Edge finder questions

I picked up a small edge finder from littlemachineshop.com since the one on carbide3d.com is sold out but haven’t had any luck using it…

  1. I don’t see a control in CarbideMotion to turn the spindle on during jogging. Am I blind or is this still missing? This post seems to indicate that it’s in there, but I don’t see it.

  2. I can use a third party program like grbl panel to turn on the spindle and jog but to do that I have to close CarbideMotion first, and when I start CarbideMotion up again, it rehomes so I lose any useful information about where the zero was. Is there any workaround for this?

  3. It looks like the edge finder isn’t perfectly true when the spindle is spinning - it looks like there is some wobble - I think it’s called runout? Is there any way for me to identify where the runout is coming from (e.g. is it from the Nomad spindle, or the collet, or the edge finger?)? The collet set I bought (to fit the 1/4" shank) was a cheap one (this one, from Amazon), so I suspect that’s where it’s coming from, but the edge finder itself is quite long, maybe 2" long, so it could be just exacerbating already existing runout in the spindle, or it could be wobbly on its own.

  4. I can hear the edge finder tap/thump (a clearly audible ratatatatatat) the material maybe .002" before it jumps to the side. Do I go by sound or when the jump happens?

I was under the impression that the edge finder is supposed to wobble when it’s spinning - and then you touch the material until it spins true, which means you are exactly at the edge, and then you move it until it jumps and that is exactly 1/2 the finders diameter. Then you raise the spindal and move it inward (or upward) 1/2 the diameter and you’re at zero for that axis.

And here is a suggestion based on what has worked for me - get yourself a feeler gauge. I use an $8 one I got on Amazon. Move the bit until it just touches the feeler, then raise the spindal and move it inward the thickness of the feeler + 1/2 the bit size. I’ve been dead accurate using this method.

Hi; yes, you are right; to be clear, it’s not just the tip that wobbles; the entire shaft is wobbling slightly (I can feel it with my hand and it feels like it’s shaking).

When I move the edge finder towards my stock, the wobbly tip does indeed start to spin true, then as I move it closer, I can hear it start to ratatat tap the stock, and then maybe .002" closer and the tip will jump.

I do have a feeler gauge (well, actually, just a flat flexible .016" strip of brass from the hardware store) that I use, but I’m not sure how much I trust the fact that my endmills will contact it perfectly no matter how they are rotated.

I think Randy might have posted something in another thread about using a 1/8" dowel and a feeler gauge, which makes sense. Maybe I will do that…