View Full Version : Dremel me this, Batman...useful bit for widening lens board holes?

Mark Carstens
20-Jan-2009, 20:25
I'd like to widen the already-bored holes in two of my cast aluminum lens boards (Technika style and Arca 171mm). Can anyone here suggest a Dremel bit that works well for this?

Thanks in advance!


Jon Wilson
20-Jan-2009, 20:37
I believe it is the carbide bit. I don't have the original packaging for it. I have used this one to open up and smooth my technika style boards. I found my at the local hardware store and have seen them at Home Depot. Jon

John Schneider
20-Jan-2009, 21:49
I'd pass on the Dremel and instead get a good half-round file for aluminum. Get it from an industrial supplier, not Home Depot etc. Mcmaster's 4218A17 and 4218A18 are good for instance. You'll have more control and get a rounder hole than a Dremel, and it'll probably cut faster as well.

matthew blais
20-Jan-2009, 23:29
I use a drum sander attachment on a drill press position on my Shopsmith.
I hold the lens board and move around against rotation to get the evenness.

So, drill press would be my recommendation.

Ralph Barker
21-Jan-2009, 09:10
From what size to what size? That is, how much material do you need to remove? If more than a millimeter or two, I'd liken the Dremel to a saber-toothed mouse attacking a woolly mammoth. ;)

Personally, I'd clamp the board in an x-y vise, in turn clamped to the table of a drill press, and use a hole saw close to the right size. Then, finish off with a good half-round file.

Steve M Hostetter
21-Jan-2009, 09:36
Irwin speedbor mortising drill bit in a drill press with lens board C-clamped tight to the
drill table..
Same procedure for a hole saw bit if you like

Jan Pedersen
21-Jan-2009, 09:44
I have made several lens boards from Alloy plate and have found this one to be the best tool for the Dremel http://www.dremel.com/en-us/AttachmentsAndAccessories/Pages/AttachmentsDetail.aspx?pid=115

Carbide is not good with alloy, it will soon be melted into the tool and will loose all it's grinding capability.
Make sure you keep the 115 as cool as you can, apply a little lube and it will last a long time.
Good luck.


Mark Carstens
21-Jan-2009, 10:24
Thanks for the feedback, guys!

A drill press solution would be great...if I had one. That not being the case, I'm looking at Dremeling, filing or paying someone else to do it right. :p

The Technika board would be a Copal 1 expanded to about 46mm to accommodate an Ektar 135 WF in Supermatic shutter. So, about 2mm of material all the way around.

The second would widening a recessed Copal 3 Arca board (171mm square) to accept a barreled 24" APO Artar. That would be more on the order of 7-8mm all the way around to make a 80mm hole. Drilling is probably the better way to go for that one, now that I think about it.


Len Middleton
21-Jan-2009, 11:37

I guess it would depend upon how steady your hand is and your level of skill.
I find that using a small Dremel bit is slow and time consuming with it depending greatly on how well you lay / draw things out.

I found in my case even though I have a Dremel and the necessary bits, that the drum sander was the better solution.

Get a drum sander close to the size of the hole you have and you can check your progress with the mounting ring or lens / shutter itself. Your 46mm diamter hole is close to 1-3/4" so a 1-1/2" drum sander would be the close enough.

Like Matthew, I use a drill press, but you could clamp it in a vise sandwiched between two pieces of wood and put the drum sander in a drill.

My $0.02 (CAD, so discount accordingly),


21-Jan-2009, 12:41
I just enlarged a graphic lensboard hole today, in order to accomodate a 152mm Kodak Ektar. I used a simple fine round file. cost less than 3 bucks and about 10 minuites of effort.

matthew blais
21-Jan-2009, 13:06
Send the shutter and board on down to me Mark and I'll do it for you.
Cost - One snickers bar. :)

Robbie Shymanski
21-Jan-2009, 14:57
Dremel tools are a huge scam. They were designed for jewelers and model makers doing small work. Like tiny.

Money is best spent on a 1/2 round bastard mill file. It will remove material faster than the Dremel and you will have much more control. Also, the file is the better tool, so long as you also buy a file card or brush to clean the thing off. And there are no silly collets to deal with.

Added that the file is a better green solution. The only energy it consumes are your calories. No plastics. 100% recyclable.

Gary Beasley
21-Jan-2009, 15:45
Ditto on the file, and it's a good idea to scribe the new opening size on the board prior to cutting so you know when to quit.

21-Jan-2009, 16:56
I just enlarged a Shen-Hao aluminum Technika style Copal 0 board to a 46mm hole with a half-round file.

First I inscribed a 35mm hole (Copal 0) on some paper. Then I lined that up underneath the actual hole in the board. Then, using the centre of the circle drawn on the paper, I inscribed the outline of the larger hole on the board.

The filing might seem a bit masochistic, but I only had the one board and no other tools. It actually only took about 15mins, far from sensitive family ears....

Wilbur Wong
21-Jan-2009, 18:08
Another vote for half round file, either a mill or a mill/bastard cut and a bit of patience.
Be careful of anything rotating inside the hole that is very nearly the size of the existing hole. If it binds and you are hand holding it, the board will do a number on whatever is holding it, preferably not your hands, but you're not using a drill press anyway so that's a moot point.

Jim Graves
21-Jan-2009, 18:31
Ditto #3 on the file ... get a good 1/2 round that approximates the arc of the size hole you're expanding. The results will be much more even and controllable than with a power grinder ... and ... at least in my experience ... it's just as fast. The 1/2 rounds that I use actually say they're made for wood but they work well with aluminum also.

I handhold the board, do 1/4 turns with 1, 2, or 3 strokes per rotation doing a long sliding stroke across 1/4 of the circle ... I go slow as I approach the correct diameter (it's very easy to get impatient and get it too big ... been there, done that ... several times) ... I check the new hole against a circle on a card or piece of cardboard so I can correct any lopsidedness (I'm sure that's not a word ... but you know what I mean) ... you can make it pretty precise just eyeballing it.

Mark Carstens
21-Jan-2009, 18:32
Wow! Thanks again, everyone!

Matt, I think I found a Snickers bar under my six year old's bed... I'll send you an email.


21-Jan-2009, 19:34
The only energy it consumes are your calories.

So that must be why Matthew is willing to work for Snickers! :D

21-Jan-2009, 20:27
Money is best spent on a 1/2 round bastard mill file.Now we are talking cheap and easy Mill Bastard File will do it fast and clean on aluminum!

Mark Carstens
21-Jan-2009, 20:29
So that must be why Matthew is willing to work for Snickers! :D

LOL...Good one.

Your secret's out, Matt.

Bummer, dude.

matthew blais
21-Jan-2009, 22:07
I may be cheap but I ain't easy...

22-Jan-2009, 11:25
I just enlarged a graphic lensboard hole today, in order to accomodate a 152mm Kodak Ektar. I used a simple fine round file. cost less than 3 bucks and about 10 minuites of effort.

You and I cobolt think alike. Leaves more $$ for film.

Elbow grease man, just use some elbow grease.