$555, including shipping, to the US. Plus about $200 for a VFD from elsewhere. Yeah, their power numbers seem a bit optimistic, the math doesn’t entirely add up. They did offer an explanation for this, but I’m waiting until I have it in my hands to take my own measurements. I’ll post about it here once I’ve had a chance to try it.
Even if it’s under-powered, it’s still about where I want to be “for now”, for my upgraded SO3. I’m thinking about building a from-scratch CNC with what I learn from all this experimenting, and that’ll be when I consider splurging more on the spindle(s).
That’s interesting about SFM vs cutting power. I’ll have to try pushing it above 3000 and see what happens
Excellent testing and documentation. These results intrigue me and I plan to duplicate them with some nice testing equipment at work I have access to. I plan to complete the following tests:
Pull polyester and steel-cored belts with 10, 20, 30, 40, 50 pounds-force and measure strain.
Bonus test - run cyclic testing of 0 to 50 lbs-f loads and see if the belts undergo any degradation.
Anyone else have other thoughts on some useful tests to try?
Great - I’m interested in whatever you learn. Do you have access to a dynamometer for the measurements? FYI - Piotr and I are continuing our discussion about his “2.5 kW” Jianken ATC spindle.
No, I was just going to measure actual input power to the spindle. If there is a straightforward way for me to measure output torque and power, I’d be interested in trying that, too.
Estimated? I forget, somewhere around 6lbs according to @gmack spreadsheet, I believe. Running around 90% of the Makita’s estimated output power, 30k rpm, .25” single flute. I’d have to look up the exact DOC, etc. which I don’t have handy, but I want to say around 5mm DOC and 1.25 WOC? Going off memory.
I don’t know the actual force. I feel like there were some parts of the cut (large circular adaptive clears) where deflection from prior passes may have left enough behind that the momentary force exceeded what the X stepper could hold, also taking into account that the 18lbs max holding force will drop off at speed when a stepper starts moving fast.
So, I think the X stepper had enough holding power in theory for the Makita, but when combined with the belt stretch, I’d sometimes be biting off much more than expected.
Definitely a healthy bite. I’m guessing you could hear chatter on the heavy circular cuts as well, especially transitioning from Y to X right? I know these belts have a bit of give but imo the X wheels do not deal well with the axial loading and unloading.
Have you seen the Millright megaV with its rack and pinion drives? It should be very interesting to see how those perform when they start coming out. Also one tip on long term use for steel cores, they don’t like being over tightened and they do have a lifespan.
I think we can all agree on belts not being the golden ticket but they are very good for a hobby machine in terms of maintenance, ease of use, and backlash.
Yes, there were definitely directions of heavier chatter… it’s been a few weeks now, so I can’t remember which part of the circle it was on. The V-wheels on mine, I couldn’t measure much deflection just pulling on the router (but maybe cutting is different). For sure belt stretch would differ a lot, transitioning X to Y.
Super interesting about the new MillRight, I hadn’t seen that… the rack and pinion would address the belt stretch and the rest of the SO3 seems pretty solid already, so that looks pretty beefy.
Steel belts do feel like a good sweet spot for most things. I guess MillRight got R&P into budget by manufacturing it in house…?
@ydrefalk 160 IPM, give or take. Normally I’ve been cutting about half that depth at that speed, but I was working on a large 24”x12”x1” piece and was getting impatient… I wouldn’t repeat those settings on my machine without additional upgrades. It vibrated my Makita to death, actually - the speed dial broke and it is stuck on min speed. Guess I’ll have to buy that spindle sooner than I was planning
Well it points to having to keep an eye out for any failure and change them more often but it may still be a good option for those who require a high level of precision. People who have purchased replacement belts normally have a fairly large quantity on hand as they are often sold 10m at a time.
I don’t know - they seem to have actually worked quite well - “not practical” is maybe a little strong. The fiberglass belts stretch pretty continuously. The steel don’t, but eventually give up. Kevlar has worked pretty well for me.
