How to Fix a Measuring Tape That Won't Retract (Broken Spring)

If you have a measuring tape which suddenly stops retracting (often leaving you with the tape part way out), there’s a good chance that the spring has broken. It’s a shame to have to replace a measuring tape because of this – after all, most of it is still fine! It turns out that, at least in some cases, it’s not too hard to fix.

• Broken measuring tape
• Assorted screwdrivers
• Needlenose pliers
• Some not-too-dear scissors
• Rubber band
• Intense heat source – fire or a torch
• Safety glasses
• Gloves if you’re nervous about cuts

While this project is pretty straightforward and safe, it involves heat and a long metal spring with sharp edges. I am not responsible for your safety. Take precautions to prevent being burnt or cut, and be alert to variations in how your measuring tape is put together – it may require a slightly different technique at some points.

Inside a measuring tape, the plastic reel (sort of a hollow pulley) that the tape wraps onto has a long flat coil spring inside it. The outside end of the spring attaches to the reel, while the inside end is fixed to the case by a post that goes through the centre of the reel. The spring wants to uncoil, so its resting position is when it’s wrapped up at the largest possible diameter – against the inside of the reel. When the tape is pulled out, the reel winds the spring onto the central post, increasing its tension. The attachment to the post is a high-stress point, and this is often where the spring breaks.

Since the break is at the end of the spring, all you have to do is form a new end to attach to the post. You need to be mindful that this will make the tape a few inches shorter, but it won’t matter in most cases.

Put on those safety glasses! And gloves if you want them.

Usually there are just a few screws around the outside of the case. Once you have them out, open the case slightly and figure out which side the reel wants to stay on. Hold it there while removing the other side of the case, and take care to not let the tape get loose and unwind from the reel. While it’s not as springy as the spring inside the reel, it’s mildly dangerous and very annoying if it all suddenly unwinds.

While pinning the tape to the reel, remove the reel from the case.

Wrap up any tape that was unwrapped when the spring broke, and put a strong rubber band around the tape on the reel to keep it from unwinding.

Hopefully, the reel will have a removable cover on one side. Pry off the cover using a slot screwdriver. As you do so, be very careful to not let the spring escape and unwind - it's very springy and sharper than the tape. If you find a broken piece of spring slotted into the central post of the case and a broken end on the inside of the coil of spring, you have a fixable situation!

Sadly I'm no expert on heat treatment of metal. However, I know that spring steel is hardened and then tempered at a relatively high temperature (~600° F) to a blue colour. In this state it's very springy but also somewhat brittle. If you try to bend a sharp corner in it, it'll just snap. To make the end soft and flexible so that you can easily cut it and successfully bend it, it needs to be annealed.

Unwrap about a foot of spring from the reel, being careful to hold the rest in. Then heat the last couple of inches until the tempering colours disappear, leaving the metal dull grey. I used a wood cooking stove, sticking the spring in through a gap in the feeding chamber, but a torch could work too. Be careful to not burn yourself on the hot end of the spring.

Cut the broken end of the spring square with the scissors. If that's not working, you probably didn't succeed at the annealing step.

Study how the spring was hooked onto the central post and replicate that shape in the end of the spring using scissors and pliers. Be careful to work only in the annealed section, but place your first bend close to where the annealing ends. In my case, the spring tapered to a slightly narrower width, then bent at a right angle and around in a "D" shape, with the upright of the "D" going through the post slot and the curved part hooking back around the outside to keep it from pulling out. Trim off any excess length.

Place the reel back in the case, attaching the spring to the post.

Remove the rubber band from the tape, and pull it out until the spring is applying enough tension to retract it - maybe 18" or so - but no farther. Holding the reel in place so it can't turn, wrap the tape you've pulled out back onto the the reel. When you're done, the spring should be constantly tensioned so that it fully retracts the tape.

Replace the cover on the reel. It likely just presses in.

Screw the case shut. You have a measuring tape again!