One of the most fundamental race or track car building tasks is to make structural reinforcements from tube; some people learn to weld primarily for that purpose. Clearly, it's important that anything structural be done as well as possible. The Ol' Joint Jigger Tube Notcher goes a long way toward increasing the level of perfection that can be attained by the non-professional enthusiast, and decreasing the time required to attain it.
Where one tube is welded to another, the joint must fit well. The Ol' Joint Jigger is a fixture for quickly making accurate tube joints. It is a metal plate with a rotatable vee-block clamp that holds the tube on center with a hole saw. The hole saw is mounted on an arbor that rides in replaceable bronze bushings in an aluminum block. The vee-block clamp has angle markings etched on the main plate. Two models are available: the original steel RTN100 and the larger RTN1000, which is made of aluminum to help damp out vibrations. The RTN1000 also comes with a pivotable mounting base, allowing it to be operated at any angle. A fixed base for upright mounting is available for the RTN100, making it possible to use either model either in a drill press or on a workbench or vise with a 1/2-in. hand drill.
Any cutting tool is only as good as its blade. Use the same size hole saw as the tube that is being mated to it. A rollcage is typically built with one diameter of tube, so buy the best hole saw you can find for the diameter of tubing you're using now, rather than a set to cover every size you might need. Dave Coleman, of sister magazine Sport Compact Car, used the Ol' Joint Jigger on his rally car and went through several cheaper hole saws before finding a carbide-tipped one. It's still sharp.
I've seen much less expensive tube notchers, but I wouldn't want to have to use them. There are faster and more precise tube notchers available, but they typically play in a ball park six to ten times more expensive than the Ol' Joint Jigger models. For the kind of work an enthusiast does, the Ol' Joint Jigger is just right.
