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Bearings: Igus Vs Triangle Mfg

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Will Aldridge

Well-Known Member
Joined
Oct 30, 2009
Messages
997
Location
Northern Utah
Maybe this will be old news to some of you but since I hadn't heard of Igus plastic bearings before a cozy builder in my local EAA chapter showed me his project I thought I'd give a short report on the differences between the Igus pillow block bearings and the Triangle Mfg pillow block bearings that i was going to use in my project before I found out about Igus.

Maybe i was just wasn't very observant but i couldn't find where to order from Igus on their site so i googled distributors and was pleasantly surprised to find that Wal-Mart sells them online and they even beat out Amazon on the price by a considerable margin. For 2 of the 1" and 1 of the 5/8" and shipping from Wal-Mart was about $25 vs $40 for Amazon.

I first heard about triangle bearings from my Thatcher CX4 plans that call for a couple 5/8 bearings for the elevator control tube. So when i was designing my plane i just found the part from triangle that i needed and drew it in, and ordered them as well. Now that I've ordered the equivalent parts from Igus i can do a side by side comparison.

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The larger bearings are 1" diameter and the smaller are 5/8".

First general impressions are that the Igus bearings are higher quality.

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As you can see there's a significant weight advantage for the 1" Igus bearing. Since I'm using 2 in my build that's about 1/3 of a lb weight savings. Size wise the Igus is about .5 inches wider but only about 2/3's as tall. The mounting holes are a larger diameter so the larger bolts will negate some of the weight savings. One other advantage of the Igus is hopefully less tendency to develope stress fractures than the stamped sheet metal of the triangle housings.

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So the Igus bearing looses out slightly in weight to the Triangle bearing and the housing is larger in every dimension, but where it really shines is in smoothness of operation.

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As you can see in the pic the ball in the triangle bearing is retained by 4 crimps in the metal housing which mean it doesn't change angles very smoothly as opposed to the Igus bearing which is retained around 360 degrees by the housing. You may have noticed that the ball in the 1" bearing was white plastic and red in the 5/8 bearing. The white plastic is much tighter tolerances than the red which for my purposes works just fine as the larger bearing only has to deal with rotation and the small bearing will have the elevator pushrod sliding through it and changing the angle slightly as it does (<2 degrees).

Initially I was very skeptical about using plastic bearings in my plane but the cozy builder who introduced me to Igus is no slouch. He's an engineer and his workmanship on his build is first rate. In addition these bearings are designed for high stress high vibration environments so I'll give them a shot.
 
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