40mm x 40mm Machined Heatsink With Custom Mounting for NEMA 17 Motors

I ordered 4x of these, plus 4x 40mm fans.Pros: the packaging was excellent. They were inside a very thick plastic ziplock bag and in bubble wrap around that. The machining seems very good, too. I have no doubt these will dissipate heat effectively.Cons: Only 1 thing, and the only reason I didn't give it 5 stars: there is no clearance around the corner screw holes for the screw head, so the fins are in the way. As a result, attaching this directly to the NEMA 17 motor using its own screws is not an option. That being said, I also bought fans to go on top of the heatsink which would require longer screws anyway, so this should not be a problem when I get the screws. But my goal was to do that after I tried it with just the heatsink first, so I'm a little disappointed that this is not possible. If you are not trying to attach it directly to the NEMA 17 motor without getting new screws, I would recommend this product, and this supplier.Related side note: the fans I ordered arrived with similarly excellent packaging.

I ordered 3 of these for the axis steppers of my RepRap, and I could not be happier with them. I also bought 3 12v superfans to cool them, but I discovered when the arrived that I didn't have machine screws long enough to mount them. So I installed the heatsinks without the fans, and they work great.I'm still going to add the fans but I need to wait for the longer screws to arrive, and I expect they will be even better at keeping my steppers cool.I should also point out that in order to install the heatsink with machine screws (which you will need if you plan to install a fan) you will have to remove and replace the screws holding the stepper together. These are sometimes very difficult to remove, so be sure you can take them off before you order the heatsink. If you cannot remove the screws you can still put the heatsinks on with thermal epoxy, but you won't be able to use a fan. But you're probably smart, you can come up with something.

I bought these for my NEMA 17 motors along with thermal paste, the fans this company sells, and 60mm M3 screws. After getting this installed I got the temperature of my motors from 50C to 30C (20C reduction / 36F reduction).The 60mm M3 screws were the longest I could easily (and cheaply) find on Amazon. I think 65mm is probably the required length. Because the screws were too short I had to spend ~1 hour drilling out holes in the fan (making them more shallow) so I could send the screw (1) through the fan (~1-2mm), through the heat sink (15mm - not 10mm as the website says in one spot), and then through the motor until the threads (~44mm).So... painful... but that's what home-built 3D printers are and why this project is fun!

Holes are a bit tiny for most normal screws. Took a bit of ripping off the fins and new screws that were a tad bit longer so it would fit on my makerbot replicator 2's motors

Arrived Nice and New and it makes a HUGE difference. Before My extruder motor was overheating and i couldn't print for more than 45 Minutes. I used thermal compound and this and a 40mm fan and used some longer bolts that i got from amazon also.

these work well for adding a heatsink to nema 17 motors that I use in 3d printers.

Fits great on stepppers

Fits perfectly!