No Tin Snips here, Use a Joint Jigger By Dale Murphy Eaa # 398547
This is just an example of how to measure tubing lengths and angles for the Joint jigger.
It’s really easy! After you go thru this example, I’m sure you will smack your head and say, “I could have used a Joint Jigger”.
Table Top Belt Sander
A few things to remember
I remove the bolts that hold the tube clamp at a given angle. I keep the center pivot bolt just snug enough to rotate. I use a long nose Vise-Grip to secure. The reason I do this is it is so much faster to select the duplicated angle and secure. And at times you have to go beyond the stop that is on the Jigger to get the angle you need.
Hole Saw Size:
The size that is used will always be the tube size you are fitting to. Example: You have the longerons set-up in your jig and they are 7/8” dia. Then the Hole Saw you use will be 7/8”.
Angles you duplicate will always be 90 degrees or more. You do not need to know that an angle is 38.7 degrees.
Use the Duplicator. If an angle looks like it’s 45 degrees, Don’t set your Jigger to 45, use the Angle Duplicator. It will give you a more precise fit.
All measurements are taken from the centerline of the tubes.
Pic 1: Example of Lonterons
We are installing a vertical tube. This measurement is centerline of tube to centerline of tube 11 1”. So we cut the tubing we are installing, 11 1”.
Next we cut the bevels of the tubes. The longerons on our jig top and bottom tubes are 7/8”. So we install a 7/8” Hole Saw on our Joint Jigger. Put the 11 1”
tube in the Jigger with the end of tube half way or centerline of the Hole Saw.
Cut the bevel. Remove the tube and debur on the Belt Sander (or grinding wheel as I did.)
Put the other end in the Jigger and cut the same way. Before you cut the other end, both cuts need to be parallel.
Use a short piece of tube, the same size of the cut . Here we are using a 7/8”. Use a 7/8” short piece and rotate parallel.
Check the centerline of the Hole Saw to tube again, that it hasn’t moved. Tighten clamp. Cut, debur, your done.