Enlarger focusing knob extension

bence8810 · Feb 2, 2016

Hello all,

I have a Lucky 90M-D enlarger - quite popular unit here in Japan.
It works great and the only one complain I have is that it's not equipped with a focus knob extension - the kind of flexible rod that's attached to big enlargers so you can focus when the head is high up.

When I print 20x24's which is more and more often, I really have to stretch my arm up to focus and it isn't exactly comfortable.

Are there any products out there I could use, even if not specifically designed for Enlargers?

Please see a picture of what the focusing knob looks like. It comes with two wheels, the larger one moves the bellows quick and the smaller one is for fine focusing only. I'd like something attached to the smaller knob as I can set the focus pretty close by just watching the image form on the easel and I'd use the extended smaller knob for fine tuning with the grain focuser.

Any tips are welcome!

Thanks,
Ben

calebarchie · Feb 2, 2016

Have a play with a flex shaft and maybe some uni joints if you can find a way to attach it to the handle or even remove it - hard to say without a better picture and disassembly.
Be creative and good luck.

RobC · Feb 2, 2016

there are tall grain foccusers exactly for this purpose. I have also heard of people using a drive belt of some sort which hangs down from the focus knob (which could be replaced with a pulley which the drive belt fits.

http://www.ebay.com/itm/New-Paterso...038995?hash=item1e7088e693:g:7SEAAOSwPTlTzTUB

paul ron · Feb 2, 2016

if its a course/fine focusing system it must be geared somehow. perhaps a flex shaft on the fine center shaft where the center knob attatches is a good solution. i see a set screw on the center knob, what size shaft is it?.

have you opened up the focusing mechanism to see how it works?

have you looked into a motorized accessory for this enlarger?... or maybe adapting one to it?

AgX · Feb 2, 2016

You could try to find in a hardware store a long steel helical (-spring). Attach a knob at one side and an adaptor to the existing knob/axle on the other.
Another approch would be with a rod and a cardanic joint.

Basic problem with likely all solutions would be play/lag.

ic-racer · Feb 2, 2016

McMaster Carr has flexible shafts but somewhat expensive, probably more than the enlarger.

These cost about double the shafts from McMaster Carr:

You can also wrap some rope around the knob and twist it that way:

mdarnton · Feb 2, 2016

Instead of the fancy spring idea, I'd try to find a two-foot-long or so piece of hose that slides on tightly over the smaller knob, and try that as a flex shaft. Flopping around might cause a problem, though.

mgb74 · Feb 2, 2016

At the community darkroom I volunteer at, there's a flexible shaft with knob that (I think) came in with a late model Beseler 4x5. I believe it's exactly for the purpose you mention. A google search found these:

http://store.khbphotografix.com/18-...nd-Beseler-Flexible-Focus-Extension-Kits.html
http://www.ebay.com/itm/12-Flexible-Focus-Extension-for-Beseler-45V-XL-Enlarger-/111153560415

So the question is whether you can remove your focus knob and what is the diameter of your focus shaft.

paul ron · Feb 2, 2016

mgb74 said:
At the community darkroom I volunteer at, there's a flexible shaft with knob that (I think) came in with a late model Beseler 4x5. I believe it's exactly for the purpose you mention. A google search found these:

http://store.khbphotografix.com/18-...nd-Beseler-Flexible-Focus-Extension-Kits.html
http://www.ebay.com/itm/12-Flexible-Focus-Extension-for-Beseler-45V-XL-Enlarger-/111153560415

So the question is whether you can remove your focus knob and what is the diameter of your focus shaft.

perfect solution!

fyi, the focusing shaft for a 23c is 5/16".

AgX · Feb 2, 2016

Dunco also offer a flexible shaft for their enlargers as accessory.

outwest · Feb 2, 2016

I used a hardware store spring clamp with a dowel taped to it.

RobC · Feb 2, 2016

it would be a lot easier to just buy a tall grain focuser.

ic-racer · Feb 2, 2016

The Patterson elongated grain focus device won't work if the focus knob is more than 12" away. It also won't allow one to view the edges of the negative. Doing a high power enlargement requires observation of all 4 corners with the magnifier to make sure you are in the image circle and to ensure the negative is in focus on all 4 corners and the center.

RobC · Feb 2, 2016

ic-racer said:
The Patterson elongated grain focus device won't work if the focus knob is more than 12" away. It also won't allow one to view the edges of the negative. Doing a high power enlargement requires observation of all 4 corners with the magnifier to make sure you are in the image circle and to ensure the negative is in focus on all 4 corners and the center.

12" ? Are you a midget?

aoresteen · Feb 2, 2016

Beseler makes a remote flexible cable kit for the 23C. Beseler part # 8204.....Remote Cable Kit

http://www.bhphotovideo.com/c/product/4147-REG/Beseler_8204_Remote_Cable_Kit_for.html

Patrick Robert James · Feb 2, 2016

The Saunders/LPL extension I have for the 4550 fits over the fine focus knob, which might just work for you. Or at least could be easily fixed with some epoxy.

bence8810 · Feb 2, 2016

Thanks for all the replies.

I don't really want to pay $200 for this, I got the whole enlarger for $70 with lenses / easel etc.

The torque tool looks very interesting from above - thanks for posting!
I was also thinking about carving the knob's shape out of wood at the top of a long stick and padding it with rubber for grip. It'd look like a fork that I just push onto the knob and then turn like an arm. Not sure if it's feasible but certainly the simplest thing to do.

I was wondering with my lost if there was something ready made like the original focus extender for other appliances or for car mechanics but I guess nothing at a reasonable price.
I also though about the little rods they use for window shutter curtains to move the blades.

All great ideas above - thanks all. I'll keep posting back with what I source and I am happy to hear of new ideas.

Thanks,
Ben

calebarchie · Feb 3, 2016

http://m.ebay.com/itm/Extension-Cor...l-Polishing-Chuck-FS-/221856984546?nav=SEARCH

RobC · Feb 3, 2016

another option is to use a wide angle enlarging lens (shorter focal length) which covers the neg format but doesn't require the head to be so far up the column for the same size enlargment. Combined with a tall grain focuser it should work fine contrary to what some are saying.

MartinP · Feb 3, 2016

ic-racer said:
Doing a high power enlargement requires observation of all 4 corners with the magnifier to make sure you are in the image circle and to ensure the negative is in focus on all 4 corners and the center.

Why not just use the right lens/condensers and also align the enlarger?

I expect most enlarger manufacturers have made flexible or extended focus handles that could be bodged in to working on the OP's enlarger. Probably the only one that didn't is De Vere, as their head-height and focussing handles are located at the front of the baseboard and don't move up and down because they operate remotely all the time. Very, very convenient

A piece of flexible neoprene-hose that can be clamped to the fine-focus knob with a hose-clip is likely to be the simplest solution for the OP.

RobC · Feb 3, 2016

also it might help if you told us the neg format size and the focal length of your current lens.

paul ron · Feb 3, 2016

I was searching flexible shafts n saw there are shafts for socket wrenches going for a few bucks. If you're handy, just adapt it to fit your needs. Im sure a set screw bushing will work as a connector... either electrical or plumbing hardware.

I just may make one for my enlarger!

AgX · Feb 3, 2016

These wrench shafts are very stiff as they are intended to transfer completely different forces.

paul ron · Feb 3, 2016

but a 1/4" shaft will be more flexable than a 3/8th.

AgX · Feb 3, 2016

I was thinking of 1/4" size. Those wrench shafts are not supposed to be bent by 90°.
Neither are focusing stages designed to take up great forces.

Enlarger focusing knob extension

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