So, this guy I worked for 15 years ago had this special tool for boring through the soffit and roof for a 2" service mast. It was more than just a hole saw extension which I am using now. Does anybody have such a gizmo, and is anybody still making it. Or is it something I need to weld up in the shop.
I've done that as well, but the pilot bit always seems to wander
One guy claimed to have welded a hole saw to a piece of 2" pipe, allowing for a better alignment. Maybe. Be interesting to see how he kept it sharp - my hole saws seem to survive but ONE encounter with the gravel on shingles ... and I'm still looking for an easy way to get the tar off them!
Now ... I just might ask a machine shop to bore a piece of 2 1/2" aluminum round to fit over a hole saw extension.
I used to drill the soffits out until one day I tried using my roto zip with the saw guard removed. I trace the hole first using the plastic thread guard off the end of the conduit for a template. You do need to climb the ladder, but it works like a charm.
I use the same method as Bill - the long 1/4" bit as a guide hole. You just have to keep that baby super sharp to avoid wandering when you get to the angled roof sheet.
WD-40 works pretty good at getting the tar off of your bits if you don't want to pull the shingles before you start. Gasoline works even better, but the flamibility factor makes it impractical. Never clean a hot bit either way!
I've seen these but they were home made at a local machine shop. They consist of a piece of intermediate conduit approx. 4 - 8' long with bushings pressed in each end. There is a 3/8" or 1/2" shaft that passes freely all the way through the pipe. The shaft is quite a bit longer than the pipe and is held centered by the bushings. On one end of the shaft is welded the sawed off end of a bit extension. This is where you attach the hole saw bit. The other end is chucked up in your drill. To use you just strap the conduit to the wall where your service mast will go, level it, chuck the shaft up to your drill, and go. It drills a perfectly aligned hole through both the soffit and the roof. Works great on spec homes where you can just punch them all out in a row.
I also use a long 1/4" bit as a pilot. I use a hole saw on the soffit for a tight fit then I use a hole saw and a sawzall on the roof. The flashing covers the hole and making the top hole bigger allows you to move the mast around to get it plumb. There is a company that make a hole saw arbor that accepts 3/8 all-thread for extensions up to 10 feet. I have seen ads in the back of magazines like Electrical Contractor or EC&M.
I like the way this idea is developing ... an extra-long guide, not only to line up the two holes, but to also locate them exactly where the panel needs them to be!
It's a bit of a change in our sequence .... the 'normal' way seems to be to place the panel first, and then decide where to place the holes .... and with this device, you would first place your mast supports, then drill, then set the box. Or, maybe, set the box, mark, remove box, drill, mount again.
Still, though, it looks like a great way to get it done better, quicker - and smarter!
I always do the mast first. Then plumb up the meter socket with the mast attached. I can move the meter socket up and down and left to right to get it just where I want it. THEN I mount it. This is of course, is so long as the hole below the meter socket into the house is not critical.