Repairing a Bench Mount Hot Knife

When using heat shrink tubing, sleeving, and other cable management materials in high quantities, it’s nice to have some of your own tools at your disposal. Heat guns are a must-have for any heat shrink enthusiast, but many might not know just how important cutting machines can be. Heat shrink cutting machines come in all shapes and sizes, but one of the most common (and definitely the most manageable) is a Bench Mount Hot Knife Cutter.

Compact and stable, bench mount hot knife cutters are a simple way to cut your heat shrink tubing and other materials to the exact size you need for your projects. While these are great tools to have, they can also be a bit finicky.

If your bench mount hot knife isn’t heating up, you’ve come to the right place.

Our Founder & CEO, Marc Savoy, is here to give you the step by step guide for fixing a bench mount hot knife that isn’t heating up. Check out the video below, or keep reading to fix your own hot knife.

How to Repair a Bench Mount Hot Knife

Before we get started, make sure your bench mount knife is switched off, completely unplugged, and cooled down. Bench mount hot knives can reach upwards of 1200 degrees Fahrenheit, which can easily slice a finger off. So, safety first!

Now, let’s get started.

1. Remove the Blade

A bench mount hot knife blade being removed from its base.

To start, loosen and remove the screws in the mount that is holding the blade into place. The most common problem with hot knives that won’t heat up is that the blade itself isn’t fully connected to the base. By removing the blade, you can reposition it and tighten any loose screws to create a better connection.

To remove the blade, simply lift it out of the mounts and set aside. The blade mounts may come loose as well, which is fine.

2. Reattach the Blade Mounts and Tighten

Adding mounts for a bench mount hot knife blade back onto the base after removing them for repairs.

If the blade mounts happen to come loose from the base, now is the time to put them back. Place the mounts back into their respective sides, and screw them into place. Don’t tighten the screws all the way, though. Leave some room for the blade, and for any adjustments.

3. Remount the Blade

How to replace the blade on a bench mount hot knife.

Place the blade back into the mounts, ensuring that it is sitting completely on top of the pins underneath. As it’s being used, the blade on your bench mount hot knife can shift and move around if the screws loosen. If it moves around too much, the pins won’t be able to conduct heat into the blade, and it won’t work. That’s most likely what is going on with your “broken” bench mount hot knife.

So, make sure that the blade is sitting snugly on top of each of the pins. Tighten the loose screws, and add the other two screws back into the sides of the mounts.

4. Test the Hot Knife

Testing a newly repaired bench mount hot knife.

And you’re done! Now, making sure that the screws are tightened, plug your bench mount hot knife back in, and test it out. Your bench mount hot knife should heat up in a few seconds, and be ready to use.

If it doesn’t you may have some other problems on your hands. Thankfully, at

BuyHeatShrink, we sell everything you need to cut, shrink, and mount any cable management material. If you need a new blade for your hot knife or an entirely new one, we’ve got you covered.

Check out our list of Heat Shrink Cutting Products here.

Repairing a Bench Mount Hot Knife