Durst M601 Track Repair

eurekaiv · May 25, 2023

Does anyone know if this rubber track material (or something else) is available for replacement? I received the M601 enlarger as part of a darkroom lot and I’d like to get it repaired if at all possible, and I’d like to do so without cannibalising another enlarger.

ic-racer · May 25, 2023

One solution would be to cut out the offending portion and slide either the top or bottom piece together. Assuming there is no engagement of gears needed at the very top or bottom.

eurekaiv · May 25, 2023

That’s a great idea, unfortunately, it’s damaged like the pic in multiple places top to bottom and I imagine I would lose ~50% of the travel at that point.

Paul Howell · May 25, 2023

You might be able to have one 3D printed if you can someone who has a printer that can print with strong enough plastic.

Niglyn · May 25, 2023

Looks like a job for a 3d printer.

Other option is to look on bangood & aliexpess for suitable rack parts.
I purchased a bag of plastic cogs, gears & racks for tinkering.
You may get lucky and find a rack with the same tooth pitch, else you would need to change both rack & driving gear.

Alternate, is to mill a new rack. Would be really easy, using a piece of aluminium, but of course you need a milling machine.

ic-racer · May 25, 2023

I recently used https://3d.jlcpcb.com/ for some 3D printing and got excellent results. Cheap and quick shipping from China. You just need to either make the file yourself or get someone who does CAD in their 'day job' to lend a hand making the file from which they can print.

grahamp · May 25, 2023

The later M605 uses a hard plastic or nylon toothed strip of a similar profile, as best I can tell by eye. I think what you want is a gear rack (there must be someone with more engineering experience?) with the right pitch and profile.

ic-racer · May 25, 2023

Just to see what happens I opened up free TinkerCad and an editable rack and pinion from Thingiverse. Making an appropriate rack looks doable with minimum prior experience:

eurekaiv · May 25, 2023

I can handle basic CAD design and have ordered my own PCBs from JLC on many occasions. Didn’t know they were also in the 3D printing business, that’s pretty cool.

Knowing this is called “rack” might help with finding something pre-made if I can get some decent measurements from a section.

Melvin J Bramley · May 26, 2023

I have similar issues with Durst M670.
I tried the super glue / baking powder route with no success.
My experience with 3D printed parts is that they do not have the necessary hardness required for success.
The Durst M605 which I also have has the rack plus spring assist which makes it superior to the M670.
There are some Dust M670 racks for sale in the UK but they won't ship to Canada!
My M670 light source is about to become a hybrid with my M605; the remaining parts to be scrap.

Kino · May 26, 2023

Try McMasters-Carr: https://www.mcmaster.com/products/racks/

Ian C · May 26, 2023

You need a small metric module gear rack. You’ll have to read an article to determine which size you have. Then you need to specify the overall length, width, and thickness (depth). You’ll also have to figure how to mount the new part to your equipment.

https://www.google.com/search?q=sma...ACAAWmIAYwMkgEEMTkuMZgBAKABAQ&sclient=gws-wiz

Here is an explanation with diagram that explains how to measure the module of a metric gear rack.

https://www.hpcgears.com/pdf_c33/rack_pinion.pdf

Basically, you measure the pitch of 10 teeth and divide by 10π. Since this is a Durst (Italy) enlarger, you have to measure in millimeters.

ic-racer · May 26, 2023

eurekaiv said:
I can handle basic CAD design and have ordered my own PCBs from JLC on many occasions. Didn’t know they were also in the 3D printing business, that’s pretty cool.

I was very impressed by the 3d printing JLC did for my shutter/meter tester. The parts don't even look like 3d printing.

eurekaiv · May 26, 2023

ic-racer said:
I was very impressed by the 3d printing JLC did for my shutter/meter tester. The parts don't even look like 3d printing.
View attachment 339716

Interested in your tester, is this an open source project? I built an Arduino tester recently but it’s not reliable at speeds above 1/60.

MattiS · May 26, 2023

Don't forget to check the gear. There must be a reason for the damage of the rack. And determine the so called "Modul" of the rack, which is the distance from one tooth top to the next (as described before, measure 10 in mm and divide by 10 ). The result should be a full millimeter result. From there it should be straight forward to find or print the right rack.

ic-racer · May 26, 2023

eurekaiv said:
Interested in your tester, is this an open source project? I built an Arduino tester recently but it’s not reliable at speeds above 1/60.

The plans are all on GitHub. The physical part is open source but the creator provides the Arduino software only as a hex file.

However, his firmware is excellent. He duplicates most functions of the discontinued Kyoritsu tester.

Niglyn · May 26, 2023

eurekaiv said:
Interested in your tester, is this an open source project? I built an Arduino tester recently but it’s not reliable at speeds above 1/60.

look at my simple shutter tester on this site. It uses an Arduino, measures shutter curtain travel correctly and measures speeds well above 1/1000s. Gives averages, deviation, flash sync etc.

mwdake · May 26, 2023

That track looks awfully similar to the belt/track on the garage door I just installed this morning.
I’m wondering if they might be similar enough to work as a replacement.

Durst M601 Track Repair

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