And so it came to pass that one day I had the opportunity to purchase a vintage Gerber System 48 CNC sign cutting router. Manufactured in 1987, the router had long been in disuse and was discarded, unloved, in the far corner of a local sign cutting shop. The times had clearly passed it by, and it was not considered viable for a refit or refurbishment. The reason? Well, there were a number of things which needed an upgrade but its major sin was that the bed, although a substantial 5x6 foot, could not accept the standard 8x4 foot sheets of material in use today. This necessitated the use of half size sheets which then required the sign shop to break jobs into pieces. "Time is money" economic reasons eventually dictated that the router had to be replaced by a larger, more modern, machine. The router was disassembled and relegated to the depths of the workshop.
It is hard to describe the feelings one gets when you see something like that covered in dust. For a person interested in homebrew CNC machining, finding that Gerber System 48 was much like discovering an old car long abandoned in a garage. Unfortunately I do not have a picture of the router in-situ. The image at left conveys the concept, except it would have been on its side and the wheels and axles would have been stacked in a far corner and also its not worth millions like a 1937 Bugatti - but you get the idea.
I soon arranged to purchase the machine "as is, how is" for a very agreeable price. Less than the scrap metal price actually since the router is very
solidly built out of steel beams (more on this later). In fact, it cost me more to pay a trucking company to move the thing 20 miles than it did to purchase it in the first place.
Wellity is just my name for the project. All of my projects have silly code names. In fact, for some perverse inexplicable reason, I cannot really get started on a project until I do have a name for it. In this case, given the size of the
router, its extreme weight and unknown mechanical condition it was a matter of some concern that the aquisition of the router might be a very unwise decision.
While deciding on a project name, I recalled an episode of the Simpsons where Homer said "Wellity, Wellity, Wellity" with vast over confidence just before he
and Flanders, with equally debatable wisdom, decided to go off to Las Vegas, get very drunk and bigamously marry some waitresses. Hence the name - click on the icon at right to hear Homer.
The Wellity router is a remarkably well preserved and functional machine mechanically. The router has a very solid bed, unwarped and perfectly usable, which contains numerous T slots for securing the workpiece. Two precision round stainless steel rails run up each side of the bed and are firmly welded to the Y axis beams. Considering the age of the machine (and the lack of maintenance over the last few years) the rails have very little corrosion. These rails form the Y axis and there is a belt running along side each of them to pull the gantry backwards and forwards. The belts are in very good condition and are both taut and unfrayed. A large stepper motor and gear combination drives the belts. Four very large legs were supplied on which to mount the bed. In the picture at left, the Y axis runs horizontally left-right across the picture.
The X axis is mounted on a very substantially built aluminum and steel gantry. The gantry rides along the Y axis rails on roller bearings which remarkably, were in good shape and (even more remarkably) not lost, since they were found rolling around loose in a old plastic bag of miscellaneous parts described as "might come in useful" by the people selling me the router. The X axis mounts the Z axis carriage on two further stainless steel rails and this too is driven by a belt turned by a largish stepper motor located in one end of the gantry. The picture at left shows the X gantry with the toolhead towards the bottom right end. The top of the gantry is at the bottom of the picture and you can get a sense of the scale of this machine by noting the bicycle tire in the far right of the image. As I have mentioned before - this is not a small machine.
The Z axis is a very precise looking piece of machined steel with two rails (each coated with a truely impressive amount of dried oil and other crud) and a fine screw shaft to provide the propulsion. A top mounted stepper motor moves the Z axis up and down and attached to the screw shaft there is a tool head plate for a router. 110v A/C power is supplied to the toolhead via a heavy cable which coils and uncoils as the Z axis carriage is driven along the X axis. Testing indicates that the Z axis stepper motor is very weak and no longer has anything like the required strength to move the heavy tool head up and down. It will have to be replaced.
A set of four bellows designed to protect the Y axis rails from swarf and dust were also provided. Upon examination it appears that some of them have not stood the rigours of time very well as there are numerous gaps and rips in the canvas material. Still, can't grumble, they are rather old and have doubtless been expanded and contracted many times while the router was in use. And to be fair, the fact that they exist at all is amazing - since they could be with the X axis bellows which are long since gone. The picture at left shows one of the bellows after it has been patched up with duct tape. The Z axis rails are protected by a rather expensive looking spiral stainess steel spring things which expand and contract as the head moves up and down.
It came with a router, did I mention that? A professional 115v Porter Cable router designed for cutting plastic and aluminum. None of this wiring up a light duty hardware store router or (shudder) a dremel and hoping for the best for me. This is the proper bit of kit. There was even a collection of slightly rusty old collets in the aforementioned bag of miscellaneous junk.
The power supply is an super heavy panel box that is mounted vertically below the rear of the machine. It contains a large tranformer which converts the 240v supply to 115v and also what looks like a really enormous full wave rectified power supply. This also has its own transformer which also contributes to the extreme weight of the power supply assembly. I'm guessing that they did not have switched mode power supplies of sufficient amperage back in 1987. Also contained in the power supply box is the very large driver board for the X,Y and Z axis stepper motors. This board is so large and so old that you could, if you had a mind to do so, map out the circuits by following the traces from component to component. Ahhh... those were the days, try that on a modern, surface mount multilayered board these days and see how far you get. There is also a box with are six very large 6 ohm resistors equipped with cooling fan beside the stepper motor driver board. I am not sure of the methodology here, it may well be that they implemented some sort of mico-stepping by dumping the excess current for each bipolar phase through these resistors. Mega inefficient - these resistors are about 6 inches long and 2 inches in diameter and, judging by the scorch marks on them, they have clearly seen no little amount of heat. Other than the transformer for the 110v toolhead there is not too much in the power supply cabinet which will be re-usable in the refurbished router. I do however, plan to scavenge the various components for other projects.
Oh dear, where to start with this. Computing was in its infancy back in the 80's and the control system for the Gerber router necessarily reflects that. The computer which controlled the system is a circuit board of about 3 foot by 1.5 foot absolutely covered in TTL chips of various types. There is a keyboard at the bottom and a power supply at the top. The case is, as I have come to expect with this device, is built like a tank and consists of a thick steel box which was bolted around the circuit board and a acrylic window at the bottom which the operator reached under to type away at the keyboard. I assume this was done to keep swarf out of the keypad. The case also came with an interesting girlie poster stuck to it by some "long-moved-on-to-other-things" operator. I have decided to retain this and put it up in my own shed in the sure and certain knowledge that it will soon be collectable "art" just like those dodgy postcards from the 1950's.
All of this (except perhaps the way too thick steel) is pretty standard state of the art for a computer probably designed in the late 70's sold in the mid 80's - however the visual interface is the truely impressive thing. There was no screen, the entire user interface consisted of a 6 (yes, six) character display through which the operator typed in the program that controlled the machine. Remember those old Texas instrument calculators with the little wire like displays? Well that's what the character display looks like. As far as I can figure out, the items to be cut (letters and such) were programmed in a kind of markup language not dissimilar in concept to HTML. The font was controlled by a font cartridge plugged into the computers bus. My router arrived with an Ariel font cartridge the size of a paperback book which I think is kind of interesting. Imagine programming HTML by looking at it via a window 6 characters wide. Admittedly the programs probably were not much more than a couple of markup characters and the text to cut - but still it can't have been easy. I am told that later on there was an add-on interface available in which an IBM PC could send programs via serial port to the routers control computer. In fact, I think I have something which looks suspiciously like it might be one of those - but no matter. I am not going to go retro, dig an 8088 PC out of my attic, run DOS 2.0, and try to talk to some ancient hardware.
The people who sold me the router also dug up a dusty old manual. Unfortunately this manual is purely for the software system control and programming system and there is nothing in there resembling technical specs or wiring diagrams. Looks like the cables will need to be traced out by hand. This is not at all as easy as it seems since the router frame is 6x6 inch hollow steel beam and these were used as convenient cable trays by the manufacturer. Still, all the wires that go into the frame must pop out somewhere, so it should all be findable.
The build quality of this machine is simply amazing and has to be seen to be believed. There is nothing "lightweight" about this machine either in the literal or figurative sense. The bed needs to be lifted by forklift. Four very strong men might be able to lift it but they wouldn't have much left of their backs after they did so. The bed framework consists of two 6x6 inch hollow rectangular steel beams under the Y axis and four 4x4 perpendicular hollow rectangular steel beams supporting the table parallel to the X axis. The legs are four more of the same 4x4 inch hollow rectangular steel beams bolted onto the Y axis beams with four large bolts (each). These bolts were missing in the above mentioned little bag of "might come in useful parts" and I had a great deal of trouble figuring out what size and thread they used. The problem was the delivery people forklifted the router frame into my workshop but when it became apparent that there was no way of bolting the legs on they left it on some wooden blocks. It is not possible to reliably use a thread gauge on holes on the underside of an unliftably heavy steel assembly 4 inches off the floor. In the end I pressed some blu-tack into the threads with a pencil, carefully pulled it out, and then measured that.
The gantry is a hefty bit of aluminum and cast iron (for the end housings) and cannot really be lifted safely by one person either. Yes you can do it, and I have, but once done you really wish you had waited for some help. The Z axis and toolhead carriage are large, carefully machined, chunks of steel which look they should be way to heavy to move. (Addendum: the Wellity router can shift the gantry and tool head about at quite some speed - clearly the mass of steel is not a problem).
The quality of the components is also top-notch. After 20 years the belts which drive the X and Y axis are still in good shape and were still nice and taut. The bearings are mostly good (I will only need to replace one) and the stepper motors (other than the Z axis one) were, for the most part, still in pretty good shape - even though they were the old style round case motors in which one expects the magnets to deplete after such a long time. Even the gear boxes on the X and Y axis which contained some plastic gears were not very worn and, with the exception of the Y axis gear with the dodgy bearing, had almost no observable backlash.
Click on the image at left to see the Wellity Router on its legs and under refit. All the sawdust is due to the fact that once it became even slightly operational I started using it for other projects. In fact, that has been the biggest obstacle in the way of finishing the off the build. Even in its half complete state, the Wellity is just too useful and every time I get near it I tend to use it for other projects rather than finish it off.
The idea is to convert the Gerber System 48 into a mill suitable for light duty CNC work. At the end of the project it should be possible to cut plastic, wood and aluminum with it. Of course, a large (6 x 5 foot) bed CNC router is not something one typically has access to and hence, the scope of suitable projects increases because of it. Because the gantry and tool head is capable of carrying a lot of weight, this too, opens up a lot of options for replacement toolheads.
All in all, when I get it finished, the Wellity router should be a pretty useful tool. The list below contains the various tasks involved (this will change as I learn a bit more about what is required). If the item is a link, it will take you to a page documenting what was done and how.