By: Blake Robinson
With tools commonly used by chassis shops becoming more affordable and available these days, many racers are taking on fabrication projects themselves in their own garages. These skills are not going to happen overnight, but once you become familiar with your equipment and the materials that you are using, you can be fabricating like a pro in no time.
Notching or fish mouthing are terms used to describe how one tube has the profile of the tube it will be welded against removed from it, this produces a semi-circular notch that's a major contributor to a strong weld joint. This process can be achieved by using a lathe, grinder, end mill, saw, or numerous other methods you can find on the internet.
We have had great results using products from The Eastwood Company on our “Getting Back on Track” Camaro and wanted to share the process we are using with other Eastwood, “Do It Yourselfers”.
Product: Tubing Notcher and Hole Saw Kit (Item #12739)
First off remember that the more accurate your measurements are, the better fitment you will have. Start by marking the center line on the tube to be notched. A second mark should be made on the obtuse angle side where the two tubes intersect.
The Eastwood notcher is adjustable up to 60 degrees, with the baseline 90 degrees being at 0 degrees on the notcher.
Measure the angle on the acute side of the tube and write it down. In our case 60 degrees. The notcher would need to be set at 30 degrees to achieve our desired angle. (this number was found by subtracting 60 from 90)
After marking your tube and finding the notcher angle, it is best to cut off any excess tube. Leaving the excess tube only makes the cut harder to do and basically it will wear out your hole saw faster.
Quick tip: before cutting your tube, use this rule. If the notcher angle is 0 to 44 degrees, add a 1/4 of the diameter of the tube to the intersecting line mark before cutting it. (this applies on a standard 90 degree notch as well, since the notcher is set at 0 degrees)
If the notcher angle is 45 degrees or larger, then cut the tube at the intersecting line mark. This practice will allow you to always have sufficient material to help spread the load on the joint. With the tube cut to proper length and the notcher angle set, we can place our tube in the notcher.
Place the center line mark at 90 degrees in relation to the center of the hole saw. Then place the edge of the hole saw on the intersecting line mark for a notch angle of 0 to 44 degrees or at the edge of the tube for notch angles 45 degrees or larger.
With our notch now completed, a test fit is done.
Before welding your tube, I would recommend that you remove any sharp edges from your notch.
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