Upgrade? Chinese CNC Machine

[Jonathan]

1) measure the distance between the axis and a convenient point

Measure how far the axis moves. So for example on X move the gantry to one end, then turn 20 turns (or whatever) and measure how far it moved. You don't need access to the screw.

The meter you have will be fine. Just connect the negative probe to negative, (i.e. ground) and the other one to the correct pins. You may have to unscrew the board to access one of them.

[Carlb1058]

Measure how far the axis moves. So for example on X move the gantry to one end, then turn 20 turns (or whatever) and measure how far it moved. You don't need access to the screw.

The meter you have will be fine. Just connect the negative probe to negative, (i.e. ground) and the other one to the correct pins. You may have to unscrew the board to access one of them.

Access to the chips wasn't too bad - off all three I got a reading of between 2.2 and 2.3 and occassionally -2.2 & -2.3 but I'd say that's my multimeter playing silly buggers.

As for turns per 20 on the X gave me 80mm, 10 on the Z gave me 40mm (couldn't turn it 20) and 20 on the Y gave me 62mm

[John S]

Recheck Y in a couple of places and in both directions
Reason for this is 62 mm doesn't work out to a normal pitch and you did say y was jerky.

I'm wondering if you have a loose coupling or similar ?

[Ricardoco]

Recheck Y in a couple of places and in both directions
Reason for this is 62 mm doesn't work out to a normal pitch and you did say y was jerky.

I'm wondering if you have a loose coupling or similar ?

I concur

Rick

[Carlb1058]

Recheck Y in a couple of places and in both directions
Reason for this is 62 mm doesn't work out to a normal pitch and you did say y was jerky.

I'm wondering if you have a loose coupling or similar ?

Just measured it at centre of table and the other end to original and still got 62??

Addon bit: Just re-checked and made sure all connections were tight and they were, this is where it gets weird again - using a spanner on the opposite end of the Y screw I turned it 20 got 80mm, turn the knob on the end of the motor and get 62 but if I try and tighten the grub screws up any more all I succeed in doing is bending the allen key????

[John S]

Is the knob on the end of the motor slipping ?

You need to sort this bit out first, try welding the stepper motor to the ball screw.









Just joking.

[Carlb1058]

Is the knob on the end of the motor slipping?

You need to sort this bit out first, try welding the stepper motor to the ball screw.

Just joking.

Welding - cool, now ya talking

The knob itself is on the motor that tight I'd break it if I tried to remove it so the only thing left is the coupling I might go tear the motor off and suss that lot out

[Carlb1058]

Y now equals 80mm on 20 turns and I've got one bent allen key