[MARV]

So, I’ve been dialing in my home built CNC and accuracy has become a primary part of that endeavor. Specifically, I’ve built a modified Avid router for doing small musical instrument and chair work (my background is in furniture making). I’ve worked with industrial sized routers before and have come to appreciate the benefit of accurately sized parts, so a home built device has presented some challenges. Measuring for square, tramming my spindle and setting homing sensors have all been in the mix and have dictated the use of devices that are somewhat foreign to my trade.

Where my previous machines had factory references for work placement, I’m finding my home built is better suited to user defined work offsets. Where I had developed templates in CAD for work placement that carried over to the machine references (in another life), with my current machine the work that I intend to do doesn’t lend itself to that approach. So, my latest fascination has become the use of “wigglers”, a rather mundane device fairly common to the machinist’s trade. I’ve watched countless Youtube videos on their proper use, but still have questions.

For instance; the metal working trade commonly uses low speed spindles (under 10,000 RPM tops), and often have the ability to throttle down to 1,000 RPM (or less). Is the use of a wiggler viable in a spindle that has a low end of 7500 RPM? Are there specific types of wigglers better suited for use in a router? What constraints come to mind when attempting their use in a woodworking environment? Are there other devices that should be considered instead? For those thinking that + or - 1/32” in working with wood is “close enough”, my work sometimes requires a quality of fit that only a + or - .005” tolerance might satisfy (think of dovetails, mortice and tenon work and second ops placement). Repeatability is also important.

I expect there to be a wealth of knowledge on the subject from the metalworking trade. So, I’m just hoping to glean a bit of it to improve my work.

Thanks

[Jim Dawson]

Unfortunately wigglers and edge finders are not going to be happy running > 1000 RPM.

It is possible to use an edge finder without rotating it by using the ''fingernail'' method. When the barrel is aligned with the tip, you can't catch your fingernail on the edge. This will get you within a couple thousandths.

An electronic probe might be a good option for you.

[MARV]

Thanks Jim for weighing in. Your response is what concerned me. I've got an electronic probe (? the unit that Avid sells), but aside from having to modify some code in Mach4 to make it work (not my forte), it is optimized for use with rectilinear stock. Much of my work involves organic forms where a wiggler would be better suited.

Thanks again.

[Jim Dawson]

Here is something that might be useful to you. I built this system for my mill for precision edge finding. Uses a camera and a centering microscope. The camera is an industrial camera (640x480) that I had kicking around but any webcam or bore scope type camera would do. I made this so I didn't have to twist my neck into a pretzel to look through the scope. The camera adapter just slips onto the scope eyepiece..



The mint mark on a penny

[MARV]

Very interesting. I presume this is centered on your quill? Probably more of a project then I can tackle just now, although I may give you a shout down the road for some direction.

Thanks

[Jim Dawson]

Very interesting. I presume this is centered on your quill? Probably more of a project then I can tackle just now, although I may give you a shout down the road for some direction.

Thanks

Yes, it's centered on the quill, good for about +/- 0.0005''

I'll be happy to answer any questions.