Rope Meter - DIY

If you despise measuring your rope inventory on the driveway as much as I do, here’s an inexpensive alternative. It took about two hours to cobble together after purchasing the required items.

Neat! Did you dismantle a pulley for that tensioned wheel part? How accurate do you feel it is? Is there any concern for the rope slipping or the tensioner not providing enough tension as you pull the rope through? Ive always considered making something like this, but feared that it wouldnt reliably get me accurate measurements.

It could also be benifcial to add an eye screw closer to each end to keep the rope aligned on the wheel and allow the rope to have better contact with the wheel.

Yes, the Petzl tandem pulley I dismantled had a wobbling sheave on one side (bearings around inner race broken down, notice the bearing pack is missing in the pic). The defective one is in the still picture overlay in the video.

As far as accuracy of measurement? I was satisfied with the margins. I ran both ropes through the device twice. The difference in measurement was between 2-3 tenths of a foot. For example, the Canyonero measured by the device at 98.1/98.2 feet. When measured by hand it measured 97' 10".

Nice diagram. The compression springs on both sides of the idler pulley squeeze the rope fairly tightly to the measuring wheel. A 2nd eye bolt on the exit side would be nice though.

Good work my friend.

My beef with many rope measurement tools is that people do not calibrate them on a regular basis, and to the task at hand. We TRY to make our measuring tools accurate across a wide range of rope sizes and properties - whether we succeed or not is another matter.

One thing helpful here is that the measuring wheel has a flat surface and therefore is diameter independent. You could use different idler wheels for smaller diameter ropes, if needed.

Tom

Copy that.

I typically mark all ropes with a standard set of rings (100/50/10) which indicates what it measured at purchase. One end signifies the length the other has a single ring. If one of these markings is absent then I remeasure.

Probably won't be seeking certification for this metrology tool, but it does add a measure of convenience and confidence. I recently cut up a 1200' piece of rope into smaller units to give away to individuals for their backyard vertical practice gigs. It was at that time I decided to make this contraption and didn't want to spend $500 on the professional metering devices out there.

I've always just broken a rope in on a few canyon trips and then layed all uncensored Ropes in a parking lot with a long tape and then put each rope in its own bag and labeled the bag. Makes it easy to get ready for trips and also in the canyons as anyone can just read the bag and know what they are dealing with

I periodically check my rope meter against a measured standard with a bit of measured rope. I’ve found that it’s been predictably accurate to within its cited accuracy. It’s consistently within +\- 1% for the 4 years I’ve owned it. It remains consistent with everything from 1/8 cord up through 10mm rope and even 1” webbing.

Not that there is anything that would come out of calibration unless the toothed measuring wheel were to mysteriously change size on me.

This practice came about by accident when I was curiously measuring webbing and rope before and after being handled off the spool. Rope does indeed shrink the second you start handling it. Webbing less so both shrink markedly after being run through hardware. A descender for rope and a buckle for webbing. Kind of interesting.


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And which brand do you have?

Olympic 1450


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