[CS900]

So, decided to let the ballscrews "break in" with minimal preload. not so good for backlash, but I guess i was expecting too much from my cheap ballscrews

so anyways, quick question. getting ready for assembly, and I'm piecing together the last of my oiling system. the only fittings I have found that will thread into the ballnuts are zerk fittings, which all have little check valves in them. I'm worried that my oilier won't have the necessary pressure to open the check valve to allow lubrication. What have you guys done as far as these fittings go? I could always drill out the top so the ball comes out, but figured I'd check with you guys first to see if there is an easier way.

and becasue everyone likes pictures:

[Mystichrome]

You should be able to knock the balls out of the zerk fittings with a small pin punch. I did that with the zerk fittings that came with my Linearmotion ballnuts. Out of curiosity, do you know what the thread size is for the fitting on the ballnuts?

[CS900]

it's an M6 i believe.

[LeeWay]

You can use these designed for light oil.
McMaster-Carr

They also have grease fitting adapters that will get you to a pipe thread for the oil line.
McMaster-Carr

[Mystichrome]

it's an M6 i believe.

My linearmotion ballnuts use M6 as well. I bought 10 Push in to Connect One Touch Elbow Fittings 3 16 M6 | eBay with the intentions of using them, but I'm not sure I'm going to have enough clearance in the ballnut locations to use them. I have a G0704 though, so you may have more clearance than I do.

[SCzEngrgGroup]

Grease fittings are nearly always one of a number of common metric sizes, and suitable fittings of any type necessary for plumbing a one-shot system are readily available, even from E-Bay, and also McMaster-Carr, Bijur, and others. Simply measure the diameter and pitch of the threads, and the correct size should be obvious.

Regards,
Ray L.

[CS900]

leeway, you have to give the part number, mcmaster links only take you to the main page of the item. Regaurdless, they probably are the fittings I have now, which still have the check valve. BUt, i drilled out the back and the spring and detent fall right out, so no worries about that anymore.

Mystichrome, thanks for the link. I may pick some of these up as my newest problem is trying to get the hose to stay on the fittings once i start moving things around.

I can almost see the light as the end of the tunnel!

[CS900]

ok, so another quick question stemming from our maintenance plan at work for our full size VMCs. At work, we don't oil our ballscrews, we grease them. and obviously, the automatic oilers oil the ways.

So my question is, why do people not grease the ballscrews, and just plum them into the one shots? Seems to me, I'd much rather have grease fittings for the ballscrews, and hook the ways up to my oiler separately.

[LeeWay]

Some of the ball screws I have are designed for oil. I have seen some designed with grease fittings. Oil will tend to help keep chips cleared out, where grease will invite them to come in and stay awhile.

[CS900]

So that begs the question, how do you know when to oil, and when to grease?

[CS900]

So, I decided to go with grease for the ballscrews. Although, had I know I was going to do this, I would have done my fittings a bit differently.

Here she is for now:


One shot oiler installed and plumbed:


I still need to get some check valves for the Z axis oil hoses, and I'll probably end up putting some on all the branches.

Here's now I ended up connecting the hose to the grease fittings. I drilled out the check valve, and RTV'd the hoses in place:


Here's how I ended up doing the grease fittings. If I were to do it again, I would have made custom fittings to go onto the ball screws, since the grease fittings I used have a very small opening that the thick grease doesn't like to go thru all that well. For now, I'm just going to order some NLGI-0 grease and call it a day. When I disassemble the mill to put on a custom stand I'll fix the problem properly.

[SCzEngrgGroup]

On a hobby machine, I very much doubt it makes one bit of difference whether you use grease or oil. Oil would certainly be preferred on a very high speed machine, like a 1500 IPM VMC. But, give the limited speeds of hobby machines, and the limited use they see, and the fact that they are not expected to run 24/7 for 10 years, either grease or oil will work just fine.

I struggled for years to get the knee ways of my knee mill properly lubricated with oil. It finally got to the point where rapid speeds had to be tuned down, due to lack of lubrication, and I couldn't force more oil in. So, I removed the automatic oiler, and put in Zerk fittings, and got out my grease gun. Within 10 minutes, I had full rapid speeds restored, and could ever hear that the servo was not working as hard. I was actually able to tune the servo to higher speed than ever before.

I used nothing but grease on my X2, and never had a problem with it.

Regards,
Ray L.

[LeeWay]

All of my linear trucks take grease and I do grease those. All of my ball screws get oil. None of them have grease fittings though. A few have actual oil holes and the others are rolled ball screws and I just lube the nuts about once a week with oil and keep 90 weight on the screws. Not a perfect situation, but seems to work fine.
The Torus I bought has a one shot oiler similar to what you are installing. Now that is the way to go.

[CS900]

Well good info right there. Although the grease I just ordered seems like a middle ground between grease and oil. It's a NLGI-0, which from what I can tell has the consistency of ketchup. Should be a lot easier to get into the ballscrews, but it's still a lithium thickened grease, so should work pretty darn good. Of course, now the part that sucks is i have to force everything in the lines currently out, otherwise my tubing will just expand and it won't go anywhere.

So now that the mill project is coming to a good (momentary) resting position, it's time to get parts on order for the cnc lathe

Leeway, how is the torus? I've heard mixed things about them.

[SCzEngrgGroup]

I would not use a Lithium-based grease. I've never seen a Lithium grease that didn't dry out and harden over time. My personal favorite at present is a translucent red high-pressure grease sold in auto parts stored in grease-gun cartridges. Not terribly messy, lubricates really well, and seems to stay nice and soft forever.

Regards,
Ray L.

[LeeWay]

Leeway, how is the torus? I've heard mixed things about them.

I love it. I don't think I could be much happier with it. The oiler just makes life easy as does the rest of the machine.
There are two of us in the shop and buying the Torus was almost like hiring another guy. It will be closer to that once I am able to afford and adapt one of Ray''s new PDB's and ATC's to it.

[CS900]

Hey everyone. I'm pretty terrible at updating this thread I know. But I could use a bit more help, so I'm back.

So I have everything up[ and running finally. My electronics box is mostly finished, 220VAC has been run and connected for the spindle, and all the wiring is finished. So now I'm having a hell of a time tuning the gecko G320Xs. I can get the servo nice and tight without any oscillation, but then the servos are very noisy and dither much more than I think they should. I'm afraid I don't have a scope to really tune them well, but I've been following the CNCcookbook method for tuning my ear. I'm finding that I rellly know nothing about servo tuning, and I've been reading a lot of conflicting data between a lot of sites/threads/manuals.

To compound that issue, the problem gets even worse when I have all 3 axis plug in at once. I can get the servos to where they are quiet but a little loose individually, but as soon as I hook all the axis up, they all start dithering again. I thought this was an electrical interference problem with the encoders, but I have since installed shielded wires for the encoders, and made sure they are (from what I can tell) properly grounded. I also re-ran the encoder wires to be as far away from the power wires as possible. So any suggestions?

[CS900]

So turns out my AMT102-V encoder covers are floppy which I believe is causing a significant amount of my dithering issues. Any one else have problems with these encoders?

[cybot]

Kind of late but might help some other servo user.

Quote: One important thing to note before we get on with the tuning. It does no good to tune a servo motor sitting on the bench. It must be installed on the machine, and the machine must be set up as near to how it will be used in production as possible. That means the gibs are adjusted and so on. I would even go so far as to throw your vise or 4th axis on the table if that's how you plan to run. Really tight servo tuning can change even with the difference between a really heavy workpiece and a light workpiece, so set up your mill table the way you expect it will be used before attempting to tune.

It sound like you need the dampening turned up just anought to take out the oscillation but not anought to over dampen and slow down the servo's reponse.

[jid2]

On a hobby machine, I very much doubt it makes one bit of difference whether you use grease or oil. Oil would certainly be preferred on a very high speed machine, like a 1500 IPM VMC. But, give the limited speeds of hobby machines, and the limited use they see, and the fact that they are not expected to run 24/7 for 10 years, either grease or oil will work just fine.

I struggled for years to get the knee ways of my knee mill properly lubricated with oil. It finally got to the point where rapid speeds had to be tuned down, due to lack of lubrication, and I couldn't force more oil in. So, I removed the automatic oiler, and put in Zerk fittings, and got out my grease gun. Within 10 minutes, I had full rapid speeds restored, and could ever hear that the servo was not working as hard. I was actually able to tune the servo to higher speed than ever before.

I used nothing but grease on my X2, and never had a problem with it.

Regards,
Ray L.

Interesting point I learned when we installed our Brother machine at work. We asked what oil to use on it and the tech told us the machine used grease. This is a 2000IPM rapid speed machine, with a 16k spindle. The grease only needs to be squirted into the machine every 6 months, and grease does not ruin your coolant like way oil. This is just one of the things that makes the machine so reliable and much more pleasant to work with. So done right grease is up to the task as Ray is pointing out.