Difference between EDR and IQ shafts?

VEX Robotics Competition Discussion VRC
1

Is there a difference between IQ and EDR/VRC shafts? I read the post that approves the use of EDR shafts in IQ robot build
[https://vexforum.com/t/help-with-something-in-easyc/18352/1) …however, IQ now sells 12" shaft packs and I’m just wondering if there is a difference between the two? Some of the IQ shafts got mixed in with our EDR storage, and although they have the same dimensions, I’m wondering if there’s a difference in composition or strength? TIA :slight_smile:

2

My understanding is that they are the same, but you can only use lengths that are for sale on the IQ website, because you can cut EDR but not IQ by rules for competition.

3

To explain a bit of history behind this: The VexIQ Long Shaft Addon Pack (228-4420) contains only one 12" shaft (and a lot of shorter ones) for $10, while the EDR 12" drive shaft pack (276-1149) contains 4 for $8.96.
In the BankShot year, some teams needed plenty of 12" shafts, but back then, the 276-1149 pack wasn’t cross-referenced as legal for IQ. This caused some troubles at the inspection at worlds, when students reported they used “the same shafts from EDR”.
There are 2 funny aspects to this:

  1. The inspectors would never noticed if not being told. The shafts are pretty much the same
  2. In reality, the IQ 12" shaft is a tiny bit shorter, as all the IQ metal shafts are slightly shorter than their nominal length to fit the system perfectly. But try measuring 12" shaft built in deep into the robot, whether it is 1/16" shorter or not…
4

Thanks for your thoughtful replies. However, is there anyone who can provide an official answer if there is a difference in composition or strength between the two?

5

Consider posting this question in the official threads that only VEX reps can answer in.

6

i got a reply from an iDesign (Canadian vex distributor) employee:

228-4420 comes with a (1) 24x pitch Shaft, which is identical to the 12" shafts on the 276-1149
228-3057 comes with (8) 4x Pitch Shaft, which are identical to the 2" shafts on the 276-2011
228-3057 comes with (8) 6x Pitch Shaft, which are identical to the 3" shafts on the 276-2011

So it seems that the parts packaged are the same…just different packaging.

Thanks everyone!!!

7

Well, I wouldn’t trust a reseller :slight_smile:
Anyway, while material should be the same, I have just verified that all the IQ metal shafts are really about 1/16" shorter than their nominal length.
Placing 12" shaft from 276-1149 next to 24-pitch shaft from 228-4420, you can clearly see the IQ one is slightly shorter (I measured about 1.7mm difference).
When measuring 8-pitch IQ shaft, I see almost exactly 100mm (99.8mm using high precision tool), which is again 3 and 15/16".

This difference is likely immaterial in EDR world, but my IQ students learned the hard way when using 12" EDR one capped by 228-3201-125 bushings and locked between large plates (side walls) that were spaced by a combination of the beams. The IQ shaft fit in and turned well, the EDR one caused troubles…