Quote Originally Posted by mattanonymous View Post
I'm following this. I've always been underwhelmed by the quality of the parts I get out of my i3v 10 inch.

longjohn119, are there pulleys you recommend?
I got a pair of these from Amazon but you can likely find them even cheaper. Some people like the smooth bore pulleys rather than with the teeth, something about backlash with the toothed idlers but I haven't noticed any problem in that regard. I just know my Y belt isn't riding in a different place and flopping back and forth all the time which couldn't have been good for accuracy. Frankly I can't see all that much savings using a pair of bearings instead of proper idler pulleys. I can understand using normal threaded rod where there is a pretty big cost difference and it can work decent **if** the rods are perfectly straight and stay that way but that actually rare. Especially with 5 mm where just using too much pressure to cut them can bend them a little and it doesn't take much of a bend to show up in your prints. Personally I think the Acme lead screw upgrade Makerfarm offers for 60 bucks is a very fair deal for what you get and that includes a better stepper driver

I like the DRV8825 Stepper Driver better because you can actually heatsink them properly. The type of IC package used is made to pull heat from the bottom of the chip to the back side of the PCB where there should be a fairly large ground plane and you put your heatsink on the back side. This type of IC does not sink heat properly from the top, it'll help a little but not a lot like the heatsink on the back side. The A4988 drivers aren't properly designed for heat sinking with most of the heat drawn through the bottom into an area that is boxed off and impossible to add a heatsink to. Putting a heatsink on top of the chip helps but not really all that much because of the way the IC is designed. The Pololu design will work but you need to derate the current by approximately 25% so instead of a max 2 amps it's more like 1.5 amps, anything more and you'll likely go into thermal runaway and burn them up. I wouldn't run out and replace all your A4988 drivers because even 1.5 amps max is fine for most designs but if one were to go bad I'd definitely consider the upgrade to a DRV8825