First, you gotta get three sprigs of fresh holly, some mistletoe that’s never seen a full moon, and a full coven…
Actually, I think the main thing(s) are at least new gantry top and bottom pieces, and maybe spacers. If you’re still on the 525 version, you might as well reprint the whole gantry with the Burly parts. Oh, you WILL need a coupler.
I recently printed all new burly parts, but re-used my older spacers that captured the nut.
I’m still having issues with the z axis not always lifting and ruining my part, and I think the lead screw or the pineapple is to blame.
Then you have it easy. Print new spacers, get your leadscrew, nut and coupler, change your steps/mm on your Z axis, and enjoy the fruits of… precision machining?
Sounds great. Parts ordered. Guess this weekend might be spent taking the machine apart again.
I think I’m going to try to rewire the steppers to make things easier to take apart. Last time I had to resolder everything and it was painful.
If you’re just changing spacers and leadscrew, it shouldn’t be too bad. Release the pineapple, unmount your Z stepper, and pull your Z axis. You should be able to get your threaded rod and spacers out fairly easily, replace the spacers with the new ones, drop in the leadscrew nut, put in a screw or two, then put in the leadscrew, mount the coupler, put your Z axis back in, and remount your Z-stepper, including the coupler grubs.
I hope you ordered 1 start leadscrews (2mm pitch) and not 4 start leadscrews (8mm pitch) the latter will easily spin the router down to the waste board when the stepper isn’t powered.
But your Z rapids can be so fast! 
Seriously, you want the resolution, not the speed. Follow Ed’s advice.
4 starts is not a problem. It’s the standard recommendation for MPCNC and default setting for firmware reflect that. I don’t have anything against one start with 2mm lead but it’s not the consensus best approach.
Agreed. 4 start is the right choice.
I got this one
KINGPRINT T8 Lead Screw + Copper Nut + Coupler+ Pillow Block Bearings Lead Screw Set for 3D Printer (300mm) https://www.amazon.com/dp/B07567KZB3/ref=cm_sw_r_cp_apa_i_Rbz-Db2F65N85
If you like your router plunging into the work piece if you lose power to your z stepper, then yes, 4 start is fine. If you prefer your router to stay put, then no. Your choice of course. I think it’s probably fine for the DeWalt 660 or other lighter weight trim routers but DeWalt 611 or Makita 070x and clones are too heavy.
I rescind my previous comment. T8 is the way to go, 4 start, 2mm pitch.
Yes, your spindle will respond to gravity when your stepper is not powered. That’s why the end of program power delay is bumped up, and it’s suggested that you move the spindle to a safe location when the program is done.
The 611 is for the low rider, not the MPCNC, and keeping the power on after a job is a good idea, until you can park it.
The trouble with the higher 1 start is the number of steps/mm can be very high. We have had a bunch of problems with too high Z speed skipping steps while lifting the Z, not plunging into at the end of the job.
They both will work, but if you don’t know exactly what you’re doing, then stick with the 4 start. If you are offering advice to others in the forums, I’d suggest recommending the standard parts, because there is just a lot less to think about. The instructions, most of the forum advice and troubleshooting, and the affected parts are all related, and based on the standard parts.
I don’t want to smash creativity, and new solutions. By all means, change your machine how you want to, and share everything you tried and how it worked.
Too high z speed skips steps due to weight resistance, though. With a 1 start leadscrew (much like the threaded rod the OP is coming from) you’ve got a better torque multiplier from the less height per revolution. It’s essentially the equivalent of using a 4:1 gearbox on a T8 4x2. And if you think the MPCNC isn’t for the 611, or harbor freight, or makita (all 1.25HP routers), then you’ve not been looking at the forums or thingiverse very much, to be honest. For the default Dewalt 660, yes, a 4 start leadscrew is fine. I started with a lighter router myself but I wanted something that wouldn’t lug out as easily. The reason I’m sharing this is because my router would plunge if the stepper motor shut off while the router was still spinning. In fact, it’d do so just from moving the gantry sometimes if the Z stepper wasn’t powered. The default works for the default router, sure. But a lot of people are not using the default router.
Honestly, I had no idea there were two different parts.
I originally had the parts in a shopping cart from Ryan, but got disappointed when shipping was $14 on $20 worth of parts. So then I followed his Amazon link, but they were out of stock. So I clicked on one of the ‘items like yours’ and liked ‘buy’.
I’ll run what I bought. If I have problems with it, then I’ll order the other one. I’m just really tired of my Z axis not raising and ruining parts. It’s 99% of the problems I’ve had with this machine since I built it years ago, and most of those problems are from the threaded rod spinning in the pineapple.
The one you bought is good. It will fix it. Most of them are 4 start, so it is hard to accidentally get a 1 start.
If you have a trim router like the DeWalt 660, you’ll be fine.
I thought that way as well, then I wrote a whole thing about it. Speed and friction come into play, friction much more so than you would think, not just a sliding friction. One start also need to be more perfectly aligned as well.
It is best to stick with the recommended, your router will not fall onto your part if you use it correctly, meaning simply end you job “above (or at) home position” One setting, very simple.
I think estlcam by default goes back to the 0,0 point after it finishes a cut. Since most of my designs has that as the lower left corner, I should be fine. I always overcut my boards and then recut after I finish CNCing them to remove the screw holes I use to hold the boards down.
Do you have that somewhere still? I’m curious because 1start leadscrews have been a solution for heavy beds on corexy printers lowering when the stepper motor isn’t powered, and I haven’t heard anyone reporting skipped steps or friction issues from doing so. Really a 1 start leadscrew is reasonably similar to a threaded rod just with better precision and further distance between the threads.