A Notch In Time, page 3 of 4

Carson Smith of Speedway Motors agrees, but has a slightly different method. "With our notcher, we can notch 1-1/2-inch diameter tubes at 55 degrees, 1-3/4-inch at 50 degrees, and 2-inch can be cut at 45," says Smith.

He offers the same advice as Peters: "On your first cut, don't cut the tube square. Cut it at a 45. Then use the notcher to cut halfway through the tube. It won't look like you're halfway through, but when you get effectively halfway, take a pair of pliers and pull that half-moon-shaped sliver off. Then you can follow it the rest of the way through."

Those suggestions may seem simple, but there are a few real easy ways of getting in trouble with these tools. First, the only appropriate hole saw is the bi-metal type. Quality bi-metal hole saws are only around $10, so there's no excuse for using something else. Also, the drill or drill press needs to be turning at the [very slow] speed dictated by the hole saw manufacturer.

Dave Williams' company doesn't offer one of this style of notcher, and he doesn't plan to, either. "If I thought they had me beat if I thought they had a better notcher, I'd step up and friggin' say so," says the always-candid Williams, "That's the way I am, but I don't have nothin' nice to say about those hole saw things.

"I walked into a shop one time many, many years ago and there was blood all over the place. A hole saw shattered and stuck this kid in the throat. Somebody grabbed a bunch of shop towels and stuffed them on his neck. They got him to the hospital and the doctor told them if they had pulled the piece of hole saw out of his neck, he would have died."

Bearings Image
JD Squared uses twin needle bearings to support the hole saw arbor. Most other companies use bronze bushings. There are arguments for both.

None of the hole saw notcher manufacturers we spoke to for this article was aware of anyone getting injured with hole saw notchers. "I haven't heard of any problems, but I know they say that," acknowledges Barnes. "I've probably done 4-500,000 notches and I have yet to have a hole saw break. I don't think I even had one split."

"They are just like a drill bit," says Barnard. "You need to have some type of coolant WD-40 or some type of oil on the cutter itself. Feeding speed is just like a drill bit it needs to be correct to make it work."

Barnes says, "Around 500 rpm seems to be a pretty good compromise between speed of cut and longevity of the hole saw."

Barnes admits the system isn't fail-proof, but says it's a long way from shrapnel in the throat. "About the only thing that'll happen is you'll knock some teeth off the hole saw. Generally, that happens when you're cutting through the top, a piece falls down, but it doesn't fall out. It catches on the bottom part of the tube and you go down through with the notcher and the loose piece gets wedged in the side. A lot of times that'll stop it and knock a tooth or two off the hole saw."

"A lot of the troubles people have has to do with how worn out their hole saw cutter is and how hard they're pushing," says Smith. "The hole saw will climb the tube as it cuts, so it actually deflects the mandrel. If you cut slower, it won't be off center as much. When you run it too fast, it really takes the teeth out of the hole saw. And we use cutting oil all the time."

Hole Saw Caution Image
Pro Tools' notcher is advertised to cut up to a 60-degree angle. Other manufacturers say that's not possible on larger diameter tubes, like the 1-3/4-inch that's common in stock car racing. Pro Tools and Speedway say an extra step or two is all that's required to get the job done safely.
(notice the large "CAUTION" tag!!)

Hole saw tubing notchers look alike and many even have similar names. Some notchers use a bronze bushing between the hole saw arbor and the arbor support bracket. Other companies use needle roller bearings. Jig-A-Joint uses bushings. "We experimented with needle bearings a long time ago," says Barnes. "We didn't like 'em. They seem to pick up chips and you're running a hardened needle on a softer arbor, so it has a tendency to chew up the shaft a little bit. That was our experience. The needle bearings were a little looser than we like to begin with, so that's why we stayed away from them."

Both styles need periodic replacement. "These bushings will eventually get loose to the point where you want to replace the things," continues Barnes. "You can just reach up there with a punch, tap them out, and press a new pair in with just a bench vise. Then the best way to get a tight fit without sending the unit back to us is to hone them using a wrist-pin hone."

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