Proper bearings for a mill spindle rebuild?

Skf has a bearing specific tool for both mounting (hot & manual) and dismounting.
As I'm rebuilding an ancient Atrump B6FC with a burned bearing and a gorilla as the previous owner (its actually worse they were students) the temperature differential cited was for a set of 7210 BECBJ

Richard,
the spacers on this beast had previously been abused with a hammer and the likes, after carefully filing & lapping down the high spots to what was previously there ( a slight outer to inner spacer difference for preload) I'm left with the mystery of how much torque to apply to the nut. I read in a thread here recently in the old days you'd wrap a string around the spindle with a fish scale to see the force required to turn it?

We picked up a Southwest Industries Trak DPMSX5 which is basically the same beast was thinking of measuring that? The Atrump is a no loose situation as it cost next to nothing originally has a good M400 Centroid and we dont hold much in the way of precision tolerance round here (largely big hydraulic manifolds for custom servo hydraulics).

Richard King said:

I used to go to the SKF site to find the temp...sucks getting old.. I must have been 220 and not 120. Thanks Tyrone for catching that.

I just looked and SKF says 110 C or 230 F...

.

skf bearing heater manual - Bing video

www.bing.com

skf bearing heater manual - Search Videos

www.bing.com

Click to expand...

No problem Rich.

Regards Tyrone.

We got the induction heater after a near serious accident involving the whale oil drum.
I was heating a biggish bearing ( 10” OD ) outside in the yard to avoid the smell filling the shop. We had the 50 gallon drum sat on two angle irons with a gas ring underneath sat directly on the concrete. We’d been heating the bearing for an hour or so and I decided to get the bearing out. I said to my helper “ I’ll go and get the hook and the gauntlets Ted, I’ll be back in a minute “. I left Ted standing by the drum.

I’d got about 12 yards away when I heard a really loud bang. When I looked back over my shoulder all I could see was a cloud of vapour. Then my helper emerged out of the fog. He‘d lost his spectacles and could barely see. Bits of concrete were falling out of the sky.

What had happened was the concrete had exploded and blown the drum over, oil was all over the place, and the bearing was lying on the ground ! Luckily the drum had fallen away from my helper and not towards him.

We’d used this method lots of times with no major problems but after that a SKF bearing heater was purchased and the whale oil consigned to history.

Be careful if you’re still using the old method.

Regards Tyrone.

IceCzar said:

Skf has a bearing specific tool for both mounting (hot & manual) and dismounting.
As I'm rebuilding an ancient Atrump B6FC with a burned bearing and a gorilla as the previous owner (its actually worse they were students) the temperature differential cited was for a set of 7210 BECBJ

Richard,
the spacers on this beast had previously been abused with a hammer and the likes, after carefully filing & lapping down the high spots to what was previously there ( a slight outer to inner spacer difference for preload) I'm left with the mystery of how much torque to apply to the nut. I read in a thread here recently in the old days you'd wrap a string around the spindle with a fish scale to see the force required to turn it?

We picked up a Southwest Industries Trak DPMSX5 which is basically the same beast was thinking of measuring that? The Atrump is a no loose situation as it cost next to nothing originally has a good M400 Centroid and we dont hold much in the way of precision tolerance round here (largely big hydraulic manifolds for custom servo hydraulics).

Click to expand...

“ DSG “ used the string wrapped around the chuck and spring balance method of loading the spindle bearings. Obviously the spindle had to be taken out of gear.

“ Richards “ also used it for setting the spindle bearings on their Hor Bores. You wound the string/electrical wire around the facing slide and walked backwards carefully pulling on the balance.

Of course you need to know 1) The dia of the chuck/facing slide. 2) The spring balance readings that were required.

Regards Tyrone.

Just for the heck of it set the spacers on a granite surface plate and check the height. If you have some bluing blue up the ends just to be sure the burrs are gone. I have never had any luck using a scale and a string. I do what my Dad taught me when I was an apprentice. 50 years ago. I indicate the push and pull or back and forth motion of the shaft. I used a .001 last word back then and now I use a Best Test .0005" . I tighten the spanner nut with a notched lock washer under it until it's hand tight or tight with a hook spanner, then put the indicator on the shaft and pry on a gear inside the head (lathe) or push with the tailstock screw or a 2 x 4 depending on the application. I look for the "lost motion" that is the slack of the indicator.

As you can bent castings with enough pressure. I say push on it and release, if it bends the indicator will say go past a number with pressure and when you release it the indicator moved back and stops. Lets say it goes to +.003 and when released it goes to +.001, Then you push or pry the opposite direction and it moves to - .005 and when pressure is off it goes to - .002". That means it is loose .003". Then I slowly tighten the spanner nut until I get no "lost motion" . Then I look at the notched washer and find the next notch that will line up from where ii is now. You usually only need to tighten the nut less then a 1/8 of an inch. Then I bend the washer into that notch.
Other people may have better luck with the spring and string or an amp-meter or some other method. The way I do it has always worked for me and I have never had any issues. Be sure to use a hook or pin spanner if it has holes. I hate seeing a person use a punch or chisel...If I had an employee use a chisel...You would here "You're FIRED" LOL

PS: If you can only use a punch use a piece of cold rolled steel that will not break off a piece of brass or hardened steel if you use one of those. Also use a 1/2" Bigger on big parts and not a 1/4" as those thing ones bend and bonce. I am also a big believer in using a BFH compared to a small one that just bounces. LOL

Richard King said:

Just for the heck of it set the spacers on a granite surface plate and check the height. If you have some bluing blue up the ends just to be sure the burrs are gone. I have never had any luck using a scale and a string. I do what my Dad taught me when I was an apprentice. 50 years ago. I indicate the push and pull or back and forth motion of the shaft. I used a .001 last word back then and now I use a Best Test .0005" . I tighten the spanner nut with a notched lock washer under it until it's hand tight or tight with a hook spanner, then put the indicator on the shaft and pry on a gear inside the head (lathe) or push with the tailstock screw or a 2 x 4 depending on the application. I look for the "lost motion" that is the slack of the indicator.

As you can bent castings with enough pressure. I say push on it and release, if it bends the indicator will say go past a number with pressure and when you release it the indicator moved back and stops. Lets say it goes to +.003 and when released it goes to +.001, Then you push or pry the opposite direction and it moves to - .005 and when pressure is off it goes to - .002". That means it is loose .003". Then I slowly tighten the spanner nut until I get no "lost motion" . Then I look at the notched washer and find the next notch that will line up from where ii is now. You usually only need to tighten the nut less then a 1/8 of an inch. Then I bend the washer into that notch.

Other people may have better luck with the spring and string or an amp-meter or some other method. The way I do it has always worked for me and I have never had any issues. Be sure to use a hook or pin spanner if it has holes. I hate seeing a person use a punch or chisel...If I had an employee use a chisel...You would here "You're FIRED" LOL

Click to expand...

My “ go to “ method was also a 4ft pry bar and a DTI.
It was interesting to compare the “ string and spring balance “ with the “ Pry bar and DTI”.

Regards Tyrone.

In this case there is no lockwasher, rather two set screws with brass inserts
the cross through tapping of course was never properly deburred and I've been having quite a job fixing threads with my files. (The nose piece threading into the quill internally was worse and someone was after that to remove it with a chisel, luckily a replacement part for that was available. The Spacers however were not, and rather than make a set we determined to use the lands left. It has been trued and measured on the closest thing we have to an inspection block)

This machine sees fewer hours in a year than one in a job shop does in a week. Part of the problem (neglect and improper warm ups from extended inactivity) the rest is age, design and the former owner.

For the readers, if you have a set screws and brass thread lock like IceCzar has. Remove the top set screw and then loosen the bottom set screw about a 1/4 turn and then use a pin punch that fits into the hex wrench socket an tap it with a hammer... This will move or loosen the brass insert. In those terrible chewed up threads I used lapping compound. I always made the nut turn easy. If it turns hard you don't know if it's tight or stuck. Yeah I would replace the chiseled nuts or make new ones because if you don't the next repairmen will think you chiseled it..lol.

psionik said:

I was looking at angular contact bearings and the prices go from affordable to insane, so I was wondering why so much difference.

Click to expand...

Google - Counterfeiting of Super Precision Angular Contact Bearings to find one of the reasons. Best to buy only from a reputable dealer in your area who is an Authorized Dealer for the brand you're after.

13engines said:

Google - Counterfeiting of Super Precision Angular Contact Bearings to find one of the reasons. Best to buy only from a reputable dealer in your area who is an Authorized Dealer for the brand you're after.

Click to expand...

Most bearing manufactures now a QR code on the bearing box and have apps that you can scan the bearing box on your phone and it will tell you it is a legit bearing. Pretty slick. Of course new old stock type bearings on ebay would not have this.

I agree, unless it is a low budget personal project getting bearings off ebay is too risky.

Richard King said:

Mottrhe (odd name, lol)

Are you a new machine builder? Thanks for your input :-)

Click to expand...

Name is a bad adaptation of motor head I made many years ago, as I like building cars etc (yes I understand the engine vs motor in this particular crowd..)

I run a spindle rebuilding co.

I'll chuck this out there as a down hill opposite direction from the OP's aspirations.
Hardinge speed lathe bought from scrap yard some years back. Sat outside a few weeks. Spindle bearings, not so good.
Just for kicks, I cobbed in 6000 series "electric motor" bearings 'fer now' and to see how bad it could be.
Quite surprised at how well they work, for what the machine is used for *. Very surprised at the rigidity (in cut) of the assembly all things considered, it does what I need it to do.

*Second OP chamfering, short length turing, facing, etc.

psionik said:

Why must my ideas be novel or practical?

I'm only trying to have fun.

I've demanded nothing. Participate as you wish.

I know I have weaknesses. That's why I sought tips from others (though not to give up before trying)

My nature? Why are you making it personal?

"Tomfoolery?" Who are you to judge what's worth my time?

I am going to put this thread down now and walk away, for everyone's sake.

smh.

Click to expand...

Aww, come on guy... I was very much looking forward to following you on this journey (not sarcasm).

We could use some more aggressively enthusiastic members around here.

It might help if you gave some more info about the machine you are building, not just the spindle... and definitely share some pictures.

A lot of these guys are super knowledgeable but you sort of need a thick skin to work with them or they'll just run you off...don't be that guy!

If the parameters are "money is no object" and they believe you are actually serious about this project - you will end up with a lot more guidance as the project progresses.

Btw, Where can I find your published works? You can PM the info to me if you don't want it made public here. I am a fellow book nerd.

psionik said:

Hey folks, I appreciate the warnings and they have been heard.

Though I may not be an expert I am the kind of guy that achieves by increasing the mass of my effort until it outweighs the weight of my incompetence. It's been my recipe for success for decades and every time I've heard someone tell me I can't do it I become that much more determined. It's never a big deal for me to fail; I've always had the attitude that failures are steps on the road to success. I take what everyone else considers a doubt to actually be a dare. So now I've been double dog dared to try.

Every achievement I've made in life, though it may seem at the time to be worthless, has been added to my vocabulary of understanding which I use to leverage success later. I am not calculating whether my test machine "is worth it" but rather what I will gain in understanding along the way.

I heard the same stories when I first got into the idea of grinding my own telescope mirrors. Telescope mirrors are not micron accuracy, but angstrom. I was told I was in over my head, etc etc and yet as far as I can tell at star parties, my mirrors beat anything commercially available and even run head to head with some boutique names.

Same story when I started school, published my first book, rebuilt my first transmission, got my first patent. Naysayers are a dime a dozen.

I'm a polymath and an intellectual omnivore. I eat books for breakfast, so I suppose my next task is to devour some of your recommendations and get to work.

I have nothing but time and money now, and my shop is my playground. You don't retire at 46 in this economy without getting some things right along the way. If I have to blow a big pile of money on granite surface plates, ovens, more machine tools and tooling just to say I can do it, I will. Roar.

Click to expand...

You don't know a research scientist in central Arkansas by any chance, do you?

I would think vertical or horizontal makes a difference.
Bill D

I suspect that some banned members are back with new names. Some missed their behavior as they needed the entertainment.