Rusty Wrench to Collet Spanners




About: I am an electronics engineer, doing a PhD at the VUB in Belgium. I have a passion for making things, both useful and cool.

Recently, I got myself a CNC machine, which uses the common ER11 collet to hold the bits and drills. Tightening this collet requires 2 wrenches: 14 and 17 mm. I have a set of wrenches, but didn't want to dedicate those 2 to the CNC and be left with an incomplete set, so I needed a dedicated set of spanners. In my old tool pile, I found a rusty wrench with 14 mm on one side and 17 mm on the other and decided to turn it into a set of collet spanners. Let's get building!

Step 1: Parts & Tools


A suitable wrench, that's about it


  • Sandpaper, files
  • Dremel (rotary tool) with sanding drum
  • Metal saw (+ elbow grease)
  • Drill
  • 3D printer
  • Vice for work holding

Step 2: Sanding, Sawing & Drilling

As you can see, the wrenches I have laying around are quite rusty, so we'll need to get rid of this. So as a first step, we will sand the wrench and make it shine once again.

Start by sanding with low grid (coarse) sandpaper and work your way up to finer grids. This holds true both for manual and powered sanding. We want all surfaces to be shiny again. A dremel with a sanding drum works great for removing the bulk of the rust.

Since my wrench is 14 mm on one side and 17 mm on the other, I can't use both at the same time. So we'll have to cut it in half for starters. Use a metal saw and have patience, tool steel is quite hard to cut through.

We now have two wrenches of the right sizes, but the handles are obviously too short, so we'll make new ones. To have a way of attaching them to the wrench, drill two 4 mm holes 15 mm apart, 10 mm from the cut end. Again, let the drill do the work and have patience if you don't want to end up with a blunt drill.

Step 3: New Handles

We will 3D print the handles, so first of all a model has to be designed. The Fusion 360 file is included so that you can customize it to your specific wrench. Measure the size of the handle part and adjust the file.

It is recommended to print this at 100% infill, to give the new handles some heft and strength. The little pins should snugly fit in the holes we drilled earlier. When the fit is fine, add some super glue (preferably with accelerator) to fix the two halves together. We now have our two wrenches with nice handles.

Step 4: Use & Enjoy

We're done! We have turned an old tool into a nice set of collet spanners.

As you can see, they work great and the idea that we made them ourselves gives a lot of satisfaction each time we use them! I hope you liked the project and have found some inspiration to get some use out of your rusty tools!

Feel free to check out my other instructables:

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    4 Discussions


    1 year ago

    This inspires me. I have a bin of rusting tools that I could repurpose ! Thanks

    1 reply

    1 year ago

    these look very useful, definately worth getting the most use possible out of otherwise useless tools. personally I've no access to a 3d printer and so would have to opt for a wood handle, probably in a sandwich of three layers, with the middle layer being the thickness of the spanner. I might be tempted to go for a little bit longer in the handle, but I guess that depends on how much torque you feel you need. just a note on drilling metal, I always find it best to drill a small pilot hole and then work up to the size I want one size at a time, when ever possible with the help of a drill press, and with a few squirts of WD40 along the way to reduce friction heat.

    1 reply

    Reply 1 year ago

    A wooden handle wood definitely look great, Jimmy Diresta has some awesome videos where he does this.