Bicycle grinder for blacksmithing – how mine works

It can grind wood, steel, antlers etc. + polish steel to mirror finish. Use 60 and 400 grid emery cloth and a leather belt with coarse compound. Open the full video description for more information.

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The frame is made in wood (oak), steel and stone is taken from an old grinder, the bicycle is just an old normal one. I have made 3 grinders like this one over a period of two years. One rotation on the bike rotates the stone 3 times. I use emery cloth instead of the sandstone, because it remove material a lot quicker and also allowed me to grind materials like wood and antler. I have a few improvements in mind in case I will make another one at some point the future… like attaching the emery cloth with wedges instead of tape and refine the look – but over all does it work fine.
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A few quick questions:

1. Do you oil it?
Yes – I oil all moving parts once in a while. You can feel and hear whenever it is needed… In my case does the bicycle chain need oil a few weeks apart and the stone bearrings only need grease a year or more apart.

2. Why not make the setup able to free spin?
It is a lot safer that the grinder only runs when you run the bike. Also handy that you can run the stone both ways and that you don’t need to wait for the stone to stop spinning. Also makes the design easier to make.

3. Why not make it run faster and why not add gear options?
I didn’t consider it important enough and it also makes the design a lot more complicated to make. I use pressure against the stone instead of gear/speed – it works well, but I would like to eksperiment a bit with speed and or gear if I at some point make a new grinder.

4. Why not cut the emery cloth in an angle?
I have found 90 degrees to be the strongest. If I cut it at an angle is the emery cloth corner more likely to bend/more likely to catch what I am ginding and the emery cloth fall off – it is after all just hold on by tape.

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Location: Denmark – my own properly.

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Video gear: Nikon D7000, Nikon 50 1.8, Røde videomacro, iMovie.

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