When milling, finding your work coordinates can be tricky. One thing to remember is that the vise is providing a surface that is parallel and flush with your piece, and it can be probed.
In this quick tip tutorial, I'll show you how to get X and Y from the vise jaws. In my case, the probe I was using was not deep enough (in the Z direction) to probe a part of my workpiece that had been machined. Thus, I wasn't able to accurately get an X & Y coordinate when I flipped the part to do a second machining operation.
But, this technique can be useful if, for example, your piece is underneath the height of the vise jaws, or if your part is held by some angle blocks.
Here's the general gist:
- Y is easy to get. Probe the surface that the piece is flush against.
- X can be probed if you know the workpiece is aligned with the side of the vise jaw. So how do you make sure it's aligned? Clamp against it using parallels.
- Z hopefully you can get by usual means
Step 1: Probe the Jaws First
I made this mistake when I did this. Knowing you will probe the vise jaws, DO IT BEFORE YOU CLAMP YOUR WORKPIECE.
You can probe X and Y very easily when there's nothing in the jaws. This also assumes that your vise is square to your table. If you don't know how to square the vise, ask your friendly shop staff, or read this guide.
Once your probe X and Y, let's make sure your stock is in the right X place.
Step 2: Clamp With a Parallel
In my case, I could only machine down 2.0", so when I flipped, I needed to locate the piece precisely so that the walls would line up when machining the rest of the walls.
Find the shortest, fattest parallel you can find and clamp it against the jaws as shown (with the parallel side, not the sides with the holes). The vise jaws should be barely tight on the piece. You don't want to move the jaws a great distance, but you want the workpiece to be able to move when you clamp it to the parallel.
Next, clamp the workpiece to the parallel. Now, the face on the parallel, should be aligned with the face of the side of the jaws.
Monkey tighten the vise, hammer with a rubber mallet, remove the clamps, and you're set!