What method do you guys use to find hole centers?

Good day.
I usually get things that are already cut and need to recut it to a new diameter.
I move the bit side to side to get the best measurement for the center to cut to the best of my abilities.

What would be a more efficient way of doing this?
probing, camera and or other methods you guys are using?

Thank you!

If I flip my probe rod around the other end has a point on it for “precise manual positioning” but I’d probably be more likely to put a regular edge finder (the ones that spin, then jerk sideways when you touch) in a separate collet and use that. It’s standard practice for machinists, should work for cnc too.

Ideally, of course, you’d have a reference corner elsewhere and not have to measure the hole’s center :wink:

You can create a M-code to turn off the Warp9 “probe failure disables Mach4” and then use the standard bore and boss probing functions that comes with Mach4. You will have to do the calibration and setup first but then you get all of those functions.

See here; Probing in Mach4

Also, while I recommend a NC probe you can get a M12 splitter and a NO probe so that you do not lose your AvidCNC touch-off plate. Then you will get surface mapping and all that other fancy stuff that is not part of the AvidCNC screensets.

Hello ! I don’t know how many parts you have with the same hole diameter, but I would cut a piece of MDF with that hole diameter and with a centered hole so you can use it to reposition the part you received on the CNC table (you place the round disk on the CNC table using the center hole). English is not my first language, so they may not understand me. Good Luck !

Approximately what size holes? You could use a router base plate centering cone. Cut a 1/4" hole in the spoilboard to match the small diameter of the centering cone, place the material over the hole, use the cone to center the material onto the 1/4" hole in the spoilboard. Now the material is perfectly centered on top of the hole you created, which you know the location of. Of course, this won’t work with larger diameter holes.

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We have these wonderfully precise machines and we should fully take advantage of the automation they provide whenever possible.

Here is a nice, cheap and accurate probe;

And here is the splitter to connect both the probe and the AvidCNC touch off plate at the same time;

And if you need it Amazon has single end M12 cables you can solder to your custom connector.

15 minutes of wiring and about an hour messing with Mach4 and suddenly you have surface mapping, bore and boss, angle and all the other cool features that come with Mach4 that are disabled in the AvidCNC screens.

You already paid for these features in Mach, spend the bucks and get a probe and take your game to the next level.

UPDATE: actually, the probe comes with clip-on connectors so there isn’t even any soldering required…

The probing should work nice…I am going to look into this.

Thank you!

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That probe notes an activation force of 0.5+ N X/Y or 2.7 N for Z. That’s over half a pound of pressing into your workpiece with a small object. Have you found this to be a problem?

I believe the pressure required for the AvidCNC touch plate is like 2 pounds? Its crazy high. Strong springs in there.

I actually use the Drewtronics and my system is NC but all of these probes are based off the expired patents from the Renishaw so they behave roughly the same.

Yeah, but you don’t have to apply 2 lbs to trigger activation with the avid plate; it sounds like the PGFUN probe requires a high force to trigger.

I got the Drewtronics based on your recommendation and really like it, but it’s so sensitive it reacts almost instantly - in fact, I disable it in software when I’m not actively using it because table shaking can trigger it. Compared to needing 2.7N of force to trigger the PGFUN probe… ?

I’m worried that it will leave little dimples on my softwood projects…

Yeah, I forgot that just a simple circuit. Essentially the same thing as the Grbl system. Well, mine died 5 years ago coming up this November so of course I put it out of my head.

The Drewtronics is way worse;

I was referring to the toolsetter.

Either way, the question remains - does that force cause any issues for you?

You know, I actually have no idea since I don’t touch off to anything other than the spoilboard on the Z axis.

The X and Y I do touch things like foam but not the Z.

On my CAM I always place things (like in foam) I do so well inside the stock and I use lots of jigs. And, as I has stated before I always touch to the jig when I use one because its part of my CAM process.

OK, lets try that again. Sometimes I speak in word salads;

If you have a precise machine and a precise probe then you touch to what is known, not what is variable. Take full advantage of the machines precision.

Wood products are always variable. So quit touching on them. Make a fixture to hold your stock. When you design the fixture, whether you are 3D printing it or cutting it, design in touch points that define your work offset.

If I am cutting into the top surface of the stock, like I am cutting a sign or engraving something, I always map the surface first. Otherwise I touch to the spoilboard for my Z and set my CAM with zero as being the bottom.

I hate having to guess about anything in machining :rofl: I make the machine do all the work.