Ways to use fasteners with printed parts?

I suppose the title says it all! I’m new to 3D printing. I’m a hobbyist and a DIYer. I’ve ordered a few prints of parts I’ve designed from online services before*. Everything I’ve had printed so far was either a proof-of-concept learning exercise or a stand-alone item. However, my next few parts are going to be either replacements parts – I like to add “repair” to “reduce, reuse, recycle” – or parts that interface between two things that are not commercially available and that I don’t have the tools, expertise, or time to make by hand. And occasionally to save on paying for the “name brand” fee for some needlessly expensive parts!

In terms of my other “maker” experience, I’ve done basic carpentry and woodworking, and am pretty good at making things that function, don’t fall down or apart, and sometimes even look good! I’m also pretty clever at walking into a hardware store with a problem in mind and leaving with a solution.

I’d love to hear people’s thoughts on different methods of using fasteners with 3D printed parts and the benefits and drawbacks of different approaches, especially for dynamic loads. I can think of these ways, but I’m sure there are more:

  • tapping holes in printed parts
  • printing threads
  • leaving space for threaded inserts
  • leaving space for nuts
  • using self-tapping or wood screws
Thanks in advance!

– Becca

[SIZE=11px]* I will be getting my own 3D printer soon – my family has the good habit of dropping strong hints on occasions when gifts will be given and picking up on those hints![/SIZE]

Welcome! I used to love working with wood too years ago. I haven’t printed many functional parts yet myself, as I mostly print miniatures. Once you get the hang of 3D printing, you will be so addicted, lol!

I also like making “stuff” that is functional and at times requires fasteners. So to that end below I will attempt to give my opinion of my experiences.
tapping holes in printed part
I have done this, but you need sufficient wall thickness to the the hole to have any strength to the joint. As a simple tapping of a hole, I do not recommend this and with all threads in plastic, should mostly be considered as a one time joint.

printing threads
This is my main go to joint for screwed threads in plastic as it gives a more solid plastic area to screw into and I believe makes a much stronger joint that just tapping. Most of the time I ‘clean up’ the threads with a tap as the threads formed by cad are a bit tight. Having said that, there have been times where I printed both the mating threads and had a plastic to plastic joint but was able to include sufficient tolerances by manipulating the cad file. I could do this for all threads, but its a PITA to do and easier just to clean with a tap and it also cleans up any strings that occur. (I mainly use PETG and it often times strings)

leaving space for threaded inserts
This type of joint is useful if you want a stronger joint than you get with just plastic threads or want a joint that will be assembled on multiple occasions. While it is stronger than plastic threads, they still can be pulled out. This of course varies with the quality of the insert. Cost wise, this is the most expensive on this list. I mainly use M3 or M4 screws and good inserts can cost around 25 cents a piece!

leaving space for nuts
If you want a removable joint and or one that will distribute the load over a greater area, this is the best choice in my opinion. It is also much more cost effective than the heated insert type and to my thinking much easier to install. It is also more forgiving of the angular tolerances.

using self-tapping or wood screws
This has worked out quite well for me at times also using common ‘dry wall’ screws’ as they have a very course thread. But again, you need to have thick walls to your holes to have any strength and consider this a one time or minimal multiple time assembly.

Hope this helps and your mileage may vary:{)

I use both heatsets (the threaded pieces that get installed into plastic holes using heat) and embedded nuts. The embedded nuts are, or can be, the strongest. The heatsets can also be pretty strong. I try to insert them so that there is plenty of plastic on the ‘inside’ end of the heatset. This gives the heatset something to push against. I feel this increases to force needed for the heatset to fail and pull out.
Heatsets don’t have to be expensive. Order them from aliexpress.com.