Tallabomba Blog

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Sunday, June 29, 2008

DIY project: Ultralight pot gripper

After reading forum threads on pot grippers I decided to get my old MSR gripper out, and start thinking about how to make it lighter without loosing stability. The original version weighs about 45 grams (1,6 oz). The Trangia version is 48 grams (1,7 oz). A new MRS gripper, the Litelifterâ„¢ weighs 28 grams (1 oz) according to their website.

Improvement of the old MSR gripper: I started with filing off the rivets that holds the two pieces together. Then I filed off unnecessary material around the edges of each piece, and mad the holes larger where the stress would be lower. I was careful at the front of the gripper, near the axle, where the stress is high when a heavy pot is lifted or tilted. The advantage of using a file for the holes is that you can shape them in any way you like to optimize the strength to weight ratio. I also shortened the gripper from about 125 mm (4,9 in) to 112 mm (4,4 in). The rivets where replaced with a small screw and nut.

After a few sessions with filing and testing I got the weight down to 31 grams (). I could not notice any problems, even with heavier loads. I started to suspect that the design is very over-dimensioned, at least for use with smaller pots.

New pot gripper prototype: Next step is to build a new gripper from scratch in a thinner material. The original's material thickness was 2 millimeters (0,08 in). I chose a 1 millimeter (0,04 in) sheet of aluminium/aluminum for the new version. I also made the new version a little shorter and narrower. The new length: 105 mm (4,1 in). The length can be shortened more or less depending on how the gripper is used. I eat from my pot, and hold it with the gripper during a meal (or while it's still hot), so I need a good comfortable length.

The width of the handle of the old MSR gripper was 24 mm (0,9 in) and the the new version is 18 millimeters (0,7 in) wide (not including side supports at the front).

The material I used came from the tube from an old vacuum cleaner. I cut off two pieces of tube (120 mm / 4,7 in each). Then I shaped the two pieces with a vise, some pliers, and a hammer. The details and holes where done with files and drill bits. After some work I had pieces looking like this:

DIY pot gripper parts
The parts after some cutting, shaping, drilling, and filing. Weight: 18 grams (0,6 oz).

After even more drilling, filing and testing, the gripper looks like this:

DIY pot gripper: 26 grams (0,56 oz)
The new ligher pot gripper prototype. Weight: 16 grams (0,56 oz).

Result: The new pot gripper weighs 16 grams (0,56 oz), and is very stable for both lifting a full pot, and tilting it (to pour contents). It's also comfortable to hold a pot while eating from it. I did not notice any problems for pots from 1-2 liters, even when full to the rim. It may be too weak for larger loads, but I have no pots to test with, and no need for that kind of strength.

Conclusions: The traditional Trangia and MSR pot grippers are over-dimensioned and too heavy. The clever design will be strong enough with thinner material, at least for use with smaller pots. It would be interesting to try this design with even thinner material in titanium.

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