Help With 3 Axis Zero Plate

[rb99]

I am looking for a way to zero the 3 axis on my older shopbot with a 4g controller. I remember there were aluminum plates with a recessed hole that the bit goes into the hole and touches 3 sides and then the bottom. Are these still the way to go? I see SB sells a plate of some type but it looks like it is for depth alone?

Thanks for the help!

[curtiss]

Not quite sure what you want to do, but one way is to use two hold-downs to secure the work piece / say on the upper left side. A third clamp holds down the Zero plate on top of the work piece / with the aluminum edges parallel to the work piece edges.

Zero to the top or the plate, and then drive/ nudge the Bot around with a 1/4 inch bit so you touch the edges of the plate from the x & y directions .... when the bit touches the edge of the plate set the proper read out to -.125

The 0,0 position should then be over the lower right corner of the material. Remove the plate and re-clamp as needed.

[rb99]

Not quite sure what you want to do, but one way is to use two hold-downs to secure the work piece / say on the upper left side. A third clamp holds down the Zero plate on top of the work piece / with the aluminum edges parallel to the work piece edges.

Zero to the top or the plate, and then drive/ nudge the Bot around with a 1/4 inch bit so you touch the edges of the plate from the x & y directions .... when the bit touches the edge of the plate set the proper read out to -.125

The 0,0 position should then be over the lower right corner of the material. Remove the plate and re-clamp as needed.


What I want to do is have a plate or something that allows me to quickly zero the X Y and Z axis'.

I am not sure which plate you are talking about. Since starting this thread I found the one I saw a few years ago. Then there is the new one. Or new to me.

Old one. It does 3 axis zeroing:

https://store.shopbottools.com/collections/accessories/products/3-axis-zero-plate?variant=7825832513

https://cdn.shopify.com/s/files/1/0300/8585/products/1-sm_large.png?v=1450365172



https://cdn.shopify.com/s/files/1/0300/8585/products/2-sm_large.png?v=1450365172


New Zero Plate. It appears to only do Z axis zeroing:

https://store.shopbottools.com/products/pressure-sensitive-z-zero-plate?variant=24782112519

https://cdn.shopify.com/s/files/1/0300/8585/products/SAM_0541_large.jpeg?v=1468358953


Are there any other 3 axis plates available? I remember some with a hole in the aluminum plate and the bit touches 2 or 3 sides and then it knows where the center is. As I remember there also needs to be a software routine as well. I have the 4G controller, but an old old bot.

[scottp55]

And then there's the old do it yourself methods(I haven't used but saved pics ) for 3 axis Zeroing, but you'd need to write a new Zeroing routine.
These were mainly for Zeroing a fixture,but maybe not to hard to rig a spot on your board for?

[tom burke]

The 3-axis zero plate isn't "old" and the pressure-sensitive Z-zero plate "new"—they have different functions, and I use both. The 3-axis plate can be plugged into the same connector on the gantry that the normal Z-zero plate uses, and placed where it is needed for 1-, 2-, or 3-axis zeroing (the software routines are included in SB3). The pressure-sensitive Z-zero plate can also be plugged into that connector, but it makes much more sense to order it with the optional extension cable and permanently mount it somewhere on the table where the spindle can reach it but it won't be in the way of normal operations. It is then wired directly into the control box. The point of the pressure-sensitive plate is that it allows you to use a routine that automatically adjusts the Z-zero after a bit change. That's convenient for normal work, and almost essential if you have an automatic tool changer (which I don't).

[coryatjohn]

I gave up on the automatic zeroing years ago after the second time I forgot to remove the clamp from the spindle. I switched to a much more intuitive method that uses a dial indicator.

34106

I've always been concerned about "automatic" systems as they can automatically destroy things just as quickly as they can save effort. I'd rather know where the bit is than trust the machine. Call me a crazy old coot but there it is.\

To do an X-Y zero, I have a 1/8" hole drilled in the table at X=1, Y=1 and use a 1/8" solid rod for doing that. My machine never loses position so I only have to change the XY if I change the axis for some reason. I rarely do that anymore.

[srwtlc]

This should get you started. You can modify to suit your needs.

https://1drv.ms/u/s!AsPqyLrhnhkRgzmUXrkRdRXNNVGq?e=dnJMAO

[steve_g]

Well… it took some hunting and digging, but here’s a jig I used to use.
The copper pipe cap is embedded in the jig. And the jig can be located anywhere on the table. The bit is placed somewhere inside the cap, the zeroing routine touches x left and right, y top and bottom and finally finds the bottom of the cap.
A very accurate and inexpensive X,Y,Z zeroing jig. Cheap enough that every jig can have one built into it!

SG

http://www.talkshopbot.com/forum/attachment.php?attachmentid=34107&stc=1

[rb99]

If forgetting the clamp is an issue, perhaps making it with a break-a-way using magnets would help?

[curtiss]

Usually, the x-y 0,0 is just set wherever you want it to be using the VA command.

One other method is to set the bit say an 1/8 inch above the material / near the corner you want to become 0,0

Use a digital caliper depth gauge to measure from the edge of the material to the edge of the bit and add 1/2 the diameter of the bit and that becomes the value for that axis

Repeat from the other direction and set those values with the VA command.

[rb99]

With my old controller it had a "motors off" command and I could manually move the router into it's final position. I had the old ball screw Z. I would put a piece of paper under the bit and turn the bit down until the paper would tear. Then MO "motors on" I was good to go. The 4g controller eliminated the motors on and off commands, and my upgrade to a new rack and pinion Z doubled down on it.

[srwtlc]

Sneak up on it with the keypad after getting it close....

"Several additional functions are provided. If you hit a <D> (upper or lower case) on your keyboard or click on the “fixed” button in the keypad window the tool will move a fixed distance. This distance is set in the small box that appears or in the Fill-In sheet by typing “VD” and changing the “KeyPad Fixed Distance” value"


http://www.talkshopbot.com/forum/attachment.php?attachmentid=34108&stc=1

[curtiss]

Years ago, I laid out a few "reference squares" on a 48x48 table to help line things up on the x y.

Squares were 12, 18, 24, 28, 36, 42 and 48 inches .... I think they were .04 deep with a .03 bit.

Also drilled in a grid on 5 1/2 inch centers with a 1/4" threaded T insert mounted to the bottom to secure work pieces. (First hole is at 2,2)

One can also come up from the bottom with a lag screw into the work piece to provide "pull down" instead of "hold down" ... The bolts come thru at the "high spots" in the vac plenum.

"Pull down" works great for many things... one just has to miss the bolts each and every time.

[rtfosmoe]

Tom,

Can you tell me where the 3-axis zero plate software routines are located in the included in SB3? I just received a 3-axis zero plate and I'm about to hook it up tomorrow.

Thanks,

Rich

[EricSchimel]

You should have gotten a thumb drive with the plate:

https://www.shopbottools.com/ShopBotDocs/files/SBG%2000444%20Three%20Axis%20Zero%20Plate%20Guide% 202015%2010%2016.pdf

In the first page of the instructions they show you how to install the scripts:

34301

If you didn't get the thumb drive just email/call SB tech support and they can get you setup with the latest versions.

[rtfosmoe]

All,

Need some help. I obtained the software for the x,y,z zero plate from Shopbot early this morning. I installed it and ran it using the following procedure:

1. I copied all files which they sent me into the Custom Directory.
2. Adjusted the plate thickness variable to the thickness of my plate
3. Test the ground loop between the spindle/bit and plate - I can see it change states in the control software
4. Ran the C10 outer zeroing routine the bit comes down and touches the aluminum plate and then it tries to go further down till the machine stops and the screen displays "Input is already triggered - Exit". I can see the change in state when the machine touches the plate.

The same test was run using the standard z plate and the results are the same. The machine stops in after trying to go further in the Negative Z direction.

I ran several tests to check on the x, y, and z using the control software to see if they actually move out a specific distance/height and then measure the distances. Everything seems to be working fine. I also can Zero the Z-axis using the C2 command with both the X, Y, Z zero plate, and the normal Z zero plate.

Removed the Control software from my computer and reinstalled it. I rebooted my computer at least 10 times between testing. I even installed the software on a Mac which runs Windows under Parallels and the results are all the same. The machine starts the test and the bit comes down on the plate and then it tries to further down in the negative Z-direction until the machine stops. Tom from Shopbot and I spent most of the day (47 emails, videos, and pictures) and he doesn't have any ideas. Any assistance would be greatly appreciated.

Thanks,

Rich

[srwtlc]

I've stopped using SB3 on my machine going on two years now, so I can't dig through the files, but I seem to remember finding a similar problem with the 3.8 beta versions in the standard C2 zeroing script where they were performing some wrong math with the pullback after the first touch. I wonder if that bad code was copied over to the scripts that are being used for the three axis plate. It had to do with adding a negative value to a variable or something like that, that actually commanded the Z axis to go down (negative) instead of up. If you compare the C2 script with the one you are trying to use, I'm guessing it will be different in the block of code I'm thinking of.

I could be wrong, but it sounds awfully familiar.

Scott

[rtfosmoe]

Scott,

You are on the right track. We found that the pull-up height wasn't enough of the thickness of my plate. We just solve the issue after about 8 hours of scratching our heads.

Thanks,

Rich