Oh yeah, so does Traceparts, 3d contentcentral and some others, highly recommend sources

FYI, most of the places with the CAD/STEP/etc. files sometimes use multiple vendors for the same part. The files do not always match. For non-branded critical fit parts, it is best to buy the parts you intend to use and verify the models before use. I have received the "same" parts from different manufacturers in the same order before, one matched the CAD, and the others were just different enough to require a design change. This has happened to me with fasteners, inserts, bearings, gears, wheels, and more. The McMaster-Carr heatsets do all seem to follow their published design guidelines, though they are different from the "Voron Approved", CNCKitchen, Amazon, and AliExpress heatsets...

Just be aware that using McMaster's 3D files in a printed part violates their terms of use. It specifically calls out 3D printing and prohibits it.

@@ChrisHeerschap To be fair I think the intention of that rule is more regarding the replication of the part itself rather than designing around it.

Really good tip, especially if your part follows any type of standard like DIN, ISO, etc.

Inserted nuts (hex or square) make the most sense for me: no extra hardware or tooling needed. It would be interesting to see them compared to the inserts tested here. Thank you, Thomas!

Yep, I make it all the time, simple to model, cheap, and works perfectly. I also do it when you got access from one side even if not the rear, you can just make a slot where it fits and it's embed there inside.

@@jmsaltzman square nuts tend to be much superior to hex nuts. They have larger faces an sharper corners which prevents rotation and they tend to have a larger surface area and square holes tend to be easier to model too.

@@Kalvinjj yes sliding nuts in slots from the side is a very good way of doing it. Another way is to just leave voids in the model and when printing pause it at that point to insert the nuts, that way you don’t need anything visible from the outside.

@@conorstewart2214 you can leave two cavities on top of each other. A square or hex for the nut, and a round shallow one for a washer. That washer (could be a fender washer, those masive ones) will increase the support area a lot so there will be no chance to just pull the nut. Even better but more expensive is a washer nut (nut with integrated washer)

I suspect that usage pattern is going to be strong regardless of the threaded insert used, so it would be a bit boring and unnecessary to make an in-depth test video covering it.

I have only rarely seen heat set inserts used as you describe, if you are going to put the bolt all the way through anyway you might as well just use a nut on the other side. Putting the insert on the other side also doesn’t stop the insert from eventually turning. There are a number of reasons why using a nut rather than the method you describe is better. Nuts have larger features that help to prevent them from turning when recessed into a part, with a heat set insert all you have preventing rotation is small teeth on the outside, with a nut you have large faces that can resist rotation, especially if you use square nuts. Nuts tend to have more surface area pushing on the part when tightened too, when using a heat set insert like you describe only the bottom area of the insert is pushing on the plastic when tightened, compared to the whole bottom face of nuts, again square nuts are better as they tend to have more surface area. You can use washers with nuts too to further increase the area that the force is distributed over. Inserting nuts is also easier and doesn’t require special tools like heat set inserts do and if you want nuts embedded in a part you can pause a print and add them then. Nuts are just overall better for structural parts. Heat set inserts should only really be used for relatively low force applications, I mainly use them when I just want a reusable connection (can be screwed and unscrewed multiple times) and when nuts wouldn’t be practical, so I only use heat set inserts inserted from the front. If you need a strong connection there is pretty much always a way to use a nut rather than a heat set insert.

@@conorstewart2214 your writing is too long, but look at prime example right behind him-Vorons are designed this way and I do design parts this way and only use inserts the way he showed only in case where connection isn’t expected to be under any significant stress

​@conorstewart2214 I design parts with heat inserts on the opposite side and know many others that do as well. They work well. I would also argue that since a heat set insert generally has many knurls in it, they actually offer more surface area than a nut, though probably at a max size of M3. Heat set inserts have their place imo in compact or aesthetic applications and generally make repeated assembly and disassembly easier. Anything designed with M5s I use trapped nuts.

Could also try wood screws

You can even cut holes later on and it will still work.

100% came here to say the same thing. At least for smaller rivnuts like m3, this has worked great for me for several years. I have also had success pausing prints, pushing in some rivnuts, and then resuming the print so the whole thing is embedded and invisible

@@ozonepat yeah I use 10-24 screws a lot. that seems to be a goldilocks size for my builds.

There are screws designed for directly threading into plastic, but they're kinda like wood screws. Last time I used them, they wrecked their own thread when I overtightened them. Machine screws are probably the way to go.

@@MMuraseofSandvich For ease of use there's nothing that really beats them, just thread in and it's done, that's why they are so popular for plastic housings and clamshells, basically all power tools use them

A better option is to design with a bit tight hole, and tap it with a tapper tool. A tapper tool makes far better threads, and the accuracy of the treads will be far superior, as opposed to just using a screw to do the tapping. If you use m14, you may use a regular 8mm flat bit, even on the backside of the screw. They last as long as the hole for the bit lasts. Just replace the screw if needed. That lasts for many hundreds, if not thousands of iterations, and you need no metal parts at all. You only need about two rotations of threads.

Slava Ukraini!

@@FrodeBergetonNilsen It is actually quite interesting which machine bolt would hold stronger. The one which goes into pre-tapped hole with a machine tap or the one which goes directly into the tight hole and tap its own thread as it goes. The machine taps are made to give some clearance between a part and a bolt. This extra clearance might weaken the joint with a machine bolt and a plastic part.

Not to mention far more likely to remain straight/true.

Oh boy. So when you can use a driver from behind, on reverse screws, where does that get you?

im glad im not the only one - and then 'you'll need to reach around from behind' - no way this was an accident

That's why you should always lube your parts, and check tolerances.

Sure. But they easily start spinning, if they are too small. Once you use too much torque, they all finally slip. The square ones are better, but same story there. I still use the regular nuts, due to their ease of availability, but always try to design for easy replacement or ways to fasten the screw, if they start to slip.

You need more clearance for a standard nut, and you have to pause the print in order to insert them. Sometimes that's OK, sometimes not.

@@larrybud Modeling pockets so the nuts can slide in is the way. The pocket can be a bit taller than the nut since it will get squeezed in that direction.

@@FrodeBergetonNilsen It’s a responsibility not to overtighten in general. If that’s a risk, square nuts as you mention are even better, or size up the hardware. I prefer using standard hardware than inserts in general- inserts can easily be melted in at an angle or too deeply, and the plastic melting around the insert deforms the model a bit. Melt-in inserts are just inconsistent without a press and temperature control.

@@jmsaltzman Doesn't that mean that if they can slide in, they could slide out?

I thing Stefan did a few test with this setup. additionally he did those Pockets, prusa likes to use.

I want to try to place an insert that a helicoil can be threaded into. I want the helicoil because it should provide reliable firction to the screw over time. Are you aware of a larger insert that matches the outside threads of a M5 helicoil? I know it sounds nutty.

Tom does that for a living. It has become his job to make KZfaq content.

It makes no difference to me if someone simply wants to say thank you.

@MadeWithLayers I completely agree with you and in this case I actually don't care. Would you agree that there is indeed a difference if it was actually specifically about the time invested? Thanks for doing your job, Tom. ❤️ that !

Also the hole should be reducing in diameter along the way to avoid pulling the insert through the part.

You can write that under every insert video out there and it will not change the mindset.. nice try though :D

In an ideal world yeah, but things are rarely ideal

Then again the entire point of going with a heat set insert is just like they do with laptop cases: you don't get the rear access, you can only stick it from the top. If you have rear access may as well just bolt and nut and call it a day, a little cavity for the nut if you're feeling fancy and need it to be hidden/stay there.

@@Kalvinjj True.. but most cases allow to do it from the back - even better in 3D printing. The most just dont consider that and leave a better design behind because of this. For any other cases a force facing mounting is "as good as it gets" and propably enought.