Loading
Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

Rivet Pivot Test

by LucidOne, published

Rivet Pivot Test by LucidOne Feb 2, 2011

Description

Since a Thing-a-Week was too often, it's time to try a thing-a-day!
TAD Day 2 - thing-a-day.com/rivet-pivot-test
TAD Day 3 - thing-a-day.com/rivet-pivot-test-2
thing-a-day.com/tag/IHeartRobotics

Previous Adventures
iheartrobotics.com/search/label/thing-a-month
iheartrobotics.com/search/label/thing-a-week

----

It would be useful for building robots to be able to cheaply and easily create a rotating connection between two 3D printed parts. This is an initial test using rivets. None of these tests produced a joint that rotated freely, but this might be useful for connection where friction is desirable such as pose-able stop motion figure.

Recent Comments

view all

They use rivets like this for linkages in a lot of things, usually with sheet metal straps of the same design as these. I think the trick is to oversize the hole so that the side expansion doesn't cause it to bind. Perhaps more importantly you need some kind of clearance between the two faces of the work, using an overly long rivet will make a sloppy joint, you want a way to get a small, repeatable and parallel amount of clearance. I know I've read somewhere to use a piece of paper like a washer between the two link arms and then tear it out afterwards, you may have to soak it in water and wiggle the joint a bit to get it to come out dependent on how tight the joint ends up.

I would say that backing washers are also almost certainly a necessity for plastic parts

I'm going to try that next. They are probably cheaper than bushings.

Try a different kind of rivet ;) Blind rivets expand - this is how they get their joint strength...

Split, press fit rivets might do the trick - similar to the type of rivet used in knives/cutlery. They're going to be more expensive than blind rivets but cheaper than using threaded bind post fasteners (which are intended for just this).

Liked By

view all

Tags

License

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag. Print Thing Tag

Comments

You must be logged in to post a comment.

jstkatz on Feb 6, 2011 said:

They use rivets like this for linkages in a lot of things, usually with sheet metal straps of the same design as these. I think the trick is to oversize the hole so that the side expansion doesn't cause it to bind. Perhaps more importantly you need some kind of clearance between the two faces of the work, using an overly long rivet will make a sloppy joint, you want a way to get a small, repeatable and parallel amount of clearance. I know I've read somewhere to use a piece of paper like a washer between the two link arms and then tear it out afterwards, you may have to soak it in water and wiggle the joint a bit to get it to come out dependent on how tight the joint ends up.

I would say that backing washers are also almost certainly a necessity for plastic parts

trebuchet03 on Feb 3, 2011 said:

Try a different kind of rivet ;) Blind rivets expand - this is how they get their joint strength...

Split, press fit rivets might do the trick - similar to the type of rivet used in knives/cutlery. They're going to be more expensive than blind rivets but cheaper than using threaded bind post fasteners (which are intended for just this).

LucidOne on Feb 4, 2011 said:

I'm going to try that next. They are probably cheaper than bushings.

WilliamAAdams on Feb 3, 2011 said:

Perhaps a slightly more complicated, but workable solution; Put one of those little silver cylinders used in beading into the hole. Then put in the rivet. The silver cylinder will act as the force to maintain enough integrity within the plastic. The rivet won't bulge out other than outside the plastic, giving you a sliding hinge?

LucidOne on Feb 3, 2011 said:

Something like a bushing may work, I'll probably test that when I test a shackle design.

With some experimentation it looks like the rivet changes in diameter from 3.1mm to 3.3mm. Also it looks like a washer on the far side of the rivet prevents distortion of the plastic by the expanding rivet.

Top