Hello all. I've got a Haas VF-1, and I have a run of 12 pieces I'm doing. Not sure what the best way of going about doing them would be.
They are 3.07" long, and I need a hole 1.5" DIA all the way through. It doesn't need to be a good hole, it's just a clearance hole.
Material is 6061-T6
So far, I see myself having a couple options.
1. A 1" drill (with a .5" shank, in a .5" end mill holder, as a guy more experienced than myself recommended to not mount such a long tool in a drill chuck. Drill chuck is ~3.5" long, drill is ~4.5" long.)
So, would you first pre drill the hole with say a 3/8 drill, or just do it all with the 1".
It's a HSS bit, and I've never really used a drill this large before. SS of ~2000rpm and feed of 5 IPM? Peck drill at .25" increments? I'll be using flood cooling, part will be clamped on a mount flange at the bottom which is 3/8 thick. Then using a 3/4" end mill, with 2" flute cutting length, mill out the top half to the 1.5" OD with a G13 stepping down .5 per pass. Flip the part over, and finish the rest of the hole. I do have a 3/4" 4 flute end mill with 3.5" flute cutting length, but it chatters quite a bit.
I need to flip the part anyway to drill some holes 4 smaller holes.
2. Using a 2 flute 3/4" end mill meant for aluminium, peck drill out the middle, then G13 the rest of the way down, flip it, peck the rest, then G13 to finish it off?
Which one would you choose? Any other options? Pre drill for a 1" drilll?
Thanks for any suggestions.