by William Billingsley (Team 6061)

I heard a lot about the 18v Dewalt motors before I bought some for my robot. My bot has two wheels and when I installed my motors I noticed it was hard to drive in a straight line. These motors have advanced timing in the CCW (counter-clockwise) direction of about 15 degrees. In a tank style setup, the advanced timing caused my bot to run faster on the left and slower on the right side when going forward and faster on the right and slower on the left when going in reverse. You could re-time both motors to neutral but I decided to re-time one motor to "match" the other but in the opposite direction so I'll end up with two motors that when put face to face will go "fast" forward and "slower" in reverse. Phasing is adjusting the position of the motor brushes in relation to the magnets.

Here's how I did it:

1.	First I removed the brushes from the motor with a screwdriver (see photo 1).

2.	Then I removed the material that keeps the motor together. I used some wire cutters and a Dremel tool to do this. Make sure you tape the motor openings so metal fillings don't drop inside. A can of air will blow out the motor when your done. I also used wire cutters to "pinch" some areas. Take your time and make sure all material is removed.

3.	Now you can pry the top up by placing a tool inside the vent and prying on the raised pry point (see photo 4). Be careful and pry on each four points a little at a time. You should see the brush holder coming off. Remove then put aside. I ended up breaking the two arm parts off of the brush holder so be careful.

4.	To turn the brushes approximately 30 degrees clock-wise you have to make room for the brushes in the motor housing. Use a cutting wheel and remove one post from each side of the motor housing but make sure you remove the ones on the right as you hold the motor in your hand. Then enlarge the brush opening by cutting out the area to the left of the existing opening (see photo 6).

5.	Now you can put the brush holder back on and line it up on the post that remains. You can adjust the degree of timing you want depending on where you drill the hole through the brush holder.(See photo 7).

6.	Next step is to drill a small hole so get a small drill bit and tap set Size 4-40 and you're all done.