How to immobilize router shaft during vise tramming

Anybody find a clever way to hold the router shaft from spinning while doing something like this vise tramming operation in the photo? (I know the indicator can’t be run over the rough knurled surface of the vise jaws seen in the photo, but this is just a conceptual photo. The jaw would have to be either replaced or covered with a plate having a smooth face.) The fact that the spindle shaft turns freely presents a problem, as the drag from the probe traversing the jaw face will just rotate it and instantly screw up the process. I’ve done this operation on “real” mills a number of times, but it’s not a problem there, as the gear train in the spindle drive presents plenty of resistance to spinning. I know there’s the push-button shaft lock used when changing router bits, but it’s so sloppy (even on my essentially brand new Shapeoko), that it can’t be counted on to fully immobilize the shaft. I have the feeling I’m missing something obvious.

One other point - I realize I could reduce the moment arm about the spindle axis considerably by losing the red indicator holder and just going straight into the router collet, but the stem on the indicator is 5/32" diam, and I only have 1/8", 1/4" and 3/8" collets. Even with that better set-up, I believe the shaft would still need to be immobilized to get good repeatable & reliable results. Like I said - the picture is just for talking purposes. Thanks.

For that purpose, you would need a test indicator holder that clamps onto your router body.

For this purpose you don’t need an indicator in the spindle/router. This is only needed to tram the spindle, not square a vise. Clamp the indicator anywhere on the Z-axis. The whole carriage moves parallel to the X axis. I’ve heard of people bolting on a small steel plate onto the machine so they have someplace to mount a mag base.

You also don’t need to sweep the face of the vise jaw directly, and certainly not the face of the movable one. (I know the photo is just for reference.) If you don’t have a flat reference on the vise itself, clamp a decently straight bar in the vise and sweep that.

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Thanks, Steve and Winston, for your replies. You both make good points and I’m a little embarrassed for having even asked the question. It will be straightforward enough to clamp on somewhere or do the steel plate trick for my mag base, which I’d previously considered. I guess I got a little hung up on something else… if you look in the background of the photo you can see a big ring bearing on a plate under the gantry of the Shapeoko. That’s part of a turntable system I am adding to my machine to have a fourth axis of sorts. I had used that indicator rig you see there to sweep the inside of the ring bearing to find my XY zero. I was thinking it would be slick if I could just use that same indicator set-up, more or less, to tram the turntable system base plate, as well as that blue vise, while I was at it. Dumb idea. So, consider this question answered, and thanks very much for your input.

Mike

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