[hoss2006]

Stick with the Oldhams, unless you want to machine all new endplates for the table
to ensure that everything is square and concentric with the motor shaft.
I posted a print for the oldhams, you can buy the center discs for $3 and make the hubs yourself.
I've been using 16AWG speaker wire for the X2 motors for over 3 years now,
they are covered with flexible conduit and haven't given a bit of trouble.
Hoss

[mwood3]

Stick with the Oldhams, unless you want to machine all new endplates for the table
to ensure that everything is square and concentric with the motor shaft.
I posted a print for the oldhams, you can buy the center discs for $3 and make the hubs yourself.
I've been using 16AWG speaker wire for the X2 motors for over 3 years now,
they are covered with flexible conduit and haven't given a bit of trouble.
Hoss

Ok, i will just buy the oldhams i suppose...not trying to be cheap i guess i was just thinking along the lines of what would make the machine better and last longer...Once i get it running under cnc i may tackle the new end plates though...i like the idea of everything being how it should be...my thoughts on the oldhams are that if they are constantly slipping around then they will wear quickly which would lead to backlash...although im sure the stock screws will induce much more than id ever notice from those couplings...but then again every little bit counts.

[hoss2006]

It's your mill, you can run whatever you like on it.
I recommend parts that will give the best performance for the long run without being too cost prohibitive.
Plenty of other ways to go depending on ones pocketbook.
More than one way to skin a cat as they say.
I just tell how I skinned mine.
Hoss

[mwood3]

It's your mill, you can run whatever you like on it.
I recommend parts that will give the best performance for the long run without being too cost prohibitive.
Plenty of other ways to go depending on ones pocketbook.
More than one way to skin a cat as they say.
I just tell how I skinned mine.
Hoss

Your advice is always spot on Hoss, Im just one to always say what if...and most of the time it cost's me more or gets me in trouble

[Starleper1]

MWood take it from me. Unless you want this to happen (See Picture) don't use rigid couplers. It may not happen right away but sooner or later it will happen.



~Scott

[photomankc]

Not to beat this poor horse's corpse further but the disks in the oldhams are Acetal and that has pretty good wear properties. I doubt you are going to see enough wear in them to need replacement due to built up backlash but even so one could order a couple extra disks and have a very easy to swap-in replacement.

[mwood3]

Not to beat this poor horse's corpse further but the disks in the oldhams are Acetal and that has pretty good wear properties. I doubt you are going to see enough wear in them to need replacement due to built up backlash but even so one could order a couple extra disks and have a very easy to swap-in replacement.

well...i guess i took my lashings on that one (nuts). thanks for the helpful insights guys

[ncdeftones]

How much travel is everyone getting on their G0704's? Grizzly claims 6-7/8" but from what I can tell I'm only getting about 6.4" on mine with the way cover removed.

It has probably been posted before, but I didn't come across anything using the search feature.


Ok I spoke too soon...found where Hoss replied to me a several pages back "I get 7.125 Y travel right now stock"


How am I getting .7 in less travel???? Did you get this amount of travel before you used ball screws? Is the ball screw nut smaller than the stock acme nut and allow for more travel?

[hoss2006]

How much travel is everyone getting on their G0704's? Grizzly claims 6-7/8" but from what I can tell I'm only getting about 6.4" on mine with the way cover removed.

It has probably been posted before, but I didn't come across anything using the search feature.


Ok I spoke too soon...found where Hoss replied to me a several pages back "I get 7.125 Y travel right now stock"


How am I getting .7 in less travel???? Did you get this amount of travel before you used ball screws? Is the ball screw nut smaller than the stock acme nut and allow for more travel?

The travel is limited by how long the opening is in the base that the leadscrew nut
or ballscrew mount passes through.
My ballnut mount is the same size as the leadscrew nut, the ballnut has clearance under the base.
You might be bumping the Z axis way cover, I can bump the table up against the column dovetail with it removed.
Hoss

[ncdeftones]

The travel is limited by how long the opening is in the base that the leadscrew nut
or ballscrew mount passes through.
My ballnut mount is the same size as the leadscrew nut, the ballnut has clearance under the base.
You might be bumping the Z axis way cover, I can bump the table up against the column dovetail with it removed.
Hoss

No the table is hitting the column in the rear and stopping at the front when the lead screw reachs the end of travel. I removed the limit switches to make sure I'm taking it for all it's worth and I'm still only getting 6.6" of travel. How are you getting 7.125???? Were those your measurements with the column off? I'm not even getting the Grizzly claimed 6-7/8" worth of travel.

[diyengineer]

No the table is hitting the column in the rear and stopping at the front when the lead screw reachs the end of travel. I removed the limit switches to make sure I'm taking it for all it's worth and I'm still only getting 6.6" of travel. How are you getting 7.125???? Were those your measurements with the column off? I'm not even getting the Grizzly claimed 6-7/8" worth of travel.

So your about a .25" off from the factory spec?

Without taking my rear rubber guard off that protects my screw below, im getting about 63 turns on the hand wheel @ .10" = 6.3"

I'm sure i could get an easy 1/2"+ more if i removed the rear rubber guard.

Ill check my other G0704 as well, and also remove the rubber and see what i get.

[ncdeftones]

So your about a .25" off from the factory spec?

Without taking my rear rubber guard off that protects my screw below, im getting about 63 turns on the hand wheel @ .10" = 6.3"

I'm sure i could get an easy 1/2"+ more if i removed the rear rubber guard.

Ill check my other G0704 as well, and also remove the rubber and see what i get.

Thanks for checking. I'm not really complaining...I'm just wondering how Hoss has got more travel cause that little bit extra makes a world of difference to me with making a particular part. I can cut out the center section now, but only by .020" to spare with a 1/2" end mill or larger and then I'm going to have to reposition the part to finish the outside edges.

[hoss2006]

Thanks for checking. I'm not really complaining...I'm just wondering how Hoss has got more travel cause that little bit extra makes a world of difference to me with making a particular part. I can cut out the center section now, but only by .020" to spare with a 1/2" end mill or larger and then I'm going to have to reposition the part to finish the outside edges.

Ok, looking back thru my pics, I found I got 6.75 worth of Y travel with the stock screw conversion
and the table bumping against the bare column.
I believe I'm getting the extra 3/8 now with the ballscrews because I removed the center stop block
on the front of the table during the changeover.
If you're looking to gain a little more travel, you can mill, drill or grind the front section
of the base slot to let the table come forward farther.
Remember, about 7.25in. will be the max usable due to the spindle to column distance.
Hoss

[hoss2006]

Finally got around to testing the TB6560 Chinese 3 Axis Driver I bought on Ebay months ago, $64 shipped.
quality-gadgets items - Get great deals on TB6560, Business Industrial items on eBay.com!
Put it in an old DVD player for a mini console that I'll use with my laptop
for a portable system to run a couple little projects.
Don't need much oomph to run them so this should be good enough.
Tested it on the G0704 since the motors and ballscrews are already there but it's a bit of a dog as you might expect.
Just needed to test it's function on something.
It runs at just 24 Volts and 3 Amps, it got the X going 60 IPM, Y at 50 IPM
but the Z only managed 20 IPM.
The 570 motors of course aren't a good match, only put out about 342 oz/in,
A 495 might do better.
If someone was seriously thinking about it, (I wouldn't) the Z could use some help from a counterweight,
still would only go about 40-50 IPM tops I bet.
The belt drive Z version could help too.
Still it moved it around and that's all that mattered, the little lathe and such it's for won't need much to be able make some parts.
I've only got $89 invested including the power supply.
Now I have an excuse to build a little desktop router or 3D printer.
Hoss


[nomedia="http://www.youtube.com/watch?v=upbr9sQRxJk"]YouTube - TB6560 Chinese 3 Axis Driver Console[/nomedia]

[ncdeftones]

Curse this mill! It's been one problem after another! Now my motor and controller decided to burn out. It was running fine and then the motor made a popping sound. I shut everything down and let it sit for a minute hoping it was just too hot (even though it was doing some really light cutting). I fired the motor back up and after a few seconds it started popping blue flames out the top of the motor and then the control box started smoking. When I took it apart I found a transistor and a capacitor had burned up. Sounds like the same problem a few others have posted. BTW, this is a stock board, no aftermarket speed control, etc. Grizzly is supposed to be sending me a new control board (supposed to be in stock) and said the motor should be fine because it is a blush type motor (hopefully that is the case). Maybe after replacing everything on the mill maybe it will work right for once.

[photomankc]

Well, I used to think I was the unluckiest bloke on the planet for getting stuff that is broke from the get-go. Sorry to hear about the troubles. It appears these controllers are not the most robust things on earth because there are quite a few reports of failures. That's what died on my machine right off the bat too. KBIC was supposed to be good stuff but I wonder if they have different OEM product lines vs separately purchased controllers?

[ncdeftones]

I know I wasn't running the machine very hard, but I'm curious...what kind of feed rates is everyone running? I was using a 1/2 4 Flute TIN end mill. I don't remember the feed rate, but it was VERY slow because I was paranoid. It was making clean cuts with no bogging. In fact for some strange reason the RPMs picked up when it entered uncut material

[photomankc]

It has some kind of torque compensation. If the motor is loaded and starts to slow down the system tries to up the power and so sometimes it will rev higher as you enter the cut. I usually only get that when I'm running low rpm in high gear and start cutting. In low gear It will not break a sweat even in steel.

I wonder if it's compensation was going overboard and popped the SCR?

I have been cutting aluminum with near any DOC my endmills can handle from 17-25 IPM. I only have to go slow with the small endmills because of limited RPM.

[ncdeftones]

It has some kind of torque compensation. If the motor is loaded and starts to slow down the system tries to up the power and so sometimes it will rev higher as you enter the cut. I usually only get that when I'm running low rpm in high gear and start cutting. In low gear It will not break a sweat even in steel.

I wonder if it's compensation was going overboard and popped the SCR?

I have been cutting aluminum with near any DOC my endmills can handle from 17-25 IPM. I only have to go slow with the small endmills because of limited RPM.

Yeah, I'm well under that even running the conservative feed rates (according to BobCAD documentation) that the software is calculating the based on the tool spec & max 2000 rpm I entered. And then I turned that down by using Mach feed rate override. I think it was feeding about 5-6 ipm. My depth of cut was .150, but I don't think that's too much especially considering the super slow feed. I've turned it faster buy hand cutting more than that. Plus, it was barely smoking up the WD40 I was using for cooling.

[photomankc]

Well, I have not taken it that deep at CNC feedrates. About 0.100" for any of my non-roughing mills. Until I get more confident that's probably as deep as I'll go. I still get nervous at the fact I can't feel it cutting anymore. I have also been able to cut pretty deep hand cranking it in AL.

Hope you get it fixed up. I doubt the cut was the culprit in this.