Comment by quesera | Hacker News Reader

Comment by quesera | Hacker News Reader

> Turns out, a slit really isn’t the best shape for the hole because if you don’t have the right kind of rubber, it can rip too easily. A circle is better because there’s equal pressure around the hole and it’s less likely to rip. I wish I had considered this sooner, but that’s what it takes to learn and that’s why I’m sharing this here.

Given the level of detail in the article, I'm led to believe that the next moment hasn't happened yet..

What you really want is a slit with a pair of small circular holes, one on each end of the slit.

  o--------------o

All the benefits of the slit without the tiny points where all of the stress is focused, which is what causes the ripping. Adjust the size of the holes as needed.

Common design trick for sheet materials, and should be straightforward to cut with the same machinery.

Enjoyed the article.

I'd take it a step further and and go with a slot. Closer to the structure of the 2 circles with the ease of a slit. I am surprised the operator/programmer of the machine didn't suggest something like your idea or mine, since it is common practice for them to make engineering designs more manufacture-able/structurally sound. (Source: I used to program water jets and was constantly re-designing parts sent by engineers/designers.)

Also, I would definitely move towards die-cutting once he settled on a final design, but with his sense of tinkering, I doubt he'll ever have a 'final' design.

The same trick is employed when repairing windshields in cars. If there is a small cut you drill a round hole at both ends to make sure the cut doesn't tear further and then you fill the whole thing with epoxy.

Yup, in shoemaking this is the "first trick" when doing some designs with straight-cut lines. Holes at the end prevents ripping completely (unless the leather is bad quality) and you can go on with your desired design.

great suggestion, i'll have to try this out. a big circle is more expensive to cut than a slit, so this could save some money!

we cut our last batch of connectors with circles - not as much friction as the slit but it's much more resilient. here's a photo: http://instagram.com/p/vSJ59WStiS/?modal=true

I came here to make a similar digression but clearly am not the post to :) interestingly though this is one of the reasons for serifs on fonts! In stone carved writing serifs help remove corner stress and cracking.

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