Hex shafts?

[Andy Baker]

Originally Posted by kramarczyk

The primary benefit of hex shafting is that there is no key needed. ...

AndyMark has largely solved that first problem for 1/2" & 3/8" shafts. Shaft tolerances can still be a gotcha if you are not paying attention. For example, the shafting you link to is 1/2" +/-.005" which means it's actual size may be anywhere from .495-.505". An AM hex hub (AM-0096) has a hex bore of .501-.505" per the web site. If your hub comes in on the low side and the shaft on the high side it won't fit. (.505" shaft going into a .501" bore) Something with have to give to make that fit. Alternatively, McMaster 6607K43 is also a 1/2" hex, but with a +0 -.008 tolerance for actual size limits of .492-.500" It should always fit in the AM hex hub.

As always, Mark has wonderful advice. We have noticed that our aluminum hex shafts are often tight fits into our hex hubs. This is exactly due to the reasons Mark lists above. We have found that the best and easiest way to take 1 or 2 thousandths off of a side is to carefully and evenly use a belt sander on each of the 6 sides of the shaft.

Also, another reason why it is beneficial to use a hex shaft is that the torque load is now distributed across 6 different points of contact (the six corners of the hex shaft) as opposed to the concentrated point of the keyway.

Originally Posted by MattC9

McMasters doesn't have 7075 they only have 6061 or 2021, im going with the 2021 if we do get it

We use 2024 and 2021 aluminum for these lightweight applications.

Andy