Edited by Chuck Larsen, EAA Designee Director

Sheet Metal Brake By Graver A. Chaplin, EAA 5507 2413 Ives Lane Redondo Beach. CA 90278 1 HE FOLLOWING INFORMATION was first published in the January 1962 edition of Sport Aviation. Since that time many things have changed in aviation, but not the need for sound basic tools. The original author of this material continue his association with EAA and is also a member of the Antique/Classic and Ultralight divisions. He is currently a member of EAA Chapter #728 of Hawthorne, California and served as its president in 1981.

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I have read with great interest about the different ways builders describe how they bend and fabricate sheet metal parts. My experience in working with sheet metal in the aircraft industry brought me to the conclusion it would be much simpler if an inexpensive, small sheet metal brake were designed. The one shown here meets these criteria plus it is easily built and eliminates the need for form

blocks hammering on the material and heating to bend it. The rig shown is rather small in its present form, but

this was a matter of choice as all I wanted the brake for was to bend small brackets. The brake could be enlarged to suit individual needs by lengthening or widening the dimensions to suit the individual builder. This brake will bend pieces of up to 5" long. Rather than design a complex hold down for the shoe, I've found it is simple and effective to get the necessary pressure by placing the clamp in my bench vice. If this design were to be enlarged, I would recommend increasing the metal thicknesses in proportion to the increase in other dimensions. The brake as shown will bend .062 chrome moly with a '/«" radius in a nice clean brake. It will form a "U" bracket with an inside dimension of as little as '//'. The simplest method I've found to fabricate a U bracket is by bending the first flange and then using a spacer on the inside edge of

the bent flange to the hold down shoe to set the dimension of the second

bend. This spacer should be the size you want the inside dimension of the bracket to be. The most critical point in the fabrication of this sheet metal brake is that the center of the hinge must be exactly center of the bottom plate on both planes; failure to do so would result in either a very sloppy bend or, a brake that will not bend a full 90 degrees or that will jam. There are a number of inexpensive brakes of similar design available to the home builder. These commercial 0R ITEMS USE /2 Ti-itc