Just for funsies?

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Well-Known Member
HMEM Supporting Member
Jul 8, 2009
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Over the past couple of weeks I've printed a few things that turned out to be mostly just for fun. This is one of them.

This sad, and slightly blurry speciman is what's left of what was originally the cap for a salt and pepper shaker set. My wife and I had that set since we got married and that would have been 43 years ago. During the autopsy the cause of death was determined to be tissue rejection. This was a Miller High Life press on cap that was living on a 7 ounce screw top PBR bottle. I guess it was only a matter of time until the cap succumbed.

But.... I have a 3D printer. I can rebuild him, better, stronger, faster - well better and stronger at least. A multi-start internal thread in the cap of unknown dimensions... How hard can it be? I can measure the pitch between the threads. I can measure the OD of the bottle above the threads - it's 25.5mm. I know that there's a section at the top of the bottle that's unthreaded. I know how tall I want to make the cap. I know that the threads rise 5mm from start to finish. I know that there are 4 starts to the threads - I counted'em on my fingers to be sure. I know that the major dimension of the threads is 27.5mm. I know that the threads rise 5mm in 90°, 4 starts so it's gotta be 90° right? That means they have to rise 20mm in a full turn, therefore I am making an M27.5x20 four start thread - piece-a-cake. It'll be fine.

This was my first attempt, looks pretty good doesn't it?
First attempt.JPG
BUT, it didn't fit. Why not? Well I'm so glad you asked. Somebody, and I'm not going to name any names - but we are VERY closely related, used the minor dimension of the threads as the ID of the cap - then projected the threads inward. Definite whoopsie. Second attempt looked pretty much like the first. Except this time the un-threaded portion of the cap actually fit over the threads like I wanted, but the threads wouldn't screw together.

Wonder why not? The bottles got 4 starts, my cap's got 4 starts. The unthreaded portion of my cap fits over the threads like I wanted it to do. The threads on the bottle only go part of the way around - same as my cap. Ummmm... shouldn't my threads sorta resemble their threads? Aw CRAP! The duration of each thread is 120°, not 90°. Their threads rise 5mm in 120°, while mine rise 5mm in 90°. That means the threads should been M27.5x15, not M27.5x20. (The picture of the threads didn't turn out - SOMEBODY shook more than the camera could compensate for.) Ok, after the third or fouth attempt - who's counting anymore - I had a cap with printed threads that looked like this.

To end this long-winded story on a happy note, here's a shot of the PBR bottles proudly wearing their new screw top caps. YUP, one of the labels has a boo-boo - but I haven't been able to find a replacement 7 ounce PBR label of that vintage yet.
Proud caps.JPG

(Long-Winded post expected to be in the spirit of the lengths taken to make a project in the post above. I don't mean for you to take offense. This is definitely tongue-in-cheek.)


It seems that you could acquire a high-quality printer to print the label. You will need the appropriate paper to print it on, probably it sells only in large sheets in pallet quantities.

You could engineer a turntable to rotate your bottle past a scanning head to produce a label file corrected to print on a flat sheet to be later adhered to the curved bottle. That would probably be a good enough reason to upgrade your computer capabilities.


You could photograph the bottle, then use software to correct the file before printing. You'll need several false starts to figure that out......

You could 3-D print two new bottles to replace both the ones you have, with a suggestion of the labels printed as you go. You can get lots of trials under your belt doing that.


You could make some more caps and offer to exchange them with anyone who has the bottle(s) in their collection. I'm sorry, I don't have one, even though I have a Billy beer can and an original "Bottled by Ed and Gene" "Ya-Hoo for Mountain Dew" bottle.


Mexican restaurants around here have salt and pepper in Corona beer bottles. So someone is manufacturing shaker tops today.


Seriously, I admire the reverse-engineeering it took to carry off your bottle-cap project. I like reading posts like this.


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