Shopbot models and features comparison?

[Andy Guss]

I am hoping that there are some Shopbot experts here that can answer a few basic questions for me.

I am thinking about getting an older shopbot model, probably from 2006-2009, but I don't know what model it is and I can't find any identifying label on it.

I can tell you that it looks almost exactly like the one in this video- https://www.youtube.com/watch?v=IlDynfOS6uA with the exception being that the one I am looking at has a built in spindle instead of a porter cable router. Does anyone know what the name is for this model and if it can be upgraded easily if all I wanted was to use the heavy duty x-y-z platform, spindle, and the stepper motors and replace the controllers and software with something more modern? I suppose I am ok if the capacity is not 4' by 8' and if the speed isn't that great, but I would hope that I could achieve pretty good accuracy and maybe upgrade the dust collection?

Thanks,

Andy

[Gary Campbell]

Andy...
The machine is a PRT BT-32 model. A smaller version of the workhorse that ShopBot has sold thousands of. They were made to upgrade. If you want to know exactly what it is, as they all look pretty much the same, post some pics of the Y car, the motor labels and one from inside the control box. The cutting area is 24 by 32.

What type of upgrades are you looking to do? I cant post a link here, but I make an upgraded controller for the older PRT models that does allow you to use the latest design and control software. Look on the "For Sale" section, second page, thread titled "PR and PRT Control Upgrades"

[Andy Guss]

Hi Gary, And thank you so much for this reply. I don't know how old this unit is, but as I said before, maybe from around 2005 based on the computer that came with it. This isn't mine yet, but I am hoping I can get this one. It seems about the right size. I went to look at it today, and if anything, it looked very overbuilt based on the frame and the thickness of the steel frame components.

One of my concerns was whether this particular model had a lot of problems, which is why they stopped making it this way. For example, instead of ball screws or threaded rods for drive, each motor turns a very small gear perpendicular to the travel motion along a long geared rod. Maybe this was a terrible control / motor scheme. Another difference between this one and almost all the other designs is that on this one, x and z move the router/ spindle, but y moves the workpiece. I apologize if I am using the incorrect terminology for these things. One other major difference is that on almost all of the newer systems the z carriage is mounted on the front of the lateral travel. On this one, the z axis rides in a fixed box that travels. You will see from my pictures.

In my experience, a company will make changes like this because the old design is just too flawed to work properly or because it is too overbuilt and expensive to keep making that way so they come up with something that still gets the job done but is cheaper.

Because the basic platform for x y and z seems like it is way overbuilt, if the motors are good, I would probably keep it as is and just try to upgrade the controls. At some point somebody got frustrated with the electronics and started unplugging things and cutting wires, but if I could go to some kind of modern pc compatible usb situation, I would be thrilled. I would rather put time and money into going that way than in to trying to reconnect all of this really old circuit board componentry that I don't even know if it works and for which I have no software or manuals.

I'll try to upload some pictures and I would love to hear your advice.

Thank you,

Andy

table2.jpgtable.jpgtable 3.jpgmotor.jpgcircuits.jpg

[Gary Campbell]

Andy...
Since it shows unistrut on the Y car, I don't think it is as new as you think. Around, maybe just before 2000. The controller has been upgraded to what ShopBot refers to as a "4G", even tho yours has only 3 drives. They are adequate machines, but you would be mistaken to call them overbuilt by todays standards. The were good by 2000 standards.

There were not a lot of problems with that model that you would need to worry about. It (the PRT design) was imitated by other OEM's and had an almost cult following. Its just not as easy to change a bit as the newer models, one of the reasons the factory changed design. ShopBot still produces a moving table model called the Buddy. They, and most other OEMs use a rack and pinion motion system to this day.

IF it runs, buy it and go have some fun. The ShopBot community will bring you up to speed on your wishlist, as these machines have been around for 20 years

[Andy Guss]

Thanks Gary,

I tried to create an account on the talk shopbot forum but they seem to have disabled the new account registration automatic process and the human involved has not approved me yet.

I have a few questions about this older Benchtop 32 PRT system.

1. If I have no software or manuals to go with it, are they available for free, or are there inexpensive software options that will work with these controllers?

2. Can I add a 4th axis for rotation if I want to go down that route at some point?

3. Can you run a long piece through this machine with a tiled cut path? I can't see a physical reason why it could not be possible to do a really long panel as long as it doesn't exceed the 32" width. For example, cut a 24" section, slide the panel through, cut the next 24" section, etc.? There is a system like that for the buddy benchtop machine. I think the weight might be a problem for the stepper motor that would be moving the lang panel, but the other two axes should be fine, I'd think.

When I said overbuilt, I was thinking of it compared to some of the tiny benchtop and table top systems that have come out recently and that are targeted for the hobby market. I was impressed by the thickness of the steel in the frame. Some of the more critical parts like those bearings and the pinion gear might be too small for commercial work. I am not sure what people have been doing with CNC machines like this, but given the initial expense, I would assume that most of the ones like this and larger have gone in to some sort of commercial application. Now that some are slipping into the secondary hobbyist market, there are probably tons of guys like me who are new to it, but who don't have the resources to get in to something that will become really expensive.

Thank you so much,

Andy

[Jerome Stanek]

The software and manuals are on the Shopbot website. You could add a 4th. Yes you could tile a longer piece

[Gary Campbell]

To add to Jerry's comments:

The PRT manual is on the SB forum, but there may not be a BT specific version. Try google.

Yes also on the 4th axis. SB probably still sells one that is compatible, and there are often ones for sale on their forum.

The ShopBot control software is free. I would recommend using a version that is at least as up to date as your computer. For design I would suggest one of the Vectric line, they start at a few hundred and go op to a couple grand depending on your needs. Easiest CAD/CAM to learn on the planet.