Cutting Strips Of Sheet Metal

[@tw!ll]

Figured I'd throw this up here.
There's lots of ways of cutting sheet metal. If you have a shear that's big enough, that will work great. Unfortunately shears of all forms generally curl the metal at least a little. You can use a bandsaw, which I did for a while. Problem is my bandsaw doesn't have a big enough table to clamp a stop to keep things straight. Even if it did, the band itself can turn with very little trouble. Making it frustratingly difficult to get long straight cuts.

Here's what you need to do it my way:

Jigsaw(decently powerful one)
Metal cutting blade for it
Piece of plywood with at least one perfectly straight edge
Clamps
Table
Sheet metal
Tape Measure
Face Protection (we'll get to that later)



So first things first you are going to sandwich the metal between your plywood and the table. I cut this wood on a radial arm saw, making sure the sides were perfectly straight. You can get a piece from a local lumber yard. They usually have scrap pieces, and they can cut it on a panel or radial saw for you. You want the metal to stick out past the table obviously. Don't tighten the clamps down yet.



Next, measure the distance from the outside of the blade to the side of the jigsaw base. You need this, as you will add your dimension to this to get an accurate cut. Make sure you are including the blade.



Speaking of blades, make sure you get ones that are for cutting sheet metal. Here's what I have for my Bosch.



Now add your measurements. I was cutting 3/4" strips, so I added that to the saw measurement of 1 3/8" coming up with 2 1/8"
Make sure you measure multiple times both sides and in the middle. Then clamp down tight, and check your measurement one more time.



Now the fun part, line up the side of the jigsaw against the wood nice and tight. Start cutting, making sure the jigsaw stays on the metal and doesn't lift up. Use your free hand to put light pressure against the side of the tool to keep it against the wood.
Here's the part where you will need face protection. I'm not Mr. OSHA who believes everyone should always be covered head to toe in safety equipment. In fact I'm a big fan of comedian Brad Stine, who has a whole thing about put your helmet on(check it out). However this is one of the cases where you really need a face shield. The jigsaw throws little particles straight up, and you have to be directly above it to make sure you are keeping things straight. So be careful ok?



When you get to the end of the cut, use your free hand to hold the metal up against the saw from underneath. Make sure your fingers aren't near the blade! Go very slowly towards the end of the cut to make sure the saw doesn't bite and jump around bending your piece to all hell. It might take a little practice to make a clean cut every time, but with patience and practice you will end up with this.



The metal shown is approx 18 awg. Pretty thick considering, and my saw cuts through it as easily as it cuts 1/2" plywood.

[yjdavid]

I'll add this, if you have a custom sheetmetal shop around you, go in and ask them if they'll cut you a few strips. they'll most likely cut them for you for no charge. I work in a custom shop and small time people like us hobbyists come in all the time and we take care of them. we have material laying around for days!

[@tw!ll]

Dang, wish you were closer

[rockhugger]

that's a great idea, but the first thing I thought of was how does one keep the sheet from flappin and bending to hell before I read that you use your free hand to hold it and the jig while putting pressure from the side.

I thought of another way that might be safer and would not require you to put fingers in harms way. You could possibly use two pieces of ply wood to sandwich the sheet metal between them. They could be the same dimensions except the lower piece will hang out further than the top piece just inside your blade creating a lip or a shelf to support the sheet metal, then screw them together with short wood screws on the sides creating a clamp for the metal. Use your large clamps to secure that all to the table and start cutting, then all you need your free hand to do is push the jig against the top guide.


hope that makes sense.

by the way, I have that same Jiggy and it works killer. It's almost as smooth as an FXR