Cat 777D Mining Truck

[9W Monighan]

Originally Posted by modelman

sparkycuda-thanks and you are right. The motors in the wheels save a lot of space and that is very important on this build. Pugs-I don't know what a forming tap is. I used new hss taper-bottom taps. My chart does not go smaller than 2-56. What size drill bit do you use with 0-80 taps? I used a #60.

Tom, On my 0-80 adventures I started using a #56 (.0465") drill but broke taps occasionally but when I got the correct size: 3/64" (.0469") that did the trick the extra .0004" made a difference in steel. I also took the Dewalt drill and ran the 3/64 drill into the holes to possibly remove a tiny bit of the burr or what ever was on the holes after drilling in the mill. On your aluminum it may be tricky to not get the tap stuck. I use Cool Tool on steel and Alumatap on Aluminum for fluid. Brass I tap dry. Are those holes blind? That makes a bigger challenge to be able to get the chips out. You'll have to turn some then back out several times to keep chips from packing in the bottom.