If you have a pair of TA Pedals you’ll notice that they have very nice knurled aluminum dust caps. While the dust caps conveniently have grease ports you may wish to overhaul the pedal from time to time. The caps have three equally spaced notches for a spanner but are smaller than say a bottom bracket cup which might take a similar spanner.
Not wishing to mar the caps by using pliers and some kind of padding to remove them, I have searched unsuccessfully for the proper tool and not only haven’t I found one but I haven’t found any record of one in TA literature, etc. I decided to make a few by drawing them and having them cut with a laser cutter, which at least where I go is very affordable.
The place where I went takes encapsulated postscript files (EPS), so I just drew the wrench in AutoCad and then opened it in Illustrator and saved it as an EPS file.
Knowing that the laser has a slight width or kerf, I drew the shape at exactly the size of the dust cap, hoping that the thickness of the beam would remove just enough extra material to allow me to get the spanner on the dust cap. I had him cut these out of 16 gauge (roughly 1/16″ thick) stainless thinking that would be plenty strong enough.
When I got them back, they fit absolutely perfectly, but I noticed two small issues: 1) While 1/16″ thick stainless steel is probably strong enough, the dust caps are aluminum and teeth that thin would probably bite into the aluminum if I ever had a really stuck dust cap and 2) when the laser starts and stops a cut it removes a bit of extra material. For whatever reason the laser started and stopped the inner cutout right at a tooth, weakening one of the three teeth on each spanner.
To solve both of these issues I simply glued two spanners together with Marine 5200, being careful to alternate the flawed teeth.
If you want to have some of these cut for yourself, here is the EPS file:
WordPress doesn’t allow EPS files, so I added the PDF extension. Download the file (right click on the link and save as…) and replace the PDF extension with an EPS extension and you can then open it in Illustrator.
One thing to be cautious of: if you make some of these, the kerf size increases with the thickness of the material, so the tool may fit too loosely. Check with the laser operator. Currently the shape is drawn at the exact size of the dust cap and the kerf with 16 gauge stainless shrinks it just enough for a snug fit.