Has anyone tried to install steppers with a higher torque rating than the ones sold in the kit? Ive found some Nema 17’s with 100oz/in vs the 76oz/in in the kit. Just trying to get some faster feeds with DOC that is at least the thickness of the bit (1/4in bit = 1/4in DOC).
EDIT: Changed title to higher torque instead of lower torque
The 76oz/in motors will do what you want quite easily.
if this is the case, what is causing the skipped steps when increasing feed rates? im already running at 1000 mm/min, what if I want to go faster? Personally, im not into cutting 17/18mm with a 1/4in bit. I feel like you are just looking for trouble doing that which is why I would rather go faster and shallower than slow and deeper…
Again I ask, has anyone tried to add higher torque motors to the lowrider?
Here are the ones I was looking at:
Steppers are stronger at slower speeds. They fight movement, and that can lead to saturating the incoming power, which reduces the current. These larger motors might even have a lower threshold for speed.
You can get a higher speed ceiling by increasing the power supply voltage. Going from 12V to 24V can give you a lot more top speed (more than double, actually). 12V is the standard because it is more common (so the other parts are easier to find, like 12V fans), and most users want the strength when milling, which is usually lower speeds. That’s why we usually suggest going deeper first, and then go faster. It’s based on the fact that steppers are stronger at slower speeds.
15mm/s shouldn’t hit the voltage limit, at least not on the belted axis. It might be near the limit on the Z.
As for your actual question. It wouldn’t take much to add them. But I wouldn’t expect much actual gains. Things are pretty well balanced, and more torque in the motors won’t show up until you push it harder. At some point, the bit, router mount, tubes are going to start flexing and you’ll need to back off anyway. The drivers can’t provide any more current, so IDK if they would even be stronger at the same current. Most of the time, when people come in with problems skipping steps, it is something mechanically wrong, or the setup is biting much more than they wanted. Meanwhile, you’ve got bigger, heavier motors that cost more. Not significantly enough that you shouldn’t try it, but I would temper the hope a little. 
But what do I know? Maybe you do have your machine tuned well, and you know your CAM better than I (wouldn’t be hard, honestly) and your motors are your limit. Buy these bad boys, and add a 24V PSU while you’re at it, and do some AB tests with each upgrade. Something like max feeds/depth that you can get before skipping steps, along with a measurement of accuracy. If you can go twice as fast, and it’s accurate enough for a roughing pass, then it would be worth it, for sure.
Hmm. I’ve done what you’re wanting to do… which is test the limit of what (my) machine could do. The end result I arrived at was the fastest machining time worthwhile with my machine, reliably, was 1000mm/min at 18mm DOC full slot with a roughing bit. This will complete my projects every time, no questions asked, whereas running a 1/4 bit at 1850 up to 2250 at even shallow DOC had problems associated with what Jeff and others have mentioned.
Numerous posts on this site with folks running higher torque Nemas. The issue isn’t the Nema torque, from my experience, it is the machine rigidity and workholding - and then a very close third is the tool strategy.
This fellow is using higher torque Nema 17s, increased the rigidity of the machine alongside other upgrades too.
https://www.youtube.com/watch?v=2ixkoNZFQb0
If you find a new recipe for faster machining times, by all means let us know!
Jeff what current rating would i need to use for the 24v upgrade? I think I have a 24v power supply laying around
Use the same current. If you aren’t running a bed, around 6A. It should use less, but you’re doing it to go faster, and it is capable of the drawing the same current, so it should be rated for the same current.
cool thanks