Help identifying this small screw

I know this isn’t the ideal place to ask this question, but given the number of experts and mechanical engineer types hanging out I figure there’s a good chance one of you can help. I’m trying to identify this screw, taken out of a plastic part, so I can get an exact (or at least, suitable) replacement:

The wide thread spacing and blunt end make me think Type B tapping screw. The major diameter of the threads is exactly 2mm, but I don’t think there’s such a thing as an ST2.0. My measurements on the pitch and minor diameters were less precise and might be slightly off. I’m not sure what you call fasteners with washers integrated into the screw head (flange screw?). The washer isn’t free-moving.

Here are some more dimensions I roughly measured in case it helps, but I don’t care about them as much:

  • ~ 0.8mm head height (measured from outer surface of washer)
  • ~ 3.5mm head diameter
  • ~ 0.5mm washer thickness
  • ~ 9.3mm overall length of fastener
  • The tip of a Phillips #3 seems to fit nicely into the head

It may not be metric; I only assumed that due to the very exact thread OD.

Looks like a Taptite REMFORM II but really it can be any number of Taptite copycat or another similar standard. They do have 2mm nominal Ø albeit maybe not in their standard catalog.

Misumi does have similar looking stuff by Sunco but I have not checked all the dimensions :slight_smile: 00000247065%3A%3Ab 00000247133%3A%3Ac 00000247065%3A%3Ab 00000247133%3A%3Ac

I’d ask on reddit under /r/AskEngineers I bet you’ll get an answer in no time with the informations you are providing

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Thanks @JohnHue I haven’t found an exact match but those are super helpful leads. I regret having but only one “Like” to give.

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That is indeed a flange head (or button head, in some cases) and are you certain it is metric vs. standard?
0.8 pitch would make it an M5, but that’s more than 2mm in diameter.

It’s a self taping / thread forming screw for plastics so not ISO or UTS. In that case a 0.8mm pitch for a 2mm nominal Ø sounds plausible. These kind of threads are usually proprietary which makes it that much more difficult to find a replacement if you don’t know the exact brand.

EDIT : @rkagerer I am surprised you didn’t get any answer yet on reddit, these guys are usually pretty helpful. I guess it’s just how this website works : some threads get buried and never attract the attention of the people who could have helped you.
Lacking the exact reference, one solution would be to drill a bigger hole if you have the space available. Or use a finer ISO Metric thread and press/heat-fit a threaded insert in the plastic parts. A M1.6 screw with a correctly placed threaded insert will probably have the same mechanical properties as your thread forming screw.

Thanks for the suggestion. It speaks volumes to the quality of the community here that your original answer was quicker and better than any of the Reddit ones so far.

Hi, might it be ST2.2 thread? For further dimension check this site:

If you are in the USA, check McMaster-Carr as they have fasteners you didn’t know existed.

The calipers were quite adamant about the 2.00mm thread diameter.

They sure do! I didn’t find mine there, though. Closest I got was “Metric Alloy Steel Flanged Button Head Screw” but those don’t have the wide plastic threads. And the tapping screws don’t have the flange. Maybe I’ll get in touch and send them the diagram.

McMaster has great customer service.

You might check automotive websites as the auto industry uses all sorts of goofy fasteners unique to them. Unfortunately I don’t have any good sites bookmarked; otherwise I’d post them.

Can you tell us what it came out of? That might make the search a little easier…but I doubt it.


I found a delta PT screw for thermoplastics… size 20. Otherwise I’ve never seen one like this in my 20+ years. Woohoo, I’m learning something new today lol