Toyo ML-210 (Manix ML-210 / Proxxon PF-230) bearing question

[james karranParticipant @jameskarran98514]

Hello. Please forgive any incorrect/inaccurat terminology, I'm pretty new to this

With an eye to some tabletop engineering and potentially some watchmaking if it/I prove capable I recently bought a used ML-210 with the extra milling head and a pile of extras. Generally it's in good condition and I'm pleased with it but I do have a couple of questions the excellent user manual doesn't cover…

The spindle nose bearing is a little notchy and noisy, it improves a little when pre-loaded and there's no discernable free play but I suspect it's affecting surface finish. If it's a straightforward job I may as well replace it. The spindle bearings are both 6003Z, only one face of the rear one is currently visible and there don't appear to be any tolerance/quality markings on it (there's a makers mark but I forget who it's from).

Perhaps sombody could point me at a suitable tollerance/quality/grade of bearing for a machine like this, I'd like to replace like with like if I'm going to do it but I'm rather overwhelmed by the options available! Also, withdrawing the spindle is not covered in the instructions, has anyone done this with an ML-210, it wont push out by hand so I'm presuming I need to carefully press it out or pull it with a threaded drawbar. I'm a bit nervous of damaging the hollow aluminium headstock casting.

My other question (I'm sure there'll be more!) relates to the milling/drilling head. This is adequately rigid when the z-axis clamp is done up but rocks significantly when it's not done up making drilling uneven material (of center roundbar for example) or plunging an endmill unreliable. Is anyone familiar with the machine, does it sound like there's a guide ring or shim missing (or worse)? It doesn't appear to be worn or abused in any way, perhaps it's just a design limitation?

Thanks in advance for any help, James.

[james karranParticipant @jameskarran98514]

[Sub MandrelParticipant @submandrel]

Hi James

Ketan at Arc Euro Trade is a bearing expert. He may well be along in a moment anyway, but I'm sure he would be happy to advise if you contact him direct.

Neil

[james karranParticipant @jameskarran98514]

Thanks. I've had no joy finding an online stockist of high precision 6003Z bearings, I'll have a look at Arc Euro Trade. I did wonder why they're not rubber sealed units, presumably it's to run cooler so radial clearances in the bearing can be minimised (especially since there doesn't appear to be a pre-load spring)?

There's a drawing of the spindle in the manual, there's no pre-load washer or spring shown but it is just the spindle and bearings out of context, I guess I'll see what the arrangement is when I get to it.

The issue I've got with the milling quill is purely related to the quill and the fact it rocks noticeably unless fully locked down, the other slideways were locked and the work secure. I can't really see where the free play is coming from, I'd have thought there'd be a point (while tightening the clamp) where the quill was just free to slide and the rocking play was minimised but it doesn't seem to work quite like that. I guess I need to look a bit closer, I suppose it's possible there's a chip or some other debris lodged in there.

[Clive HartlandParticipant @clivehartland94829]

Simply Bearings  list a load of 6003Z bearings at good prices. These are deep row ball bearings and come shielded with rubber or metal. Try the FAG ones at about £3.20.

From checking about there are lots of online dealers for these popular bearings.

Clive

Edited By Clive Hartland on 06/03/2013 10:50:29

[james karranParticipant @jameskarran98514]

Thanks Clive, it was really the higher precision and lower radial clearance variants I was having trouble finding. Of course it may turn out to be a bog standard bearing Toyo spec'd in which case you're right, there's loads of choice. I'll have to bite the bullet and pull it apart completely to find out. Fingers crossed it's that easy and cheap!

[Ketan SwaliParticipant @ketanswali79440]

Hi James,

You are unlikely to achieve anything special by trying to find a higher precision bearing for your specific application.

6003Z is probably 6003ZZ – i.e.metal shields on both sides. What you are reading is the marks on one shield only which probably reads 6003Z, along with the makers mark. If Toyo machine, then the makes was probably NMB, NSK, NACHI or similar.

Z = Metal Shield = about a hear line gap between the shield and the inner ring. this allows free running, but can allow a certain amount of dirt in, as Graham said.

RS = Rubber Seal = located in outer ring, with a rubber lip which touches the inner ring, giving better protection against dirt getting in. Greater friction when running, but not really a big issue considering the 'low max speeds' your machine is capable of.

So, you may want to consider 6003-2RS. (2RS means two rubber seals – one on each side).

Pre-Load: as a general rule, radial ball bearings do not like pre-load above a certain point. Angular contact ball bearings do. They are designed for this purpose. So, if you really want to introduce pre-load, look at 7003 B, or 7003 B – 2RS. Arc does not do these, but dig around and you will find. Dimensions for these will be the same as 6003-2RS.

7003 B is 'open' not shielded or sealed. easy to find, but you will need to find some way to seal against dirt ingress. 7003 B – 2RS is sealed, but more difficult to find. Angular Contact ball bearings would be better for your application then the radial ball bearing route.

If you cannot find the angular contact bearings, stay with the standard 6003-2RS bearings. Most Japanese and Chinese origin ones you will find are fine for your application. Depending on where you buy from, they will have a 'C0' or 'C3' raceway clearance. C0 is tigher than C3. Arcs are C0 for this bearing size.

Ketan at ARC.

[Ketan SwaliParticipant @ketanswali79440]

James,

Forgot to add: C3 clearance raceways are a looser fit, giving a more run-in feel, and also designed to deal with expansion in hotter running conditions such as with the big end in an i.c. engine. 'C3' is not really good for your needs, as it will probably introduce more chatter over time.

Ketan at ARC.

[james karranParticipant @jameskarran98514]

Ha! I'd been to that site several times since buying the thing yet somehow I'd missed that page. Thank you.

And thank you Ketan for the detailed info on the bearings. I think I now have all I need to strip it and ensure that what goes back in is as good as what comes out.

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