Hex broaching in thick aluminum stock

[MisterG]

For reasons that are somewhat complicated we want to hex broach 1" aluminum square bar stock.

We have successfully broached thinner material.

Can someone please share knowledge about broaching in thick material and whether it is recommended?

Also we have access to either 6061 or 2024 so any advice on alloy for this purpose would be appreciated.

Because you are bound to ask, we are transferring torque from a hex shaft. Originally we were going to use square tube with laser cut inserts that had the hex shape. The issue that we are running into is compactness. Having external fasteners that hold the 'torque plates' inside of the tube is adding unwanted width to the mechanism.