cutting lens flange

[S. Preston Jones]

I am going to mount a lens to a 4x4 board. The opening in the board will be 3 1/16 inches. The lens flange is aluminum and is 4 1/8 inch across. What in the best way to cut the flange so that I will be able to mount it with no overhang? Do I have to find some one who works in metal? Thanks for your help.

Preston

[wfwhitaker]

While it may be tempting to simply remove 1/16" of material along four sides of the flange to fit your board, don't forget that you'll need to remove more of the flange to clear the lens board retaining hardware which overlaps the board. Taking that deep a cut into the flange may be too extreme; you'll have to measure it and see. Another possibility, especially when using wooden boards, is to make the board thicker than normal by an amount equal to the thickness of the retaining hardware. You then can undercut the board to provide a recess into which the retaining hardware can slide. It's easier to show in pictures than to describe, but I've used this technique on a couple of occasions to get around having to have a flange milled. On other occasions I've simply had the job done professionally. That option, while more expensive up front, often results in a lot less frustration.

[Hollis]

if you can do it, draw the line you want on the flange with a sharpie, then grind it off.

[S. Preston Jones]

Thanks for the responses so far. The lensboard is wood for a 4x5/5x7 Deardorff. I have reducer boards for all of my view cameras to take the 4x4 boards. I should be able to remove 1/4 to 3/8 inch without harming the flange and the depth of the ring is slightly less than the thickness of the board. Would grinding be better than a metal cutting saw?

[Turner Reich]

Grinding allows for some control while metal cutting with a saw can be uncontrollable.

[Struan Gray]

I just use a hand file.

The only tricky bit is making sure you get the orientation of the flange right so that you can still use the mounting holes. Don't forget to allow for the heads of the bolts and any nuts on the back side.

[Vick Vickery]

The easy way is to mount the flange, then mark what needs to be removed, then remove the flange and cut/grind off the excess; but if you make a shim as Will suggested, you won't have to remove any stock from the flange...just let it hang over the edges.

[John Schneider]

You should never grind aluminum (or brass for that matter; both clog the wheel).

A good file made for aluminum (e.g., McMaster's 4218A13 or 4218A14) will make short work of it with plenty of control.

[James E Galvin]

When the flange is too big, I mount it upside-down. I use spacers on the screws, to hold the flange close to the lensboard. I use black shoestring wound around the flange behind the screws, and glue it in with black paint (for a light seal). Works fine with an Ilex #5 on 4 inch square Calumet boards.