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Any advice on pressurizing (grinding) spindle?

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hanermo:
 :hammer:

Pekka ... I have the perfect solution for You- in my non-humble opinion.

Nilos rings.
Google it.

They are zero-contact, non-contact, industrial labyrinth seals that are easy to apply and use, seals of zero friction and airtight, to an extent re:pressure.
And easy to apply, and cheap.
About 17€ each, maybe less for your smaller size.
Can be bought one at a time.

Absent fancy methods/tools, you apply it, and run it in 24 hours.
It self laps to an airtight fit, non-contact after run-in.

One of the coolest, fanciest, cheap gadgets I know, along with .. other Greatest Stuff:
+ hi-res cheap optical encoders, and ..
+ optical encoder hw readers/readouts (35 kHz iirc) for 60€ (import, runs on 220V or 110V, as-is. Great !.).
(+ NSK Spindles from Japan, but another price level (2-6k€). Amazing. Tiny at 40 mm D. Noiseless. 400W, more than my Bp M head (1/2 hp). 30.000 rpm (-to 60.000 rpm.)

Afaik Nilos rings are a german product, made there.
I would also expect to distribute/sell Nilos rings here in Spain, if I actually start to sell components.

BTW...
If anyone knows where to get hi-res encoders 50.000 counts - 1/2 M counts, at reasonable prices, and preferably upto 4 Mhz (CSMIO-IP-S limits) speeds, or 4 revs/sec at 1 Mhz = 240 rpm... please help.
Currently the better encoders don´t seem to provide prices on-line, and I am aiming for sub 150-200$ pricing in unit quantities.

These would be for secondary feeds into T&C grinders, etc. while aiming for modern higher-end industrial levels.
Ie to read via sw and use the actual real angles from very high resolution(=/= accuracy) rotary tables, displacement stages, etc.

PekkaNF:
HHH Hannu Humble Hammering :lol:

Have you ever used them sucesfully?

I have some and agree, they are pretty good, but you have to design them in. You just can't slap them in most of the time.

Here they would need some carefull modification, biggest issue is to make the shaft nut (that squeses the two bearings together) much thinner, the Nilos ring would seal to inner ring and interfere with clamp nut. Now this nut is aluminium and it would need thinning to make space for Nilos ring.

I did consider it and I'm reconsidering it, probably even enough to buy some more Nilos rings, always need some components at hand they are great to stack on see if they can be crammed in.

Thank you,
Pekka

hanermo:
I looked at the seals/nilos rings as a completely separate issue re: spindle.

Ie a separate component holding/positioning them re. shaft nuts, collars, etc.
Kind of like a cover, over the spindle, from which the spindle protrudes, and is then sealed by them.

Thus the cover does not really need any precision, any strength, or any mechanical properties, or any precision, for the tiny-force Nilos rings.
The mechanical solution is bolts, to spindle housing face ... but I think/suggest any suitable locktite-stuff of low strength is probably better.

Probably, even any diy glue of low strength is ideal, easy to remove with hot-air gun, cheap.
Any collar, cone, taper, shaft surface can be used to align stuff, well enough, imho.
After all, You are probably never going to remove the cover, in your lifetime ... and if You do, or someone else needs to, they can always align stuff in a 4-jaw well enough.

As a reductio ad absurdum, a 1 mm thermoplastic, hot-air gun, hand pressure, would likely be fine, as a cover, and the rings slipped on after, glued in, lapped in.
(maybe a temp washer on the spindle, to create a tiny air-gap. Anything, really, from a 40 mm washer to a felt ring - grin).
These type of things have lowered hdd costs, machine tool costs, appliance costs, electronics costs, etc. 100-200x in 15 years.
Everything is small, light, cheap, plastic  .. lasts forever .. but is hard to repair/fix/unmount.

Maybe .. If you want to have access to the nut in front, make a larger collar, 2 mm thick, in any metal of you choice..
Use the (bigger) nilos rings to seal to that.
Allows unmount options later.
I would prefer zero nuts at front, drawn in from back via screws, bolts, bellevilles/springs/whatever.

PekkaNF:
Ordered some Nilos rings that looks about right with the bearings. They haven't left the Germany yet, looks like it's not going get fixed this week.

I think that Nilos rings should be pretty concentric and on the same plane with the bearing: After all they wear a small grove into bearing ring. Best mounted into same seat with bearing.

However, while I was playing with the bearings I noticed that they were noticeably magnetic! I.E. when soft iron was bought into contact with bearing it would stick to it. Wonder if that explains the bearings affinity to black iron muck? It has pretty big ferrite magnets.

Pekka

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