iplusmile 100Pcs M3 Threaded Insert for 3D Printing, Brass Heat Set Inserts 5.7 x 4.6mm, Knurled Nuts for Injection Molding & Plastic Parts, Compatible with Prusa, PLA PETG ABS

These inserts work great because the cut pattern locks them in place. The 3D printed part will delaminate before these inserts come out. These are far superior to the dumbbell shaped ones. One side has a decreased diameter which holds them in the hole prior to soldering. These are very easy to insert. You will need a large soldering iron tip. Otherwise, the iron can poke through the insert and melt the bottom of the hole. The hole should be slightly deeper than the insert so the screw can go all the way through. Setting the iron to 400°F (205°C) works well for PLA. A solder iron can be used to remove them too and then the melted plastic can be cleaned off with a propane torch.

The actual size is 4.6W by 5.6 L @m3. In measuring the width is slightly smaller or 4.4mm. The perfect insert where the ooze is minimal and insertion is easy. The bottom has a smaller ring to make it easier to align the insert. Again it works perfectly for some Voron parts a Voron takes 3mm x 4w x 5 d

It took a little while to get this going. I got the insert installing tips for my soldering system. It is important to have the holes the correct size printed and to have them set into the holes before you try to heat and press them in. Keep the soldering iron straight and square. Then all the other parts will align nearly perfectly. I use them for several parts that need to mate with screws. Makes life better than trying to insert nuts into the side of or back of parts where you have to hold the nut in tight places. And you don't need as long of screws to assemble things. Getting the flush with the surface takes some practice, but gets easy with practice. You will get a little bit of rise in the plastic around these inserts, that may need to be scraped off with a razor or sharp knife.

While they are a bit overpriced they do work really well. The quality and machining are really good compared the cheaper but less functional inserts on Amazon.

I really like these m3 inserts. They are slightly smaller diameter than some of the other inserts on the market. I think this is a plus as it allows you to fit them into tighter areas. But if you are trying to use somebody else's design the modeled holes may be a bit too big. I haven't seen how big of a hole these inserts will seat into, but find they work very well in a 4.0 to 4.3 mm hole. Fit and finish and threads are all very nice and they have a nice non-knurled nose that helps get them aligned and going into your holes straight.

I'm on my second bag of these inserts and like them a lot. I have used these on both ABS and PC 3D printed parts and had only one spin (due to improper insertion). I like that the end has a smaller and round OD, which helps with centering during insertion. For ABS parts, I design parts with a 4mm hole for the insert. My soldering tip has a 2.75 mm round shaft with a 5 mm shoulder and pushes them into the plastic just fine. No other insertion tool is required. The OD of my parts are 4.6mm, which is less then the photos show, so measure a part before designing it into your project. An M3 screw fits the threads well. I use SS screws, which can easily ruin the brass threads of these parts if you start them wrong.

I had some parts I needed to print and they required heat inserts. I always swore off them because I didn't like the idea nor did I have a temp controlled soldering iron to install these. Having finally solved the latter issue, I ordered these and wish I embraced heat inserts sooner. These are really satisfying if a bit stressful to install. You do need to actually have a part designed for the size inserts you're going to install. One of those purpose made tips for installing these inserts would be convenient but I was able to make do with my iron's regular tip. One good thing to have on hand is a flat piece or block of metal so that you can press your heat insert and the surrounding plastic area flush. Not completely necessary but it's a good trick if you need parts to mate perfectly.

I purchased these for use with 3d printed parts specifically my voron and sadly they are a little too long and a little too small so they have a loose fit, I will have to either return them or recalibrate my prints to account for the difference in size, they see exactly as described in the listing but i sadly did not take better precautions in measuring for the correct size