E-Z LOK Threaded Insert for Plastic Flush Brass Thread Inserts 1/4-20 Pack of 25

I use these in 3D prints and they work great, I use a 6.5 mm hole but your printer may behave differently but once you get the size dialed in these are great.

These items are as described by the mfr. However, they totally failed in my application as threaded inserts for HDPE plastic. I made sure the pilot hole dimensions were exact with my CNC mill and pressed them in with a proper arbor press.These inserts pulled out very easily. I'm thinking perhaps the split being on the bottom side actually pushed them out as the screw was inserted because they spread most at the bottom. Don't know for sure but they didn't work and pulled out very easily in my application.I have used the flanged top models with the split at the top. Those ones with the same mounting hole dimensions locked in like a rock and cannot be pulled out without destroying either the plastic or the insert. So they work properly.In the correct material (wood?) I assume they will work but they didn't work well for me hence three stars.

They are strong, they hold in place extremely well.Due to the design, it can be difficult to install perfectly aligned in plastic. I would recommend seeking out the correct installation tool rather than trying to 'make do' with a soldering iron.Due to the design, I would suggest these are better for fit and forget installs, rather than end user, as the screws when turned are difficult to get it, squeak, and potentially can end up cracking plastic if not careful. These seem to be intended for locking the screws in place, as well as the part itself.Do I recommend them? Yes. Just be sure you need these and what they are used for.

These are very good quality threaded inserts and these work perfectly with my PETG 3D prints. Just make sure to get an appropriately sized reamer for the recommended size hole and ream the hole to spec before trying to press fit the insert. I’ve used dozens of these now and the way they expand when the fastener is screwed down into gives them an incredibly strong hold. I’ve found that adding a tiny drop of light machine oil onto the fastener helps to eliminate the squeaking sound you might otherwise hear when tightening it down. Also makes it easier to tighten properly. Highly recommend!

Expensive but do the job