Anatomy of a Z Spindle

[Digitalwoodshop]

A while back I removed my Z Spindle as with over 500 hours on the cut spindle bearings as it sounded like a rock banging around in a old tin can.... My plan was to have LHR replace the cut bearings not the mounting bearings. I had sent back a Z motor for credit as it would no longer work with the new Z Bundle so it just hitched a ride in the box.

Got a call today and the rebuilding price is about $65.00 and I consider that a good deal.... But.... They said a new Z Spindle is about $45.00..... O' Contrair.... Much better deal to buy another... Plus you need to buy 2 eccentric bearings and the screws as this part comes with the 2 solid mounting bearings but not the 2 eccentric. Add about $5.00 for each one of them and shipping and it was about $66.00.

Added a set of sand paper belts to save on shipping next time and then asked to buy 2 sets of spindle bearings..... Won't get a price on that until tomorrow but I would like to give the spindle bearing replacement a try. What do I have to loose... I replaced bearings before.....

SO.... the next few posts on this thread will be everything you ever wanted to know about the spindle bearings but were afraid to ask.

Granted this repair is not for the average user. Just getting the Z Truck off is a trick in itself and the readjustment of putting it back on is something that is not for the faint of hearts.....

Saw someone else replaced the Bearings too, a 6000 zz something.... Should not be that hard.

The Spindle in question has over 500 hours on it..... When my 100 hour machine came back it was as quiet as a church mouse....

AL

[DDV]

SO.... the next few posts on this thread will be everything you ever wanted to know about the spindle bearings but were afraid to ask.
AL

Quick question. As I recall both bearings have to come off the top (drive end) . Mine had what looked like a steel block that seemed to be attached with JB weld. This will have to come off to be able to remove the lower (chuck end) bearing. I didn't think to check it, is this block a magnet? I assumed it was and was for the machine to read the rpm's of the spindle. Wonder how much you can be out of position with this block before it effects the machine and would you use JB weld to reattach it?
DDV

[Jeff_Birt]

You press the shaft out from the top. The ID of the bottom bearing is larger than the shaft/magnet so the shaft comes right out. The magnet is not needed as they are doing away with all the electrical parts in the Z-truck.

[Digitalwoodshop]

Never thought there would be a magnet in the spindle..... I did see the circuit board on the inside of the spindle for the old optical homing sensor and the jack for the Probe data.... Never thought to look at the circuit card....

I bet LHR has a jig to press the bearings..... Anyone been there seen it?

AL

[DDV]

You press the shaft out from the top. The ID of the bottom bearing is larger than the shaft/magnet so the shaft comes right out. The magnet is not needed as they are doing away with all the electrical parts in the Z-truck.

Jeff:
Are they doing away with it or have they already done away with it? Is that something that the version 1.120 softwear took care of?

This sure opens up working on the Z spindle by the owner. Thats what stopped me from making my own Z spindle last spring and finding a QC that can replace the QC that comes on the machine.
DDV

[Digitalwoodshop]

I ordered a replacement spindle when I found that the cost for a replacement was less than the labor to replace the internal bearings. Got it back and also ordered 2 eccentric bearings and screws as it does not come with the 2 adjustable bearings.

I say give me a DAH..... When I really thought about it and did the installation... Note the picture of the bearing. It has a small flat spot closest to the wrench. When installing the Spindle that flat spot is facing the inside, this will allow the most space between the bearings. Looks like engineering designed the spindle to allow the max tightness to be when the flat spot closest to the screw pivot point is facing outside.

SO the DAH for me was realizing there is no adjustment, just placing the bearing to max tightness with the flat spot facing out. I drew a line on the wrench to know where the flat spot is on the wrench but the bearing flat spot is off set from that.

So the trick to replacing the bearings is to tighten the screw with a quality Philip's then turn the bearing wrench the last 1/4 turn to tighten it up. Not sure about using lock tite, I didn't but it's your call.

Just thought I would take the mystery out of the bearings.... It's like a dead bolt on a door.... Either open or closed.... The trick is to move the spindle and make sure something is not pinched as you tighten it.

I am not trying to encourage anyone to play with the bearings but it is possible to tighten a loose bearing with this knowledge preventing further damage to the machine on a weekend when you can't get help on the phone.

To further identify the flat face I took a scribe and scratched the black off the flat face. White paint on that face would be easier to see. That way you know it's tight when you can see the flat spot facing out.
AL