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double long hole saw
My problem has never been with the notcher mechanisms them selves,but with the damned hole saws that the industry forces us to use. I mean face it they are made mostly for one purpose to cut holes in 2x4 studs. Yet we metal workers have been using them for notching pipes and tubes for ages. Do they make them for us? Hell no. you can get any size you want so long as you don't expect to cut any deeper than about 2".
Well that just wont do if you are notching at any sort of angle through even just 1-1/2 " tube like we do here at HillJack Fabrication every day. ( OK it was a little plug. lol) so on to my HillJack solution. I take one of our worn out (tooth wise) hole saws. Put it in the lathe and cut of the teeth off about a 1/16" below the teeth leaving a bevel going all the way around the edge. It does not matter which direction the bevel is going so long as you have the second bevel going the opposite way so that the bottom nests into the top, or vice versa,when you put them together.
This is your alignment, so be careful to get it right. Then you have to take a perfectly good hole saw and cut the bottom off it. Again be careful to take as little off as you can and try to avoid the welded ring. Take it very slow. The hole saw walls cant take a lot of stress like the lathe puts on them. Once you have both halves of your new "HillJack Double Long" as I call them, you need to set them up in a v-block fixture, perfectly aligned and tack weld them together then sand / grind off the little weld bumps.
One of my tricks is I use some old rolled up sanding belt material with the grit facing out and place it tightly rolled into the two halves of the hole saw this then expands and not only holds the two halves pretty well together but also helps prevent letting the weld from making a bump on the inside of your hole saw too.
The sanding belt is then removed easily. Practice on an old worn out hole saw to get the heat right, I MIG mine at heat level 3, and 35 for the feed rate, on my Hobart Handler 190 if that helps you. You should end up with something that looks like this.
I have heard that JMR is trying to get back into making long hole saws again in January, but in the mean time this could help you get through. Yes you are using two hole saws but the first time you use your "HillJack double long", and it sails right through your tube, or what ever, in one smooth pass you will thank me for telling you about this. lol Oh and by the way, use lennox, most everything else is crap and we have tried them all.
PS: If you do find weld bumps inside your hole saw just use a dremel tool to grind them flush.
PSS: I weld the hole saws in about 8-10 spots around the saw.
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