Autodesk Inventor Cut Part

For the life of me I cannot get the Chassis Rail 2x1x25 cut down to a 2x1x17 size.

I am going into the part, clicking “offset from plane” then I get it, but the split tool is not available. If someone can show me what to do to cut that metal, or if someone can do it.

thanks!

Edit part
Plane
Selct the end of the chassis rail
Move mouse until plane shows desred cut plane then click
Split
Selct the work plane and the face you are cutting
Select the “split solid” option
Make surethe arrow is pointing in the direction that you want to renove
OK

1200B’s tutorials on youtube are really helpful.

This may help.

https://vexforum.com/showpost.php?p=190102&postcount=3

What my team did for our custom parts is create a sketch on the end of the part, project all the geometry, and just extrude (cut away) the right amount. It worked for our C-channels, but I don’t know if the end of the part extends past the normal dimensions (C-channels have no additional metal on the end, obviously).