squeezing precision out of a cheap shear

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Without the space or budget for proper equipment, sometimes we have to make do.  Recent order of 20 post caps, I was dissatisfied with the accuracy of my method (sharpie marker and a pattern), so I made a gauging table for my Northern Industrial $99 shear.  I need to refine my sequence of cuts, but all in all it was pretty damn accurate for the time and $$$ spent.  The material is .100" 3003-H14. Attached Images
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Reply:Nice work!Regards,RobGreat Basin WeldingInstagramBlue weldersRed weldersMy luscious Table DIY TIG Torch cooler
Reply:Are you able to position at the edge to get the inside cuts?  Not sure if those are a stack of on half of the cap that you will bend over, or if it is 2 stacks of 1/4 of the cap and the light just looks like it is one piece.
Reply:Looks like 1 stack of 1/2's that get bent. 1st picture you can clearly see the bend on the left cap seam, and in Picture 2 you can see the center is solid better.I wondered the same thing at 1st. The glare dead center obscured if they were one piece or 2 in the 1st picture.Nice job BTW. Good jigs are well worth the effort if repeatability is key. I've had guys b1tch at me about the time it takes to make a jig, vs doing each one individually, but then they wonder why my stuff all comes out perfect while they waste time trying to get things to fit up right on assembly. In teh long run the extra time "wasted" on the jig turns into a better result and less time used overall..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Nice job, even on a one off thing, it pays to make a jig.
Reply:Yup it's two halves that get bent.  Forming beats welding/grinding any day.....except sometimes when you have to make an acute angle notch.  I tried a way illustrated in an old sheet metal book I have.  I stacked about 10 parts and used a vertical bandsaw to cut out the notch.  It worked, but it was kinda slow and didn't leave a weldable edge. I looked into a machine that would make notches, but since there are around five different versions of this cap I make, each with a different angle, I would need a machine with variable angle notching.  I don't have $28k for one of those so I tried using the tools I had.  The shear distorted the sheet too much, so I just sheared as far into the notch as I could, and finished the corner with a file.  Still too slow, but it was cheap and accurate.    Now I just need to grind and paint. Attached Images
Reply:I made the same ones as bases to cover bolt heads. Been there, done that. I finally drew them in cad and cnc plasma cut them out.
Reply:They look great. Nothing beats a good jig. It's almost always time well spent.
Reply:Did they come off the plasma table ready to weld, or was there a second op to prep the edges?
Reply:Usually you need to prep plasma cut edges on alum because of the heavy oxide layer that forms from the cuts. You wouldn't have that issue with water jet cutting..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Ready to weld. Mine were 16ga steel though, it cuts them clean enough. Minor touch ups with a sander. Only difference, as I recall, was, yours were cut out with the beveled part attached together, mine were cut out with the bottom section attached, more like a large "M". That way both beveled parts are bent in the brake at the same time, then bent inward to meet each other.
Reply:Originally Posted by DSWUsually you need to prep plasma cut edges on alum because of the heavy oxide layer that forms from the cuts. You wouldn't have that issue with water jet cutting.
Reply:One thing I learned kind of the hard way that you do not want to do as part of your prep for getting aluminum ready to weld is glass bead blast it.  That fine dust that gets embedded in the surface makes for some really dirty looking welds.  You end up having to do a lot of manual wire brushing to try and get rid of it in the weld zone.   It's a huge PITA.I've now got that Black Magic grit in the cabinet.   When I want to blast aluminum I turn the air pressure down to around 40 psi.   When you take them out of the cabinet you can just blow the dust off them with an air nozzle and be good to go for welding.