Cat 777D Mining Truck

[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.

[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.

[pugs]

Originally Posted by 9W Monighan

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.

Yet another advantage of form taps.....no chips.

They work good in steel too, I just don't usually have steel to tap.