Joe's 1000x600x200 steel and aluminium router started

[devmonkey]

Nice work Joe!
I see you are milling small slots to locate perpendicular sections to each other...... I enquired about doing just that in another forum with almost no reaction.
It seems to make sense to me ( no expert) What better way to ensure components are aligned correctly?

How have you found the process? A good idea or problematic?

I'm considering doing the same thing...when I eventually start my own build.

I see you have maximised the distance between your x rails, by placing them top and bottom of the Gantry.
Did that make things excessively more difficult?

Steve

Hi Steve,

I also thought twice before milling the locating slots on the different plates. On some joints it is not so critical, such as attaching a stepper mounting plate but when you are joining two plates that locate the axis at exactly 90 degrees such as where my gantry end plates join the X bearing plates it is super critical. In this example it was also critical the slots in the top of the X bearing plates were not only planar with the plate surface but also identical depth on both X bearing plates.

When I mill out shapes from plate I clamp the plate to MDF so the cutter clears the mill table. MDF (particularly when it has sat in the garage for a year) is not sufficiently uniform for accurate Z milling. Therefore I mill these slots after the outside profile has been finished. I set the Z height on the mill and lock the axis then I clamp each X bearing plate to the mill table directly and mill the slot. I do both plates without unlocking the Z axis so they should be identical.

Before doing any of this critical stuff (particularly milling the gantry extrusion flat where the Y rails are mounted) I checked the mill table was flat within 0.01mm over the entire travel with a DTI in the spindle. You don't want to do this if your saddle is sloppy or any long work really.

I'm an amateur machinist at best, only been playing around with the manual machine for a few months really so take this advice with a pinch of salt. The slots are within 0.01mm in depth over their length which is good enough and no worse than the milled plate itself. It is quite satisfying when you get a friction fit on the joint between two plates.

Also bear in mind that the milled plate isn't exactly whatever nominal dimension you purchase, mine in nominally 16mm but is infact 16.055mm thick, also your cutters are not exactly whatever dimension they are supposed to be. This means if you just mill the slot to the DRO readout it wont be the correct width.

What I do is designate one side of the slot as the reference since my cad drawing assumes 16mm plate, then mill that. Then open up the slot and use a piece of clean spare plate to test the slot until you get a nice fit, this is much more accurate than trying to measure with a vernier or micrometer as the slot is too shallow.