Thursday, 13 November 2014

Teething Problems

Today the long-awaited steel spring guide arrived, so I got to open up the AUG gearbox. Again.

Some violence and swear words later (I only had to reopen the box once because the trigger return spring got out of its hole), I actually had, on the table, a real-life closed gearbox with an M135 spring, steel spring guide, aluminium piston and piston head, and an o-ring nozzle in there.

Now I would just need to see if the default motor was strong enough to wind the whole thing. Since the MOSFET setup didn't really work after attempts one and two, I've decided to look into it later, and thus soldered the wires back to their original places.

I plugged in the battery and hesitantly pulled the trigger: The motor gave a short whine, the piston moved maybe a centimetre backwards, and then everything fell silent. Pulling the trigger didn't do anything anymore.

After some troubleshooting I looked at the fuse and it was very obviously blown. At first I just thought that the motor had too little power to pull the heavier spring, but decided to open the gearbox (again) to see if something else is wrong. Maybe the piston was still getting stuck to the sides.

And it truly was, but not the way I thought. I had shimmed the gearbox a bit wrong. The sector gear was riding a bit too high, and the piston had a lip overhanging the rack. What happened was the sector gear dug into the piston and the fuse naturally blew once the tension got too high.

You can see the dents where the sector gear teeth have dug into the piston body

So now I'm going to need some new fuses. And I've just ordered a high torque motor, just to be sure. The gearbox shall now wait until I get everything, I just don't have the energy to start mucking about with the trigger right now.

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