Help with settings!

[Tenson]

No, there wasn't any reason for me to do so on such a short axis. It just adds complexity.

So it was just a cheeky quip? How nice of you, even though I paid you for the parts.

The acceleration is low at the moment since the machine isn't working fully yet.

[Jonathan]

So it was just a cheeky quip? How nice of you, even though I paid you for the parts.

I guess so, but I apologise if you considered the response cheeky as that was not my intention. If I recall correctly I advised not to use one on the shorter axis, but you had other reasons to use it which seemed fair enough and it shouldn't make the machine perform worse, so I made it.

The acceleration is low at the moment since the machine isn't working fully yet.

I see.. looking forward to seeing it cutting soon.

[Tenson]

Then, why do you wish I didn't use a rotating ballnut on the shorter axis? Has my choice caused you bother in some way?

My recollection is that you said it was overkill. It's not your job to tell me if I'm making a bad choice but I also don't expect 'I told you so' comments when I'm struggling to get it all working.

I think I know what the issue is anyway. On the ballnut mount I didn't have those massive retaining nuts on the shaft tightened up very much. That means when it pulls on the shaft the pulley inside the mount rubs. Does that make sense? However if I tighten the nuts on the end of the shaft to keep it in place, the shaft then rubs on the body of the mount since the two bearings are not perfectly parallel. I think I need to put a tiny spacer in there.

For those who don't know what I'm talking about, here is a picture of the mount.

[Jonathan]

My philosophy is different there so we'll just have to agree to differ and leave it at that.

I think I know what the issue is anyway. On the ballnut mount I didn't have those massive retaining nuts on the shaft tightened up very much. That means when it pulls on the shaft the pulley inside the mount rubs. Does that make sense? However if I tighten the nuts on the end of the shaft to keep it in place, the shaft then rubs on the body of the mount since the two bearings are not perfectly parallel. I think I need to put a tiny spacer in there.

I was going to suggest checking that the angular contact bearings are both the right way round, since if one was the wrong way that could cause rubbing and hence a noise in one direction. However what you suggest here sounds much more likely. I recall only leaving a very small shoulder (0.1mm ish) on the shaft so that the portion of the shaft close to the bearing acts as a second seal/shield. If this shoulder is too small then the shaft could rub on the mount if the bearing outer ring is not flush or protruding from the surface of the mount? The mount should only be run with the locknuts correctly tightened, so tight enough to eliminate backlash but not so tight as to damage the bearings. As the shaft is rubbing with it tightened properly I need to either skim about 0.2mm off the place on the shaft to stop it rubbing, or make a spacer as you suggest.

Since I'm currently in Nottingham in the week I could only modify the shaft next weekend, but if you want me to make an accurate washer (25mm ID, 35mm OD and 0.5mm thick should do it) then I can do that now and post it to you on Monday?

[Tenson]

Hi Jonathan,

I just reassembled it with a thin plastic washer in there I cut from some packing. It seems to work nicely now, so thanks very much for the offer to make a washer, but I don't think I need it. I'm still to put it back on the machine and see if that noise has been sorted though! Off I go!

[Tenson]

Excellent, it is now working :) I only get about 4500mm/min from that axis though, is that normal given the driver is running on 42V and 4A?

Next I need to get the spindle going. Can anyone recommend an suitable in-line pump? I plan to use a bit of aluminium extrusion as a radiator.

[JAZZCNC]

Then, why do you wish I didn't use a rotating ballnut on the shorter axis? Has my choice caused you bother in some way?

My recollection is that you said it was overkill. It's not your job to tell me if I'm making a bad choice but I also don't expect 'I told you so' comments when I'm struggling to get it all working.

Credit to Jonathan here because if you talked to me like that after I'd been good enough to make you a rotating nut assembly of my design for what I imagine is fraction of the cost of the rotating nuts real value you'd be getting told where to jump mate.!! . . . . Advice and help is given freely from peoples good nature and whether your struggling with frustration or not thats a bad attitude to repay such help.