Ok fella’s, I’ve had a few comments on my method of x/y/z zero method. I do it the way I do because that is how I’ve seen it done on many you tube video’s. So I ask you, what is the correct method to ‘zero’ out the x/y/x axis?
There’s any number of workable ways, a lot of it depends on how you like to do it. If you don’t have a touch probe for the Z yet, get one! They’re easy to make, or cheap to buy, and they are not difficult to wire in. It makes setting up your Z so much easier.
Other than that, I tend to just home, then put in a pointed bit (usually my 45-degree engraving bit) and use that as a pointer to align my tool on X0Y0. Zero out, then raise the Z and swap to whatever tool I want, jog to X1Y1, and run the touch probe cycle to set the Z-zero.
The correct method is any way that I choose to do it… 
Like @DanBrown said, there’s a number of ways to do it. I made one in the last couple days and have yet to use it for an actual carving. I got the smallest piece of .064" aluminum I could find at the local hardware store, which was still ridiculously large (and 0.065" in my chosen touch-area), added an LED, a AA battery and holder, and a copper alligator clamp.
Here’s a picture of it “in use”, staged for this post. The metal has a slight bow (up in the middle), so I added the tape measure as a weight to ensure it’s as flat as reasonably possible.
Here’s a raw picture of it.
I could have cut it smaller, but I was worried that by doing so I’d accidentally bend it the wrong way or somehow introduce some other form of error.
Long story short, the correct method is whatever you use that gives you the accuracy you need. If this is +/- .001", I’ll be ecstatic.
I used to use the paper trick for setting Z, but found my rough and detail cut projects not coming out so well. The depth of cut was close but not perfect. Always left a ridge either high or low. I have since changed my approach to using the drop bit to surface method. You chuck up the bit loose, move bit close to surface and then drop bit to make contact and tighten.
Since I’ve used this, my 2 cuts are exactly flat and at the same depth. Don’t have a touch probe, not sure if I ever will as this method seems to work just fine for me, but things could change.
Guess I will try that tomorrow as I am doing a dual carve then.
I am waiting for inventables to issue their touch plate to use this method.
Yeah, the touch plate for me just seems to introduce another variable, and we certainly have enough of those. So depending on the thickness of the touch plate, do you have to change all your doc settings to account for this? If you depth is set to cut .125" and your plate is .125" thick, I guess you won’t be cutting anything huh. Just don’t see it!
I’ve seen many people use the ‘touch plate’ method and it looks good to me. I assume the machine accounts for the thickness of the plate and adjusts accordingly.
I don’t think the machine can do anything you don’t tell it to do…but may be wrong.
Every time the machine messes something up…it is always the machines fault, never my fault!..lol
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Mine works the same way! 
Since I use Easel, what I plan to do is to zero it out until the LED is solid (no flickering), lift it up .035" to remove the plate, then drop it .100" so it’s zeroed out on the table.
The machine does indeed take account for the touch plate. All you have to do (in ChilliPeppr, which is my choice of sender, but UGCS can do it too) is tell the program how thick the plate is, and run the probing cycle. It touches off the plate, and adjust the tool-length compensation to set the z-height to the height of the plate, plus back-off distance. In short, if you tell it to go to zero after touching off, the tool tip will be touching the surface precisely.
It’s VERY easy to do, and much more accurate than doing it by hand unless you are supremely good at the hand methods.
Yes, I understand the process in ChilliPepper, UGC and the like, but I believe James is using Easel which doesn’t account for touch plate settings. As far as accuracy, maybe it is, but it is another variable and setting to remember and possibly forget. When the bit hits the surface, it’s on the surface. When your next bit change hits the surface…guess what. “Much more accurate”… not sure that is an accurate statement. Guess we all use what we’re comfortable with. (and yes, I am supremely good at hand methods) 
Man, that sounds like a lot of work. I don’t like work!
Using a touch plate is preferred for zeroing out your Z-axis, it is also what most would consider the “industry standard”. So, when Easel supports it, I will be pretty happy, but until then when a job needs to be that accurate then I go to ChiliPeppr or UGS.
The “bit drop and tighten” trick is an interesting one, but it has it’s problems. Increase in tool stick out to name one. Personally I like to have a good amount of space to tighten the collet properly, so it wouldn’t really work for me, but your milage may vary.
For multiple runs in Easel the paper method is a good fall back. Provided it is done right each time. It has been pretty reliable for me and one of the more complex jobs I run in Easel is an iPhone case that has between 4 and 6 passes to run and on 2 different sides. If the zeroing isn’t right then the case doesn’t fit. So, that being said… what is the way I approach it? Here is a list of steps that I take and a little explanation to them:
- bring the bit above the surface you will z-zero to (pick a surface that as flat as you can get for the material you are carving)
- lower the bit until it is less than 0.5 of an inch above the surface then switch to lowering the bit by 0.1 inches at a time
- once the bit is less than 0.1 inch from the surface (you can usually tell this from a distance) switch to .05 mm
- this needs a little explanation… given a regular “20lb bond” sheet of paper, the thickness is roughly 0.1mm thick (0.97mm) this means you need to be moving your bit less than the thickness of the paper in order to catch it anywhere near it’s surface otherwise you will more likely drive most the way through the paper if you are moving at 0.1mm or more per jog down
- now slide a fresh piece of paper (the regular 20lb bond stuff) under the bit
- start clicking to move down and as you click click click moving down to the surface of the paper 0.5mm at a time feel and listen for the paper to just start to catch… if it is making scraping sounds and feels like it is catching, then it is touching… most likely this will stop the paper from moving under the bit
- now up by 0.1mm
- position for your X and Y zero
- now down by 0.2mm
- you are at zero and should choose to use that as home for the first run in Easel
- after the bit returns to X and Y home then you can move the bit up only
- change the bit
- repeat the process for z-zeroing the bit only z movement this time
- run the second pass choosing to set the new home position and not use last home position
I know that looks like a long process, but it really isn’t. I switch to using mm for the small units because it is quicker and more like the thickness of the sheet of paper.
@JamesMitchell I believe that when I watched the video where you explained your paper method you were moving the bit as if the paper is 0.01 inch this is more than twice the thickness of paper, so that might explain why it wasn’t working so well for you. Try switching to mm during the process after you get real close to the paper and only move 0.05mm at a time and once it has caught the paper move up 0.1mm out with the paper and then back down by 0.2mm If you must stick with inches then paper is more like 0.00382 inches thick.
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My question is , when switching from end mill to ball nose do u have to keep the same length bits. And do u rezero the z axis, I’m assuming yes to that question.
bit length doesnt matter, you just reset the Z zero
i never had very good luck with the paper method. touch plate made all the difference in the world
i wonder if you could use easel machine inspector to enter the gcode to use a touch plate?
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