Tools for tools: Making a saw stop

WARNING: MACHINING CONTENT

One of the most common uses for tools, is making other tools. At least that's the joke among machinists...we don't actually make stuff, we just make tools. I'm not sure the previous was a complete sentence, but I recently had the need to up the ante on my efficiency. Each light has four main components that need to be machined. So, if I am making a batch of 20 lights, that makes 80 pieces of stock that I need to cut off from 10-12 foot bars. Kind of a pain, and 20 is a pretty small number. Time to make a depth stop for my chop saw.

The DeWalt Multi-Cutter is a low RPM chop saw
designed specifically for metal cutting. 

I made the stand for the saw back in welding school when I was living in Boston. Remember that Tushar? In any case, it's served me well but it's time for an upgrade. Most of my work is "one-sies" or "two-sies" so measuring each cut isn't that big of a deal. One of my quirks; however, is that I hate repetitive work...but love refining processes. That is to say, I can handle some repetition if I'm always learning something and working to make it better.

I have lots of chunks of scrap metal and I dug up a piece of 1.25" steel round bar that would match the diameter of my 1.25" inch tube. Normally I like to take some photos of the raw stock materials but I forgot this time. Things will be more clear in a second. The first task was to turn down the solid bar so that it would fit into the end of the tube.

I use collet chucks almost exclusively when I have the right size available.

This chunk of steel is about .75" thick. This end will fit inside the tube and the wide flange will match the outside diameter. The material is just some 1018 hot roll. Next up, turning the back side.

This is a different (smaller diameter) collet chuck. 

For the non-machinists. Collet chucks are used for holding the work piece, but they have a very limited clamping range. This means the diameter of the chuck must match the diameter of the part within about .01 inches...roughly the thickness of three sheets of paper. Over the last year or so I've bought bucket loads of these collets at local industrial auctions. They are indispensable.

Here is the final part mated with a piece of 1.25" DOM steel tube. The hole is threaded and is explained in the next shot.

I'm using the bolt and the wing nut as a "fine adjustment" setup. I can loosen the wing nut, turn the bolt a little bit, and then lock the wing nut back down to give me really precise control over the depth.

I went ahead and TIG welded the parts together. I managed to take a photo of the weld start/stop line so it looks a little worse than it is. Not quite a master welder yet...give it 10-20 years.

Some more detail shots follow, but this is the basic setup. The stock clamped in the vise gets pushed against the stop, allowing me to cut multiple parts to the same length with no measuring.

This shot shows the bracket a bit more clearly. I used some scrap DOM tube and a scrap of rectangle tube from a custom job I did for Jin Kim at BareBones Training in Palo Alto. The stop can swivel up and down so I can move it out of the way when I'm making a cut.

Just a shot from the other side. I can set the coarse adjustment by loosening the black knob and sliding the tube back and forth.

In action! Pretty exciting right? It might not look like much but this is going to save me hours in the long run.

Of course I had to try it out and cut down a 6' bar of 1 inch 6061 for making flashlight bodies! Time to get this thing on the road. Should have my first run of lights any day now so stay tuned.