HLV-H spindle preload cylinder has odd dates written on it.

I have a 1976 HLV-H serial number HLV-H-5719M. I'm replacing the spindle bearings and saw these dates written on the preload cylinder. They look like dates to me, but I guess it could be somethng else. Maybe somebody at Hardinge has a wacky since of humor? Anyone have any ideas?

Good Luck. Hardinge was sneaky and they had their own bearings lapped a bit bigger ID and smaller OD, so people had to send the heads back to them to rebuild. I would always send them back after trying to do one myself. I visited Hardinge factory once and they had a special room with black curtains so they could lower them when people took tours to keep their methods secret. I used to clean out the old bearings, re grease them with Mobil # 28 grease 30% fill and that always worked, so if the old bearings look good re-use them. I suspect the marks signify the bearing spec they used on that spindle. Good Luck. Hardinge still rebuilds headstocks. Rich

I would have it rebuilt, but I can't afford the cost. So far, the bearing replacement has gone well. I followed the instructions I found on this forum. I agree that those numbers are probably some type of specification.

There will be marks on the cylinders indicating high spots. You bearings will have marks indicating points of maximum run out. Those marks would be lined up for absolute best concentricity of the assembled spindle. Ordinary mortals like us will not be able to do the best assembly because of not understanding all this stuff. The eccentricity of the bearings and cylinders will be a few millionths off, just doing the best you can without optimizing all this stuff will still result in a pretty good spindle, but not quite as good as Hardinge would have done it.
I bought a couple of pairs of matched bearings for my HXL and was amazed that Hardinge sold them at such a reasonable price. These are the same matched pair used in the HC and HLV-H. Only one pair needed for them. Less than $400.00 a set if I remember right. The bearings were premium Japanese, I guess Barden are no longer available.

FredC said:

I guess Barden are no longer available.

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Probably not at the $400/set that you paid. Barden is still in Conneticut.
JR

Just checked in the cabinet on the Tsugami and the bearings I bought for it were Fafnir, purchased from Hardinge about 20 years ago. Never opened the box or installed them, turns out I got 2 pairs of bearings instead of 2 bearings. Forgot what I paid for them.

I still don't know how to interpret the measurements. But the spindle is engraved with the number "9" and the front of the headstock is engraved with the number "9". The preload cylinder has the number "2-57" engraved on it and the headstock has "2-57" engraved on it. When assembling the spindle I will line up the corresponding numbers. Hopefully that will be the most accurate position, similar to the spindle bearings. I ordered my pair of Barden O-11 114HCDUL for $450 plus shipping.

Buy some Mobil #28 or 32 red synthetic grease or 30% fill similar precision grease. Kluber Isoflex grease works too. 25% fill. If you fill it to much that will increase the heat. Hopefully all will go well. Rich

Richard,
I am going to ask a question that may be helpful to the OP. When I replaced the bearings on that Tsugami HC, I pushed one of the bearings the wrong way and dropped all the balls on the floor. I cleaned them up turned the bearing around and reassembled it. The other thing I did was not use grease but an oil bath was set up so the bottom 1/2 to 3/4 of an inch runs through the oil, I use velocite #6. The spindle bearings made noise any time I ran over 1600 RPMs. For the last 20 years I have just used 1400 RPMs as max and it still keeps on going.
Any guesses as to preload, dropping the balls, or lubrication was the issue?