I bought this plate set sometime last year in hopes to build an OX.

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(Flying Goodspeed) #1

I bought this plate set sometime last year in hopes to build an OX.

Few questions for now:

  1. This plate set I got from some store on Aliexpress - the main plates seem pretty thick but the other are thinner… I.e. corner braces, etc. Is this an adequate plate set to get started - I think so but never built anything like this before.

  2. Are the main vslots 20x80 ?

  3. What size is really the max size for this X/Y? I am not really set on how large/small to make it. I don’t want to make it so large it takes up too much room but then I want to be versatile too. Is there a calculator of some sort to determine the length of vslot and then what the true cut area is?

(Darrell n) #2

That’s a plate set for the Ooznest Ox. It’s a bit different from the standard ox design. (https://ooznest.co.uk)

To answer your questions:

  1. Yes, this plate set is OK, at least equivalent to the regular Ox, a bit better in some ways, but they could have done better. Corner plates and inside Y plates are just 1/8", I think, which is adequate. Better than the original, which didn’t have those plates at all. It also adds an extra pair of wheels for the Z axis, which is good, but still uses the crappy 20x60 Z axis with the very light end plates which is not good.
  2. The Y axis v-slots are 20x80, but the X axis v-slots are 20x60. They did the right thing by adding the inner plates on the Y to keep everything in line, but the Y axis main beams are still only supported at each end, there is nothing to keep them from flexing side to side, just like the original Ox. Bad design in my opinion. Also, the X axis is pretty flexy unless you glue, screw, or otherwise join the two 20x60 rails together over the whole length.
  3. I wouldn’t go more than 800x1000 on this build. Too much flex otherwise. Figuring out the max travel is easy, the distance between the side plates is the length of your X axis, minus the width of the X axis gantry plates is your max travel. Same thing on the Y, length of the Y axis beams - the width of the Y gantry plates is the max travel. Maybe minus a centimeter or two for clearance.

Look at my design on Openbuilds for the Big Ox HD to see how it should have been done. This is all rendered somewhat moot, the Workbee (also by Ooznest) and the Lead machine are much stiffer than the Ox design will ever be. If I were you I would sell those plates and buy a Workbee. (Where do they get these names??? Ooznest? WorkBee?)

Metalguru

(Flying Goodspeed) #3

@Darrell_n Thanks for answering my questions.

The Workbee is that basically more rigid due to the use of the C beams or is it the combination of C beam and the plates?

On the Ooznest Ox couldn’t a person just skip the 2080 and go with C beams to make it more rigid? The C could be used on the X too right?

(Flying Goodspeed) #4

@Darrell_n Is there caution to be had for looking at something like this?

(Darrell n) #5

@Flying_Goodspeed

The Workbee does use c-beam, for all 3 axes, which is a lot stiffer. The plates make no difference.

With the Ox design, at least the Ooznest design, there is really no way to use C-beam for the Y rails because of the inner plates. You could theoretically use double rows of wheels, but you’d still be stuck with belt drive, as the plates have no provision for lead screws.

No, C-beam cannot be used on the Ooznest X axis because there is no way to mount it, it is 20mm wider than the 60mm Ox X axis. Also, the wheel spacing on the X plates is set up for 60mm width, and an 80mm C-beam won’t fit.

The Workbee is a far better machine. For the $50 you spent on those plates, you would be much better off to just scrap your Ooznest Ox plates and buy a Workbee, than to try and modify the Ox. You would still be stuck with belt drive.

I have bought and assembled dozens of the kits from Bulk-Man 3D, (the Ali Express dealer you mentioned above) they are very good quality, easy to assemble, and cheap. Even with Fedex shipping they are cheaper than OB. I would definitely not go larger than 1000x1000mm, though, because it is belt drive, and the stiffness really suffers when you get longer than 1000mm on any axis.

The Ox design is a bit long in the tooth, and the Worbee class machines are much better, IMHO.

MetalGuru

(Flying Goodspeed) #6

@Darrell_n I have been studying this afternoon and now see what you are pointing out.

In your opinion on the Workbee which is better Belt or Lead Screw - Pros/Cons?

(Flying Goodspeed) #7

@Darrell_n I am considering this one based upon your comments about the Aliexpress store.

I don’t know enough about the controller GRBL or Mach3 ?

I only have 120v AC in my garage so I am looking at this complete workbee with the 1.5kw spindle.

For a starter do you think just going to the largest is ideal or is it best to start smaller ? Is making it larger a difficult task? If starting smaller what size would you suggest ?

(Darrell n) #8

Already asked and answered - Screw over belt for sure - 4x the resolution and torque.
Don’t go over 1000x1000mm for the workbee. See last post
No comment on the VFD, I’ve never used one. Dewalt DWP611 is 1/3 the price and you can get parts for it.
Grbl or Mach3 - I would go with GRBL, but definitely NOT the GRBL controller BM3D sells. It is junk. Just an arduino, 4 stepper drivers, and a Mean Well 24v 350W power supply is all you need.

(Flying Goodspeed) #9

@Darrell_n thank you!

(Flying Goodspeed) #10

@Darrell_n I was able to sell the Ox Ooznest plates. I think I will go with the Workbee 1000x1000 kit. I am wondering if I should add anything else on to the order from BM3D? I already have an Arduino Mega - I am not sure about what drivers I need or steppers. I have three of these steppers ‘Nema 23 Stepper Motor 2.8A 1.9Nm (269oz.in) 76mm Length’ https://www.amazon.com/Stepper-Motor-269oz-Length-Router/dp/B074JJQJVP

(Darrell n) #11

GRBL does not run on an ATMega, I don’t think. It only runs on an Arduino Uno or Nano. They are only a few bucks anyway. I think the BM3D kit comes with motors anyway, but you need 4 motors, not 3.

You will need decent quality stepper drivers, choose carefully because some of the Chinese made drivers are junk. Unfortunately, very hard to tell until you try them. The drivers sold by OpenBuilds seem like good ones, if a bit pricey.

Do not go with the GRBL electronics setup sold by BM3D, it is a junky little CNC shield with 2A drivers which are not large enough for any NEMA23 motor. You could use this and just throw away the CNC shield, use the Arduino and buy separate drivers. The kit does come with power supply and all the wire, etc you need.

I would also buy the power supply from BM3D, the Mean Well LRS-350-24 is a good unit, and they have it at a good price.

MG

(Flying Goodspeed) #12

@Darrell_n Sorry I over looked the steppers were included. I do have an Uno and Nanos as well. Out of curiosity what software do you use or recommend to drive the GCODE into the Uno/Nano?

(Darrell n) #13

I use GRBL Panel, but there are dozens out there, including UGS, Carbide Control, Openbuilds Control, etc. Pick the one you like.

MG

(Jonathan Roeder) #14

Man I wish I had your advice about 3 months ago. Really fighting this 1500x1500 OX, finding it hard to get any real work done.

(Darrell n) #15

@Jonathan_Roeder A 1500x1500 Ox is a pretty limited machine. Stiffness really suffers at those lengths, especially with an Ox. The Workbees in that size also suffers from the same problem.
Belt drive is less desirable as well. I don’t sell anything larger than 1000x1000mm for that reason.

But, if you haven’t got everything ironed out yet, ask away!

(Jonathan Roeder) #16

I have been ruining piece after piece, sometimes after hours of cut time. I got mad last night and took a drill to the y axes, put screws through into the spoilboard, and made the thing like 10,000 times stiffer. I’ll post a pic in a minute.

(Darrell n) #17

Just because you CAN do a thing, does not mean you SHOULD. Just because v-slot is available in 1.5m lengths, doesn’t mean you should build a machine that size. The Ox design has so many shortfalls that I redesigned it as soon as I had built a couple of them. See my Ox HD build at https://openbuilds.com/threads/big-ox-heavy-duty.7930/. The Ox has a poor Z axis, weak X axis, and extremely poor Y axis rails. I wouldn’t build an Ox any larger than 750x750mm just for those reasons.
https://openbuilds.com/threads/big-ox-heavy-duty.7930/

(Jonathan Roeder) #18

This is my first rodeo, and I’m a little dense, so you may have to repeat things. It’s funny how I like to take things for granted, accept certain authorities, and let slide obvious shortcomings. As I was building the OX, I saw the floppy Y’s and said to myself “Oh somebody has seen this and knows it is no big deal, otherwise they wouldn’t sell it, cuz they probably self- brace in tension against the spoilboard, so, yeaaah.”
OX HD looks nice…