SP-400 threads? about threadlib HOT 18 OPEN

Something like this?

for (i=[0:starts])
   rotate([0,0,i*(360/starts)])
        thread(str(designator, "-ext"), turns=turns, higbee_arc=higbee_arc, fn=fn, table=table);

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See also http://www.gpi.org/industry-resources/finish-drawings

from threadlib.

["PCF-33P-ext", [6.35, 14.74, 29.49, [[0, 0.76], [0, -0.76], [1.195, -0.549], [1.195, 0.07]]]],

use <threadlib/threadlib.scad>

type = "PCF-33P";
turns = .6;
higbee_arc = 45;

union() {
    bolt(type, turns, higbee_arc=higbee_arc);
    // second thread start
    rotate([0,0,180]) { thread("PCF-33P-ext", turns, higbee_arc=higbee_arc);
    }
}

https://www.amazon.com/Motts-Apple-Juice-Pack/dp/B01IRHDZKY

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Sounds interesting. Thanks for this input. I'd like to add it but I would prefer to do it with some kind of test. Do you by any chance know the spec of the matching (internal) thread? I could then add both and the test would be to check for collisions between the two.

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No, as far as I know with bottle finishes the external thread on the bottle finish is standardized, but the caps are completely proprietary.

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Thanks for responding. This just tested that I properly receive notifications from Github (now ...).

Regarding SP400: That seems to be similar to PCO-1881 that also specifies the neck but not the cap. Maybe we could add a mating thread by hand and check for consistency. Did you produce a part with the code you posted above? Did it work?

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Yes I've printed lots of these now. They are working great.

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Aaah :) There is no better test than that! I'll gladly add it!

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Just make sure the cylinder supporting the threads is long enough that the bottle cap seals against the end of the tube, instead of ripping it off the object.

A nice feature of this kind of cap compared to the PCO-1881 apart from the larger size, is that the seal is flat instead of having to seal around a specific thickness of cylinder wall.

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One more question: I'm currently trying this and also checked the spec. From the spec I interpret that the pitch should be 3.18 mm but your code suggests 6.35 mm. What am I getting wrong?

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@dholth: Could you check whether PR #27 works for you?

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from threadlib.

Got it. I‘ll have to think about that. I‘m not sure I‘m ready yet to extend threadlib to multiple thread starts.

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Yes. But what I need to think about is

• does this belong in threadlib or is the user expected to write that loop? I think it belongs in threadlib.
• in THREAD_TABLE: Add new column "number of starts"?
• backwards compatibility: what will happen to those users having created their own private THREAD_TABLEs (without that "number of starts" column)? Will their code break? How many such users are there?
• What about unit testing?

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I applaud your effort to produce high quality threads.

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Adding to the SP-400 thread thread. A few things for me have come together and I thought I would share and get feedback. I was looking to 3d print a neck my ketchup and shampoo bottles and stumbled upon the Glass Packaging Institute. First - the SP-400 designation seems to be a neck description: https://www.paramountglobal.com/knowledge/bottle-neck-thread-finish

I also found a few cap diagrams : https://www.thecarycompany.com/media/pdf/specs/68WF34.pdf

A previous project I had ws trying to redo a base for my Bud Light Goal light glasses - which I now know is an m63-410.

I have created 2 profiles - GPI-33 and GPI-63 for quick testing. The GPI-63 does work on my glass, but is a little tight. I will be making a PR for eary feedback. I'm using GPI - but that can also change. I'm not certain about the angles, and judging by the documents I found, there is some looseness - most likely since the threads are cast and not machined, and the standard originates from Glass manufacturing - so the Sharm angles are not there, like they could be in plastic.

I have written the awk tests et al. but would like to generate them rather than do it explicit as I have done now.

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Yes, they say the caps are not standardized, only the bottle's neck finish.

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I noticed that. I don't think that is "doable" in this lib beyond the thread, to me that's fine - someone else can do a "bottle neck" lib ;-)

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