Fix z-banding w/ no backlash- "Slop Nut" (Level 2 techie - Consumer ) (Page 6 of 7)

very nice good job

Humm ok sounds about right. I'm trying to locate a M3 threaded rod locally but might just end up buying one online. I remember you said you got the aluminum bed, did you take the PEM nut off right away and install a M3 rod or did you not bother with the PEM nut?

I'm figuring the M3 rod coupled with the slop nut is the best way to eliminate my banding problems, cause I can't figure them out otherwise.

Another thought I had, when space is tight, could you use a lock washer in place of a spring when it comes to a double nut anti backlash setup?

Awesome, I'm pretty excited since I just found a place locally that sells metric threaded rods, and I'm gonna pick one up in a few hours. Of course they come in 1meter lengths, so hopefully they'll be able to cut it for me

Has anyone used to the slop nut with a flexible coupler as well?

I tried a single nut anti-slop device with poor results. So decided to try a flexible coupler.

I like the idea of a flexible coupler to prevent z-wobble as it removes wobble right earlier in the Z mechanism. It made sense to to upgrade to an M5 Z-rod too as the diameter of the stepper motor is 5mm, so I could use a 5mm flexible coupler.

I then realised I would need a different mount for the M5 nut so thought I may as well try the anti-slop parts as I will need to print a mount for an M5 nut anyway. Would this make the z-rod 'floating'?

I'm not sure if this is just my printer or not but the holes for the aluminum bed don't line up with the holes for the slop nut cage.

Here are some pics, this one is on the thin plate laid over the holes. It should line up right? Looks like the holes aren't wide enough. I can measure the space between the holes on the bed and the printed piece if you want to make sure.

Or, is this the way it should be? Should I just force the bolts in there and screw them down? Or should the holes for the slot nut assembly match the aluminum bed perfectly?

I noticed a few posts back that you mentioned the outter cage should remain in place, while the inner should move freely. I don't understand how that would work though. The M3 bolts I'm using to secure it to the bed fit extremely snuggly into the two plates that trap the nuts (enough that they cut a thread in the walls of the hole). The same M3 nuts slide right through the holes in the outer cage and the thin plate that presses against the aluminum bed.

Could it be my printer that's printing these parts poorly? I'm using an Afinia H series to print them, and I believe it's calibrated correctly. There just doesn't seem to be any play with my slop nut setup at all. Or am I installing it incorrectly?

Edit: I took another quick picture. I used a tripod and lined it up as best I could to try to show the differences in the size of the holes for the plate that traps the nut and the box that encloses the entire setup. As per your description in the first post it looks like the hole diameter is flip flopped, with bigger holes in the containing box and with smaller holes in the plates that trap the nuts. Sorry the pic is a bit blurry, but I think it shows the hole diameter difference.

dOh, I'm using the 3mm version.

So far I got it installed like the picture below. I'm definately loosing some Z height because of the monstor coupling I printed so I'm going to try to print a smaller one. I just sandwitched the two nut trapping pieces together and forced the screws into the holes bowing them out a bit. It's pretty tight against the bed so I don't think it'll relly matter.

However, when I bring the bed pretty close to the bottom, it gets locked up. I don't think the threaded rod and the nuts are lined up perfectly but as long as I don't go that low I think I'll be fine. Though that does make me want to get the slop nut working so the rod isn't messing with the bed at all, and just let the smooth rods guide it.

Really appreciate the quick reply, I'm generally so impatient that I don't want to wait a day and I'll just end up doing something dumb in the meantime haha

Now I'm trying to calculate the Z steps per/mm. Solidoodles guide for updating the EEPROM settings (http://solidoodletips.wordpress.com/201 … on-update/) seems outdated. There is no "Config" menu, but under "Printer" there is "EEPROM Settings" but clicking on that gives me the window below...

So I guess I'll end up entering the Z steps per/mm manually, or adding it to start code somewhere so that it happens every time...

Ah thanks for that! I'm going to print it as soon as the bed heats up, and probably install it tonight or tomorrow morning. I set the Z Steps to 6400 and using my McGyvered caliper-clamped-to-solidoodle-frame-to-act-as-dial-indicator it seems to be accurate.

I'm pretty sure I can make the coupling a lot shorter, so the threaded rod will come down pretty much to touch the end of the Z Stepper motor axle. Figure I only need a small portion of the threaded rod to be sandwiched so long as I tighten it down really well. Hopefully this kills my banding for good! Going to test it soon and will report back with results.

ok, so I have my printbed out and I'm looking at the PEM nut... do I remove this and then place it in the enclosure? Thanks guys!

Bingo, got it! Thanks!

On a stock 5/16 I have 4 pieces. Dumb question how do I install them?

it looks like I remove the 4 outside nuts, place the 5/16 big nut into the pressed piece then bolt the large cover using the 4 outside bolts?

what are the 2 thin pieces for? can I get away with out using them?
and Can I just install form the top nut portion without removing the Z at all?

@2n2r5 - I'm a little unclear similar to @jjcuff1. My SD2 is only 3 weeks old so it's all stock except for my jigsaw. I Printed the 5/16 version and even have a nut handy. I've sort of installed it but I don't want to tighten everything up/down until I'm sure I'm understanding it all correctly. So tell me if and where I'm making a mistake.

1. Print parts

2. I have only 3 pieces. The thin one, the nut hugger, and the cover. they go on the machine in that order. Thin, hugger with nut inside, cover. Now, in regards to the hugger, I notice I can tighten this up until the slop nut is firm/tight but, it isn't lined up right and when lined up properly the nut is a little loose. Not x loose in the hole but z loose so the nut can slide up and down the rod as the z goes up and down. I'm thinking that is correct.

3. Bolt the whole thing down in the four corners. This will tighten the part but still let the slop nut "float" inside it.

Is it just that easy? Logic tells me it is because of the stock rod. I see there are links about removing the z rod and PEM nut and other stuff. Am I correct to assume that that all applies to changing your rod before using your part and not relevant to the 5/16 rod?

So just to be simple, on the stock aluminum bed with the stock 5/16 rod, all I have to do is print the part(s), and put it on. I'm sorry there is just a lot info and I don't want to start messing with stuff that doesn't apply to me and my situation. Maybe in a month or so I'll switch out the rods but I'm fairly happy with it now. I know I have a z issues because my parts will band a little and start to miss entirely once I get to about 17-18 mm high. So I'd like to install this and then print a calibration part to get my numbers to change my steps in the firmware.

Also, there is very minimal hardware on my aluminum bed. I have that PEG nut and that's about it. There are 4 little holes that this part lines up with and from reading around, it looks like previous versions of the SD2 used those holes for something. Mine are free to be used for whatever like, this neat part. Question is, what size screws/bolts should I use in those four corners to finalize my installation?

I'm really loving my printer and I'd like to get it all dialed in but I don't want to Ef it up in the process. Thanks

@Antron007 did you ever get a response to this? I'm in the exact same boat.

Could anyone offer help?