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Hey Justin:

The outside of the spoil board is attached to the 20x80's with screws through the board into tee nuts installed on the top outside slot . I usually use 4 tee nuts/screws on each side, and an additional 4 on the front and back rails. This way the spoil board is firmly held all the way around the perimeter and in the center.

I usually recess the front and back screws into the MDF so there is no chance of the bit hitting them accidentally, and they don't interfere if you have material hanging over the front or back of the bed. The left and right side are not recessed because the bit is physically unable to reach them.

MG

 

I pretty much always use an Arduino Nano with a screw terminal shield to make wiring easy. It runs GRBL. I Never use XPro's, I have a very low opinion of boards with no replaceable drivers. Also doesn't have the current capability to properly run a NEMA23 motor. $200 down the tube if you blow a driver. Arduino/GRBL is definitely the best bang for the buck. You can get the whole thing for $15 on Amazon.

I use Sainsmart TB6560 individual stepper drivers, beacuse they are configurable and compact, only about 60mm square. They seem to be really reliable, only had one fail in 3 years. You can also use the ones OB sells, the 542's, but beware of cheap Chinese knockoffs. I've heard horror stories about some of those drivers having way substandard electronics. They all look the same from the outside. It pays to give a little bit more for them from a reputable dealer.

There are lots of other options for controllers if you want more funtionality. If you want to use MACH3, you can use a 32 bit controller like the UCC300 or the Ethernet Smooth stepper for smoother and more precise motor control. Easily upgraded from the arduino once you get the hang of it. You can also get some good 8 bit boards, the Panucatt Gradus M1 is a nice board, low cost with lots of replaceable driver options. It also runs GRBL. Be aware that Panucatt's customer service is horrible, it takes weeks to get an answer to a question out of them. Sales and shipping is quick, however.

MG

 

Cool. Glad I could help.

MG

 

I think it depends where you get your kit. Some have it, some don't. Perhaps it's been a general upgrade. I thought just my kit supplier was adding the extra beam. If you look in the PDF documentation from OOznest, they just show the two. In any case, the other mods I have done are not there...

MG

 

I stand corrected. Thanks Ryan.

MG

 

Steal away, Gary. I stole it from OB CBXL plates anyway. No honor among thieves, right?

Hey that kinda looks like my Ox HD design. But I see some different stuff. Your own design?

MG

 

Kewl. I'm working on a design that uses all HiWin style square linear rails. Parts on order. Uses 9mm rails for the Z axis, 12mm rails for the X, and 15mm for the Y. It will be a 500x500mm for proof of concept prototype. Need something more durable than these polycarbonate wheels.

MG

 

Yeah, I think those are a bit overkill for the Z axis. The MGN9mm rails fit actually just inside the v-slot, right at the top, so they should work good. And the MGN9H long carriages static load rating is 2.5KN each, which is an incredible 562 LbF. Static load rating is about 900LbF. For each one! I figured the Z axis has the least weight to support, the X has to support both the X and Z axes, so I went the next size up. The Y has to support all three, so I went another size up there. I'm a bit concerned that the MGN9's are light for the Z, but they are easily swapped out for MGN12's. We'll see once I get the prototype up and running.

The HGH15's you are using have a dynamic load rating of 3300 LbF, and a static load rating of 5200 LbF each! As I said, a bit overkill. You have a static load rating using 4 of those of nearly 21000LbF!

BTW, if you want cheap rails and lead screws, try RobotDigg.com or BangGood.com, Chinese suppliers with good prices and stock. They also ship DHL, so you get the stuff in a few days rather than a few weeks...

MG

 

Can't beat free...

MG

 

Easy answer - make it shorter. Hard answer - there's been a ton of speculation about ways to increase the stiffness. Everything from filling the c-beam with concrete or epoxy, tension rods inside the beam, bolting flat aluminum and even carbon fiber plates onto the c-beam, you name it. I don't know if there is much you can do with the Workbee because of the design of the c-beam and the carriages with plates on both sides. You can't make the c-beam much wider because you can't get long enough screws for the wheels.

The channel in the c-beam has to remain accessible to run your lead screw, if you were running belt drive you can bolt a piece of 20x40 into the channel which helps. Other than that. live with it, and work with the flex. Take your heavy cuts first, leaving them a bit oversize, and then do light finish cuts to minimize deflection.

If you can figure a way to make c-beam a lot stronger without altering its outside dimensions, you'd have a winner. If you used linear rails instead of wheels, you are no longer tied to the v-slot profile and you can get much heavier extrusions and do things like double them up. But that's a ground-up design.

MG

 

Hi John:

I don't have a parts list for the upgrade, but it's all mentioned in the build description.

MG