VersaPlanetary gearbox discrepencies

[ekapalka]

I'm not sure if I'm measuring this wrong or not, but all of the VersaPlanetary gearboxes I've downloaded from Vex are way off from the specs proposed in this PDF. The centre to centre distance between the holes should be 35mm, however the measured distance in Inventor is 35.46350237mm. Additionally, although the implied angle between any three consecutive holes should be 90 degrees, Inventor says its 88.51192648 degrees. The models I'm measuring are this one and this one. Here's a few screenshots for reference. Is inventor screwed up, or is there some issue with the models? Thanks

[cxcad]

I haven't. Used inventor for a while, but it appears that you're not actually clicking on the center points of the circle. Have you tried putting a sketch on the part and using driven dimension to measure?

[ekapalka]

Yes. That's what I did in the pictures in the imgur link to show what was happening. I also checked the angles and distances using the angle and distance tools in the inspect tab, and made a part with properly spaced holes (35mm apart) and attempted to constrain the gearbox to it

[Jared]

Originally Posted by ekapalka

I'm not sure if I'm measuring this wrong or not, but all of the VersaPlanetary gearboxes I've downloaded from Vex are way off from the specs proposed in this PDF. The centre to centre distance between the holes should be 35mm, however the measured distance in Inventor is 35.46350237mm. Additionally, although the implied angle between any three consecutive holes should be 90 degrees, Inventor says its 88.51192648 degrees. The models I'm measuring are this one and this one. Here's a few screenshots for reference. Is inventor screwed up, or is there some issue with the models? Thanks

Both the model and inventor are just fine. I think you might be reading the dimensions of the wrong side. The angle between the holes on the output side is not supposed to be 90 degrees. The two mounting holes are properly located on a 2" diameter bolt circle. The 35mm dimension on the sheet is for the holes on the side where the motor mounts. On the side you are dimensioning, two diagonal holes are on the 2" diameter bolt circle, just like the drawing shows.

[ekapalka]

Thank you! I understand now