Here's a 4" by 7" by 1" pan. I'll use it to hold parts. 20 gauge seems very strong for an ash pan. For a tray this small something thinner would have worked. So, 4 by 7, in inch tall. Add 2" for the sides and an inch of the hem. I cut it 7 by 10" I marked at 1 1/2" and 1" with a fine tip Sharpy then scribed with an awl. When I cut the corners I cut by eye a shy 1/8" inside the lines. The tabs are by eye at about 30 degrees and I aim to leave a bit of space at the inner cut. I bend & break the tab. This allows for the bend. The tabs actually end up about 5/8", aftet the bend around the corner it leaves about 1/2" to weld. I put text in one photo to show inner tab and to show I forgot to cut the outer part of the tab shy. This is necessary as during the final bends the mating tab takes that space. I set the brake to bend the hems. You'll simply have to bend a scrap to get a feel for where to set it. I bend each hem as far as possible, remove it, turn it over, and finish the bend. After all hems are bent I reset the guide to bend the sides.Bend the two sides with the tabs first, then the sides without the tabs. If you do not have a guide you'll have to eyeball the scribe line. Be exacting as if they are bent differently the top edges won't line up. When bending the final two sides the brake fingers need to be set so the tabs pass by the fingers. Before the final two bends I bend the tabs a bit using pliers so when the final bend occurs the tabs land on the outside of the box. Now off to spot weld, rivet, or solder the tabs. The final touch is to use a fine tooth file and take the curse off the eight corners. A bit of silver touch up paint on the spot welds is pushing the limits of upper class.
Magnets in photos are just holding it to allow photography.
