Build Log: 3-4 Axis Mill/Router

[IanS1]

I'm considering re-designing my gantry to something more suited to self build. The hassle and cost of machining it all from ali plate is putting me off the current design. My only worry is the hassle I had with the out of square/bowed/twisted 80 x 80 I used for the frame, would make building a gantry nice and square very difficult indeed.

Any thoughts on using a heavy duty ali extrusion, say 160 x 80, instead of RHS/SHS? Would it be possible to build a gantry from extrusion strong enough for machining mostly aluminium?

[IanS1]

Any thoughts on the Ali extrusion please folks? I'm still thinking of using the same gantry ends but with 2 extrusions top and bottom with a 10mm plate across the front for extra support. Workable in the short term?

[njhussey]

Hi Ian, if you look at Kingcreaky's build and EddyCurrent's builds you'll see that they went with the Ali extrusion and plate on the front route for the gantry so it's a perfectly viable solution.

[EddyCurrent]

The gantry was easy to build using 100x50x6 aluminium box section with a front mounted 6mm plate.
http://www.mycncuk.com/threads/6565-...5076#post55076
Aluminium angle is much better than steel for being straight but you have to make sure it's all on a very flat surface before gluing and screwing, I used a cast iron machine bed for that purpose.
Also on the front plate, countersunk screws would have looked better, but because the holes were marked out and drilled by hand I didn't want any screws pulling the plate in a wrong direction as they settled into a slightly off centre countersink.

After completion I did some stiffness tests here.
http://www.mycncuk.com/threads/7155-...6572#post56572

[IanS1]

Thanks Neil, Eddy,

I have had looked at both builds before. Just wasn't sure how well they would perform on a machine mostly cutting aluminium. Eddy, are you using your machine for cutting aluminium? The stiffness figures you've quoted seem pretty good.

[EddyCurrent]

No, just wood but I've no doubt it could cut aluminium easily it's just I don't have it geared up for coolant sloshing about.
It's a pity that stiffness thread wasn't refined with a process and added to by others