[ballendo]

Chris,

Total agreement about cleaning the lower cost ballscrews and ballnuts (rolled thread types).

Also want to add that a single body(single circuit) ballnut CAN be an anti-backlash type. There are two common methods used: oversized balls, and "preloading" the grooves in the nut body itself that the balls run in. (When preloaded grooves are used the ballnut may be a multi-circuit type, and still "look like a single body nut.)

There is a third methos used with single circuit ballnuts, but I've only ever seen it used by Techno-Isel. This uses a clamping-down-across-the-body technique which is similar to the method used with pillow block thomson style linear ball bushings. Seems to work okay, according to Techno-Isel owners.

Ballendo

P.S. I think it's more than "probable" that most low end ballnuts and screws, regardless of distributor --like so many other motion products these days-- are being sourced in China. I know that a supplier I use for motor couplings is sending me Chinese stuff. The related point is that we need to run a reamer in these before use, and replace the "cheese" steel 4-40x3/8 socket head capscrews with decent Domestic screws. (Had problems witrh slippage until we did.) I too have seen those "1/8 pieces" when doing this. The Chinese parts do not seem to be finished well, and the de-burring is incomplete at best!

Ballendo


[QUOTE=ckirchen]Taus,

I can't tell for sure from your pictures, but the link for the ballnut you gave is not an anti-backlash nut. If that's what's on your machine, the only benefits you'll see are smoother motion and higher efficiency. To eliminate backlash, you'll need to use preloaded ballnuts (like the ones on carlnpa's machine).

I'm a strong believer that cleaning the ballscrews/ballnuts is the only way to go. When cycling my machine by hand after initial assembly, the X ballnut jammed on the ballscrew. When I cleaned it, I found, along with the grit and dirt, a couple ~1/8" steel chips. I promptly cleaned the other two axes. It was a good thing the machine wasn't under power--I hate to think what would have happened...

[ballendo]

[QUOTE=tauscnc]Hey carlnpa,

I love that aluminum top! Wow. How did they finish that, looks like one HUGE flycutter

Taus,

A fly cutter can't give the required flatness and surface finish...

Mic 6 alum plate is blanchard ground. A blanchard grinder is like a HUGE floor polisher that you see being used to polish the floors in supermarkets sometimes. One large grinding wheel, which cuts on its face.

Blanchard grinding is the typical process used for flattening large metal plates, like those on machine table tops--like a table saw.

Here's a link to an explanation about how mic-6 plate is mfd. (It didn't mention the grinding specifically, so I added that here.)

P.S. I use 5/8 mic-6 plate for my "expensive" PCB mill CNC machines; because it has the best flatness spce of the thicknesses around 1/2". (IOW, a 5/8 mic 6 plate will arive flatter than a 1/2 or 3/4 mic 6 plate.)

Ballendo

Helps to add the link<G>

http://www.designnews.com/article/CA270744.html

[tauscnc]

Hey ckirchen,

The link I sent is the link we found while talking with Nook. I don't think this is a preloaded ballnut. Just a single one.

Can you guys please explain to me the cleaning process in some detail.

For example, if I use scotchbrite pade or #0000 steel wool should I hold it again the screw as I have something turn it...should I do this 50 times, etc. For the ballnut what should I do? I can put paper towel into it and get it clean but after that I have no way to "clean" the hole edges etc. Also, since there is no wiper on them aren't they just going to get jammed with saw dust etc. quickly?

Any ideas are welcome.

Thanks!
taus

[tauscnc]

I added some more pics to my website and a movie !

http://cuttingedgecnc.com/cncrouter.htm

taus

[ckirchen]

Hey Taus,

You should definitely use wipers. You never know what is going to end up on the ballscrew (chips, sawdust, or otherwise). I run wipers on all three axes, even though two of them are hidden by steel. The ones that the manufacturer sells are good, so are rolling your own (http://bellsouthpwp.net/A/r/Arts_home_page/cnc/) or using hot glue (post #19 in http://www.cnczone.com/forums/showthread.php?t=7180).

To clean the ballscrews, chuck one end in a hand drill. If you can't use a drill, connect the drive to the screw. Run the drill/drive slowly and allow the towel/scotchbrite to move back and forth as guided by the threads. Also, don't overdo the scotchbrite. All you want to do is take off any hard-to-remove grit. You don't want to remove the oxide and make the screw silver. When you're done, you should have a clean dark brown surface. Put some 3-in-1 oil on a towel and apply it by running the drill/drive again.

Like you said, it's a little more difficult to clean the ballnuts, because you have to reach all the inside corners. I used degreaser with a couple different sizes of pipe brushes (from Walmart). Then, blast them out with air (I don't have a compressor, so I use a can of compressed air). Do it over a white towel, so you can see if any dirt comes out with the air. Repeat the degreaser if necessary. Finally, oil/grease the bodies as soon as you're done to ward off any chance of surface rust.

Chris Kirchen

[tauscnc]

Hey guys,

I was just playing around testing the "enclosure" I have almost finished and the Y axis stopped! I checked and the Gecko seems just fine. So I opened the motor (I did not pull it out of the casing...have already leaned that and found 3 wires were yanked off! Man, I lucked out on this one. I have put it all back together and it works find. Wheeee... All is well.



I also found that the ballscrew on the Y axis runs very free if it is not fully tightened down. So I did some more investigating and found the mount must not be perfectly 90 degrees. I put a "plastic paper" shim at the bottom and the Y-axis is MUCH SMOOTHER!!!! I am not kidding, it has LOST a lot of its gritty feeling, sound, etc. I can even push on the Y axis and it will "run" through the ballscrews (w/ belt off).



I think I will now have to check the X-axis. If I recall, I noted the mount had to be pushed down a little for it to slide over the crossbrace. I can now jog the Y-Axis a full speed with out any problems.



taus

[cbass]

Taus, Its looking very nice.

Sounds like you're well on your way to fine tuning your machine.

One question about this...

I also found that the ballscrew on the Y axis runs very free if it is not fully tightened down. So I did some more investigating and found the mount must not be perfectly 90 degrees.
taus

I'm assuming that you want the axis to move through the screws when they are pushed. This is without the screws being connected to the motors, correct? When the motors are hookedup, they'll create resistance, which is why the z axis won't just drop when the machine is turned off.

Am I on the right track?

Carlo

[JavaDog]

taus

Hey, is that the Kobalt workbench from Lowes??

[CNCRob]

It looks identical to the Kobalt at Lowes but I beleive his said WaterLoo on it. I bought the two drawer Kobalt version from Lowes for my router.

[JavaDog]

It looks identical to the Kobalt at Lowes but I beleive his said WaterLoo on it. I bought the two drawer Kobalt version from Lowes for my router.

Same here. Seems really nice and sturdy. Much better than the overpriced "Craftsman" ones...

[tauscnc]

Hey Carlo,

Thanks! I am starting to enjoy the machine more and more but am thinking of upgrading the stepper motors. The 180 oz/in work fine but I just want more speed... (getting greedy now . Your right on the axis movement, sorry for not being clear. When the belt is off of the motor I can push on the Y axis and can get it to run through the ballscrew (with a little help). Before it was just difficult to turn it by hand.

I also checked out the X axis last night and as I remembered, the block is also too big. I will post pictures later when I get home to show this. I "flycut" a little off the top and it not only fits better it is also "more" 90 degrees to the mount. K2 (unless my finding are wrong) has some machining issues to work out.

I also found that running 2 transformers in series to get 52 volts really does nothing for my motors. I can run them at 36V and get the same speed. So I backed that down and the motors seem a bit cooler.

Hey JavaDog,
It is the "waterloo" bench but am sure it goes by many names. Here is a link, I think I got it at Lowes. Here is a link of the "same" workbench by kobalt. (update, you guys already figured this out

I took the back off and cut the two mouting pieces. I than added about 5, 1/2 inch pieces of pine to clear the machine. I used some 90 degree mounts for the side panels. I will post some pics tonight of the setup so far.

I just remembered I have no fuses on the steppers or power supply and I have to put an on/off switch on it too.

Still more to go.

taus

[tauscnc]

Here are some other pics of it:

Here you can see one of the mouting posts for the top part that need to be cut for the router. Dremel with cutoff wheel makes quick work of the steel

PICTURE 1

Here is another pic of the side where I added a shelf for the power supply. Its hidden away nicely. I am going to drill a hole in the front for a switch. You can also see how I simply mounted the printer port.

PICTURE 2

The Gecko's are on the back and simply doubleside taped to a piece of wood. I have them resting against the table.

PICTURE 3

Thats all for now.
I will post more pics tonight.
Back to work

taus

[JavaDog]

Great pictures! Thanks for that!

Makes me feel even better about buying that bench. Now, it just needs casters!!

[tauscnc]

Hey guys,

Here are some more pics of the X-axis. K2 you really need to check your setups!

PICTURE 1
Here you can see how the mount is not really cut to sit 90 degrees on the X-axis. While I don't "care" as much since I have other machines, desire, etc. to fix this, I am diappointed again at K2 for their machining ability on these very important part.

PICTURE 2
Here you can see how the mount is also to big. At the end of the travel it was still almost this far down. I understand the ballscrew is falling a little under its own weight here but even flipped over I had to push it a little to get it to fit. (unless it is to be this way I see it as being to big.)

PICTURE 3
Here I took the mount off and put it on my trusty Shelrine. I flycut "some" off and noted it did not cut all of the part at one time. The block was indeed not 90 degrees. I cut just enough to get it level. This is a picture of it back on. Much less force to get it to fit over the crossbrace, much better mounting.

F for workmanship on this part.

taus

[JavaDog]

The SERVO Package that K2 sells what do you think about it? I am sure the Gecko Drives are wonderful but how are the motors, the rapid of the machine the setup, etc.
taus

Since I am using the same motors and transformers (PSU) - I am pretty interested in that too.

I think you can get the motors cheapers from Jeff at HomeCNC though...that is where I got them. :cheers:

[cbass]

Hey Taus,

Seems like you should be on salary with K2.
You are, after all, doing all the QA on your machine.
Maybe I should just have them ship my order to your place first

I'm starting to get cold feet. I want my machine yesterday, but I don't want them to skimp on the details and so I'm not asking them to rush anything.

Have you mentioned any of these errors to them?

Do you guys think I should let them in on our little secret? (wedge)

Carlo

[DieGuy]

That is just sad for the $$$$$$ put out.

[HomeCNC]

Tauscnc,

You are lucky that the error was on the more material side

[tauscnc]

Hey guys,

As for K2, I have had long talks about their KT-2525 but not much of anything on the KG-3925. Before I ever bought the machines, I told K2 that I would do a review of their machines on cnczone and my website. I was (and still am) really excited about the machine. So they knew I might be "trouble" . When I sent the 2525 (which was horribly made) I wrote them a personal letter with many honest suggestion. I also own my own practice (going on 7 months now) and we are not only in the health care field but also customer service. For us to survive we must have 100% better service than anyone in the world HONEST feedback is very hard to come by and when we get it I jump on it. You get feedback everyday but much of it is not "real stuff." I think the more K2 knows we know the faster they will need to fix these errors. A company as "small" and concentrated as K2 will not survive if they don't take the next step ASAP to get these problems resolved. I think they have a "great" product and I think they have a great nitch in the cnc community....they just have to get some bugs worked out and check over their machines/shipping ways.

-A letter with each machine or a note card saying "Thank you for choosing us." SOMETHING should be sent with each machine. Heck it took 8 weeks to make it, I am sure a little note card saying "thanks" won't take that long. I can make one on my computer in seconds. No information is sent with the machines and that is just poor. Nothing.

-A part list MUST be made and ASAP! When I spoke to Kevin and Ron I had to describle the parts and then I was asked to send a picture. Again, for me, I don't mind (that much, but many others will) and for a machine to not have a part list....poor, Poor, POOR. I suggested I could make one for them for an aluminum top that has pics, etc. I have not been contacted. When I talked to Ron it did not seem like he even knew a note was sent and no mentions about it was made. (Again, feedback is only good if you make something of it).

-I suggested not to send the machines assembled but partically made. Mine, another guy that just wrote me, CNCRobs (I think) all had some dents etc from the shipping. These are just to big and heavy to be shipped by people that don't care about the purpose of the package. K2 also, in my opinion does not package the base well. It is in a thin box. The other stuff is packed well. Its pretty stupid to get a "percision machine" all dented up.

-To check their machining setup and do it ASAP. I have a sherline and I could of made the KT-2525 better. For them to be using the "real stuff" there is very little reason for some of these mistakes. Check fixtures, G-code, etc.

-To not promise something and not deliver. I was never upset that my machine was not made sooner. I was upset that I was told I would get phone calls returned, it would be out today, tomorrow, etc.

My intentions with this thread is to have HONEST feedback for anyone interested in these machines. I figure if I show my experience with K2 it will help everyone out including myself I also figure it will push K2 to get things sorted out faster then what they might of wanted too.

I am not sure K2 knows about this thread and they shouldn't be surprised when they find out/are told, etc. They knew first hand I would be sharing my experience in detail.

I guess I have been SPOILED by Sherline, (and now by Gecko Drives (Mariss)their products and customer service. K2, as they mentioned to me is a growing company and (like myself taking over a 30 year practice) have many things to learn. I guess that is one reason I look at it a little differently now....before, I would of just been really pissed.

man, my fingers need a break,

taus

[carlnpa]

My experiences mirror yours Taus in every regard. I also sent emails and phone cons about my concerns that were quite specific, always professional. I am in the sales and service business, and would not survive long with this level of customer service. I am really torn about applying my engineering knowledge to fix K2 issues, for their benefit and at my expense.