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- Good depth tracking requires very precise adjustment, so that as errors accumulate, they don't become significant.
- Electrodes and springs should not be touched.
To make a This custom screwdriver for half-circle/ half-moon screw heads makes adjustments much easier by breaking the step of getting the screwdriver onto the screw head into two steps:
- Roughly engage screw driver with screw head, correct rotation doesnt matter in this step.
- Gently rotate the screwdriver until it engages with the screw head and is locked into the same angle as the screw. It will slip a bit (~1mm) further onto the screw when it engages.
- Now you can apply more torque to rotate the screw.
To make the screwdriver for the 1mm OD half-moon heads used on the custom screws in the flexDrive, you'll need;
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- Get a piece of 1mm ID steel cannula, cut a piece to the length of the screwdriver that seems comfortable for you to use.
- make sure on end of the cannula is cut cleanly and has no sharp edges or burrs. Polish if necessary.
- The aim is to solder a screw into one end, so that it's head can engage the head of the screws on the drive. For this, cut a small opening into the side of the cannula, near one end. When you insert a screw into the cannula, you should see the threads through this hole.
- Clamp the cannula horizontally so you can see the opening you just cut.
- Insert the screw into the cannula, so that the head sits almost flush with the end, but is recessed by about 0.1-0.3 mm. This will make a ridge that will hold on to the screws even if the rotation of the screwdriver is 'wrngwrong' and doesnt engage the screw head. This way it's much harder to accidentally slip and damage the drive.
- add a tiny drop of stainless steel solder to the hole on the side. If the flux flows to the opening of the cannula where the screw head sits, you added too much - remove the screw, clean everything and repeat. Too much flux will make solder flow to the head and ruin the screwdriver.
- Add heated solder to the hole at the side..A lot of solder will wick into the cannula, so keep adding enough to make good contact with the screw, but not so much that it flows out the front.
- remove any solder sticking out from the opening with a razor blade or fine sandpaper.
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