[Titaniumboy]

I took apart and cleaned all of the X and Y components last month. I also adjusted the X and Y gibs, and the X and Y leadscrew backlash. Along with some Vactra II way oil, my mill is running silky smooth on the X and Y.

Up until now I have been avoiding tearing apart the Z axis components, but finally took the plunge yesterday. So far I have removed the head, the vertical slide, the side handle and gear, and the entire Z leadscrew. I didn't touch the two lock nuts on the Z leadscrew, and removed the Z leadscrew and the column top plate as a single assembly.

Now that I've gotten to this level of disassembly, I've got several questions before I continue.

1. I removed the two setscrews that hold the leadscrew nut extender block onto the vertical slide. I'm not sure if I should have removed these, and I'm not sure what function that the setscrews provide.

2. I didn't removed the two lock nuts off of the Z leadscrew/column top plate assembly for fear messing up the adjustment on the bevel gears. Should I remove the lock nuts and get into the bearing?

3. How does one ensure that the two bevel gears align properly?

4. The Z leadscrew is covered in gunky sticky grease and I plan on cleaning all of that grease off. Should I put my own grease on the Z leadscrew, or just use 10 or 20 or 30 weight oil like I did on the X and Y leadscrews?

5. I hadn't adjusted the Z gib at all so far. What I found during operation is that as I lowered the head, the Z handle wasn't driving the head down, but was instead only lowering the head due to its own weight. I haven't had a problem with the head operating this way, and moving the head up and down is very smooth, although it takes a lot more effort to move the head as compared to moving the head down. Should the Z gib be tight enough so that the head doesn't lower of its own accord as the Z handle is lowered?

6. Is there any reason to remove the column from the base at this point?

7. I plan to do the Three Bolt Mod while the head is off of the mill. Is there anything else I should be doing while the head and Z axis is disassembled? Any tips or things I should watch out for during reassembly?

Thanks!

Titaniumboy

[hoss2006]

1. should have left the setscrews alone, they adjust the leadscrew distance from the slide.
2. leave well enough alone unless there is slop and you want to adjust the bearing preload more.
3.if you reassemble the same way there shouldn't be a problem. been a long time but iirc the pinion can be adjusted in and out for a better mesh.
4.use grease, you are in manual mode (slow moving compared to cnc) so oiling is unnecessary.
5. the weight of the head will still pull it down with the gib adjusted properly, if it doesn't they are too tight and you'll have a jumpy travel condition called stiction.
6. no
7. use some loctite threadlocker on all the screws during reassembly. I imagine you are doing this to also lightly remove any burrs on the dovetails and gib, i.e. some 600 grit paper on a flat surface plate with oil.
good luck
Hoss

note about #1. there's slop in the column top plate so you may have to adjust the setscrews anyway to prevent binding at the top of the travel.

[Titaniumboy]

Hoss,

Thanks so much for the feedback. I searched on your thread and didn't find anything, but had you covered the Z axis disassembly/reassembly on a video or somewhere else?

1. Drat. Figures I should have left the Z leadscrew nut setscrews alone. It sounds like adjusting the setscrews to avoid binding won't be too bad.

2. How much slop is too much slop on the Z column top plate? If I pick up the Z leadscrew/column top plate assembly by holding the column top plate and letting the leadscrew hang down vertically, and I wiggle the column top plate, I can see that the leadscrew flops around a little.

6. Cool beans on not having to remove the column from the base!!

7. Thanks for the idea of using loctite on the bolt threads. On the X and Y gibs I had used a file to deburr the edges because only the edges seemed to have burrs - the rest of the X and Y gibs seemed pretty flat. Interestingly, the dovetail of the Z column is WAY rougher than the X and Y dovetails or the vertical slide dovetail. The flat part of the Z column is nice and smooth - it is just the angled dovetail that is rough. I have a small granite surface plate, but how would you use the surface plate to smooth out the column dovetails?

I forgot to mention it last time, but I was surprised to find that the Z leadscrew nut is different from the X and Y leadscrew nuts in that the Z leadscrew nut is not slit and hence does not have any backlash adjustment.

Time to get to work cleaning, doing the 3-bolt mod, and putting everything back together again. And then it is time to tram everything.

Titaniumboy

[hoss2006]

2. i mean axial slop, can you feel any slop pushing/pulling on the leadscrew in/out of the bearing.
there should be 2 jam nuts to adjust load if needed.
you still want free rotation.
7. the surface plate with oiled 600 grit for ensuring the gib strip is flat, a nice flat file is ok for what you've
done on the dovetail before.
more info here if interested, Shop Info
Hoss