New CNC Mill on the horizon

[JAZZCNC]

I have not put any feet on the frame design and was thinking about sitting it on a concrete pad in the garage that I will run some levelling screws over. Does this sound like an ok base for a machine like this? I will be bolted down ideally which is why I'd rather it was as level as poss to avoid distortion to the frame

Or should I bolt it down as I weld it up?

Best if bolted down but it will be heavy anyway so won't exactly float away. Thing you need to avoid is not putting machine in twist.
Don't know how you plan to get X axis rails on same plane but which ever way then do it after the machine has been situated where it's going to live and fastened down.

Don't bolt it down has your building it. When building try to find level and flat surface that is not in twist to work from, don't just work from floor unless you absolutely know it's perfectly flat and not in twist. If you don't have decent surface then It's worth taking the time to build one. If the work surface is in twist then the frame will be in twist when welded up.

[fvfdrums]

My original idea was to pour a temporary surface to do all the welding on and then remove this once done.

Alternatively I suppose I could make a torsion box to assemble from.

[fvfdrums]

Got a text at 7am this morning to say the Motors and drivers should be here today, thats crazy they were collected in HK at 10pm on friday night and are here this morning now thats service!!

So hopefully I should be able to add a few more pics to the component pile.

I had "yet" another question, whats the smallest or should I say recommended diameter for a 5mm pitch HTD timing belt pulley running 1:1 - is there a minimum number of teeth people would recommend (other than as many as possible) being in contact with the pulley at any one time?

The reason I ask is not for the z or the y as they are simple straight connections with the pulleys in front of each other.

Its the X where I am driving the two screws with the single belt, I can get half the way round the pulley on the left hand side however on the side with the motor I am going to have to put in some idlers to make the belt contact more with the pulley so I can nearly get about 120-130 degrees around one side of the pulley would this be enough?

I thought about doing one belt connecting the two axis and then stacking another pulley on top of the right one and driving this but my concern was "if" the belt were to snap (the long one between two axis) then one side would still be driven by the drive pulley and could cause some bending if it carried on and the other stayed still. Where as if the one belt were to go they would both stop.

Suggestions?

[JAZZCNC]

Wouldn't go lower than 20T.

Regards the one belt connecting 2 screws then that's how my machine runs and I've not snapped a belt in 6 years use so wouldn't worry about it.!
If you want to be extra careful then use spring loaded NO limit switch with bearing on end tensioned against the belt and wire in series with E-stop so if belt breaks tension releases and causes an E-stop.

[fvfdrums]

I think I have them as 24 teeth at the moment so i guess that should work.

Motors and Drivers have just arrived. Well packaged and look good so one more package to come from Chai and I can start on the Gantry. I would just rather have the parts with me to measure from before I start drilling and cutting.

How long does Chai generally take to get things machined etc once the order has been placed? I know it takes 1-2 weeks to ship.

[JAZZCNC]

How long does Chai generally take to get things machined etc once the order has been placed? I know it takes 1-2 weeks to ship.

Can't tell you that but Usually arrive between 9-12 days from placing order. Often any delays comes from UK end.!!

24T will work fine.

[fvfdrums]

Had a reply from Chai, says it should be 9-10 days from now as something to do with fed ex and HK I did not quite understand but nice to know they are on their way.

So I have been thinking about siting this machine on a concrete slab poured on top of my garage floor which currently is not particularly level. Has anyone done this before? if so what sort of thickness do you think I would need? I was thinking I could lay down about 1" and then screed the top with a self level compound?

Then once I have built the frame bolt that down to the pad (hopefully eliminating too much twist) and then do some of this wizardry with self leveling epoxy?

Does this sound overkill or feasible? I am going to this much effort on the machine I would hate for a wonky floor to put pay to the accuracy.