Gabe and Mike Pari hosted our Socal Camp again, and it was a good one! A lot of new faces this year, and some very familiar ones as well.

We began the day by being SO absorbed in meeting one another ( and eating donuts) that we totally missed feeling a 4.+ point earthquake that was centered about two miles from Gabe’s shop. Not a crumb was spilled by this crowd!

Most of us began the day by wandering around Gabe’s parking lot to check out some of the great Teardrop trailers he had on display. His line of models keeps expanding, and so does his business. In fact we’re one of the last things he’ll be doing at this location as they are moving into a new shop which is double the size of the current one, in a few weeks!

After things got started we collectively gave some “advice” to some new Shopbotters from the University of California who were in the process of assembling their recently acquired machine. Everyone had stories about what should, and should NOT be done when getting started too.

Then after we figured out what people were interested in we ran through a bunch of sessions which included everything from how to slice a 3D file, to what bits and speeds Gabe was using to cut out many of the aluminum parts for his trailer fleet. Gabe showed us a lot of new parts which he is now doing “in house” on his machine, instead of sending them out as he did earlier in his career.

Ross and Sue Piper of Rainbow Bridge Kits brought in one of their incredibly intricate miniature doll houses, and everyone was floored by the level of detail they produce in their products. They not only cut each and every piece out of Precision Board, but they texture, and paint, EVERY single stone, tile, and decking board ! They even had miniature signage cut out of Rowmark plastic, and a “chicken coop” that went along with the entire motif…

Tom Sansoterra brought in a great dished , and inlaid maple platter that he cut on his machine.

Wally Quanstrom, and Harry Warren had a beautiful Padauk piece which is used in their local church for flattening fliers, etc., and they showed pictures of some elaborate church furnishings they have assembled out of some VERY large Mesquite boards they milled themselves.

George Seebeck showed us  another inlaid dish that he cut on his machine, and then painted for additional effect.

Information overload struck in the late afternoon, and everyone said their goodbyes and exited into a beautiful (upper 80′s ,blue skies) Southern California afternoon while telling Gabe that they were all looking forward to next year’s event at the new shop…

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Wayne Locke has probably hosted more Shopbot Camps than anyone at this point, and they keep getting better over the years.

The 2012 edition was no exception and as previous versions it ran for two days.

Friday was a day where we all spent some time learning who was there, and what we were doing with the machine.

Santiago Laverde led off with a presentation of some recent projects done by he and his wife. He also showed us a pretty surprising free program called ’123DCatch’ which will “stitch” a series of digital photographs together and then “assemble” them into a usable 3D file ( .obj format)  for cutting !

Brett Dickinson gave his annual update of the progress he and his students have made in working with their Shopbot (s) as they continue to receive multiple awards for excellence in craftsmanship. Brett also brought, and assembled one of HIS new projects which is a “knock down” stand for the new Shopbot Desktop machine.

Brooke Davis, a local designer showed off some of her current 3D projects, and explained how she is tryng to setup a local facility to encourage the use of CNC machinery.

Gary Beckwith, of Beckwith Decor Products gave a talk about router bits. What they are, which ones work better in specific applications, and how to tell whether you are getting the most out of your current bit arsenal.

Joe Crumley did a few presentations. One dealt with the use of “finishes” for sign makers. In the first one he showed all of us the benefits of using Mica powders to enhance the final look of lettering. Then he gave a great session about designing signs, and what to consider when taking on a client’s proposal. He brought in some samples of his work which showed what elements you have to consider when building a sign from an idea.

Gordon Bergfors of Shopbot spoke about the new desktop machine, and he also showed some of the latest software innovations in the Shopbot control software.

Terry Jones showed some of the work he has been doing with both Sculpt Nouveau , and Modern Masters coatings on foam.

Our host, Wayne Locke then spoke about some methods he has used to create some uniquely shaped tables. Wayne rarely deals with straight lines, and his catalog shows some excellent design work.

I did a short session on the concept of running a “Shopbot business” and showed some examples of what has worked for people over the years.

And then there was the Show and tell stuff! Everything from carved walking sticks (canes) , to foam fish, solid wood inlays, memorial plaques, soap molds, luggage tags, patinas, AND some incredibly small plastic parts which are used by medical laboratories to hold a rats leg steady enough to do grafting of bone tissue..We NEVER know what will show up at these sessions, and as usual this year didn’t disappoint …!

Our thanks again to Wayne for hosting the event, and to everyone who attended…

Dave Rosenbleeth invited us back for the second Ft. Lauderdale area Florida Camp and this year was a two day event. Shopbot used it as a sort of “launching pad’ for a few new items, and we had a great turnout from a pretty wide geographic range ( including Brian Moran of Vectric who flew in from England at the last minute…!).

Friday was geared more toward the concept of using a Shopbot in a “production environment” with cabinet making being the focal point. Our host Dave Rosenbleeth presented his method of producing his ‘boxes’, and then Gary Campbell of Shopbot gave an overview of how similar products could be generated using the “E Cab/Shopbot link”.

Ted Hall then gave all of us an overview of some of the upcoming changes in the Shopbot control software which will facilitate some easier ways to allow machine operators to store, and call up files they use on a regular basis. He also showed us the new “RBK” control box which will allow owners of machines going back as far as the “PR” series to upgrade their machines to a much faster/smoother operation. In fact the box on display was going back to the island of Aruba right after the Camp with Jerry Lourens who flew in for the Camp !

In addition to the new control box there were two desktop machines running, one was cutting “rotary files” using the new desktop indexer, while the second machine was producing “3D parts” using the new “3D printer head”. ALL of these units are featured in the gallery of pictures for this Camp, as well as on the Shopbot “Facebook page”:

http://www.facebook.com/pages/Shopbot/204183026284101#!/pages/ShopBot-Tools-Inc/220266404651470?sk=wall&filter=1

There was a LOT of great “Show and Tell” on hand, and the items ranged from LED signage, to parts and files which are available FREE to all Shopbotters through the web page, and Vectric software. Tim Merrill, and Michael Tyler were the principals involved in these files, and they both had a number of items on hand to show what the tools, and software are both  capable of producing. And David Beede came in with a “Show and Tell first” when he not only SHOWED his portable electric bass guitar, he PLAYED it for the group !!!

Dave Rosenbleeth explained the odyssey of how he has been constantly upgrading his older PRT machines, and he showed how “current” his machine is because of all of the improvements he’s made.

Bob Schwartz of Onsrud tools gave a presentation about tooling, and answered all questions regarding specific applications those in the group were dealing with.

Bill Young and Ted Hall went over the new, revamped “100K garages.com ” project and explained the goals they were hoping to achieve.

I finished up the Camp with  a session on the idea of running a Shopbot business, and that brought in some great feedback from those in the group who have had various levels of success with some of their ideas, and products. We had a pretty wide range of experiences, and I think it may have opened some ideas to newer ways of doing things.

Good group, good presentations, good food, and a great chance to catch up with friends. Thanks Dave !!!

Throughout the day we had close to 30 Campers, ranging from people who had never seen a Shopbot, to some with very extensive experience.

We got into a little bit of everything from cutting plastic, to running a Shopbot probe , with a continual dialogue about how to make a “‘Bot business” work.

Bill Young brought along a small DIY CNC machine which was cut out of plastic by a Shopbot.

William Davis, and Adrian O’Neal brought in a few signs they are cutting for the North Carolina parks out of  “color core”, and they explained how the Shopbot has allowed them to do more, with less staffing on hand. We used their experience to get into the sign making process for awhile, and a number of people shared their own experiences with customers, and installing signs they had made.

Joe Johnston brought in a sign he has partially completed, and explained how he plans to use gold leaf as a finishing touch for added impact.

Frank Allen brought in a few samples of pieces he had probed so we could review the process of probing, and then cutting a “2D profile”.

There was some interest in the mold making process and we went into the idea of using the Shopbot to make “masters” for a mold.

Angus showed a few things that he has been making in his shop, with both his Shopbot, and laser. He also showed how his double zone vacuum system works/sounds when in operation.

I also brought along a small vacuum pump/pod setup, and a “Brady vac”system, so we got into the various possibilities for holding parts down which led to  some feedback regarding the use of larger systems such as the “roots blower” system.

Angus’s wife Jacqui served up a killer lunch, and Bill Young brought along plenty of goodies from the infamous “Yellow Duck bakery” so in fine Tidewater tradition everyone listened, and ate well throughout the day.

Only glitch at all was the fact that for some reason my camera stopped working early in the day, and I only have two pix to document the Camp. One is of Bill Young and the DIY CNC machine, and the other is of the signs being done for the North Carolina park systems.

Many thanks to those who attended, and to Angus, and Jacqui for opening their shop/home to us for the day !

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Dave uses an older “PR” model machine which he has upgraded to a “4G PRT” with E-chain, spindle, etc., etc. and when you see the quality of the pieces he had on display it’s obvious that he’s dialed in his rig to very exacting standards.

There was a lot of interest in learning how to do 3 dimensional work, as well as picking up some tips on the process of building signs. We also got into the concept of what it takes to run a Shopbot based business, and there was some great feed back from all sides on that topic.

The “Show and Tell” pieces on display were exceptionally good. Our host Dave does cribbage boards, but unlike any cribbage boards you may have seen before. Using a little mathematics, and wizardry he has incorporated multiple bevels, beautiful hard woods, and hidden magnetic latches to create folding units which look great even when they aren’t open! Outside his shop, and in a few neighbors yards, you could also see some of his working water wheels in action.

Daryl Boulton stopped by Friday afternoon to drop off an “experiment” he had attempted on his newly acquired 12″ Shopbot indexer, and it stopped everyone in their tracks with it’s detail, and “accidental” blending of design and wood grain!  He carved  a dragon which wrapped itself around a log of about 12″ in diameter, and it looks as though he’s certainly figured out the process !

Larry Peterson brought in one of his “long boards” which are totally unique skate boards which  he builds by cutting, and layering multiple veneers of thin wood in hydraulic presses to create truly “organic” molded shapes unlike ANY plywood you have ever seen before. And that was only one of many different styles his company produces.

Mike Miller brought in some of his custom parts for marine use ( rod holders, cup holders, etc) which he cuts out of ” Sea board” and then incorporates them into VERY beefy aluminum frames for “real world” usage.He gave some great examples of how one could get more efficient production by “nesting” smaller parts between larger ones in the planning and layout stages.

There was also some VERY nice abalone inlay work on a guitar neck, and as soon as I can remember who did it I will post their name as they truly deserve recognition for it (particularly the 5 piece inlay on the neck….) .

Alan McCarthy showed off a large mantle which took a couple of days to complete , and was obviously worth the time and effort.

And as usual there was just as much information exchanged during the breaks,and lunch as people met one another, and tried to pick up as many tips and tricks as possible..

Plus, the weather turned in our favor and we snuck in a beautiful blue sky day  which had some of the “locals” squinting from the excessive amount of sun shine…..

There are many times when our computer controlled machines seem to have been taken over by gremlins.  Usually, these “gremlins” are erroneous settings that cause unexpected actions in the machine, or unexpected reactions to commonly used commands.  Windows (all versions) has long been plagued by errors that occur when the OS is closed abruptly.  The same is true for most Windows software.   SB3 and the SB Link are no exceptions.

Since ShopBot 3 and the ShopBot Link both require a large number of settings be stored accurately to enable our machines to operate properly, keeping a backup copy of these settings is essential to a quick and painless recovery from a software crash.  There are a number of causes for these crashes, many are a result of external electrical charges, or in some cases, the machine has hit a limit switch or experienced a power surge or flicker.

Without going into what can cause these crashes, I will show you how to recover from them and be back up and running in a few minutes.  Of course, before we can restore from a backup, we must first create a backup.  Here is the method I have shown to a good number of users.  There are many ways to accomplish these simple tasks, this one uses Windows Explorer and select, copy and paste mouse commands.  On some computers, you may have (or wish) to select these commands from a menu or drag and drop instead of using a mouse click.  Use the method that you are the comfortable with.

Note: In cases where a user would call ShopBot Tech support, they will ask you to install the latest version of the software and proceed as per instructions.  This method gives  Tech Support a known baseline that will allow them to repair most software related problems.  Installing a new version of SB3 overwrites many of the settings and customized files we users have stored in our machines.  My method allows us to keep our current software version, all of our custom settings and files intact, and should take less time than a call to support.

If you are not comfortable using Windows Explorer to copy and paste files have someone help you, as it is important to get this right.  This procedure cannot replace tech support for all users, but in cases where the user has fairly competent computer skills, will allow him/her to self repair without a great deal of effort.

Create a Backup:

Open My Computer > Double click to open “C:” drive  (may be named something like C: “special name”)

Select C:\  then R click and create new folder, name “BACKUP” or “ZBACKUP” to have your folder displayed at the bottom of C:\ drive contents.  If you have multiple drives on your machine, locate the BACKUP folder on one other than C:\.

SB3 Control Software:

Find (if you have saved a local copy) the SB3 version that was used to install your current Control software.  For example the latest version is named: “Setup_sb3_6_38.exe”.  Once located, R click and select copy.  Navigate to where the BACKUP folder is visible, R click and select paste.  Verify that the file has been copied there.  You can download the SB3 software, but I prefer the speed of a local copy.  Saving a local copy also keeps you from forgetting which version is your “known working”.  When downloading a software version from the ShopBot website you have the option to “Save As”.  Navigate to your BACKUP folder and save your preferred version there.

SbParts Folder:

With the C:\ folder open, R click the “SbParts” folder, select copy.  Navigate to where the BACKUP folder is visible, R click and select paste. Verify that the file has been copied there.  You should repeat this copy/paste (select overwrite) anytime a change has been made to the software, your custom files or setup. A routine should be implemented to backup these files at least once a month.

SB3 Settings:

The next step assumes that SB3 is running, all your settings for speeds, ramps, homing (via the SB Setup), etc. are to your liking AND your machine has been homed and sitting at the 0,0 location.  Do not make the SB3 backup unless your machine is working error free.

From the SB3 Console enter [U]tilities [S]ave Current Settings to a Custom Settings File.  In the Save dialog box, navigate to the C:\BACKUP (or your other location) folder and save the file as, in my case, “GC SB3 Settings.sbd” Use a name that you will recognize as your SB3 software settings.  This file will store all your current settings, most of which we users do not know exist.  Make sure that the proper file extension is not overwritten.

IF you are a not ShopBot Link user, skip the next section and go to the “Restoring Your Settings” paragraph.  For Link users, the procedure is similar to SB3, but has an extra step:

SB Link:

Like SB3, make sure that your Link Settings are as you prefer them and are working well.  I usually go into the [Load] dialog and select [Clear All] to remove any parts loaded, but this is not important.

From the main screen, press the [Export] button.  Navigate to the C:\BACKUP folder and select [OK].  A command window will appear, the file is created, and you will be prompted to “press any key to continue”.  The name of this file cannot be modified during the save procedure, so navigate to the C:\BACKUP (or your location) folder, R click on the file named “ShopBotLink1-0-xx.cab” and select rename. (xx refers to current Link version)  Rename this file, in my case, “GC Link Settings.cab”, in yours, select an appropriate name for you.  Make sure that the proper file extension is not overwritten.

Restoring Your Settings:

In most cases the control software does not need to be reinstalled.  IF you feel that it does, remove the current version using  Windows Uninstall.  The path to this varies a little between versions, but “Add or Remove Programs” or “Programs and Features” are located in the Windows Control Panel.  Select “ShopBot 3 version 3.x.xx” from the list and press “Uninstall”.  You may choose to skip this step, if so, proceed to “SbParts:” below.

SB3 Control Software:

Once Windows has completed the uninstall procedure you may want to reboot the computer and possibly run a registry checker to remove or repair any errors.  Next, navigate to your BACKUP folder, double click on the “Setup_sb3_x_xx.exe” file to install SB3.  For this install it does not matter which of the install options you select as we will overwrite all the OEM with your saved files.

SbParts Folder:

Next, navigate and open the C:\BACKUP\SbParts folder.  R click and select all (or [Control] + [A]), R click and select copy.  Now navigate to the C:\ drive, R click on the SbParts folder, and select Paste.  When prompted, select overwrite or replace, depending on your windows version.  I have a trimmed down version of SbParts with no OEM files in it.  I usually delete all the existing prior to paste of the backup files.  Unless you have a large number of modified files, you can skip this step.   You should now have a clean version of SB3 installed and have kept your user defined variables and customized (if any) files.

SB3 Settings:

Turn on your machine, Start SB3, square the gantry, zero the X & Y axes (home) and leave (or move) the cutting head at (or to) the 0,0 location.  From the SB3 Console, enter [U]tilities [R]eset Default Settings, Load……  Select [YES] to the “Do You Want to Clear the System Log….” dialog box.  Select [Yes] to the “Do You Want to Load the Default Settings or Load a Custom Settings File……” dialog box.  Select [OK] to the “Select and Load Settings….” dialog box.

Navigate to your BACKUP folder and select the “Your Saved Name SB3 Settings.sbd” file.  SB3 will load all those settings that were saved when you made the backup. SB3 Settings are done.

If you are not a SB Link user, you are done and should have a machine that responds as expected.  Once you go thru this process a couple times you can accomplish it in a few minutes, and knowing how to do this may save you a good number of calls to SB Tech Support.

SB Link Settings:

Open the SB Link, and from the main screen press [Import]. Navigate to your BACKUP folder and select your “Your Saved Name SB Link Settings.cab” file.  That’s all there is to it.  You are good to go.

In most cases this will repair lost or erroneous settings caused by a software crash.  In the cases that it didn’t, you will most likely have to install the latest version of the control software and possibly call support.  In other cases there may be a bad component or computer problem that these settings fixes cannot repair.  In any case you still will have the ability, once your machine is up and running, to cherry pick Custom files, variables or user modified files from your backup folder.  When doing this, make sure you save the existing OEM file with another name, in case there is a problem with your backup version of that file.

If you are able to diagnose that your problems are isolated to either SB3 or SB Link settings, you can restore those settings alone, but if you are not able to diagnose and isolate which is the cause, Follow the steps above, In Order!

Winter, and its never ending supply of static making dry air is almost upon us.  Hopefully, this procedure will give you a way to recover from software crashes caused by this static and some of the other gremlins that make our ShopBotting experience not so fun.  I would recommend that if your experience these problems more than once a month, that you make a concerted effort to find and repair the root cause.  You can also save your BACKUP folder to a thumb drive and use these files to allow another machine to have the exact settings as your original.

Hopefully, this will allow you to get up and running quickly after a crash and truly have a “5 Minute Software Fix”

(Note: Many versions of SB3 software contain improvements over the previous versions.  This method does not allow you to take advantage of these improvements)

One of the tasks at which the ShopBot excels is processing sheet materials.  I love that I can slide a sheet of melamine or plywood onto the table and a few minutes later pull off a small pile of parts, ready for edgebanding and assembly.  If you have done your design and programming properly all the machining operations – holes, dados, rabbets, notches, pockets, joinery, etc. – are completed by the machine before the parts are cut to shape and size – as long as they are all on the same face of the sheet.  However, when processing sheet goods it is virtually inevitable that you will need or want to perform operations on the other side of at least some of the parts.  Often these back-side details are referred to as “secondary operations” since they normally are performed on the individual parts after the parts have been machined out of the full sheet.  More colloquially they are called “flip ops” since you have to flip the part over to machine the other side.  In a larger shop these secondary operations might be performed on a different machine, freeing up the primary machine to start cutting the next full sheet.  They might even use a different primary machine such as a beam saw to quickly cut large quantities of rectangular parts and use the ShopBot or a similar CNC machine to perform operations only on those parts that need them.  In any case there is a big difference between cutting parts from a full sheet or an oversized blank, and machining operations on a part that has already been cut to its finished size and shape, primarily when it comes to locating the operations accurately on the part.

A few minutes ago this was a full intact sheet of white melamine. Now it's a stack of parts ready to be edgebanded.

When cutting out of a full sheet or a larger blank, the same machine performs the operations and then cuts the outline of the part without the part moving in between, so even if the sheet is not located precisely on the table, or the machine is not zeroed perfectly to the reference point of the table or the sheet being cut, the operations will be in the correct locations on the part.  With secondary operations there are serious issues of registering the part correctly on the table, and having the machine calibrated accurately, so that the operations are correctly located in relation to the edge or corner of the part.  After all, what’s the point of using CNC equipment to process parts if the parts aren’t going to fit together perfectly, or the holes aren’t going to be precisely in the right place?

So a lot of effort is made to address these issues when secondary operations become part of a production setup.  Let’s look at the two issues I mentioned separately.  First, we have to ensure that each part is positioned exactly in the same place relative to the table of the machine.  On a dedicated secondary machine this should be pretty simple – put stops or fences along the reference edges and slide the part up to the fences or stops.  If you are only making holes or pockets, and are not doing any operations to the edge of the part, that would be all that is needed, but if you might be routing rabbets, dadoes or pockets that extend past the edge of the part you might have a problem with the stops being machined away – and depending on what the stops are made of that could get ugly.  When cutting full sheets you might or might not have a similar problem, depending on how close your parts are to the edge of the sheet – I like to put my parts pretty close to the edge to maximize how much of the sheet I can use and minimize waste.  The stops also need to be removable in order to surface the spoilboard without the stops being in the way.  So one of my requirements is that the stops have to be easily removed or dropped out of the way after the sheet or part has been registered against them.

My original stops consisted of slotted hardwood blocks which were bolted to the edges of the table with threaded inserts. They worked well enough for several years but proved to be too cumbersome for day to day production.

My initial solution to this problem was to install large threaded inserts into the edge of the table, and make some hardwood stops with slots so I could bolt them to the side of the table, then loosen the bolts to drop the stops out of the way or raise them into working position.  This worked pretty well for a good while, but as our throughput increased and we were spending more and more time raising and lowering (or replacing) stops, I needed a better option.  I recently re-built the edges of my table to incorporate pneumatic “pancake” cylinders which can be raised and lowered with the flick of a switch.  I borrowed heavily from Gary Campbell’s article and his expertise while designing and implementing this system.  The result is a robust, repeatable system which is fast and easy to use.  We now use these stops for virtually all the flat work that we cut, from full sheets, to individual parts, to flat solid wood workpieces, often in conjunction with an “L” shaped mask or fence to move a small workpiece away from the table edges, as I have previously shown.

The new pneumatic cylinders are mounted to an extension that I added to the base layer of the table. The aluminum pistons pop up or down at the touch of a button and are extremely solid.

So that takes care of part placement on the table.  With the other issue of machine calibration I also started with something simple, that I could implement quickly, but that turned out to be a little more time-consuming than I could justify as our needs increased.  You might ask, “why not just use the proximity switches that came with the ShopBot?”.  My understanding is that the switches that are currently used are somewhat better than the ones that came with my machine, but my personal experience with my own switches is that I could not rely on them to hold the level of accuracy I needed.  Those switches are held on by only a single small bolt, which made them susceptible to rotating slightly if bumped or just due to machine vibration.  (I’ve since started taking measures to prevent this when setting up a new machine, such as sanding the paint off the area where the switch will be mounted, and using a little epoxy in addition to the bolt when securing the switch in place.)  Also, one of my switches had started to fail, and I replaced it with a home-made version that worked reasonably well, but again could not be relied upon for the repeatable accuracy we require.

My initial method of calibrating the X and Y axes was based on how I was taught to set the hairline on my tablesaw fence – by measuring an actual workpiece after making a cut.  In this case I wrote a routine that routed an “L” shaped dado with its shoulder exactly 1” from the edge of the sheet, then paused while I measured the resulting distances with digital calipers, and entered the actual measurements using an INPUT statement.  The program would adjust the proximity switch values, re-zero the X and Y axes to the switches, and make another cut to verify that the current set up was accurate.  How accurate?  For my purposes, I decided that anything within .01” was acceptable.  Using this system I was typically able to get to within a few thousandths in each direction without too much trouble.  We used this system for several years, relying on the prox switches for general use and full sheet cutting, and using the custom calibration program for flip ops or any other tasks where accuracy is critical.  Eventually, however, the custom calibration routine became too cumbersome, as it required an empty corner of a sheet, or a dedicated calibration blank to be placed on the table, and once the corner of the blank was used, a fresh corner would be needed for the next go-round.  Also, if the operator did not hold the calipers correctly the measurement would be less than accurate.  So a faster, more repeatable, less subjective method was called for.

My 1st generation method of calibrating the machine to the workpiece involved milling an "L" shaped dado and measuring the distance from the shoulder to the edge of the sheet. By adjusting the prox switch values and repeating the process, I could get accuracy to within a few thousands of an inch.

So as part of my recent table re-build, I also incorporated a permanent aluminum XYZ zero block near the 0,0 corner of the table.  I used the “Super Zero” block which I purchased from Morris Dovey several years ago, but since I’m not using the fences that came with it, it’s essentially just a small block of aluminum with a hole.  It’s bolted into a recess in the table base layer, and wired to the control board with a double nut on the end of the bolt underneath the table.  The flat top surface of the block acts as a Z zero plate, and the hole allows the bit to plunge in and zero the X and Y axes to the sides of the hole.  This allows us to re-zero any or all axes quickly, regardless of whether or not the table is in use or even completely covered with a workpiece or a full sheet of melamine.  To accommodate spiral and compression cutters, which need to plunge fairly deeply into the hole to ensure that the bit will contact the edges of the hole at its circumference, regardless of rotational position, I embedded a short piece of aluminum tube (actually a closet rod cut-off) into the hole.

The parts for the new XYZ Zero block are ready to be installed into a recess in the base layer. After being bolted down, the top face of the aluminum block was surfaced flush with the table using an aluminum cutting end mill.

Now we can initiate an automatic re-calibration of all three axes at any time, and have the confidence of knowing the cutter is accurately located in reference to the pneumatic stops, and therefor to the edges of the workpiece.  Our accuracy has increased and setup times and re-work decreased tremendously.  My only regret is not doing it a long time ago.  Check out these YouTube videos to see the new stops and XYZ Zero Block in action.

Video link: Pneumatic stops on a ShopBot PRTAlpha

Video Link: Automatic X, Y and Z Zeroing on the ShopBot