DIY CNC Milling Machine From Scratch

**EddyCurrent** · 21-08-2014

That's a nice piece of oak there but if you plan using that for the control cabinet don't. The enclosure should be made from non combustible material, also tannnic acid in the oak will react with the steel.

**Jonathan** · 21-08-2014

Originally Posted by totts

Okay after managing to get on the computer i have made sure my plates are made of steel, and from what i can find the 2.2kw spindle is around 5.15kgs then the z axis is around 45kgs.

Just realised I forgot to reply to you about this. Using the script I posted here, the difference in torque required with and without the gas strut is around 20-30% and the absolute value is low enough for a 3Nm stepper motor to work well. I'm guessing a bit with some of the parameters, but suppose you put a 20T pulley on the motor and 30T on the ballscrew, the required torque (taking into account inertia of ballscrew, pulleys, carraige and motor, plus friction of bearings, ballnut etc) for 3m/s^2 acceleration is 0.87Nm without the gas strut which is well within the rating of a 3Nm motor below the corner speed. That means you'd easily get about 3.3m/min feedrate. The torque requirement for the same acceleration with 30:30T gearing is almost twice as much (1.67Nm), but if you use 20:20T it's 1.1Nm. The belt stiffness goes down with smaller pulleys, but it's still higher than the ballscrew torsional stiffness so not too big a concern ...

I'd recommend 20:30T pulleys on Z, as around 3m/min should be plenty for this size machine and you get higher resolution compared to 1:1.

**totts** · 21-08-2014

Ahhh okay right so steel enclosure will be on order soon! And will add some braces to the frame, dont want this one walking through a wall! Haha.

Thankyou all for the help and advice, adding work... Tut :p haha

Thats good to know! Thankyou for the calculations, surprised at the gas strut adding that little!

**totts** · 03-10-2014

Finally some more work, been a bit slow the past couple months with a few problems, but nearly finished the bed,

Rail slots machined and fixingings tapped!

Ready to bolt the rails on!

Slots machined and ready to accept 14mm t nuts

Next on the list it to fix the rails on and finished grind the surface.

Then purchase the electronics cabinet, start painting and building and adding strengthening bars to the machine stand and a few little odd job bits! Light at the end of the tunnel??!

**GEOFFREY** · 03-10-2014

Looking great, I think this will be a really nice machine. Great stuff. G.

**JAZZCNC** · 04-10-2014

Originally Posted by totts

Light at the end of the tunnel??!

Ahh ahh ahh . . .. You poor dillusional Fool.!! . . . It's only just begun.!!!. . .LOL

Nice work by the way, impressive.!! . . . . wish I'd got a big surface grinder it really does make a difference in accurecy and finished look.

**totts** · 04-10-2014

Thankyou, Yeh they are awsome machines, shame they are so damn exspensive! Lucky to be able to use one really.

Just changed all the countersunk screws to stainless ones, they were jolly tight! Doing their job !

**totts** · 11-10-2014

More progress today, cut the rails to length and screwed them onto the bed,

Countersunk screws and dowels in place,

Hopefully get it finished next week :)

**EddyCurrent** · 11-10-2014

Great workmanship, it's a thing of beauty, the T slot bed especially.

**Lee Roberts** · 11-10-2014

Looking really nice !

Question 1: What is the orange/red'ish color coming from the bottom of the rails?, looks like a layer of crafting felt or something?
Question 2: Am I right in thinking that, the dowels allow for fine adjustments of the rail towards the Datum Edge ?

.Me