[1875]

Hi Folks,

I'm about to order a top end rebuild kit. Do these kits cover the CNC version mill with the nod and tilt head? I noticed that my top end quill assembly is longer than the typical manual machine. I'm also curious if the kits usually come with the bearings below the bull gear, which is where I am now.

I do not know which bolts [or nuts] to remove here? I've read a few counts that one set is NOT to be loosened as that is a factory alignment. Does anyone know which set to remove here, upper bolts or lower nuts?

Thanks for any assistance.

[mactec54]

1875

It does not matter, you can take it all apart, it is almost self aligning when you reassemble it, Bearings are individual, You just get good Brand name bearings,from a bearing supplier, Put 2RS sealed were ever you can put them, don't get the same open bearings that are in the head

[1875]

OK, I ordered a rebuild kit from H&W. It has 7 bearings, not sure if they are sealed. I also ordered the motor bearings.

I wonder why the warnings about loosening the bolts? The only thing I've read about adjustment is to float the castings back in by running the motor as you tighten the bolts.

[mactec54]

OK, I ordered a rebuild kit from H&W. It has 7 bearings, not sure if they are sealed. I also ordered the motor bearings.

I wonder why the warnings about loosening the bolts? The only thing I've read about adjustment is to float the castings back in by running the motor as you tighten the bolts.

Unless they are quality Brand name Bearings I would not buy from them, ask what the brand of the bearings are, & are they sealed, if they are not, get them from a bearing supplier

No you don't run anything to align the plates, when you get to that part I will tell you how to do it, it really is almost self aligning, In fact you would do more harm than good trying to align by running it

[1875]

Hi All.

I'm ready to start putting the machine back together. How do I remove the bearing from the top spindle veridisc/pulley? There is an aluminum casting with the bearing pressed into and onto the top pulley, where the speed changer connects?

[1875]

This is the piece.

[1875]

Just an update - I had to pay one busted knuckle to get that off, but they are both off and cleaned up.

I also discovered that removing the hi/lo gear shift shaft/pinion allowed the bull gear to lift out.

[1875]

Has anyone discovered a parts diagram for the CNC version of the head and quill drive? This is the nod/tilt head...

[1875]

Are the spindle bearings here in the Boss3 CNC always sealed? The head has a feed from the automatic oiler. I think it is for the quill and quill Z drive only. These are working fine and feel smooth and quite, so I may not need to tear into it. I just don't know where the oil feeds and if all parts are getting the oil they need.

If the oil just drips on the Z-axis quill drive, then it is probably OK since the belt and pulley tend to get wet with oil, which I've read is common.

BTW, all 7 bearings I've removed from the head were sealed bearings, but there is a large visual gap where the rubber seals have shrunk back away from the movable races. All the bearings feel like they have sand in them. The new bearings I got in the kit are shielded. I'm wondering if it is really worth it to try and exchange them from the parts supplier at this point?

Thanks for the guidance.

[mactec54]

1875

The oil feed is for the Quill & Ballscrew, the spindle bearings are not normally sealed,They are Matched Pair Angular Contact Bearings, the top spindle support bearing is sealed, is a regular Bearing

Make sure the oil is flowing from this tube & it is getting on the Ballscrew, it spills from the Ballscrew to the Quill, if the spindle feels good then leave it, you can always do the Spindle any time, you don't need to take everything apart, the front Spindle nut is removed, & the Spindle can be removed from the front, you turn the head on it's side

The shielded Bearings are not as good as the rubber shielded, I said this in the first post to make sure you got 2RS which is for rubber shielded

[1875]

While cleaning out the old grease inside the head, I found a row of small ball bearings just sitting on top of the quill.

I can only imagine they came from the quill ball screw, but how? Could that happen if the quill was over extended? It does not seem possible. I can see a lock ring in the quill that would seem to prevent that from happening. I suspect the ball screw could still function if it was missing some balls, but it surely would not be good. :?:

[mactec54]

1875

That does not sound good at all, if the block on the front of the quill that trips the limit switches was removed this could happen, you could then wind the Ballscrew Nut off the top of the screw, that will need a rebuild, it would not work very well with balls missing, could do lots of damage to the Ballscrew if you run it like that

[1875]

Well then, off it must come. Any idea how many balls I should have? 199?

[mactec54]

1875

There is a lot more to it than just putting the balls back in, these have zero backlash & have a mix of different size balls to achieve this, these Ballscrews are a special custom made C3 Ballscrew

This company is your best bet or if you can find another Ballscrew
International Ballscrew Repair Service Ball Screw Repair Service Ball Screw Repairs Ballscrew Repairs Ballscrew Rebuilding Ball Screw Rebuilding Ball Screw Services Ballscrew Services Ballscrew Manufacturer Ball Screw Manufacturer Fast Nationwide Serv

[1875]

Well, I got the ball screw housing out. It runs smooth and I cannot detect any play. Seems almost impossible that those balls would be sitting there unless they came from this screw though. I did not find any other balls floating around.

I also cannot see how oil would flow down through the ball screw and get to the spindle bearings? Bottom of the screw is bolted to the quill, so the oil runs out around the outside of the quill. I have read that some of these spindles have grease sealed bearings.

I'll clean things up and stare at the ball screw for a while and see if I can figure out if it needs service. Anything to look for? Is there a way to tell if balls are missing? I'll measure the ones I found and compare sizes. I hope it's just a matter of replacing any missing balls. Are they put back in to the end they came out?

Thanks for all the help so far and for the link to a repair shop.

[mactec54]

1875

The spindle Bearings have Grease, the oil flow, is only for the Ballscrew, then it runs down on & around the Quill, make sure everything is very clean in the quill housing, if it is not you will seize up the Quill

The balls would not of come from any were else, but the Ballscrew, they are quite small dia, & will be 2 different sizes, they also will need to be put back in the right order, the return tube is were you would put them back in, but be careful taking it off, as it will be full of balls that will go every were, have it on a tray so the balls don't run away, use some grease to keep the balls in place,when you try to do it

[1875]

Thanks MacTec...

Here I am.

[mactec54]

1875

Looks like there has been a lot of condensation, in there, not much oil, to protect it, If you take the nut off, be very careful with those Bearings, they are a matched pair, & are spendy

You can disassemble the Bearings to clean them & see if they have been damaged by the condensation

Did you put the plastic on top of the Screw or was it there???

[1875]

I put that plastic there first stop to keep the ball screw from falling out as I took things apart. Bearings feel good, but a good clean is in order. They did look like the expensive kind of bearing. Things might slow down a bit during the week. I also need to clean up and put all the parts in order. I've come across a ring and key that I now don't remember where they go... The seller said the machine sat in a barn for years.

[1875]

Some questions are:

how do I properly reassemble this ballscrew and what kind of assembly lube? Do the recirculators have any particular orientation or order.

which grease should I use for the ballscrew bearings (the large mounting bearings)?



I retrieved 36 loose balls. Some measure 0.1245 and others measure 0.1235 and that is +/- a couple tenths for me, and I do not have a standard to test my mic. That matches the dimensions of the balls out of the ballscrew. The loose balls show a bit of pitting under a microscope, so I should be looking for replacements. This is a link I found here somewhere: Bal-tecâ„¢, Manufacturer of Precision Balls, Ball Bars, and Kinematic Components

I found the following numbers on the ballscrew nut, but they are a bit faded and hard to read:

NSK Japan
W5001W - 1PT - UPZ
7N3 - G13


Now, the spindle bearing is tight (meaning no play), but I can hear a slight click about once per rev with my ear against the casting, so there is either a pit or particle in there. I'm considering removing them and clean/repack if that is a good way. It may work out to the side if run, or grind to dust, etc... I think the advise there is to consider that later, but it looks like there is a nut on top pf the spindle, and this quill is bolted to the ballscrew, so it cannot be removed without complete disassembly of the head again?

Thanks