Happy Holidays! This post is the public CAD release of Team 2637’s Planar Bearing Blocks, designed for nested elevator configurations. It is a series of aluminum bearing blocks designed to be compatible with a range of different boxtube sizes and thicknesses, all while using off-the-shelf components and flat, common-thickness aluminum stock as construction.
This project started off as a challenge, two years ago when I was still a student, when our 3D printed blocks kept breaking, two weeks before worlds. Since then, it has developed into a design that could be manufactured as easily as possible, while still being as strong as possible.
The Planar Bearing Blocks use standard, 10-32 and 1/4-20 button and socket head screws, and bearings found on common FRC parts suppliers. All washers can be 3D printed, while some can be found on component catalogs. It is fully machinable using traditional CNC methods, without requiring multiple setups for each component.
Key Features:
-Single side machining
-common components easily found on most suppliers
-Extensive use of standard aluminum sheet thicknesses (1/8“ and 1/4“, with few exceptions for 3/16”)
-Center through hole for Dyneema routing on S2 and above blocks
-Compatible with both rivet and bolt mounting (shorter height can be achieved for size 1 blocks with bolt mounting)
-Easy alignment provided by large, flat surfaces designed for flush mounting
-Can be assembled with the help of vices or even hammers (if machined to press fit)
-built-in hard stops to prevent damage to bearings
-multiple sizes available fitting 1x1” inner boxtubes in 1/2” increments, up to 3x3” external boxtubes
-models fit any combination of 1/8” and 1/16” boxtube thicknesses
Advisory:
This block is designed with CNC as its primary manufacturing method, using a 3/16” endmill (anything less than 1/4“ is ok for most parts, except for the pocketing designed with 3/16” in mind). The 1/4“ minimum corner radius is there to reduce chatter, not to fit 1/4“ endmills. No tolerances have been accounted for in its joints, besides a 0.01” clearance on the bearings and boxtube mounting dimensions which is adequate during testing. Each team has their own CNC machines, tool bits, and machining practices, and this product is designed to challenge each team to improve their machining tolerances through trial and error. Press fit or slip fit tolerances are both ok, as the block is held together primarily through static friction generated by 2 screws.
Also, this block is merely a generic design, and therefore will not fit every single team’s needs. Each team will very likely have to modify this design to fit their own needs and manufacturing capabilities.
This block is also undergoing patent applications, but much like Volvo, who opened up their patent regarding the now mandatory 3-point seatbelt, anyone is free to make this for private use or donation to other teams, but it is highly encouraged for a team to attempt manufacturing it themselves, as it can prove beneficial for their machining abilities. Patenting this block was not for profit, as I do not think that follows FIRST ethos. If any manufacturer wants to manufacture this design, please message me, so we can provide an alternative option for teams who might not have access to a CNC machine.
Feedback:
This block only uses 1/2” diameter bearings, which have a maximum static strength of 90 lbs each. In actual application, the bearings held up without any fault. But if there is a large enough demand for stronger, 5/8” bearing designs, with some compromises, then I am willing to design a set utilizing those too.
The zip file down below contains both the STEP and .f3d files for all available Bearing Blocks, with the .f3d files containing all sketches and timelines, so teams may modify them to suit their own needs.
There are frequent updates made to this zip file, so make sure your version number is the same as the one here:
Bearing Block Files V4.zip (14.6 MB)