JdotPo,
Get the new anti-backlash nuts. This will greatly improve performance. Also check your guide wheels to make sure they are at the correct tightness.
Unfortunately, I was trying one of the new spring loaded anti-backlash nuts. I donāt know if I mangled some threads or there was an issue with it, but it might just be easier (and cheaper) to order a new one than find a tap the right size.
I also replaced and adjusted the guide wheels as part of my reassembly, but I appreciate the suggestion as I think I had them way too tight originally so itās a good thing to doublecheck.
I am have the same Stalling issue on the X of my 30x48 MK2. I have a PWN Spindle which as been working great with the Longboard. Since installing the SLB I have stalling and lock up issues on the X. The only way to unlock it after hitting the e-stop is to cycle the SLB power on/off switch. I will try the suggested setting.
If no luck I going reinstall the longboard witch work great.
Iām also having stalling on the x and one y axis intermittently. Works just fine and then doesnāt. I tried to slow down the speed in the firmware to $120 to 750 but it wonāt hold, it reverts back to 1000. And yes I do hit the save changes button and it still changes back. I have the 48 x30 with a pwn spindle.
Unfortunately Iām getting some occasional binding again 
I used VCarve to design a pattern (10"x45") that has long back and forth movements between cuts and just ran it in the air. It made it through the process once fine, but bound on the second run. I have ordered another spring loaded anti-backlash nut (SLABN from now on because Iām lazy) so when that comes in Iāll give it another shot and report back.
To note: I decided Iād combine the two separated threads into one so that I could combine all relevant conversation which mostly surrounded motor step missing at high speeds, hopefully thatās useful to everyone else as well.
It seems that some people arenāt finding theyāre able to successfully change their settings to fix this issue, so Iām going to record a short video on this process form my home desk to show what you need to watch out for when doing this. Weāll also be implementing a clearer visual change in the next gSender version so itās less confusing in the future
Hereās the video that hopefully helps out
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I have had the same experience that JdotPo describes near the x-axis home position. When I turn the X-axis lead screw by hand near the home position, I can readily feel the resistance increase. Iāll have looked for contact or interference and havenāt found it so far, will recheck. I cannot get the spring-loaded anti-backlash to work on the T-12 lead screw, I uninstalled it and went back to the original which turns on the lead screw much easier.
It took a bit of work, but Iām currently running the spring loaded anti-backlash nut at 5000mm/min @ 1000 mm/s^2.
Steps taken:
- I had to remove my lead screw, chuck it into a drill, and cycle the nut back and forth for 10 or so minutes to āloosenā it up a little. (Make sure you chuck the same side you slide into the coupler).
- After reassembly, I wiped a little pneumatic tool oil on the lead screw in front of and behind the nut and ran it some more
Issues:
- I cannot do any sort of movement over 1000mm/min on start up or it binds. If I jog it around at Precise speeds, it will eventually glide around enough to use Homing and after that I can Normal jog for a bit. Then I can use Rapid jogging or g0 speeds.
- After itās been running for a bit, 5500 mm/min will work for long movements but will still bind for short movements.
It seems the friction is warming things up and allows the nut to turn without as much interference. Iām hoping that the more I use the CNC with the new nut, the more it will break in and not have as much grab.
Iāve torn it down and rebuilt the X-axis a few times so at this point I donāt think my binding issues have a straightforward solution if the majority of folks arenāt encountering the same problems with or without the spring loaded anti-backlash nut.
I feel like Iāve beat this topic to death, but hopefully something will help the next person do some troubleshooting. Iāll update if anything miraculous happens.
-Jon
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Hi @JdotPo, if youād like Iām sure we could send you out a replacement nut since it seems like yours is tighter than is should be. If youāre able to hit the speeds after a break-in session then that seems to me like the nut is the cause and weād be happy to replace it if you sent in a ticket.
Thanks for keeping us updated on your progress, Iām sure there are others who gained valuable insight for this thread since they found their issue much earlier on and got fixed up all the same 
If anyone else is still encountering issues who made previous comments in this thread then definitely continue to reply so we can get you sorted out too
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I really appreciate that you and the team are always stepping up to help solve the issues that get posted! Unfortunately, this last attempt was with a new nut that CS sent out so Iām not sure if a third would make any difference.
I just checked and Iām getting .4705" on my caliper for the lead screw diameter. The original anti-backlash nut spins freely on the lead screw during installation, but is finicky to set correctly for smooth travel in both directions once assembled which is why I wanted to use the spring loaded version. I havenāt tried the original again after reassembling the X-axis but maybe Iāll try it just for a data point.
Just to raise the awareness there, I have the same issue with my 48x30 and SLB and have been lurking on the thread. Yesterday it jumped the left and right axis out of alignment while running a very minimal carve in softwood . Iāve reduced the $120 value to 750 as you suggested and as I watch it run the job now this seems to have resolved the issue at least on this very lightweight, low resistance job.
It does seem odd to me that the direction changes are so jerky. There is no ease-in, ease-out so it seems logical that the millisecond lag of the bit dragging as it lifts through the material would be a natural limiter to the acceleration being excessively dialed up. Iām cutting my tests on soft cedar so if that caused the axis to jump out of alignment it could only be worse on harder material I would think.
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Thanks for adding in @JeffMcL, appreciate it. Iāve got some more testing in the works to further improve SLB performance that I hope to have completed by the end of the summer which Iāll talk about more as the testing completes which might help with all of this, the current solution though is a good one and luckily still allows the SLB to perform better than our previous controller.
Cheers 
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Just wanted to drop a āthank youā here.
I had similar issues to what you were helping Jon with and was pulling my hair out with the x axis bogging down when running it at higher speeds (300 ipm and higher).
This tip seems to have solved my issue. Aligning the anti backlash nut this way it seems to have done the trick. Thanks!
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When I was having the issue of x loosing position and backlash and wheels adustments and even replacing wheels and backlash nuts did not solve the issues I eventually changed the STEP IDLE DELAY to 255 in firmware. Since then I am able to run at full speed without issue.
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