Suggestion: Parametric screw holes

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Jason M Bryant
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Suggestion: Parametric screw holes

Postby Jason M Bryant » Mon Mar 16, 2015 3:02 pm

In fiddling around with resizing a hand, I felt like changing the size of the tensioner box and the tensioner pins was problematic. I only have two sizes of screws, the two sizes that are recommended in the Raptor assembly instructions. When I scaled the box to the size I wanted, the holes were just a little too big for the biggest screws I had. I ended up redoing the holes in Blender 3D.

Even if I had more screws, I wouldn't have enough to fit all the different possible scalings.

What if the screw holes were parametric? We could figure out the ideal size holes for two or three sizes of screws, then make sure that the holes in the tensioner box and the pins stick to those sizes. I imagine that would make the screws less likely to strip out.

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laird
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Re: Suggestion: Parametric screw holes

Postby laird » Wed Mar 18, 2015 11:45 am

That's a great idea. It would be easy to make the tensioner screw holes parametric! I've got a parametric tensioner pin model already. So we'd just need to figure out whether we want to make the screws one constant size, or perhaps let users pick between a few sizes? Note that with wood screws the sizes don't need to be exact, just close enough that the screws get a "bite" into the plastic. Is there a single hole that will fit a common metric wood screw and a common "US" screw size? If so, we should do it!
- Laird Popkin

Jason M Bryant
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Joined: Mon Feb 16, 2015 1:59 am

Re: Suggestion: Parametric screw holes

Postby Jason M Bryant » Thu Mar 19, 2015 3:40 pm

I feel like it should be at least two sizes. If we pick something small enough to work on the smallest hand, that seems too small for an adult sized hand. A bigger screw means bigger threads, which means it will be able to withstand the force of an adult.

Plus, even if we made it always be the same size hole, people would still need different screws because they would need different lengths. The tensioner box will get bigger, even if the holes don't. They might as well be thicker, too.

LydiaOST
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Re: Suggestion: Parametric screw holes

Postby LydiaOST » Sun Mar 22, 2015 11:04 pm

Don't we need to make all the holes parametric? Or do big hands really need bigger Chicago screws/Snap pins as well as the other screws to be strong enough to hold up under adult use?
--Lydia
eNABLE'S Organizational Support Team founder, Team Facilitation Team member, eNABLE Help Desk member, Google Plus teacher, and Junior Forum Admin.

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laird
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Re: Suggestion: Parametric screw holes

Postby laird » Mon Apr 20, 2015 1:29 am

When the pins are printed, you don't need to make the holes parametric, because you can scale the pins along with the parts with the holes.

For the Raptor designs, the only screws are in the tensioner. The wood screws have wide threads, so the size doesn't have to be exactly right, because the screw threads will "bite" into the plastic, so you just need to be approximately the right size. So you can go to the hardware store and pick out screws that look right and be fine.

The Cyborg Beast uses tons of metal Chicago screws, which do require exact sizing, so it'd be worthwhile to make those holes parametric.
- Laird Popkin


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