Greetings and a very happy Friday to all.
Today's project is to hog out holes in the pole mount solar panel rails.
I am using a pair of H beams on an 8' trailer axle (no camber) to set angle
of panels towards the sun. One beam rides on each end of axle. I have to
drill a 1.5" hole through the 0.170" webs in order to mount the bushing.
I am thinking to use a Milwaukee hole saw. Go slow with lots of water to c
ool it. Does this seem reasonable?
More reasonable would be water soluble coolant made for cutting metal
or cutting oil. Plain water by itself won't help with the cutting.
Hardware stores usually sell little one pint jugs of thread cutting
oil. It will work just fine. Don't use motor oil or any type of oil
that's made for lubricating. Use an oil that is specifically made for
cutting. Your hole saw will last much longer. The threading oils sold
in hardware stores is usually sulfurized. This type of oil actually
gets between the cutting surface and the work, making the cutting
easier and greatly slowing the wear of the cutting tool. Plain water
will not do this and will in fact just boil away from the hot chips
and cutting surfaces.
Cutting dry works too, as long as you keep the speed down. I drilled
holes for up to 4" conduit in steel electrical control boxes without
any cutting oil or coolant which would have run into inaccessible
places. Go slow and expect the saw to grab.
What Eric said.
Also, hole saws suffer from not being able to clear the chips. Pecking
works, but even better is to drill a couple of small holes, 5/16 would
be good, touching and inside the kerf of the hole saw. They will let
the chips that build up in the saw teeth gullets to drop out.