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Replacing Warco WM16 spindle bearings

How do I remove the head for changing the bearings

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Geoff Byman22/06/2019 16:32:35
5 forum posts

Hello All,

New to MEW. I have a Warco WM16 mill that has been upgraded to CNC milling - quite successfully. However, it has just developed a judder and has been tracked down to the spindle bearings. I need to remove the milling head to replace the bearings and although I have removed all bolts/nuts the head will rotate but not come off the vertical slide block. Is it held in by any spring rings or such - does it just prise off?



Bandersnatch22/06/2019 17:18:11
1248 forum posts
40 photos

You don't actually need to remove the head to replace the spindle bearings - you can do it in-situ probably just as easily. (Probably easier actually since the head is supported).

If you dig around you-tube there are a number of videos for this .... many of them referencing the Grizzly G0704.

(Just be warned to take some Gravol first .... a few of these guys hold the camera in one hand while doing the job with the other!)

alan-lloyd22/06/2019 19:02:13
157 forum posts

There is a grub screw on the boss, where it pivots this needs to be backed out to clear a groove in the spigot that the head swings on

mechman4822/06/2019 21:35:54
2458 forum posts
371 photos

No need to remove head to replace bearings; there's a circlip at the top of the spindle to be removed after you compress the return spring, the spindle can be removed quite easily you will need to make up a pin spanner to undo the spacer/threaded collar at the bottom of the spindle once you get it out, You will also need a bearing puller set up as they are on quite tight to remove / replace bearings. I changed the spindle assembly on my WM 16 approx 18 mo. ago as I had cracked the taper sleeve section by inadvertently overtightening the draw bar on to a collet.

If you have the manual look on page 1...' Mill head assembly' 1 … follow the gen' arrangement drawing from item 206 1 - 2 then follow leader lines down to 248 - 251, it shows all the component parts that can be removed from within the head casing without the need to remove he complete head.

A couple of pics of my spindle replacement …

Spindle replacement 1.jpg

Spindle replacement 2.jpg

Spindle replacement 3.jpg

Hope this helps


mechman4823/06/2019 18:36:36
2458 forum posts
371 photos

Hi Geoffb

Just in case you haven't got the exploded view diagram, also for any other WM16 owners ...

wm16 head assy.jpg


Geoff Byman24/06/2019 12:47:01
5 forum posts

Hello all.

Well thank you all for the quick response to the question. I knew that there was something holding the head - had looked initially for a grub screw or something, but couldn't find one. With this info from Alan Lloyd (thanks) I had another look and then removed a bolt and nut that had been fitted to the side of the head to hold a bracket for an airline attachment - looked in the hole and lo and behold, there was the grub!!

Thanks George, I do have the parts list from Warco that came with the machine, but, although I did search, this doesn't list the errant grub screw.

Hadn't known that the Grizly G0704 was the same machine so wasn't searching for the right videos. Many thanks to Bandersnatch for pointing me in the right direction. Just having to go to a darkened room to get over the shakes!!

Having watched the video and read the comments posted about the bearing upgrade - what are your thoughts on the bearing change, as my mill is doing the sort of RPM that is shown in the video. The head does get hot - 40- 50 C - after 1/2 hour or so running - being CNC, some jobs will be as long as 60 minutes plus running at 4000 RPM. Having said that, the machine has done a few years work as it is on these bearings. Also looking into the high seed grease equivalent of the one mentioned in the video (Kluber NBU15) with Omega Isoflex SSP.

Is there anything else - apart from the bearings and slide way clearance - that could be causing the recent onset of judder? Has been cutting beautifully for a long time then suddenly developed this judder.



old mart25/06/2019 14:58:12
576 forum posts
54 photos

The preload on the bearings should be only slight and can be empirically tested easily. You run the machine at maximum speed for 20 minutes, the part of the casting nearest to the lower bearing should get luke warm. Cooler may require a tiny bit more preload and the opposite if it gets over luke warm.

Creep up to the point of contact using a dti to check for radial play.

Leave plenty of room for any excess grease to be displaced away from the bearings (don't overpack).

Geoff Byman25/06/2019 23:14:23
5 forum posts

Many thanks for the info on bearing preload. You didn't mention whether you thought it OK to go for the taper bearings as per the original or the upgraded bearings mentioned in the videos, as according to some comments, there seems to be conflicting opinions as to which is best. Any idea where I can obtain reliable info to help decide which bearings to go for?

Regarding warm up, being CNC, I ALWAYS run the spindle up for at least 15-20 minutes before using the machine to do work - never run it cold - gradually running up the speeds from 2000 to 4000 over the first four/five minutes and then hold it at 4000 on computer read out and watch for the RPM counter on the head (actual spindle speed) to creep up to the correct speed as it warms up. When it has come up to temperature (readings matching), then I run the machine.



Hopper26/06/2019 00:22:38
3712 forum posts
73 photos

Taper roller bearings are generally considered the bearing for the job. What are the "upgraded" bearings you refer to?

It is well worth spending the money to buy good quality bearings. SKF brand are reliably good. Take a look through their online catalogue to see what they offer. They do some higher-precision lines in certain sizes but whether they are worth the extra money for this application I could not say.

RMA26/06/2019 09:04:18
193 forum posts
4 photos
Posted by Hopper on 26/06/2019 00:22:38:

Taper roller bearings are generally considered the bearing for the job. What are the "upgraded" bearings you refer to?

It is well worth spending the money to buy good quality bearings. SKF brand are reliably good. Take a look through their online catalogue to see what they offer. They do some higher-precision lines in certain sizes but whether they are worth the extra money for this application I could not say.

Agree. If the bearings aren't up to the job, what chance have you got with accuracy and life span? It's a bit like putting cheap tyres on a performance car. Incidentally, what make are the original bearings? I would always opt for Timken, but I would say that wouldn't I.

Geoff Byman26/06/2019 14:36:18
5 forum posts

Hello Hopper. Thanks for the reply. I had always thought that taper rollers were the best for the job - having worked in the racing industry we used mainly taper rollers wherever possible. The ones in the video are angular ball race bearings - these, they said would not get as hot as the taper roller type, although a few comments suggested that this is not really an option - however, these comments come from "armchair" critics and not from actual experience, so where does that leave us?

My machine, as I said earlier, does get reasonably hot but not unbearably so - maximum I have ever measured has been 40-50 C but that was after a long 4 hours machining run.

RMA - As regards the original bearings - well, being a Chinese origin machine, I would suspect that the price constraint would dictate cheaper bearings, so I have looked into replacing with SKF/Timken (we used these in motor racing quite a lot!) but to be honest, how high a quality do you go for with a machine of this build? Do you know of anyone who is suitably versed in bearing technology to give me a reliable guidance?



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