use for a 50mm hole saw, and McMaster Carr has these. I already have a jig set up on my drill press to do lens boards, so I'm curious if the 50mm hole saw would be the best bet, or 1.875" and open up the hole a bit with a drum sanding bit.

Thanks.

[Bob Salomon]

Proper way is not to drill a board.

[C. D. Keth]

Proper way is not to drill a board.

That may be but it's not rocket science. It's a hole in a panel of wood or aluminum.

The 2" will do fine. 0.02" won't make any difference once the flange is screwed to the board.

[Bob Salomon]

That may be but it's not rocket science. It's a hole in a panel of wood or aluminum.

The 2" will do fine. 0.02" won't make any difference once the flange is screwed to the board.

And the pressure and heat from drilling can warp the board. That’s why they should never be drilled.

[goamules]

I simply shoot a hole in my boards. 20 or 12 Gauge works for most lenses.

[Bertha DeCool]

I simply shoot a hole in my boards. 20 or 12 Gauge works for most lenses.

I've used laser vision but I get best results through sheer force of will.

[C. D. Keth]

And the pressure and heat from drilling can warp the board. That’s why they should never be drilled.

And here I've been tempting fate all along. I must be a couple dozen drilled lensboards into borrowed time by now.

[BrianShaw]

I've used laser vision but I get best results through sheer force of will.

Between that and your sharp wit...

[Peter De Smidt]

Me too, Chris. I've used hole saws, fly cutters, router, CNC....All have worked just fine with proper setup and use.

[pendennis]

Me too, Chris. I've used hole saws, fly cutters, router, CNC....All have worked just fine with proper setup and use.

When cutting metal, I always keep the hole saw lubricated with machine oil I've never had a warp. My main concern here was whether the 2" or 50mm hole saw would be correct.

[Drew Wiley]

If it's a holesaw you have to measure the ACTUAL outside tooth diameter with a caliper. Brands differ, even within the same nominal size. Hole saws are not precise with respect to diameter. Someone might want to debate that, but I doubt they've sold the thousands and thousands of them I have.

[Duolab123]

In wood you can cheat a couple of millimeters by rocking the hole saw using a hand drill. I have mostly wooden boards that I get from Zimba (or something like that) off of Ebay. These are machined, lathed, flawless. I will never again hack away at a nice board with a hole saw. Especially a metal board. I found a semi retired machinist who has cut back to 40-50 hours a week. He's helped me with some metal parts, worth every penny.

Still if you want to do it yourself go ahead, caution even clamped and held down its easy to warp metal boards.

[goamules]

When cutting metal, I always keep the hole saw lubricated with machine oil I've never had a warp. My main concern here was whether the 2" or 50mm hole saw would be correct.

Is this an April Fools joke?

[Keith Pitman]

As Duolab123 said, for a metal board, find a home machinist who can cut a perfect hole for you. It will be worth a couple of bucks versus a hack job you can do with a hole saw.

[Kiwi7475]

In the old days, if not in a hurry I would contact Luland on eBay and ask them to build me a Linhof or Sinar or whatever plate with a custom hole. It’s usually same price as the standard Copal hole sizes. It’s CNC’d and they do a great job. They can also machine custom retaining rings etc

You still can if you don’t mind buying directly from China (and apply whatever handling provisions you are comfortable with).

Turns out it’s cheaper for me than going to a CNC machine shop around my area, they know already what I need without having to provide a drawing, and usually takes about 7-10 days to arrive which is not bad.

[LabRat]

For metal, boring bar on a mill...

For wood, I use a circle cutting attachment on my router... Beautiful hole...

On some retaining rings, there is a shoulder that can go inside the board that is a little bigger than the threads that might be a standard size... Measure that too...

Steve K

[seall]

I always like to drill a hole before I drill the hole, a whole lot better hole.

[John Kasaian]

I always like to drill a hole before I drill the hole, a whole lot better hole.

A holistic approach, eh?

[BrianShaw]

A holistic approach, eh?

Holy Cow!

[BrianShaw]

... and now we know the whole story!!

[Roger Thoms]

The 50 mm holesaw sounds like the one. But what I’d do is take a piece of scrap material and drill a test hole, then you’ll know for sure. You’re 1.875” hole saw and a drum sanders is certainly an option.

Roger

[Bernice Loui]

Best way to make a lens board hole for any lens is on a lathe with four jaw chuck. Once the proper size hole is done, drilling the holes for the flange is not as easy as it appears.


Bernice

[paulbarden]

I make custom 3D printed lens boards for all my lenses. If you don't like the black plastic look, you can always glue a wood veneer on the front (I've done that too)

[pendennis]

The 50 mm holesaw sounds like the one. But what I’d do is take a piece of scrap material and drill a test hole, then you’ll know for sure. You’re 1.875” hole saw and a drum sanders is certainly an option.

Roger

I have a few scrap sheets of 6x6 aluminum plate, about the thickness of a lens board. I always make a test hole in one of them. This one won't be any different than any others in my work process. Test, test, test (a variation on "measure thrice, cut once").

[Greg]

First off, my experience has been pretty much all with older gray "Norma style" lens boards. First off I place the lens board on a Granite Surface Plate (bilateral tolerance +/- 0.0001). Few of the lens boards that I checked and looked to be flat were in fact "perfectly" flat, especially the ones that were previously cut. Even some OEM uncut Sinar gray lens boards that I acquired were not perfectly flat. Since these OEM boards haven't been manufactures since 1970, in the 50+ some years that they have been stored, whose to say how they've been handled or if even dropped.

First thing I do is to get the lens board to be "perfectly" flat, actually quite easy once you get the hang of it. Overcorrection the greatest problem since it is so very easy to do. For cutting the holes, I use modified Forstner bits. I use the ones with the saw teeth around the perimeter. The 2 metal "bridges" between the center of the drill and the outside cutting teeth I ground down to a little more than the thickness of the lens boards, so only the center "drill" and the outside cutting teeth do the cutting. Trick is to slowly, I mean really, really slowly cut the hole and to use Aluminum cutting fluid. Distortion from heat eliminated. Lens boards rechecked, after cutting the hole, and are undistorted. Circular hole in the lens board checked and also undistorted. Before cutting the hole, I very securely clamp the lens board to a 1/2" sheet of PVC and secure it to the table of the drill press.

Before I used to just drill a lot of holes inside the hole to be cut and then with the lens board in a vice, file the opening round. Once I got the Granite Surface Plate, I checked my lens board when I was finished, and it was "warped", but too small for me to measure so probably not enough to matter in practice. To hold the lens board when I was filing the opening, I repeatedly would secure it in a vice in different positions, and I think this procedure caused the "warping". Also maybe the filing?

FYI: I have and use 3 OEM carbon fiber Chamonix lens boards which came with pre-drilled holes. Placed each of them on the Granite Surface Plate and all 3 were "perfectly" flat.

[LabRat]

The hole saws transfer a lot of torque to the workpiece as the entire diameter has teeth that are cutting/grabbing during operation and potentially distorting board... And the clamping has to be very secure to hold down board which also can tweak it... Then there's heat generated and work hardening while cutting... So not as easy as it looks...

With a boring bar, there is a single cutter insert held steady in a mill that requires much less force to go through material... Or as Bernice sez, on a lathe where there is just the sharp cutting tool cutting through...

Be careful if trying some operation on a drill press, as they spin too fast for most of this type of boring, and the piece can break free of clamping creating a very hazardous situation...

Steve K

[Bernice Loui]

If the lens board is not absolutely stable with zero ability to shift or move as the hole saw is cutting, there will be a disaster if what is used to stabilize the lens board lets go.. That lens board can become a lethal projectile. One of the harsh lessons from working with BIG machine tools, item being worked on can NEVER get away from the set up.

That said, hole saws and similar produces a LOT of friction during cutting, this results in a whole lot of torque that could cause a long list of problems. While a hole saw can and does work for making holes in a lens board, absolute awareness of what can and will go terribly wrong must be accepted.

Im fortunate enough to have a lathe in the garage to do with with ease, and controlled precision. IMO, it might be better in many ways to pay an individual with the proper skills and tools to get this done properly. The results are usually better and the risk of injury greatly reduced.



Bernice

[Greg]

Be careful if trying some operation on a drill press, as they spin too fast for most of this type of boring, and the piece can break free of clamping creating a very hazardous situation...

Steve K

Agree 100%. My father was a self employed carpenter when I was growing up. He showed me how use the table saw in our basement when I was years 8 or 10 years old. Vividly remember some 60+ years ago him showing me how a board being fed into the saw blade can become a lethal projectile... he fed a 2x4 into the saw blade and standing on the side let go of the 2x4. I saw it "fly" to the other end of cellar.

When I cut my lens boards, they were absolutely clamped to the drill's table with 2 back-up "plates" bolted to the table acting as a back-up even more permanent clamp. After rock climbing for about 25+ years, having one back-up anchor was the absolute minimum - whenever possible rigged up a back-up anchor to the back-up anchor. Carry that mindset over when working with "table top" power tools more and more as I grow older and older. Gave up using a Ramset 22 (or 45?) caliber nail gun that I inherited from my father several years ago, when I just didn't feel safe using it anymore.

Agree that using a boring bar the better way to go, but the Forstner bits were all I had at the time. There is a Harbor Freight store near by, but I just don't trust any cutting tool that is sold at a bargain price. Did once look at one of their boring bars, but it seemed to be poorly machined, so put it back up on the shelf.

[Bob Salomon]

“... Gave up using a Ramset 22 (or 45?) caliber nail gun that I inherited from my father several years ago, when I just didn't feel safe using it anymore.”

When we moved to our new warehouse, 20+ years ago, we were putting up metal shelving against the walls. After assembling one of them they just weren’t stable enough. Since the Ramset 22 was mine I crawled between the shelves and fired it.
My ears were ringing for the next week!

[Bernice Loui]

If you're going to hole saw a lens board, setting it up in a Bridgeport milling machine using a Kurt milling vise and related set up tooling is likely the best-most stable way other than using a four jaw chuck on a lathe.
202240

Drill press works, IF the lens board is absolutely clamped and proven to be absolutely stable set up.

Do not push the cut-feed rate as the higher the feed rate, the greater the forces involved with cutting are. Other deathly important detail, use SHARP cutting tools of known high quality. This makes the BIG difference in cutting forces involved and allows the chance to produce a clean cut, good finish and hole accuracy.

Emphasis on how lethal using cutting tools can be is often not appreciated until a serious or even fatal injury occurs.




Bernice

[Drew Wiley]

holistic information

[Michael Dodd]

If you're going to hole saw a lens board, setting it up in a Bridgeport milling machine using a Kurt milling vise and related set up tooling is likely the best-most stable way other than using a four jaw chuck on a lathe.
202240

Drill press works, IF the lens board is absolutely clamped and proven to be absolutely stable set up.

Do not push the cut-feed rate as the higher the feed rate, the greater the forces involved with cutting are. Other deathly important detail, use SHARP cutting tools of known high quality. This makes the BIG difference in cutting forces involved and allows the chance to produce a clean cut, good finish and hole accuracy.

Emphasis on how lethal using cutting tools can be is often not appreciated until a serious or even fatal injury occurs.




Bernice

Nice mill about how many 8x10 petzval's would that cost ? If I had the room.

[Jerry Bodine]

I'm reminded of the time I had a master machinist cut a hole in a Sinar aluminum lensboard. He put the board in a lathe and cut a perfectly clean hole ALMOST all the way through the metal, then with his little finger he pushed lightly on the disk and poked it out of the board. With my jaw dropped, I asked him how he knew when to stop cutting; he said he could tell by the sound. I asked what if it's a different board material, and he said it would have a different sound!

[Bernice Loui]

This bridgeport is a bit odd, the table is 32" x 9" which is the smallest Bridgeport they made. These were made up to the mid-1960's. This specific BP was made in 1959. Previously owned and used by a grinding shop that likely rebuilt it. After that it went to a local machine shop that closed. This BP is in remarkable condition given it's age.

As for cost, the most common BP has a 42" x 12" table. Good condition ones or their high quality made in Taiwan clones or improved ones made in Spain are easily available for $2,000 to $3,000 all the time in the local want-ads. They are 50% or less at a machine shop door closing auction. Owning a machine tool like this is a serious commitment. They take up signifiant space and need a professional machine tool mover (rigger) to get them moved then placed where it will live. Cost of the machine tool is really not bad at all, what IS expensive, tooling to support the machine tool. The Kurt vise runs about $700, decent drill chuck about $300, R8 collets about $20 ea, good cutting tools such as a Niagara 1/2" end mill about $50... and so on.

Then comes measuring tools which is another $ pit.

There was a time when there phase power for machine tools like these where a serious problem for a garage shop. The modern solution is to apply a VFD or Variable Frequency Drive which converts 240VAC to three phase 240VAC variable frequency allowing variable speed with the turn of a knob. These work very well in many ways.

Parts and service for a Bridgeport is easy, plenty of good support nation wide.


Bernice



Nice mill about how many 8x10 petzval's would that cost ? If I had the room.

[Bernice Loui]

This is the kind of stuff good machinist do all the time. It is why lens board holes in a lathe is the best way to make a lens board hole for any specific lens. It is not difficult to achieve a 0.001" to 0.003" clearance fit between lens board to lens flange on a high quality lens board like Sinar and the hole can be precise on center or offset as needed.


Bernice


I'm reminded of the time I had a master machinist cut a hole in a Sinar aluminum lensboard. He put the board in a lathe and cut a perfectly clean hole ALMOST all the way through the metal, then with his little finger he pushed lightly on the disk and poked it out of the board. With my niagara dropped, I asked him how he knew when to stop cutting; he said he could tell by the sound. I asked what if it's a different board material, and he said it would have a different sound!

[reddesert]

The Bridgeport lathe (I know, it's a vertical mill, not a lathe) is also the only machine tool that I know of to have an entire New Wave song dedicated to it, by "The 2x4s" from Boston: https://johnhovorka1.bandcamp.com/track/bridgeport-lathe

I want to hear the sound of the Bridgeport lathe.
It's metal to metal it really is.
Your basic ordinary men they work at Bend-on Gear.
And the screech of shearing metal is what they wanna hear. ...

[Havoc]

If you're going to hole saw a lens board, setting it up in a Bridgeport milling machine using a Kurt milling vise and related set up tooling is likely the best-most stable way other than using a four jaw chuck on a lathe.

Drill press works, IF the lens board is absolutely clamped and proven to be absolutely stable set up.

Do not push the cut-feed rate as the higher the feed rate, the greater the forces involved with cutting are. Other deathly important detail, use SHARP cutting tools of known high quality. This makes the BIG difference in cutting forces involved and allows the chance to produce a clean cut, good finish and hole accuracy.

Emphasis on how lethal using cutting tools can be is often not appreciated until a serious or even fatal injury occurs.

Bernice

While I agree with most said, I would never put a thin, flat piece like a lens board in a vise. A vise clamps 2 sides and will bow the board. I'd use a piece of new MDF under it (these are more than flat enough) and clamp that and the lens board with setup clamps to the table. If you don't trust MDF a piece of flat alu. Same for putting it on the lathe, use the face plate and clamps.

A boring head is also an option. But I'm not a big fan of those.

And for something like a lensboard a smaller machine will do the job as long as you have enough space to clamp the piece. Just measure as you go along. Just go slowly, don't rush.

[Bernice Loui]

Don't do flimsy sheet metal lens boards. The cast aluminum Sinar ones with raised Sinar lettering has never been any issue being held in a vise or four jaw chuck if done carefully. Setting up sheet metal to be worked on in a machine tool demands making a jig to fully support the flimsy sheet of metal.

Thick wood lens boards can be held in a vise or four jaw chuck OK, if done with great care.

Better way to put holes or shapes into sheet metal is water jet or laser. Traditional hole making in sheet metal is to punch, which has a completely different set of problems. Shearing action cutting tools do not do well at all with sheet metal.


Boring heads work, skill, knowledge and proper tooling is mandatory to get good results. Nifty boring heads like the T100 series are made by D'Andrea in Italy. These allow very precise movement of the cutting with the machine tool spindle running. The T120 has power feed options.

Regardless, the proper machine tool for this job remains a Lathe.

Bernice





While I agree with most said, I would never put a thin, flat piece like a lens board in a vise. A vise clamps 2 sides and will bow the board. I'd use a piece of new MDF under it (these are more than flat enough) and clamp that and the lens board with setup clamps to the table. If you don't trust MDF a piece of flat alu. Same for putting it on the lathe, use the face plate and clamps.

A boring head is also an option. But I'm not a big fan of those.

And for something like a lensboard a smaller machine will do the job as long as you have enough space to clamp the piece. Just measure as you go along. Just go slowly, don't rush.

[Peter De Smidt]

So, let's sum up: use tools properly. If you don't, there might be a problem. I'm glad we have that settled.

[Bernice Loui]

Precisely.. Choice of tool used is lesser than being resourceful and applying the tools with proper care and consideration for the consequences of what is possible.


Bernice


So, let's sum up: use tools properly. If you don't, there might be a problem. I'm glad we have that settled.

[Drew Wiley]

I mount the lensboard to a much larger wooden board using four perimeter sheet metal screws with metal-cap rubberized washers. This holds the lensboard completely tight without marring it at all. Then the wooden board is what is tightly clamped to the drill press table. This also allows a cleaner cut by the bit entering the board at the end of the cut, rather than pushing the metal through. Not as elegant as a milling machine, but good enough. One does not punch diecast alloys; leave that technique for electrical box knockouts.

[Bob Salomon]

I mount the lensboard to a much larger wooden board using four perimeter sheet metal screws with metal-cap rubberized washers. This holds the lensboard completely tight without marring it at all. Then the wooden board is what is tightly clamped to the drill press table. This also allows a cleaner cut by the bit entering the board at the end of the cut, rather than pushing the metal through. Not as elegant as a milling machine, but good enough. One does not punch diecast alloys; leave that technique for electrical box knockouts.

A good Greenlee punch can make a good hole in a metal board if used properly and without excess force.

[Drew Wiley]

You mean an old Greenlee punch. Greenlee is now mostly just a marketing label for things made on another continent in the same bit factory as half a dozen or more brands.

[Bob Salomon]

You mean an old Greenlee punch. Greenlee is now mostly just a marketing label for things made on another continent in the same bit factory as half a dozen or more brands.

That’s why I said good.