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LHC
09-10-2014, 12:04 PM
I’ve been looking over the spindle from a lathe that I am trying to restore.

It appears to me that the installation of the bearing on the nose end of the spindle shaft is a “one way trip”. i.e. I see no way to remove this bearing without doing the unthinkable – i.e. yanking on the roller cage. Not that I am going to replace this bearing any time soon – the cost of it dwarfs what I paid for the machine and I will be trying it out as is once I get it all back together again. However, I can’t see any other way to remove the bearing. Am I missing something basic here?

Here’s a picture of the spindle and the bearing. This is an L00 nose, and the nose/shaft are all one piece. There is a dust seal/ring that is held captive on the assembly and the L00 locking ring cannot be removed either. Looks like the bearing would have to come off for both of these items to be removed.

Looking closely at the bottom of the bearing you can see the bottom of the cup race, and it’s flush with the shoulder on the shaft. No way to hook onto it.

Picture of spindle

http://i307.photobucket.com/albums/nn286/LHC_02/Raglan%20Lathe/Spindle%20Removal/a_zps1c51de19.jpg (http://s307.photobucket.com/user/LHC_02/media/Raglan%20Lathe/Spindle%20Removal/a_zps1c51de19.jpg.html)

Picture of bearing

http://i307.photobucket.com/albums/nn286/LHC_02/Raglan%20Lathe/Spindle%20Removal/SpindleB_zps55f5455b.jpg (http://s307.photobucket.com/user/LHC_02/media/Raglan%20Lathe/Spindle%20Removal/SpindleB_zps55f5455b.jpg.html)

Again, this is more of an academic study for me at the moment, but should the day come and I attempt to replace this bearing, I’ll need to have a plan of attack and I’m interested to learn how it’s done.


Thanks !

gundog
09-10-2014, 12:12 PM
I would use a bearing splitter I am not sure that is the right term but more than likely the bearing would be ruined, pressing on a new one would be easy enough. If it were mine I would change it, it looks pitted. You could probably source that bearing from a bearing house type business cheaper than from the manufacturer of the lathe. A press is a must it may even need to be torched off once the bearing cage is broken. This is the tool I am talking about. http://www.globalindustrial.com/p/motors/pullers-extractors/puller-splitters/gear-bearing-separator-4331-114-to-214-capacity-m-10x-24-hole-thread?infoParam.campaignId=T9F&gclid=Cj0KEQjw7b-gBRC45uLY_avSrdgBEiQAD3Olx0RMtjuUGx8vhI3YC01TzZKW_ VSCfgSnEG7K8_5yuZUaAthk8P8HAQ&gclsrc=aw.ds

Make sure you replace the bearing race as well.

If the bearing is stubborn once the bearing cage is off careful work with a torch to heat the remainder of the bearing will make it come loose with the splitter and press.
Mike

lakeside53
09-10-2014, 12:14 PM
Yes, you have to pull it of. A bearing separator will push down and lock behind it; then you just use a puller that pushes on the shaft end.

Mike Amick
09-10-2014, 12:56 PM
Not sure .. but .. you may find that piece next to the bearing is an oil slinger. and +1 on the
bearing separator.

Here is what my timken bearing looked like coming off. Just click on the mill head to get to it.

http://www.mikeamick.com/millrite_project/

I also didn't replace .. it works fine.

Mike A

john hobdeclipe
09-10-2014, 01:55 PM
Put it in a press with the locking ring supported. Press on the tail end of the shaft. I think the locking ring will push on the bearing inner race and any other spacers or slingers that are there. The ring is sturdy enough to hold the chuck in place, it should be sturdy enough to press the bearing off. I can't imagine that any lathe manufacturer would build a spindle in such a manner that you could not get these two parts off.

LHC
09-10-2014, 02:08 PM
Mike- that's a fantastic rebuild job you did there and the photo/documentation is top knotch as well. I'm going to study that more tonight.

Class 3 bearings for this lathe are 600 bucks apiece.....hence the "let's try out the ones that are in it first" approach - lol

Interesting information though - thanks for the tips. I sort of suspected it was "ruin it removing it" deal after doing a little googling and youtubing. The bearing near the chuck is in worse shape than the opposing one. In fact, the opposing one looks pristine. I think it's a result of chips and stuff getting into the bearing closest to the chuck. There's a couple of nasty looking black lines on the cup at the chuck end of the spindle too. Can't feel them with my finger, but they are there. Possibly due to a crash or two over the decades.

If I decide to replace, I guess there's no harm in doing just one the one (cup and cone) near the chuck first. I just have to figure out a way to get it for free - I do some electronics work for a local metal fabricator and they might just have to pay me with a bearing at some point - hehe.

Oil Slinger - that's a term I have not come across, but the bearings are lubricated with oil - there is an oil port on top of each in the headstock casting. I was surprised to find old grease in there too though, and man it was old.

Here's a picture of the rude looking cup that goes with the bearing shown above -
http://i307.photobucket.com/albums/nn286/LHC_02/Raglan%20Lathe/Spindle%20Removal/FrontBearingCup.jpg (http://s307.photobucket.com/user/LHC_02/media/Raglan%20Lathe/Spindle%20Removal/FrontBearingCup.jpg.html)

Doozer
09-10-2014, 03:04 PM
Heat the cone with a oxy-acetylene torch real fast. Then give the shaft an end tap on hard wood.
The bearing should fall off. Maybe could even reuse it. This is much better than mechanical methods.

-Doozer

CCWKen
09-10-2014, 08:48 PM
Use a bearing separator to remove the bearing from the shaft.
http://www.harborfreight.com/large-bearing-separator-3979.html

Feel behind the race and see if there's cutouts. The cutouts will allow you to either use a puller or tap them out from the opposite side (bore). If no cutouts, MIG weld a bead across the race face and let it cool. After it cools, it will practically fall out.

JoeLee
09-10-2014, 09:06 PM
Put it in a press with the locking ring supported. Press on the tail end of the shaft. I think the locking ring will push on the bearing inner race and any other spacers or slingers that are there. The ring is sturdy enough to hold the chuck in place, it should be sturdy enough to press the bearing off. I can't imagine that any lathe manufacturer would build a spindle in such a manner that you could not get these two parts off.I would be careful about that method because the lock ring is probably cast and it could crack.

JL.............

J Tiers
09-10-2014, 10:18 PM
If I had to remove the bearing, I would NEVER USE a bearing separator. That slinger is too close, and looks to be actually in the way.

If you have to remove it, you will be removing it only to replace it. No matter how you remove it, you probably won't want to re-use it, the force method would likely distort it anyway (and maybe the spindle too). So what happens to it is of no consequence.

I would take a dremel or similar tool, and grind a split in it with a narrow small wheel. When you get close to the spindle surface, it will probably crack the rest of the way on its own, due to the force-fit. It will then come off with minimal force.

The new one will assemble in the usual way with the cone heated somewhat, and the spindle cooled.

Don Young
09-10-2014, 10:34 PM
There are special collet type tools made to remove bearings like that. They are split to go around the bearing and have a collar to hold the halves together. They pull against all of the rollers and the rollers are kept tight against the cone by the collet. Very expensive and only fit one size bearing.

I doubt a bearing separator or splitter will pull it as there does not seem to be any sort of groove for it to get a purchase on. If it is not very tight it might come off by pulling against the retainer and rollers but I doubt it.

To replace the bearing, you can cut the retainer and rollers off and carefully groove the cone with a small cutoff wheel, then split the cone with a chisel. Doing this at an angle works best.

My suggestion would be to leave the bearing as is.

oldtiffie
09-10-2014, 10:40 PM
It is quite possible/probable that after the bearing has been pressed into the casting and onto the shaft that there will be compression on the lathe spindle and the casing bore that will have the possible effect of reducing the "class of fit" of the bearing when it is re-installed (existing) or installed (new).

I'd have adjusted the cone's free "end play" and rolling resistance and given the lathe spindle a trial run with no load and then under load - if its OK - leave it alone. If its a "bit iffy" its a "judgement call" that should not be taken lightly.

On the other hand "change for the sake of change" may not be as rewarding as you may have thought (hoped?).

A lot of work may take a lot of room, time, and money and if that were the case for me I'd be considering a replacement lathe - new or as near new as I could get and afford for the class of work that I wanted the lathe to do and when I needed it to do it.

LHC
09-10-2014, 10:46 PM
Guys - the shiny ring under the bearing in the picture above is not a slinger - it's the shield that presses into the headstock casting that keeps debris (somewhat) out of the bearing. In the picture it looks like it's parallel with the bearing bottom, but the thing is actually loose and just sitting where it is due to gravity. Same goes for the large L00 lock ring.

After some digging around on the Timken site I've learned a bunch more, but the removal of this is still a bit unclear. Add to that the conflicting replies on here and I'm still scratching my head. :)

Good info and lots to consider. I like the Dremel technique and in fact saw something similar on Youtube - BUT - the idea of that spinning disk so close to the irreplacable spindle gives me the willies. One wrong move, or cut too deep and I've damaged the spindle itself. Having never done something like this I'd be sweating bullets. On the other hand, the force method with the bearing separator, or some custom separator, if it has the potential to cause distortion of the spindle itself, well, that's not good either.

Timken specifies a lower temperature range for the precision class of bearings than the standard (automotive) class when heating/cooling to install. I'm not sure the thing would really "drop on" to the spindle as a result - for those of you that have done this before, what happens if the bearing slides down part way and then grabs the shaft? Do you have the thing at the ready under an arbor or hydraulic press and an arbor at the ready to force it the rest of the way should this happen?

Thanks again for all the input.

Lewis

Doozer
09-10-2014, 10:55 PM
.... Do you have the thing at the ready under an arbor or hydraulic press and an arbor at the ready to force it the rest of the way should this happen?

Lewis


Yes.

--Doozer

LHC
09-10-2014, 11:36 PM
Here's another thing that puzzles me - Being curious, I thought I would measure the diameter of the spindle to compare against the ID of the cone

The ID spec on this cone is 1.5000"

I took a 1-2" digital micrometer with a resolution to .00005" and calibrated it, and verified the calibration after I measured the spindle as close to the bearing as I could.

The spindle diameter measured 1.4965.....what's with that? And no, the bearing is not falling off when I tip it upside down !

Could the spindle be mostly ground slightly smaller than the ID of the cone along it's length to allow for easy (rapid) installation, with the area under the cone left at 1.5000 plus a bit?

GNM109
09-10-2014, 11:38 PM
Some Harley-Davidsons had a similar situation on the left main bearing and also the transmission main drive gear. Assuming that you would not reuse the bearing, you could remove the outer race by cutting it off with a Dremel tool and then Arc weld a nut on either side of the race. It could then be pulled off with a puller. I've done this several times on Harleys.

Perhaps you could at least reuse that bearing and perhaps replace only the outer one nearest the chuck.

My .02.

chipmaker4130
09-11-2014, 01:59 AM
. . .Could the spindle be mostly ground slightly smaller than the ID of the cone along it's length to allow for easy (rapid) installation, with the area under the cone left at 1.5000 plus a bit?

This is common. Also, you often don't need a torch, try a heat gun on the bearing. Cooling the shaft with damp rags during the process may help too.

J Tiers
09-11-2014, 08:52 AM
Yes, the bearing area above is likely made undersize so it doesn't cause trouble during installation. The difference is of no consequence in strength etc. Absolute amount undersize is not very important.

The answer to the cutting wheel issue is a question: Would you rather apply heavy force to the spindle, or be very careful with a small cutting disk? I know my preference.

And we are NOT talking about an angle grinder, or the like, not a 5" cutoff disk.... A Dremel or Foredom, with a small 1" disk is the best tool. You do not generally need to cut all the way, as it usually will split on its own when you get close.

And if you do touch the spindle with the disk, it doesn't cut fast enough to do more than put a small scar on the spindle and damage your ego.

As for installation.... WHO SAID ANYTHING ABOUT A TORCH? Fer gosh sakes, do NOT use a flipping TORCH on a bearing..... It's only a few hundred deg above annealing temp..... let alone the temp needed to draw the temper of the hard bearing.

A good heater is an old-fashioned light bulb. Won't get too hot, if you don't actually rest the bearing on the bulb. You really don't want to go much if any above 100C. The spindle needs to be cooled, though, to get the clearance. As cold as possible is good, if you can avoid getting dew and frost on it.

Tiffie.....

The tapered roller bearings are not as affected by shrink-on size changes as a ball bearing,the class is the roundness tolerance etc, since "clearance" has no meaning whatever to a tapered roller bearing. A slight change of diameter due to fit would just move the rollers and cup along the spindle a small amount.

Even ball bearings, if single row angular contact, are not as affected... but a double-row opposed A/C bearing with zero clearance or in-built preload would be. (Some Logan lathes use that type).

oldtiffie
09-11-2014, 10:03 AM
Your points are well made and well taken JT, but never the less I'd have determined that is was a" must do" job and not just a "nice to do" or "just in case" one as well. It seems from the OP's pics that he is at the stage where he can replace/re-instal the bearings, try for free-running and if OK end-load them to the manufacturers specs. and load test the set-up by cutting a reasonable amount of a spare bit of mild steel.

The bearings from what I can see from the pics are not too bad but physical examination may well prove otherwise.

So far as I am concerned the decisions are in the OP's domain and I will respect what ever he decides.

Add to that that I am not criticising him nor am I making any adverse comments.

I wish the OP well.

DR
09-11-2014, 10:36 AM
Why was the spindle taken out of the machine? Was there evidence of a bad bearing?

$600 for a new bearing? How much shopping have you done? I was quoted around $350 for a set of Hardinge spindle bearings so $600 seems a bit high for this single bearing.

Paul Alciatore
09-11-2014, 01:17 PM
I can understand your confusion. Many methods!

I would try the torch idea first. It seems to have the least potential for causing problems. And it may help loosen any corrosion or thread locking compound that may have been used. If that does not work then I like the bearing separator but you may need to find a good one (not HF or local auto parts places). I would save the Dremel idea for last.

JoeLee
09-11-2014, 02:24 PM
In my past experience with precision spindle bearings is that they are not a tight press fit, like a motor shaft bearing. Usually they are just a snug hand force fit. Reason being is that if the bearing fit was too tight you would more than likely loose the class of bearing tolerance due to the inner race expanding or deforming. Some may be sticky from dried oil but shouldn't be a nightmare to remove. I've done spindle bearing on grinders and lathes. I had one lathe spindle that gave me problems once. I packed the spindle in ice for a couple hours and when I removed it I quickly flashed the bearing with a propane torch and the bearing practically fell off.

JL...............

chipmaker4130
09-11-2014, 02:36 PM
. . .WHO SAID ANYTHING ABOUT A TORCH? Fer gosh sakes, do NOT use a flipping TORCH on a bearing..... It's only a few hundred deg above annealing temp..... let alone the temp needed to draw the temper of the hard bearing.

A good heater is an old-fashioned light bulb. . .

Doozer mentioned a torch in post #7, and the reference was made with regard to removal, not installation. A light bulb is useless for removal.

LHC
09-11-2014, 02:40 PM
Back again.

The spindle was taken out as I am in the middle of a complete tear down/cleanup and repair process. There was a back gear buried deep in the headstock that had a few teeth sheared off it as well and there's no way to get to it without removing the spindle. My plan has been, and still is, to poke the spindle back in as is and run it to see what sort of performance I can get out of it, but I am first going to search out someone that can actually physically look at the bearings and give me some advice as to whether I should plan on replacing it, or if it's good enough. I realize that can't be done from pictures and postings on a forum. I'm more interested at this stage in understanding the issues, problems, best practices if I have to replace the bearing(s).

On the cost - well, 600 bucks is on the cheap side based on a few places I have tried. The class 3 precision - the closest to the original precision grade that is not made anymore (information from Timken themselves) - is about 450 bucks for the cup, and 450 for the cone for each bearing. Surprisingly Amazon has them listed at 300 bucks each.

FWIW, the bearing part numbers are
Cup - Timken 16284B - Class 3
Cone - Timken 16150 - Class 3

Automotive (standard) grade bearings are quite a bit cheaper - about 120 for the cup and 40 for the cone.

Gents, this is all great information and advice - even if it is somewhat contradictory at times. The level of detail that some of you have provided is really appreciated.

I'm not a big fan of forcing things or wailing on them, and I have in fact spent a week of evenings building a jig to separate parts in a controlled fashion while I was taking this machine apart. I'm happy to say that other than dropping the saddle on the concrete floor, I have not had any incidents at all. And in that case, I had access to a guy with a mag particle inspection system and we checked it out and cleared it for any possible cracks etc.

A book on the Timken site on bearing maintenance has oodles of information on the removal and refitting of tapered roller bearings - even a calculation procedure to estimate the bore increase with temperature of the cone when heating to install it. At 1.5" ID, and a maximum of 150F temperature (for precision class) and 70F ambient, the bore of the cone will only increase by 7 tenths ! However, if one is to take the same formula and reverse for chilling the spindle, I can get another 1.5 thou with an isoproyl/dry ice bath. I have access to this stuff at a friend's place of work too if/when needed. The comment that was passed along that I will need to chill the spindle AND heat the cone, is quite obvious from these numbers.

Thanks again for all the help.

Lewis

LHC
09-11-2014, 04:08 PM
In my past experience with precision spindle bearings is that they are not a tight press fit, like a motor shaft bearing. Usually they are just a snug hand force fit. Reason being is that if the bearing fit was too tight you would more than likely loose the class of bearing tolerance due to the inner race expanding or deforming. Some may be sticky from dried oil but shouldn't be a nightmare to remove. I've done spindle bearing on grinders and lathes. I had one lathe spindle that gave me problems once. I packed the spindle in ice for a couple hours and when I removed it I quickly flashed the bearing with a propane torch and the bearing practically fell off.

JL...............

The temperature ranges specified for fitting precision bearings in the Timken literature would tend to support your comments. I re-calculated with the maximum and minimum temps specified and for a 1.5" shaft and ID of the cone, I would only get 7 tenths increase in the cone ID and 8 tenths decrease in the shaft diameter. I guess that's still a respectable 1.5 thou though.

Doozer
09-11-2014, 05:03 PM
I see you are proceeding with so much caution, it is giving me the frustrated shakes!
I have worked on a lot of stuff with a lot of different methods.
I have messed up a lot of stuff, but I have learned what not to do, and what works.
If it were my spindle, I would use the oxy acetylene torch. First burn off the cage
and get rid of the rollers. Then rapidly heat the cone on the spindle. You will probably
only need to start turning it straw color or blue, and the cone will fall off. Even if
you had to heat it near red, it would not hurt the spindle. Just because the cone
is pressed on the spindle, does not mean all that temperature will be transfered
to the spindle. To prove this point, think about burning hex nuts off a threaded shaft
and not hurting the shaft threads at all. If you have done it before, you can wash
away the nut and not hurt anything else. I am not saying to burn off the cone,
just heat it and expand it, and let it drop free.
As to the $400 bearings, if the bearings you have are really messed up, you can
pretty much assume that a set of $75 truck axle bearings will run better and be
more precise than what you have currently. I am all for doing things right. I can
assure you. But I am also all for putting things in their proper perspective. Maybe
you don't have the experience with heating things to separate them. I assume
you are here to gain knowledge of how to proceed with your situation.
So I ask one thing when taking all this in. Try to gauge the experience of the person
contributing each reply. It is easy to be partisan and ally with the thinking along
similar lines of yourself. But is that really what you seek? You can talk sports
if you wanted that. With that, I have submitted my proposed solution to your problem.
I can only assume you will come up with a collective middle ground solution to this
bearing replacement issue. But at the very least, take away that even though you have
a piece of precision equipment (lathe) that it may be OK to enlist more primitive
methods (fire) as long as they are applied with care, thought, and experience.

--Doozer

J Tiers
09-11-2014, 07:33 PM
Doozer mentioned a torch in post #7, and the reference was made with regard to removal, not installation. A light bulb is useless for removal.

Well, of course it is.... that's for installation, as seemed to be the topic at the time....

But I have never found heat to work well on removal... The parts are so interlocked that usually heat rapidly moves from the one you want to loosen to the one it is tight on, and the fit stays as tight as ever.....

I STILL am not good with the torch, just because if it is hot enough to get the bearing loose, it probably isn't really good for the spindle either.... But that depends on teh machine.....

I'd use a torch happily on some Atlas machine, when I would NOT on a better class one.

LHC
09-11-2014, 08:18 PM
I see you are proceeding with so much caution, it is giving me the frustrated shakes!

--Doozer

This gave me a good chuckle. For those that are old hands at this sort of stuff I certainly can understand the frustration when dealing with a glacial speed newcomer like me. However, like I said at the beginning - this process is mainly to educate me for the future, as I am not touching the bearing until I try it out in the reassembled machine - and that's going to be awhile still. However, if some as yet to be found local expert looks at the bearing and says don't bother even trying it, then I will refit sooner. I sort of doubt that the bearing is "full on trash" though. It seems to be reasonable considering it's age and the non-space-shuttle work I am going to employ it for.

At this point I think I have assembled all the options from both this thread and the Timken manual that I have, and as pointed out, I must decide, or come up with an approach - even if it's a hybrid of the approaches proposed. I tend to favor the approach that is minimal force/light handed first, then progressively work towards the heavier artillery no matter what the task, and this will be no different. It's served me well up to this point. I don't have an oxy fuel torch, and the acquaintances I have that do have them I would never let them near the spindle. I do have a small propane one for copper water pipes and I do have a nice Foredom setup as well. Access to a place locally with a thermostatically controlled heater and cooling chambers that are accurate to 1 degree are also free for the using for me as well. There's an arbor press there too. I think I can come up with much of the gear is what I am saying, but the "human expert" standing beside me probably won't exist.

Once again, thanks very much indeed for all the input here, it is very much appreciated.

Don Young
09-11-2014, 10:02 PM
I hesitate to say it, but if you were to split the cone with a cutoff wheel and accidentally cut a small groove in the spindle, only you and whoever took it apart next would ever know! It certainly would not effect the operation or life of the spindle in any way whatsoever.

Of course do fully understand why one would not want to do it.

lakeside53
09-11-2014, 10:14 PM
I know I said early in this thread.... but.... just use a bearing separator (also called a bearing splitter). No heat, no grinding, no cutting. I'd have that bearing off in less than a minute while waiting for my coffee to cool.

To put it back on - (assuming you don't have an induction heater) put a new bearing in smoking hot oil (care...), wait 20 minutes then drop it on the shaft. A convection oven is my second choice - 300F for 30+ minutes.

spkrman15
09-11-2014, 10:21 PM
I am going to assume you are replacing the bearing and have accepted the fact that you won't be able to re-use it. Here is how I would do it.

1. With the tools you have, I would cut it off. Cut it in multiple places on an angle. If you try to go straight across you will most likely hit the spindle shaft. The multiple cuts will each release some of the forces keeping the bearing on. I would not use the propane torch. It won't heat that amount of material up fast enough. Believe it or not I feel you will put more heat in the shaft that way.

2. to install the bearings I would put the shaft in my freezer overnight. I would then heat up the bearings using this https://www.facebook.com/TIRServices/photos/pb.120291008102018.-2207520000.1410487047./442999945831121/?type=3&theater

That is how I do it. :)

Make sure your shaft is clean and free of burs. When the bearing goes on go fast. Wear welding gloves and put it on. Make sure it is where you want it to sit.

BTW I would use a torch to remove it. I have gotten good at heating bearings to remove them. The trick is to run the torch hot. It puts heat in the bearing fast, expanding quicker and then coming off sooner, giving it less time to transfer heat to the shaft :)

Good luck :)

Rob :)

RichR
09-11-2014, 11:36 PM
Hi LHC

... as I am not touching the bearing until I try it out in the reassembled machine ...
Considering the price, verifying the condition of the bearing before making a decision is a good idea. I will suggest you clean the bearing well and oil it. Then
assemble the bare spindle with only the bearings into the headstock. Adjust the preload and slowly rotate the spindle by hand to see whether it has any
rough spots or moves smoothly. Then give it a few spins by hand and see if it sounds alright. If all is good so far, I would take a short piece of 2x2 wood
and saw off the corners to form a tapered cone, screw a shaft into the end, and chuck it up in a variable speed drill. Push the cone into the hole in the
spindle and run it up to speed. If all seems normal, keep the bearing. If it doesn't seem right, you'll know you need to replace it before you've assembled
the whole machine.

DR
09-12-2014, 05:10 AM
Back again.

The spindle was taken out as I am in the middle of a complete tear down/cleanup and repair process. There was a back gear buried deep in the headstock that had a few teeth sheared off it as well and there's no way to get to it without removing the spindle. My plan has been, and still is, to poke the spindle back in as is and run it to see what sort of performance I can get out of it, but I am first going to search out someone that can actually physically look at the bearings and give me some advice as to whether I should plan on replacing it, or if it's good enough. I realize that can't be done from pictures and postings on a forum. I'm more interested at this stage in understanding the issues, problems, best practices if I have to replace the bearing(s).

.................................................. .................................................. .................................................. ...............................................

Lewis


Is a new back gear even available? If so, I bet that makes the bearings look cheap in comparison.

My assumption is any lathe beaten up enough to break a back gear might have so many other problems it doesn't warrant investment in new spindle bearings.

J Tiers
09-12-2014, 08:14 AM
Is a new back gear even available? If so, I bet that makes the bearings look cheap in comparison.

My assumption is any lathe beaten up enough to break a back gear might have so many other problems it doesn't warrant investment in new spindle bearings.

You are my kinda guy! I get great deals when you turn down machines!

A back gear can be broken for a number of reasons. Some might mean that there are other worse problems due to extreme abuse, but more likely in many machines, the back gear broke before anything else.

And, gears are not that hard to make, especially if not heat treated, or if you do not intend to do the full heat treating routine (which, admittedly might be better to do if it was done in the original).

I've been slowly repairing and re-scraping a machine where the back gears were essentially stripped off both the pinion and the bull gear. You'd think that would be grounds for scrapping the remaining broken pile of cast iron shards, but in fact with that machine it's a known problem, and extensive back gear damage is commonly seen. It's one reason I got the machine for about 5 cents on the dollar versus typical used price.

LHC
09-12-2014, 08:26 AM
Is a new back gear even available? If so, I bet that makes the bearings look cheap in comparison.

My assumption is any lathe beaten up enough to break a back gear might have so many other problems it doesn't warrant investment in new spindle bearings.

I was thinking the same thing some time ago, but was surprised to find everything else is in good shape. I know the history of the machine quite well. I got it from a local research type place (government outfit) that did one offs and never any production. They bought the machine new, and the original manual and factory inspection sheet was even still in the files there when I got it. It had sat unused for probably 10-20 years in the corner of a heated and air conditioned shop, and other than the roof leaking on it at some point, it had a comfortable stay there. The roof leak caused some rust in places but much of it cleaned up with Evaporust. The beds are a bit stained but they don't appear to be worn much - I have not measured them yet.

The back gear business is a bit amusing as I could almost visualize what happened - and J Tiers comment is right on the money that it was the first thing broken. When taking the lathe apart I came across all the teeth – sitting in a little pile on a shelf in the headstock casting – covered in nothing but dust. Obviously, some fool jammed it into low gear while running, or tried to start it in low gear with the main gear still engaged. Realizing the error of his ways, he probably then turned the machine off, pushed it into the corner, and that’s where it sat for 10-20 years before I happened along at the right time. They were trying to make room for a new machine and this old machine was in the way. I asked the director of the department (a neighbor of mine who I was in there visiting) if they would sell it to me. He said “give me 100 bucks to make it legal with the accounting department and get that damned thing out of here”, I happily dragged it home and up the driveway where my wife stood shocked at the sight of this “filthy old machine” coming into the garage…..

The company is long gone that made the lathe, but they tend to be popular in the UK and every now and then a back gear pops up over there on ebay. However, I have come up with a cutter, and some durabar stock and oilite bushings, and as soon as I can find someone with a dividing head that can help me, I am going to attempt to make one or get one made. The bull gear is fine, I have to cut off the pinion and make a replacement for that and press it into the larger gear. But that’s another project for a future thread here :)

LHC
09-12-2014, 08:50 AM
Hi LHC

Considering the price, verifying the condition of the bearing before making a decision is a good idea. I will suggest you clean the bearing well and oil it. Then
assemble the bare spindle with only the bearings into the headstock. Adjust the preload and slowly rotate the spindle by hand to see whether it has any
rough spots or moves smoothly. Then give it a few spins by hand and see if it sounds alright. If all is good so far, I would take a short piece of 2x2 wood
and saw off the corners to form a tapered cone, screw a shaft into the end, and chuck it up in a variable speed drill. Push the cone into the hole in the
spindle and run it up to speed. If all seems normal, keep the bearing. If it doesn't seem right, you'll know you need to replace it before you've assembled
the whole machine.

Hi Rich -
That's a good idea. Before I started taking the machine apart, I did put a dial indicator on the nose of the spindle and grabbed it and yanked it a bit back and forth to see if there was any movement. Slowly rotating the spindle by hand the needle of the dial indicator did not budge a bit - it was rock solid. I guess that's a good sign, but I know it's not a full check. I wish now I knew more at the time and I could have done a few more checks I guess.

It's a good thing I did reduce the machine to component parts though - there was old oxidized oil and chips jammed in it everywhere - even places I could not for the life of me figure out how they got there. It finally dawned on me one day why it was in such a state - they were using compressed air to blow the ways off and "clean the machine". When I had the motor off and ran it up on a VFD (it's a 3phase one) there was a bit of squeeling - so I tore the motor down - and out came a few little curls of brass and swarf !

DR
09-12-2014, 03:02 PM
I was thinking the same thing some time ago, but was surprised to find everything else is in good shape. I know the history of the machine quite well. I got it from a local research type place (government outfit) that did one offs and never any production. They bought the machine new, and the original manual and factory inspection sheet was even still in the files there when I got it. It had sat unused for probably 10-20 years in the corner of a heated and air conditioned shop, and other than the roof leaking on it at some point, it had a comfortable stay there. The roof leak caused some rust in places but much of it cleaned up with Evaporust. The beds are a bit stained but they don't appear to be worn much - I have not measured them yet.

The back gear business is a bit amusing as I could almost visualize what happened - and J Tiers comment is right on the money that it was the first thing broken. When taking the lathe apart I came across all the teeth – sitting in a little pile on a shelf in the headstock casting – covered in nothing but dust. Obviously, some fool jammed it into low gear while running, or tried to start it in low gear with the main gear still engaged. Realizing the error of his ways, he probably then turned the machine off, pushed it into the corner, and that’s where it sat for 10-20 years before I happened along at the right time. They were trying to make room for a new machine and this old machine was in the way. I asked the director of the department (a neighbor of mine who I was in there visiting) if they would sell it to me. He said “give me 100 bucks to make it legal with the accounting department and get that damned thing out of here”, I happily dragged it home and up the driveway where my wife stood shocked at the sight of this “filthy old machine” coming into the garage…..

The company is long gone that made the lathe, but they tend to be popular in the UK and every now and then a back gear pops up over there on ebay. However, I have come up with a cutter, and some durabar stock and oilite bushings, and as soon as I can find someone with a dividing head that can help me, I am going to attempt to make one or get one made. The bull gear is fine, I have to cut off the pinion and make a replacement for that and press it into the larger gear. But that’s another project for a future thread here :)


Okay, based on this info, the assumption would be the spindle bearing is in good shape too.

I thought this was a gear head lathe, maybe not since you say the gear teeth were collecting dust. You rarely really need a back gear, why not just put it back together and use it?

chipmaker4130
09-12-2014, 03:37 PM
. . . You rarely really need a back gear. . .

Unless you're like me. I do all my threading in backgear. Couldn't live without it.

Doozer
09-12-2014, 04:59 PM
.... I do all my threading in backgear. Couldn't live without it.

NEWBEE!!!;)


--Doozer

krutch
09-17-2014, 01:45 PM
I have not read all these answers so my method may have been offered.
I have a bearing similar in position to remove from a long shaft from time to time. I cut the roller separator, remove the rollers, and then grab the bearing body to pull. With the rollers out of the way there is a lip which can be used to pull the body with.
Yes, the bearing is destroyed but one shouldn't reuse it anyway. Especially if the bearing is not readily accessed without such an extensive teardown of an assembly.

LHC
09-17-2014, 02:01 PM
I have not read all these answers so my method may have been offered.
I have a bearing similar in position to remove from a long shaft from time to time. I cut the roller separator, remove the rollers, and then grab the bearing body to pull. With the rollers out of the way there is a lip which can be used to pull the body with.
Yes, the bearing is destroyed but one shouldn't reuse it anyway. Especially if the bearing is not readily accessed without such an extensive teardown of an assembly.

Krutch -
Thanks for the input - That technique specifically did not come up I don't think. Most people agree that you should cut the cage, remove the rollers but then either cut the cone off with a dremel/foredom, or pull it off.

The fact that these are precision class bearings means they might not be as tight on the shaft as usual. The theory that tighter = more deformation and throwing off the precision class of the bearing.

Thanks for the input.

Lewis

schor
09-17-2014, 03:54 PM
I use back gears mostly for reaming and power tapping.


Unless you're like me. I do all my threading in backgear. Couldn't live without it.