Servicing a High Precision GMN Spindle 

Great job Alex! Many thanks for praising our spindle. Although this is a “simple” spindle from our extensive range of grinding spindles, it is still precisely manufactured with over 90 years of experience. In addition to this model, we also successfully manufacture motor-driven grinding spindles for manual or automatic tool changes as well as milling spindles.

OH my you almost lost your bearing...;) Great video as it was great to be able to see inside the spindle of such a precision machine - thank you, subscribed

Great to see you post again. Looking forward to seeing some more content

That was good thinking at 10:30 when you checked for a left-hand thread.

[Alex does what we've all done and forgets the welding ground clamp] "Thats Classic!" Well, you're only human, but what an expert and entertaining human you are. Thanks for another interesting and enlightening video lesson!

It was absolutely worth it to service the spindle... I am refusing to use my Schaublin22 which is in near factory state, exactly for the same reason... She has been sitting for over 50 years with OEM grease in the spindle and all other bearings, as well as the spindle gearbox... To use a virgin machine with such lubricant, which has to have had been chemically contaminated, even if it never saw a single revolution of the shafts... Moisture and oxygen get in there and slowly deteriorate the lubricant and it`s properties... Sure, some of these greases can operate far beyond their proscribed service life recommendation, but all in good reason and sensible limits... ``Lubricated for life`` only makes sense to the witless and ignorant... Glad you ran across a lovely machine! Some of my acquisitions have not been as stellar, some have, like the S22, but some will take hell of a lot of effort, altho, that only means loads of material for video-making... All the best and kind regards! Steuss

It's a real pleasure watching a skilled person doing what they're good at. So yes, it was worth it :) I know what you mean about that fit, the sound of if in the video had me thinking 'that's a great fit'.

Happy new year Alex! Thank you for showing us your spindle; I can only imagine what it cost new!

A very precise spindle. The one micron runout would be fine as it will take up any thermal expansion in the axial direction when the machine is running. Thanks for posting, enjoyed watching.🐞

Always so much to learn from you Alex, all the best in the new year, and thanks for the video!

Good to see all the practical issues of service. Thanks for sharing!

Brilliant stuff with excellent results. Looking forward to the next one

Thanks for taking us along the ride Alex, very nice! (when setting axial play to such specs I prefer to rest the mag base on the spindle housing itself, not the vise, to minimize reading error)

Nice job there Alex. While it is all still clean you could carefully dis-assemble the bearing packs again and re-assemble them with the bearing balls in a different order to get rid of that measurable run-out. Come on ,we know you want to.😂😂😂😂😂😂😂😂😂😂

Great to see you back Alex. That spindle is a superb piece of engineering, the fits and finishes are astounding. I can't wait to see the rest of the refurbishment. Happy New Year to you.

It is an honor to have recorded the intro music for your channel, thank you Alex! And also for the endless nerdy talks we use to have about engineering topics 😅

Very interesting video! Amazing runout on that spindle.

Thank you. Looking forward to more fascinating presentations like this 👍😎👍

The heavens have opened and given us a new video to enjoy ❤

Why do I love spindle rebuild videos? Am I strange?

Really high precision spindle : D Interesting to test it again after some work and with different temperature : D

Very nice; thanks! I don't know if I will ever rebuild a spindle, but that's not why I watch -- it's not so much school, it's more just the interest!. :-) Well, maybe it is a little bit school. The sound and the results were very satisfying. And when that outer sleeve slid in so nicely... just magical. I will have to go back and watch again to see how loosening the nut reduces the runout; I missed that part, and it continued to confuse me! "Alex! You're going backwards!" :-) But I'm sure I'll find it in there somewhere, when I watch again. Cheers. Happy new year!

Good job! I hope the spindle of my FP1 is in as good shape when I decide to overhaul it. Happy New Year !

Alright Alex, my wife has comments... First, she came in this morning just in time for -inserting the spindle-, her comment was "Yes, now I have sex on my mind." She also said that "Everything he said for the next two minutes sounded sexual to me." So thank you for that! :) At the end of the video you asked if it was an improvement and her response was "I don't know, one micron could be a loss of accuracy if it started at perfect". Her favorite quote from you was "The conical end of the spindle very much helped inserting it, yes, it was VERY GOOD". I think she is now also a big fan, as am I.

It's a beautiful thing.

35:15 - lol... can't wait to see it running. Thanks for sharing.

Nicely done!

Great running spindle you have there Alex

Excellent! Very interesting.

Hi Alex, I think you came up with a new term for fitment: "Speechless Fit" 😁😁 Happy holidays Cheers

When you remove the AC bearings , I was screaming check the radial position. Hardinge lathe spindles are aligned, but I guess this is unimportant on a grinder spindle.

such a great channel, equal to any of the rest.

Great video! I had to do a similar operation for 2 grinding spindles I got on an auction. I think it would have helped if you added some grease into the rings labyrinth. That grease in there also helps in catching any dust that might get in there.

I would cal 1 angstrom the norm. 😋 Happy New Year. Good service!

nice machine

A dust particle fell on my screen during assembly process and I was like: Oh shit, that thing went right in the lube. I just ruined the repair. 😂

Beautiful work, as always. How did your adjustment of the axial play turn out relative to the "original" adjustment? I think that you tightened it beyond where it was at the start?

33:45 In my shop we would call that a ring fit or a line to line fit.

hoi alex, why not drive the spindel outside the machine to check for heat, so you can simply adjust the preload of the bearings when to much/to little play? thanks for sharing your video,s, they are always very interesting to me. happy new year, cheers ben.

I hope to see more from you in the future. I noticed you have your machines up on wood blocks, can you comment on why you did this?

Thanks for showing us this beauty! Kannst du Bücher über Spindeln empfehlen?

i m wondering if that could be the right amount of play on the spindle while its cold.

Having some experience with German spindle cartriges many of them specificly required Kluber grease not using it resulted in failure.

I thought you are meant to spin the bearings to distribute the grease before assembly. Also, is the orientation of the outer bearing race important? I thought there was some trick where the high and low variations in spacers and bearings are alternated to reduce the bending forces on the arbor. Is that a ground glass syringe? Haven't seen one of those in ages.

Is this an internal grinding spindle?

Why is the radial run-out (one micron in your case) so crucial? I can imagine that you run a dressing-stone on your grinding wheel before any operation - would this not correct for run-out? Am I missing something?

Moin, darf ich fragen warum du beim einstellen des Axialspiels kein Fühlhebelmessgerät verwendet hast?

Hi Alex, I’ve got a dismantled maximat v13 lathe… with missing parts also. If you can send me some pictures of the apron, gearbox, etc. Then I am grateful…!