Dremel me this, Batman...useful bit for widening lens board holes?

[Mark Carstens]

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!

~Mark

[Jon Wilson]

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]

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]

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]

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]

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]

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/Attachme...Accessories/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.

http://www.dremel.com/en-us/Attachme...l.aspx?pid=115

[Mark Carstens]

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.

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.

~Mark

[Len Middleton]

Mark,

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),

Len

[cobalt]

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.