For those folks looking for a shutter for their brass barrel lens...
I can offer factory new 100% reliable 3-1/2 inch #6 Packard shutters on a front mounted baseboard,
with a custom sized clamping collar to fit your lens perfectly without vignetting.
Watch a #6 Packard (on a Cokin style mount) here:

The complete assembly is light weight (340g, 12oz), stable & secure.
A textured rubber belt under the nylon screws gives a secure grip without marking the lens barrel.
The timing pin can be inserted from either the front or back of the shutter.
A similar arrangement for smaller Packard shutters (3 inch, for example) is also available.

The complete 3-1/2" shutter assembly with clamping collar, #6 pin, bulb, & rubber tube: $298 + shipping.
The Board only, with a custom sized clamp collar (you mount your own 3-1/2"shutter): $98 + ship.
The #6 Pin assembly (Pin with chain, acetal fitting, & screws): $20 + shipping

The photo shows a unit sized for a 250mm, 335mm, 500mm, or 1000mm Wollaston lens.
Need something smaller? Ask for a quote. Your custom sized collar will be similar.