Joe's 1000x600x200 steel and aluminium router started

[devmonkey]

Got to be careful here because it can and often does actually does make things harder for your self and not always more accurate by milling slots etc.? Reason is unless you can accurately machine all the major areas of the machine accurately then you will need some room for adjustment.

If you have read the forum you'll see I've said it many times that at DIY level the key to a great machine is to build in as much adjustment as possible. Nothing as changed in this statement.
Groves etc that are fixed will limit your ability to adjust out any errors coming from other areas that haven't been done to the same level. This is when you regret doing it.
The larger the machine the more this adjustability comes into play.

A better way I find at DIY level is not to limit adjustment with slots etc but use dowel pins that can be drilled and reamed after the machine adjustments have been made. This locks the machine in place but doesn't limit adjustment.

I would only consider milling slots etc if you can build the whole machine to the same level.! . . . . If not you will regret limiting the adjustments.

Wise words about infinite adjustment.

I've built 4 machines in the last 20 years and milled slots in all of them for plate-plate, albeit these were all done on CNC not a manual mill. My approach has always been to make each sub-assembly locally square/aligned and only adjust between sub-assemblies (usuallly by shimming bearings). For example my gantry end plates are squared to the gantry and X bearing plates in 3 dimensions helped by milling the slots, this complete gantry/Y assembly will always be locally square assuming I can setup a milling machine properly to take a straight cut which I can. However the gantry itself could be twisted, unlikely but wont be known until final assembly, in which case X bearing interface with X plate will need shimming.

Sometimes you can't accurately determine a location for a joint until assembly in which case I estimate it and drill the pilot holes for the bolts then spot through to the joining plate with a centre drill once assembled, this was the case with the upper Y bearing plate on this machine. I don't use slots for this type of joint. However the slot in the bottom Y bearing plate guarantees that the two Y bearing plates (and therefore the Y bearings) are exactly the same distance behind the Z axis.

If I was using a hand router to cut aluminium as some brave chaps on here do then I definitely wouldn't be milling slots.