Changing Spindle Bearings in a late model DV59

Hi just got a quote from Hardinge to replace the spindle bearings on our DV 59 lathe they quoted $4735 Dollars! The bearings are only $395. But they tell you theres no waranty if they dont install it. Is there any secrets to this. This machine is not doing any high tolance work but the bearing is noisey and the machine is handy for small jobs. Thanks for any info. PS the machine isnt worth more than 1500 dollars.

I think the only thing they are talking about warrenting is the brg. Do you want to pay $4730 to protect against possibly damaging the brg. during instalation? If you work slowly and carefully, you'll probably do OK, and even if you don't you can buy a lot of replacement brgs. for$4730. I'd go for it if I were you

Read this: http://aafradio.org/garajmahal/Hardinge_spindle_bearing_replacement.htm

It is good practice to make a proper (special) wrench to remove the spindle nut. I use a piece of thick wall steel tubing with two dowel pins in the end to fit the holes in the nut. I drill a radial hole in the tube and use a standard pin spinner wrench to do the turning. I hate to see a nut that has been attacked with a hammer and pin punch.

As to warranty, I think Hardinge would warranty the spindle runout to be within new specs if they install the bearings and grind the collet taper in place. Grinding would be a big part of the cost.

The bearings might be a little less if you get them from a bearing store instead of from Hardinge. But you need to know what to order.

Larry

Thank you for posting the link to mark weber's
instructions. I think they are among the best.
When I took the preload nut off the spindle in
my ESM59 it was hella tight so he should be
prepared for that.

Mark always recommended Alpine Bearing in the
Boston area, I purchased the replacements for
the Elgin headstock I re-did. They were able to
convert the New Departure numbers and shipped
the correct goods.

Jim

There, In my opinion is a couple of possible fatal flaws in those instructions.
Never ever under any circumstance strike any, even a cheap bearing with a hammer and a steel drift, or use the precision spacing tube to tap a bearing home.
The rear bearing would more logically be seated in the headstock casting with a threaded rod and a couple of machined disk fixed to pull the rear bearing in by its outer race.
Never use a heat gun to warm a precision bearing, that will force dust into and contaminate the bearing.
The marks on the bearings indicate the high spots. These can be used to make a spindle run truer if you have the measuring equipment to take advantage of that manufacturing flaw.
All bearing mounting surfaces should be inspected under 15X magnification and the micro scratches from removing the old bearings carefully dressed down.
Always, draw up an assembly sequence plan and follow it.
Mop the floor if the assembly is on the shop floor, close the windows and shut off any fans, lock the door, dont eat, drink or smoke, use talc free gloves.
Bitter experience dictates no room for mistakes.

Thanks, Donie. Those are good additions. With your permission, I'll rephrase in my own words and add them to the writeup as alternatives/precautions. I still need to integrate the photos I took in my own rebuild. In Mark's original post in RCM years ago, he invited someone to make a FAQ out of it, which is what I tried to do without changing the format too much. I added a number of minor clarifications to Mark's original writeup (with his review), and the document was always intended to be a living document.

Best wishes,
Mike
AAFRadio

"couple of machined disk fixed to pull the rear bearing in by its outer race..."

Interesting issue there.

On the HLVH and the DV59, the rear bearing
is constrained to have its inner race with
a very snug press fit over the spindle OD.

At the same time it's outer race is a very
snug fit into the bore of the headstock casting.

So the conclusion is, a good amount of force
must be used to press the inner race onto the
spindle, *and* a good amount of force used to
press the outer race into the headstock bore.

All, without applying *any* force that might
appear between inner race, to outer race, via
the balls.

The implication to me is, the fixture that
is applied to the outboard end of the rear
bearing *must* have a precisely sized step in it,
so that force may be applied to both inner and
outer races, without putting any pressure across
the bearing via the balls. This is what I tried
to do when I re-did my ESM59 spindle - but it
was made easier by the fact that the rear
bearing is pretty much a pure radial one.

Those machines have an angular contact pair
at the front of the spindle, and a single radial
one at the rear. The radial one seemed to have
a fair bit of axial motion allowed between
the inner and outer race. I'd be worried that
a pressing fixture like the one in discussion
would have to have a step in it accurate to a
couple of thou so the press force goes 'where
it's supposed to.'

Thanks again to mike (aafradio) for hosting
mark's description for this task.

Jim

The micro scratches may be used as an auxiliary indicator of a matched pairs' preferred position, if the front slinger is obscuring one of the faces (this can be an issue on the older TL, and possibly also the TM/UM).

Carefully dress down with a hard stone, only if necessary.

Use latex-free gloves, more particularly the purple polymer gloves which come talc-free.

These are intended for surgeons/technicians who are allergic to latex.

Most larger drug stores should have them. Also some industrial supply stores.

Wear a Tyvec® cap on one's hair.

A Tyvec "gown" would be good, too.

If someone jokes that you've become a cross-dresser, tell them to go to Hardinge Hell (somewhere in the Eastern hemisphere).

At the risk of appearing anal-rententive, I'm primarily concerned with the older oil-lubricated bearings, which are open (that is, unshielded) and have phenolic or brass cages, not the newer bearings which are shielded.

I am advised that these unshielded bearings come pre-coated with a protective lubrication which prevents oxidation, that this coating is compatible with the recommended lubricant, and should not be flushed with Bra-Kleen, or any other solvent prior to installation.

Donie's observation that the spacer is a precision device is significant. It is carefully honed to its final dimension (length) and it sets the bearings' preload. Never use this component as a "tool".

Make a set of removal/installation extractors/drivers, perhaps actuated by a length of 3/4" all-thread rod.

Banish all "dead blow", lead or brass "persuaders" from your workplace while working on the spindle bearings.

Go slow, take rest breaks, make no mistakes. You only get one chance to get it right and to still maintain the 40 millionths tolerance these machines are capable of.

"Mark always recommended Alpine Bearing in the Boston area, I purchased the replacements for the Elgin headstock I re-did. They were able to convert the New Departure numbers and shipped the correct goods."

As with a lot of esoterica, there are specialists.

A bearing house in the Los Angeles area seems to have every Monarch bearing in stock, and at decent prices, too.

Good to know that there is a similar supplier for Hardinge bearings.

What I did for the rear bearing on the HC Chucker was, I obtained an electric heating element from a restaurant supply friend and rigged it through the headstock to heat it up. Then installed the rear bearing. Leaving the bearing installed for some time, the bearing heated up. then the spindle slid though easily.
I also used lint free wipes obtained from a hydraulics supply.
Sure, use anything that I print, if you find it usefull.

Thank guys. This machine is no longer the high tolerance machine it was. It is used for small run stuff and was an orphan fron a shop next door. Does a good job but needs tlc. Discused it with the plant manager and we will plan to do it when our new CNC Teach Lathe arives in two weeks. Even with this new machine there will be work for this machine. The new Machine will replace a VERY tired #3 J&L turet lathe. The Boss won't replace machine until its dead! (Same with employes ) Real old school. Thanks again

Hi I know this is an old thread but it definitely fits my issue. A customer of mine has a DV-59 that chatters no matter what he does with it. I went to his shop and put my own grind on the tool and it did the same thing. This machine doesn't howl or make any noise as to indicate bad spindle bearings. But I put an indicator on the front of the spindle nose and the Y axis has about .008 run out this is obviously not acceptable. Is this possibly a bearing preload issue? I don't want to take anything apart unless it is necessary other than having the tube out of it which I already do.
So I thought I would turn to the experts.
Thanks
JF

Put the dial gage on the *front* of the spindle and push/pull to find the total *axial* play. It should be zero. If not the preload is worn out of the bearings.

machineshaft said:

Hi I know this is an old thread but it definitely fits my issue. A customer of mine has a DV-59 that chatters no matter what he does with it. I went to his shop and put my own grind on the tool and it did the same thing. This machine doesn't howl or make any noise as to indicate bad spindle bearings. But I put an indicator on the front of the spindle nose and the Y axis has about .008 run out this is obviously not acceptable. Is this possibly a bearing preload issue? I don't want to take anything apart unless it is necessary other than having the tube out of it which I already do.
So I thought I would turn to the experts.
Thanks
JF

Click to expand...

Preload is not adjustable on a Hardinge lathe. The bearing maker sets the preload to the spindle maker's specified amount during the bearing grinding operations. The spindle maker (Hardinge) simply makes the bearing retaining parts to the required dimensions to maintain the bearing maker's assembly specifications. The exact spindle bearing design can be either two angular contact spindle bearings separated by exactly matching spacers for the inner and outer races or a three bearing design where the pair of angular contact bearings are clamped together and a radial ball bearing is located at the left end of the spindle.

Axial or radial runout on the spindle nose caused by loose bearings means it is time for new bearings unless someone has messed with the bearing retaining parts and left them loose..

Larry

thanks for the good input guys was very helpful
JF