Officially sad. My screws that came in my Solid V wheel kits are 25mm not 30. Guess I have to go to the hardware shop tomorrow and see if they have 30mm versions. Guess I'll see what else I can make without the wheels.

 

Agree 100% here

The screws that secure the v-wheels on the "fixed" are not well supported in the spacer block as they are drilled to suit eccentric adjusters, they tend to splay outward. I used eccentric spacers on the fixed side of the z-axis, all set to neutral position, and it adjusted up fine. I believe this was mentioned somewhere very early in the thread also.

 

Hey guys,
Just a heads up to let you know that the OX plate models (V-Slot OX_Build_77) hole spacing's have been updated to allow for a tighter pre-load on the eccentrics. The original spacing works but it uses most of the adjustment allowance of the eccentrics and we wanted to be sure that there was more than enough adjustment room to work with, So now there is.
Special thanks goes to @@Robert Hummel for originally catching this and also who's AI plates we used to fix it
You can download the new version under the Files tab at the top of the OX build page.
If anyone would like to help out by sharing different formats of these new plate layouts that others could use, for instance CamBam, etc.. please send them to me and I will add them to the build files.
Thank you
Mark

Mark,

I plan on making my own plates with a drill press and jig. I know it may sound crazy, but my total cost for the ¼” aluminum was under $35. When on a budget innovation is key. I also bought an 8” drill press for $79. Aluminum and drill press cost less than retail plates.

All of the plate drawings I download in both inches and metric have different dimensions when I check them in AutoCAD 14. They vary all over the place depending on which drawing you measure. Also many of the holes are not round.

So this begs the question… What are the new “tighter pre-load dimensions” from center to center of the wheels for 80mm, 60mm, 40mm, 20mm and 10mm beams? Nobody seems to reference dimensions except for your “V-Slot Gantry Plate” and “Universal Build Plate” drawings newly posted as 99.70, 79.70, 59.70 and 39.70 (39.71)for spacing. Your previous published plate dimension a couple of weeks ago were 100.64, 80.64, 60.64, and 40.64.

Please, a straight answer as these are the most critical dimensions when working with eccentrics, wheels and V-Slot Beams.

Rob

 

Thanks Chris

 

Thanks to all you guys for the fast and valuable response to my questions.
Dave

 

There should be a warning about using thicker plates. I made the same sad discovery in building myOX.

The good news, you can use the 25mm screws which came with the wheel kits to mount your steppers. If like the ones I got, you don't even have to tap the stepper holes (if 5 mm), just use a nut to bolt on. Sure, a bit long, but it won't show since the extra length hides right along the steppers' body (got plenty of room there).

Make sure you either get the flatter head screws (clear some of the tighter spaces as with the X axis wheels) or add an extra washer/precision shim in the right places (as in the X wheel axle assemblies making sure wheels line up with the V-slots).

 

I better order some 30 mm now along with 3 x GT3 pulleys/ belt so it's here for the fiber OX

 

Will you be making all plates with that resin fiberboard material ?

 

That would work too Was it really there? Seems like I read that list maybe way too many times and lines just blurred together because I ended up with a bunch of M3 that have absolutely nouse on any OX.

 

Yes a complete OX will be milled with the fiber board and tested.
It will be a small footprint 700x700

 

You are really into this, eh ? How many OX (oxens ?) do you have at this stage anyways ? Or is this a play OX you keep taking apart to taste plate designs ? Just curious ...

 

This is something I'm working on...
A little surprise, few pics now and then for OX porn and yes it is also for testing different options to improve performance this board is going to be a good alternative

 

The OX build parts list does reference 30mm for the wheels. The 25's from the wheel kits can be used for the step motors or to connect gantry plates to V-slot (not references in the build parts list. I went through this last night while building "Babe".

 

Mark,

Thanks for the dimension clarification as 0.94 mm can make a big difference.

 

I am a Mac user. I am using the TinyG. It has the drivers built in, but you can use external drivers if you want. As far as control goes, it's web-based - all driver/stepper control happens on the board, so there's not such a high-performance requirement for comms. There are a couple of apps - tgFX and Chilipeppr - of the two, I prefer Chilipeppr.

You need to compile tgFX on the Mac, but Chilipeppr is web-based: http://chilipeppr.com

This does mean you need to be connected to the web while you machine - or at least you need to while you load the Java code - but I don't see that as much of a disadvantage. I have reliable ADSL.

For CAM I am using CAMBAM in a Virtualbox VM - just because there doesn't seem to be much in the way of good CAM software on the Mac. There is MeshCam, but I don't like it. There's also a couple of CAM add-ins for Sketchup, but they don't give me the kind of control I am after - they're OK if your requirements are fairly rudimentary.

The reasons I went with the TinyG were many - I don't have a parallel port, so that lets Mach3, LinuxCNC out. I did a lot of research and the way the TinyG guys have gone about forking from GRBL and the specific improvements they have made appealed to me. And I wanted an all-in-one board, at least to start with, with the option of going to heavier-duty later on. It met all my requirements and is a reasonable price (about US$130 all-in, I think).

I'm sure there are better solutions out there, price-wise and better solutions that give you a wider range of CAM options, but I wanted flexibility of platform. I have a bunch of computers from Linux-on-a-stick embedded ARM boxes, Raspberry Pi's, Intel-based micro PCs, Intel desktops and a couple of Intel laptops, as well as 4 Apple pc/laptops and so wanted to be able to mix-and-match and to try different ways of machining.

If I wanted to, I could screw a wireless-enabled Raspberry Pi to the back of the gantry and talk directly to a similarly-mounted TinyG and do everything via Chilipeppr remotely - even down to monitoring the process remotely using a attached USB camera.

That frees me up to design in a comfortable office environment, do my CAM work then submit the gcode to the machine as if it was a stand-alone entity. Pretty much the way I control my 3D printer with Octoprint.

Obviously I need to be present when machining, but there's no reason I have to do the rest of my work out of the hot, dusty and aircon-free workshop, when I can be drawing at a comfortable workstation set up for design.

 

No, you have it right - 2A per winding. You can probably drive 2.5A with good cooling of the A4982 drivers.

The TinyG I mentioned before runs reliably at 2.5A per winding with cooling and 3A with GOOD cooling (i.e. with mounted heatsinks and a fan blowing across both sides of the board.)

From their wiki:

I would expect the same from the Smoothstepper. Dissipate the heat and you can push more power than 2A through it. While it doesn't have as good a driver as the TI DRV8811 in the TinyG, it is a tried and true solution.

The only advantage I see of the Smoothieboard over the TinyG is the addition of an SD Card socket. For me, that doesn't matter so much. As it has a bunch of thermistors, I suspect it is more geared to 3D printing than CNC routing.

 

If you haven't ordered it yet, look at TinyG - essentially the same spec as what you are proposing, but more advanced by some way than the GRBL 0.8 they are using. And the same price.

 

Yeah. I continued on with the build until 02:30 and figured I should go to bed seeing as I work in 4 hours. I substituted the 25mm screws wherever I could. Managed to get quite a ways. Now that I have some 30mm screws, I'm going to finish the mechanical build tonight. I feel another early morning coming on.

 

I think the exact same thing happened to me. I went back over the parts list just now, and there it was staring me in the face. Even told me that the 30mm were to replace the screws from the wheel packs. I seem to have a lot of important looking stuff left over. Oh well. I know I'll find a use for it all!

 

Serge,

Same problem I had. Mark would it be possible to post a blurb on the first page, letting new builders know that they will need longer bolts for the wheels with the aluminum side plates?

As a side question, I am using the CNC xPro controller board and I am unsure of how to set the stepping. 1/2 1/4 or micro? Will the stepping affect how accurate the machine is?

 

I ended up with a bag of M3 and thought the same... until it came time to mount my Z-axis stepper... well, I have enough to mount 3 z-axis steppers, with a spare, but it's no biggie.

It would be nice if we could order wheel sets with a specific size of screw, though. I have accumulated a bag of 25mm screws, as my gantry and other plates are 6mm thick, the 'standard' 25mm screw doesn't quite fit.

 

I am confused about the current needed to drive stepper motors. I currently use a gshield. The are pots to control the current for each stepper, I suppose that all drivers have some way to control the amount of current.

My understanding is that, the more current, the more torque the motors have. For each axis, I increased the current until if was very hard to manually keep the router from moving along that axis. I suppose a router will not exert more force than this, so I suppose this is enough. The higher the currents, the more wear and the higher the risk to get into thermal shutdown.
Is this correct? The thing is, I now have a total current consumption of 1.1A at 26V. That seems very low, when I see discussions about the need for 2.5A or 3A for each motor...

Thanks,
Frederic

 

This is probably the best resource for teaching you about steppers: https://www.geckodrive.com/gecko/images/cms_files/Step Motor Basics Guide.pdf

 

Thanks for the info, Zoot. I decided to go for the Planet CNC MK 2/4 controller and software with external TB6600 drivers (up to 4.5A). Everybody is very positive about that controller and the software seems to be equal quality to Mach3. So I'll give it a shot. The waiting is now for the plates and some more hardware from OB and then the building can start hopefully in the next few weeks.

To my big surprise, they suddenly started to sell the Makita RT0700C here in Thailand (that model will probably soon be replaced for a new one, Thailand never has latest tech) and got one straight away with the complete set of router bases and other goodies. Fantastic little router, I say.

Also ran into the discussion about the double timer belts and will go for that option too. Glad I ordered a large quantity of that belt! Looks to me a great solution to have some more accuracy and strength without going to rack and pinion.

 

Already in the build box, so I will use it for now. Thanks for the info

 

Ok guys I just finish my Ox build now I need some help. Im confuse with the steps x mm. On my Z axis I have an Acme 1/2-10 screw and with this no problem. But in my other axis if I use the calculators if giving me a 26.66 mm. Find this number very low comparing other using numbers as 300mm. Can anyone help me clear this up, my first time working on mm.

Thanks

Alberto

 

Double timer belts? Where?