High Strength Metal Inserts Bar Stock

With increases in motor power, chain strength, sprocket strength, and gear strength over the years, axles have become the limiting factor in many high performance VEX designs. But obviously, simply increasing the size of the axles would mess with the well established VEX hole pattern. In order to limit teams less on torque transfer designs, I’d like to propose a new product.

It would use the same material and cross-section as the metal inserts for high strength gears, but be sold in segments up to a couple of inches long. This could be used in lieu of inserts between two concentric high strength gears to transfer torque, or just as a sleeve to slip over a standard shaft to increase its torsional resistance. Ideally, other VEX motion products could transition to using the HS gearing inserts, to allow them to be used with this product.

or they can do nothing and we, as engineers, hafta design around this issue :wink:

Another option would be stainless steel shafts, or a material the could be hardened after cutting. We did make a few drill bits this past year, and even with gears being spaced only about 1/16" apart saw some distortion between them.

Oh trust me I agree. I’m a relative old-timer at VEX and people are always shocked at how often I use regular gears and low strength chain, just because I learned to design smartly with them before the high strength options were available. None of you young whippersnappers consider chain directionality anymore :p.

But when people are scared to do compound gearing because it relies on transferring torque across an axle, there’s a problem. This is one possible solution.

This sounds extremely useful, I know I would use this.

An alternative could be to bolt a large number of Shaft bar locks together as a sleeve on the shaft, or bolt those bars to a gear, or bolt the gears together.

One problem, none of those solutions (nor the proposed part) can interface with a 12-tooth gear.

True, but putting the insert on the outside of the 12-tooth gear will still basically stop the shaft from twisting because the gear itself is sort of acting like the insert.

Correct me if I’m wrong.

The 12t gear could be re-issued with small pockets with the quarter inch square profile on each face, or just with a quarter inch all the way through (might be cutting it close on material left).

Stacking these such that they butt against parts would provide some twist resistance, but at a certain point the shaft would simply shear in the gap between parts. A setup which uses this part to actively transfer torque between gears/sprockets/wheels would be stronger.

It certainly would be stronger, but I sincerely doubt that any well built robot would ever need that amount of force. I feel like the 12-tooth gear would break well before the shaft shears anyway, no?

You may be able to make one from four axles. Unfortunately gluing & welding are not allowed.


Cool solution! Wouldn’t work in a lot of cases due to the need to interface with standard VEX bearings, but for some spots this could be a good workaround.

Make bearings out of stacked Lexan. Not too much other use for it this season.

I was thinking of using broken 36 tooth gears as bearings and just drilling the square hole. This way you can just use the holes already in the gear to mount it to the metal.

The other thing I noticed was we are allowed to use identical parts: so this means we can use the 5/16-18 nuts that are on double acting pistons. This is the perfect size for you to cut threads on the axles and use the nuts as a shaft collar. I did a simple CAD of what I was thinking of.

The next picture shows the amount of material you would need to remove to tap a 12 tooth gear and use it. Of course this would be a lot of custom work [http://db.tt/yKJlNZCE

With the amount of machining and the fact most parts could not be reused with this solution I have another solution for transferring large amount of torque. But again would require a bit of machining or VEX to make a new part. I will try to post a CAD at some point.](http://db.tt/yKJlNZCE)

I found a pretty good way to make extremely high load bearings for “super axles”

The green gear would bolt into the metal support.The gray bit that the axles goes into is free spinning and performs infinitely better under load than a vex bearing.

wouldn’t it be better if screws were inserted through the sides of the gears? Especially since 36 tooth gears and 60 tooth gears and the turntables are the only systems that can use super axles?