Denford Software & Machines

Got most of the way through my first part, everything went well and then as the grooving/parting tool came to inline with the front of the part there was a loud vibration and no more travel in the Z axis.

The same tool had already travelled past this point earlier to groove out the back of the part including where the part off was supposed to happen.

On jogging the machine back it made the same noise at the home position until it reached where it was supposed to be. I’m thinking that it’s something loose on the z axis or the ball nut is skipping. I’ve had the way covers off on the Chuck side of the way and couldn’t see an issue from the front of the machine.

Are there any machine diagrams so I can see where to look for any issues before I have to go stripping the machine again?

it sounds as though the Z axis has stalled, can you manually jog it past the point it stalled? you may have something under the covers causing the axis to jam.

I would start with trying to jog the machine first though and see if it moves freely.

It stopped the Z axis but the readout carried on moving until it reached where it was supposed to be. My guess (not knowing how the stepper is connected to the lead screw) is that a belt has skipped or a connector that is held on my grubscrew has broken loose.

It does the same at the home position until it reaches the limit switch and stops.

There is nothing on the Chuck side so I’ll have to pull the cover on the back side to see.

They are direct drive with a coupling.

the newer machines use oldham style couplings but some of the earlier ones use a flexible coupling, which can break.

you can inspect the coupling by removing the bellows at the spindle end and removing a small cover plate from the bearing housing underneath.

if you need to remove the motor then this is a bit more involved. it will require the removal of the encoder and the covers on that side.

I’ll have to get a look under that plate when I get a chance. As you can see it all looks clear at least.

Can you remove the bellow on the right hand side & check the cable going to the X axis home switch is clear of the leadscrew as it moves.

Martin wrote: ↑

Tue 05 Sep , 2023 10:48 am

Can you remove the bellow on the right hand side & check the cable going to the X axis home switch is clear of the leadscrew as it moves.

Just tried jogging it again and nothing happened this time.


I took the right hand bellow off and the wire was wrapped around the lead screw. I’ve untangled it now but I’m concerned it’ll get around it again. Is there a way to keep it from happening again?

You should be able to bend the wire & lay it in a position which is away from the lead screw.