Well here goes... Aluminium frame router design

[JAZZCNC]

Another question, Do all these plates need to be 20mm, If I make them 15mm will it affect the machining ability substantially? I'm on a cost/weight cutting exercise!

Well first I'd dump the gantry back plate as it adds nothing but weight with very little strength gain and unless perfectly machine and setup could cause you all sorts of trouble with bearings to binding up.!
350mm rear plate and bearing plates etc could be 15mm but wouldn't change the front plate.

Don't go chasing weight it will be your friend when cutting and if you need really high speeds with high velocity changes then put the correct motors on it and you won't have any trouble.

[CharlieRam]

Well first I'd dump the gantry back plate as it adds nothing but weight with very little strength gain and unless perfectly machine and setup could cause you all sorts of trouble with bearings to binding up.!
350mm rear plate and bearing plates etc could be 15mm but wouldn't change the front plate.

Don't go chasing weight it will be your friend when cutting and if you need really high speeds with high velocity changes then put the correct motors on it and you won't have any trouble.

Actually that back plate is connected to the ball nut so without it my Y axis will go no where!