Cutting Constant Force Springs

Any issues about shortening a constant force spring to save a bit of weight?



From what I have seen they can be a bit dangerous to cut if you don’t clamp them right, the edges will be very sharp and you run the risk of creating cracks/splits in the spring.

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We split the end from the hole, and cut a new end and drilled a new hole carefully with a Dremel tool.

Please don’t. In the grand scheme of things it’s only .5lbs of extra weight. It’s really easy for an uncut spring to cut someone, please don’t make a weapon that could remove fingers for slight weight loss.


I would not have a student cut a CF spring or try to handle a cut CF spring. Pretty dangerous stuff.

I have cut very low load (1-3lb) CF springs with tin snips and then filed off the corners, by clamping the spring firmly to a table. It was still a pain. This would be a last resort weight savings for me, would much rather not touch them. Quite frankly I would rather just not counterbalance the elevator at all if that was the last place I could save weight on the entire robot.


This is a “buy the right part” situation imo. CF springs can be scary.

I have seen them cut to width with edm. This seems to work fine.

If you are going to try this anyway I highly recommend practicing on some smaller ones before the actual article. All normal disclaimers about safety, leather gloves, face protection, etc.


If I had an EDM, I would have the resource to buy the right length spring. :slight_smile: