Bambu has a good selection of Self Tapping Screws and at good prices.
But their shipping is slow.
Anybody have good alternatives they use in the US?
Self tapping screws suggest they do more than achieve, at least at smaller sizes.
The CyberBrick models are a good example, they come with M2.5 Button Head Cap Machine Screws (BHCS), not a self tapping variant.
The designer makes a 2.5mm hole, no taper and the user screws them in.
The same goes for most of the other screw sizes. Problems may occur at much thick thread sizes.
I do not bother with self tapping as they provide no benefit. I am more interested in the cap style, socket (flat, hex etc) and colour, black or silver.
I buy them from Amazon in multi packs most often as 200-600 often cost the same as 20-40 of a specific single size. I can always use a good screw (that is what she said, just never to me).
Just a few of the recent purchases.
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Harbor Freight has self tapping sets but they are 1) in Murican sizes and 2) more geared towards self tapping INTO SHEET METAL.
What you’re often wanting in printing is labeled as thread forming / thread cutting
Not to be nitpicking, but not sure if M2.5 is going to do well with 2.5mm hole when doing 3D printing.
Nowadays, I tend to use 2.8mm hole for M3x0.5p screws, and the hole with no thread at all. But still sometime the screws are a bit undersize, close to 2.8mm OD and hence it comes loose easily. Please note that 2.8mm hole ID is in the drawing, and the actual hole is about that dimension but with the seam adds extra meat makes its ID likely 2.7mm or 2.6mm at the seam.
With the hole of 2.5mm, I have to tap with M3x0.5p thread before use or else it will be really hard to drive the screw in. If I forcefully drive the screw in with battery drill, it usually end up in stripping screw head or melting the hole inner surface due to high friction when drive it in fast enough.
I suppose, 2.5mm hole would work well with M3x1p coarse thread like this
I prefer that over one with a cut cutting edge like this
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And yet, every single model I have in design for CyberBrick, vehicles, remotes and more all use a 2.5mm hole.
I have done the same thing all the way up to M5 screws/bolts.
While you are guessing, I am showing real world examples each of which utilise the advice based on actual real world testing and design.
The same goes for my other models that use normal screws, just a couple of examples:
- Squirrel Feeder Adirondack Wooden Chair M3
- Candy Dispenser (Sweets^) M#
- CyberBrick Prototyping Remote Control 2.5mm
This is the part I don’t like about prototyping with 3D printing. Like, screw hole has to be compensated when sent to printer but reversed back when being sent to CNC machining.
It’s a part of the job I guess.
I have no experience with CNC machines.
The important part is that we are only discussing 3D printing and not translating it to another medium.
My advice is factual and accurate.
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You should check out the community post by Makerworld user Wuguigui titled How to design screw hole for a CyberBrick Project? if you haven’t already. I haven’t used a round screw hole in any design since reading that post.
Also, I found that the techniques outlined by Makerworld in the community post titled Ways to Fix Filament Sagging in Supportless Holes work really well with Wuguigui’s rhombus technique and I used both quite effectively in my latest Cyberbrick model.
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Square hole! That makes sense, thanks for clearing up.
Unrelate of topic but this reminds me of square hole meme
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I recognize Some self tapping screws might be a higher pull out strength than standard threads. But that is very situation dependent. The difference in strength between the two if very small. for 3d prints. Most of the time I just use standard threads in a tap drill dia. that way when machined it is the same model. The biggest difference is automated assy
The biggest difference in screws is the head and color. Most of my stock of screws is Socket head cap screws. For my designs. But there is an eclectic set of sizes, length, and head shape.
to address the initial question of sources. Most cheap sources on amazon are marginal quality. They do often have good lead times. Another good lead time is Mcmaster Carr. I have same day service from them. The have a variety of quality, and most of the sizes and shapes needed.
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A trick to use standard threads on 3d prints with a lead in ramp between to outside thread dia and the tap drill dia.
A little different if the hole is Perpendicular or Parallel with the build plate.
My approach with screws is always that I start with sets from Amazon. Then I watch which kind of sizes I use the most and order those in bulk through AliExpress, JLCMC or similar places.
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