Getting a Leica Hood back to Round

[alonbenav]

The V3 Summicron 35mm I just picked up came with the metal 12504 hood. But it is slightly out of round on one edge. Not a huge deal, but I'd like to get a plastic cap to go over the top of the hood, so a perfectly round hood would be nice.

Any resources for getting this thing back to round? And tips or tricks?

TIA

 

[Beemermark]

Ditch the lens cap

 

[Vickko]

It is tricky. To get metal to deform, you have to go past its elastic limit, and then it will spring back. So you gotta "bend it just a bit more than what you need". It is iterative. And at the end of it, you might never really get there. But you should be able to get close.

Oh, the tools you need - probably need to make your own. Something like the Filter Straightener tool.

Threads:

http://www.pbase.com/pganzel/diy_straightening_lens_filter_rings

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=000sIm

http://www.rangefinderforum.com/forums/showthread.php?t=2816

 

[Mute-on]

I successfully returned an IROOA to round using a broom handle off-cut. A piece of wood dowel about an inch in diameter would work as well.

Do this on a wood surface so you don't damage the hood surface.

I just supported the bent edge on a flat surface and gently rolled the broom handle across the dent. Some gentle tapping on the high point was necessary as the IROOA unvented construction is very rigid. Gentle tapping and rolling got the hood perfectly round. Take your time.

Cheers

J

 

[alonbenav]

Thank you all for your input. I'm going to cautiously attempt to get it back using mute-on's method.

 

[peterm1]

One thing I have done in the past is to use an appropriately sized hole saw bought from the hardware store (the cheap kind that fits on a power drill) to drill a hole the size of the outside diameter of the hood in an off cut of timber. Then using a saw, slice the timber through the hole so you now have a semi circle. This can then be placed in a vice so it's facing up like the letter U and used as a mandrel by placing the hood in it. I would normally use the piece cut from the centre of the hole (or a separate piece of wood appropriately shaped) as a former (by placing it inside the rim of hood and tapping it with a hammer. To do this with the 12504 hood is harder though due to the shape of the hood (sloping inwards). You might achieve it with some additional filing of the wood to match that shape. It does not need to be ultra precise. Just precise enough.

Here is a video of the kind of thing I do.

https://www.youtube.com/watch?v=JCCx7rSwC3s

It shows how to fix similar damage on a lens filter thread.

It is also possible to buy a metal tool for fixing lens filter rims. The two parts screw together to exert force needed but as you appreciate there is a cost which may not be worth it.

https://www.youtube.com/watch?v=mQ9Paz4zSD8