G0704 (sort of) CNC'ing

[Dr.Fiero]

G0704 CNC'ing

I've had my King Industrial mill (let's call it a G0704) for a couple of years now.

I used it maybe... once? Twice? Then tore it all apart, and started to CNC it.
I'd already made a CNC router completely from scratch (sheet of HDPE, a table saw, and a drill press!) so how hard could this be.

Well - time was the enemy.

But hey! I got laid off 4 months ago, so now I've got LOTS of free time! Yay! Oh.. wait... that's a bad thing. :nuts:

Anyhow - notice I'd asked and answered a few questions regarding these machine, but hadn't posted anything of mine.
I got to work the other day doing the electrical box for it (worked on the mechanicals for the last while too!) and this is today's result


(excuse the mess)

Inside

Yes, I know a few of you are saying WOW! It's NO WONDER that guy is still unemployed!

View from the outside


I hated the idea of having the control permanently attached to the mill (or the computer!).
So, worked with what I had (hence the spare holes!). Added the IEC power outlet so I could use a standard PC power plug - then if it ever got killed, it was an easy replacement.
The 3 yellow connectors are... uhhh... I have no idea! But they're 5 pin, MASSIVE overkill at 16ga. But I had 3 matching pairs of cables and connectors, so what the hell.
There's a DB25 on the left that you can barely see.
This is the bottom, so all the cables hang down.

Anyhow, it's been done a million times over on the machine itself, but if anyone wants to see the mounts or whatever let me know.
I actually made the ball screw mounts myself. Split between cheap, and a masochist I guess? Ha ha ha.

 

[fretsman]

Excellent, and love those connectors, nothing cheap about those, good find!

What electronics are you using?

Yes, by all means show your CNC progress pics of the conversion as I hope to do the same to mine someday. (Right now I'm using it manually).

Oh, and good wishes to you for employment soon!
Dave

 

[Dr.Fiero]

Excellent, and love those connectors, nothing cheap about those, good find!

What electronics are you using?

Yes, by all means show your CNC progress pics of the conversion as I hope to do the same to mine someday. (Right now I'm using it manually).

Oh, and good wishes to you for employment soon!
Dave

Job fair tomorrow. Keeping fingers crossed.

Electronics:
350W 24V PS, a 2A 5V (the black box).
Motor controllers are from Wantai (2X same as Kelling KL-4030, 1X KL-5056).
El-cheap breakout board (same as Kelling KL-DB25) that at least has opto couplers. Want to replace it with a SmoothStepper so I can ditch the parallel port and go USB.
X&Y axis are Nema 23, Z is a huge Nema 34 that I hope doesn't shred my coupler!

Home brew nuts. Bought a 1.5" thick 6*12" block of 6061 (off cut from a metal place near me).
Just had the lathe to work with (seeing as the mill was in 2700 parts!).


Y-axis (original nut, my nut, ball screw)


Z-nut (no, I hadn't trimmed the screws to length!)
It's a two part design, like the original one. More work, but WTF. Gave me more practice.

edit: Oh yeah - those cables and connectors (big 5 pin ones) I *think* are from an RV application.

 

[fretsman]

Good info, thank you for sharing. Good luck at the job fair!

Dave

 

[Dr.Fiero]

Well... mocked up the PC to a stepper or two via the above box... No smoke!

One note though... and that's with regards to the couplers that Chi from Linearmotionbearings2008 on eBay is supplying...
I had my doubts about them when I first got them. Seems my doubts were justified!

I don't even have the actual milling head on the "Z" yet (just the mount for it), and when I did a slow up/down movement I half pretzeled it!
I don't *think* the gibs are too tight (see my other thread on that!), as I could move things quite freely.
See what happens when I try the "Y" in a bit.

Oh well - guess I'll have to order up some love-joy ones.

 

[Dr.Fiero]

I half pretzeled it!

For those unclear on the concept...

This is what they look like new (picture stolen off eBay!)




This is what happens when a mildly stuck (from not moving) Z axis coupling gets twisted by a big honking Nema 34 stepper

Uhhhh, yeah. That.

Found a place in town that's a LoveJoy dealer - they're checking stock and getting back to me.

 

[fretsman]

Yep, I had those on a CNC router (aluminum just like those) and yes, you could actually see them and they were supposed to be rated a LOT higher than I was using them for.

Never Again.

I went with the OldHam style couplers with the Delrin inserts from Mcmaster and they're awesome. Much more pricey, but worth it.

Dave

 

[Dr.Fiero]

Just ordered up a set of LoveJoy couplers with urethane inserts.

Only thing that sucks is they're imperial, so I'll have to bore them out to metric (went with the smallest imperials I could find).
Oh well.

(btw, yes I know I could order them online, but I'd be 10 days out at best - great white north here 'eh?')

 

[Dr.Fiero]

Re: G0704 CNC'ing

Forgot to update....

Got my little pile of love joy couplings. Inserts weren't quite as tight as I'd hoped. If I find I have slop, I'll know where to look first!

Turns out its really hard to find a 14mm drill bit on a whim... So I got a 35/64 one which was only about .1mm under size.
Which was a killer excuse (in my mind) to justify buying a nice adjustable reamer set!!

Fits like a glove now.

Then realized that the motor shaft was now about 1/4" too long, since the solid coupling in the middle didn't allow the shafts to come as close as they were before.
So, out came the motor. Zip disc, bit of filing, and boom. Done.

Mounted the head back on it too, since without the weight, it's impossible to set up the stepper.
Good to see it no longer beheaded, and it's one less thing to trip over!!

So, I now have semi accurate Y & Z movement (just not precision tuned).
Would like to figure out why I've had to slow down my in/min to so low though. Any faster, and I get the shriek of death as the motors stall out.

But, it's all motivation enough to keep going. So I'll machine up the X shaft tomorrow, and get that moving.

I'll post a video when it looks like its doing something cool enough to justify it.

 

[Dr.Fiero]

Thought I'd post my version of the X axis nut mount:


Top of the ball nut is obviously already "shaved". Cut off wheel made quick work of that.

So, go to test fit it together - nut is still rubbing on the underside of the table.
Shaved the saddle a bit to lower the nut, but still no go.
Took the grinder to the underside of the table, but after much grinding, it just wasn't working out (too slow, and too irregular).

Since I've only got one milling machine, I figured I'd give this a shot!

Flipped the table over - and then - got a REAL GOOD respect and appreciation for the crap that these machines go through!!

I'm only about 1/2 way done, and my arms are killing me from holding this thing down and X/Y'ing it manually..... phew!