New build – input/comments appreciated

[routercnc]

Every thing neil says is correct .

Was me not Neil but agree with you on use of the term 'absolute'.

I ran without homes and limits for several months, then added some switches (but never got round to wiring them up) and one day jogged into one and smashed it to pieces and banged into the end stop. Makes you realise how powerful these machines are and to keep your hands out of the way.

Just got round to adding limits and homes so should be OK now.

[JAZZCNC]

Was me not Neil but agree with you on use of the term 'absolute'.

Doh I blame coolant fumes.!!

I ran without homes and limits for several months, then added some switches (but never got round to wiring them up) and one day jogged into one and smashed it to pieces and banged into the end stop. Makes you realise how powerful these machines are and to keep your hands out of the way.

Ye try snapping a 12mm Carbide cutter by hand.!! . . . Even a small machine will snap one like a carrot.!!

[ngundtoft]

Thanks - lots of really useful info. I know a lot more about limit/home switches now.
So 3 switches it is. Based on the above, I cannot really see why you would want to use separate home switches - unless you want some very special home position?
And let us switch tune. I have updated my model with a single Nema 34 motor for the Y-axis and an adjustable mounting flange, as suggested by Silyavski. Is 20T pulleys/idler pulleys ok for this, or should you choose larger ones?

[JAZZCNC]

Is 20T pulleys/idler pulleys ok for this, or should you choose larger ones?

Yes they will be fine arranged like this with nearly half the teeth engage. Don't want to go too large other wise the extra interia starts to affect things.

[ngundtoft]

I have been thinking about how to design a holder so that you can route dove tails at the end of boards.
This is not a function I will be using every day, so it should be simple and it should not compromise the machine in other ways.
I read the thread by EddyCurrent and how he has done it. It looks good and stable and I am sure it works very well.
However, I don’t want this function to interfere with the precision of the bed, so I am not too happy with the removable plate. Also, for handling, I find it somewhat impractical to have this opening in the middle of the machine. All that is needed is a jig that will hold the work piece in an accurate and repeatable position. So I was thinking of placing it at the end of the machine, as shown in the model. You simply fasten the work piece with one or two clamps. I may have to extend the cantilevers/ rails to get sufficient overhang for the spindle or alternatively reduce the length of the frame, since this machine is already getting fairly large.