JWhitten published a new build:

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Great! I hope you'll post pictures so we can all follow along. I have found my OX to be a very nice machine. The only modification I'm really thinking about making to the design is to add a mid-rail support along both of the Y-Axis rail. I'll get a couple of 20x40 blocks and use angle brackets to connect them together. I haven't had any problems with sag so far, but I want to keep it that way into the future! ;-)

John

 

That's what I'm doing with mine. Works fine.

EDIT-- Oh wait, you mean across the middle-- yes, that's what I'm expecting. I need to get some 20x40mm rails so I can give it a try.

 

Thanks Mark, I had a good instructor! ;-)

(Your videos are really good and easy to follow)

 

Thanks for the nice words! Yes, my kids and I do lots of projects together. They have a good time helping out and I'm hoping that all this will become second-nature to them and help give them opportunities as they get older.

Due to height issues I finally just removed the center support. I originally was going to put in about four. The parts store was out of stock and I had to wait and wait and wait... Eventually I realized that since I have the frame firmly bolted to the table with angle brackets, it wasn't going anywhere, so I just removed the center support piece entirely. I still may revisit it though. My thought is to buy some 20x40 (or 20x20 regular aluminum extrusions) and lay them sideways to use as a poor man's "T-Table".

John

 

I haven't had a lot of problems with racking. Maybe I got lucky. I did have a problem with binding on one end initially. But as a totally serendipitous side-effect, I swapped the end rails from 20x60 to 20x80's and when I put it all back together the binding was completely gone. Now it operates smoothly from end-to-end. My guess is that there was a slight parallax error towards the one end that didn't bother it as it got wider, but was a problem when it got narrower. In any case, I'm glad it's gone.

Now, my next trick is to take apart the cheap-Chinese-junkola stepper motor drivers and see if I can rebuild them into something a little better. Or else toss 'em out completely and go with Geckodrive 203V or 213V units.

 

Hi John,

My original plan was to use four stepper drivers and slave the Y by just glomming on to the same control signals. Works fine, just need to reverse one of the pairs of motor wires so that the left & right "Y" motors operate "backwards" from each other (opposite directions) which has the effect of moving the gantry in the same direction. My concern was that the motors supposedly draw up to 5 Amps of current while operating. However, the reality is that they get far less than that. I haven't measured it to be certain, but I know those HY-DIV268N-5A stepper motor drivers are, in essence, CHEAP CHINESE CRAP and can't actually deliver 5 Amps if they wanted to. So, ultimately I just put both motors into one of the drivers for the Y and it's been working fine-- which is to say those HY-DIV-268N-5A drivers are CHEAP CHINESE JUNK. (I'm hoping that everybody gets the message!)

(There is a long thread here on PlanetCNC which goes into great detail about the general overall CRAPPINESS of these CHEAP CHINESE STEPPER DRIVERS. I cannot say that my opinion of them is any better)

I am saving up to get some nice Geckodrive drivers to replace them with. Maybe some G213V's. They look nice, but at $166 (MSRP) they're a little pricey. They also make a G203V which is a little more affordable $149 (MSRP). I've seen both on Amazon and Ebay (among other places for 20-ish% less than that). I've never used either one personally, but in reading what other people use and recommend, they seem well-regarded. Perhaps someone with more experience than me might offer an opinion?

EDIT: I forgot to answer your other question-- many of the controller ("break-out") boards support "Slaving" an axis. Also the Mach3 software supports it also. So there are a number of ways to achieve it.

John

 

By the way, I have uploaded some new photos of my CNC Router here. You can see my new Bosch 1617EVS variable-speed router, and the spiffy new motor mount and dust shoe that Chris Laidlaw made for me! You can get one too if you contact him. His Ebay seller handle is ChrisClub1.



John

 

Heh, we do computers and model railroads too! ;-)

We just moved into this house a couple of months ago. I had to take down our previous train layout. One of the reasons I wanted to build this CNC Router was to help me make benchwork parts, front panels, and other useful items for the model train layout. Especially do all the repetitive cuts involved to do the helix.

 

That's a nice rig you got there. What kind is it? I like the way you have the wiring cabinet set up. I'm looking to do the same thing but I'm going to see if I can fit it all into a mid-tower computer case. I think it will all fit. Plus it's already fitted for fans and whatnot which should make cooling the motor drivers a bit easier. I'm going to see if I can spring for the Geckodrive drivers after Christmas unless I get a set from Santa. I'm hoping that will fix my "power" problems-- the rails never seem to run as well as they oughta given the NEMA 34 motors.

 

Yes, I was thinking of doing something similar myself, although my thought was centered around making railway cars.

 

That really sucks.

 

My kids, especially my oldest (he's now 7) have both been doing "projects" with me since they were barely old enough to stand. For instance, when we built our last model railroad, I would hold the drill and they would get a big kick out of pulling the trigger at the right time to screw in the screw. And we've always practiced safety at every opportunity. We always wear eye (and now ear) protection, and have always stressed the importance of wearing shoes when doing construction, etc. The whole idea is to get them used to thinking about safety as a normal facet of doing projects. I don't let them anywhere near the saws or drill press (or similar tools) though. And we always unplug our power tools after using them. A little bit overkill maybe, but again, we stress the importance of safety.

In my case, I'm not planning on using the original power supply, I've got standalone power supplies to use with the router electronics. Although, in hindsight, perhaps I could have. So my case has a lot of extra room up at the top where power supplies normally go. Oddly, one of the biggest problems I had in getting up and running was finding a computer with an actual parallel port! This ubiquitous feature available on every computer just 5 / 10 years ago is now virtual extinct it appears! Go figger.

How hot do your Geckodrive drivers get? Do you really need the heat sinking?

John

 

I couldn't agree with you more. My goal is to help them see beyond the tools and techniques and into their own imaginations. To help them get to the point where they are thinking about what they want to do more than how to make it, secure in the knowledge that when they come up with something, they probably can fabricate it somehow. Too many people-- myself included for far too long-- are held back by their fears of what they can't do, rather than emboldened by their innate sense of adventure to "give it a go and see what happens". I am hoping they grow up to be "big picture" thinkers. When you have that sort of curiosity and imagination, there's almost always a way to manage the details.

Hmm... I'm glad to learn about the Smoothstepper. I looked it up online, it appears to be a very nice unit. The specs say it has 34 I/O ports (which I assume mean "pins")-- so are you able to use that to connect all your limit and home switches and such? That's what I've been needing. The board I have does sort of allow me to connect switches, but only in a limited way-- you have to connect them together (either in parallel or serial) and then hook them up to one of the input pins available on the parallel port. There's only a small number available on my setup. Sounds like something worth looking into as a step up. I started my machine on the cheap. I figure that I can start with less expensive motors and stuff and then move up as I can. They can always be reused for other projects.

28 Amps! That's a lot of power.Is that just what they're rated at or do you actually push that much power?

John

 

Our next project, probably after the New Year sometime, is to build a 3D printer. I know I can probably just buy one, but like you said, I'm interested in learning how to do it and to have the experience doing it. Plus, I want my kids to have the experience doing it also. I've been encouraging my oldest to get more creative with his legos. I'm more than willing to buy him more sophisticated parts to play with, but I want to see him actually trying to figure things out with them. Sometimes we sit and look at things other people have made with legos on Youtube and it gives him ideas and exposes him to new concepts and things he hadn't thought of before. My youngest is extremely sharp but keeps it to himself more. Some days he just floors me with how much he really pays attention. Anyway, I am hoping both of them will grow up with electronics, mechanical engineering, computers and automation as "old hat" so they can focus on the "fun stuff".

Yup, that sounds like about what I need. I was thinking I could use the old drivers to run the 3D printer when we get around to building that.

Well, the CHEAP CHINESE CRAP drivers I have have a built-in feature (read: design flaw) that cuts their power down to about 30% output, all the time. And even though they claim to be able to do 5 Amps, analysis of the circuit suggests strongly that even if they didn't have the 30% output problem (an error in copying the original reference drawing shown in the data literature for the driver chip), it probably wouldn't be able to push more than about 2-3 Amps max anyway. So no matter how you look at 'em, they're CHEAP and CRAPPY, and they drive my motors way too weakly. As a result it has probably saved my machine a couple of times when it has snagged a cable or run into a limit, but apart from that, they do not work well at all. I am anxious for the day when I can swap them for better Geckodrive units.

John