Thanks boyan.

Well that was my thinking too.
The project started out as just a nailgun bridge and was going to size components accordingly as the forces involved from the small nails is minimal and the there's no real deflection forces from the tool other than upwards.
Then I managed to acquire 55mm thk profile rails and carriages off an old machine which got me thinking why not design a more capable machine with a spindle.
Will enable us to do so much more!