Surface grider, Angular contact bearings

Let me start by saying I am new to surface grinding.

I just bought a Parker Majestic No.2 grinder off Craigslist. I finally got it powered up and there was a little noise "Whrr" from the bearings, not bad but not silent. zero movement in the shaft, and it grinds nice.

The seller told me he had just cleaned and grease the bearings so to confirm I pulled apart the spindle.

When I pulled apart the spindle the bearings were nicely greased, it has four Barden 107H angular contact bearings, but I kept thinking they look like they were install backwards

Main question, How can you tell what is the "front" of an angular contact bearing or the correct orientation of the bearing to apply force? Is there a marking? Does the stamping identifying it
"Made in USA barden 107H" mean that is the larger end of the taper on the outer race? That is what it looks like but I am not sure.


I drew up two images showing the Parker spindle, this one is how I believe they should go.


This one is how I think it was.



Any help would be appreciated.


Jon

Do you have a maintenance manual? That would help a lot. Can you contact the seller and see if he had a book? Grinder spindles bearings are usually not installed the way a milling spindle is where you have a lot of trust, but the grinder spindle has less trust and more Concentricity.
The spring on the way it was installed is pressing the outside race the wrong direction. The drawing you have on top looks correct to me too. The way I have seen them set up is the front set is back to back or outside race thin end facing opposite way and out.

This holds the spindle in place from moving in and out and in many super precision spindles the rear set are face to back or thin OD of both face backward. This keeps the spindle moving in a perfect circle. So the front set is for the trust and rear is for Concentricity. Hopefully another member has a drawing of the spindle and can be more help. Also the grease is important and the amount used. I suggest Mobil # 32 or 28 Red Horse Aviation grease and a 30% fill. I also clean the bearings in clean mineral spirits several times in coffee cans replacing the mineral spirits until when you rinse them the liquid doesn't change color.

The Precision bearings many times have a line scribed on the OD to show the way they are installed. If not look for a small * TIR(total indicator run out mark) on the bearings and they are usually set facing the same way. Many time grinder spindles have a stamped 0 (zero) on the spindle itself that shows the TIR of the spindle. Those marks on the bearing are installed the opposite side of the TIR of the spindle to off-set the run out's. I looked online and I see a company called Penn says they rebuild Parker M spindles. Maybe you can call them and ask. Good Luck, Rich

PS: Page 10 of following catalog shows the lines I talked about.
http://www.schaeffler.com/remotemed...alogue_2/downloads_25/machine_tools_us_en.pdf

I have taken some photos of my harig spindle taken part. It's not the same configuration by any means, but should give an idea of the thinking behind it.

Beneath the wheel and guard, the spindle in held inlace by a front ring with 4 screws. With them removed the shaft and bearings can be removed out the front. The ring pressesthe front bearing against a shoulder inside the spindle hosing, immobilizing it's outer race solely. There is a stationary tube that bridges the two outer races, with a wavy spring washer the set the pre-load. Both the stationary tube and the spindle hosing press against the back side of the first bearings outer race. The rear bearing is held by a retaining nut that drives it's inner race into the step in the shaft directly. The saft is connected to the motor by a LoveJoy type cog connector to the motor, care must be taken to the orientation when reinstall the shaft to the motor.



Should the shaft be pressed in, the force goes directly into the first bearing then out to the shoulder of the spindle housing.
Should it be pulled out, the far end of the shaft pulls on the retaining nut and directs the force through; the rear bearing, spring washers, stationary tube, front bearing outer race, then to the front ring.

When heat from the bearings radiates into shaft and to account for slight changes bearing width, the rear bearing will slid deeper into the hosing and the spring washers will maintain bearing load.

This is an excerpt form the harig manual after the Hardinge Merger. The main difference is the addition of a second front bearing. Note:Both of the front bearings face forward. The older models like my own use a single front baring and got away with using simple angular contact bearings. Having bearings face to face or directly parred like the lower section of a bridgeport spindle, necessitates Duplex bearings.
Duplex bearings are 30-80% more expensive for the same size and runout. The difference is that when loaded, a duplex bearing will have sides of the races perfectly flush. Where a basic angular contact bearing will likely have either the inner or outer race protrude .001 or more.

When I looked to replace the bearings in my machine, I first phoned the Harig representative at Hardinge and was quoted nearly $500 CAD to get them to my door. Instead I took basic measurement form the out side, scaled an image from the manual, then made an educated guess as to the bearing code. I didn't want to take a part the spindle with out the new bearings in hand, as removing bearings often destroys them. I got 7204CYP4 and 7205CYP4 bearings made by Nachi in Japan. They fit just the old US made ones, and I saved $200.

Jon, it looks to me like the way you have suggested would be more correct than it was as received.

Charles

Oops sorry Alex, I looked at the wrong post....thanks.

My two posts above are strictly discussing the Harig design. For P M machine I don't want speak beyond my knowledge. My opinion favours the first you illustrated as well as the one below. But you should entertain the idea that it may be like the DoAll grinder were the adjacent bearings are toe to toe, not in line.

http://www.gmn.de/upload/30_Spindles/Zeichnungen/Spindeln_Typenreihen_TSA.gif

http://www.benchtest.com/images/angular_contact.jpg

Benchtest.Com - Workshop - DoAll D624-8 Surface Grinder
GMN Grinding spindles / Milling spindles / Motor spindles

Ps. Get your self the manual, it saves us the guessing.
http://www.amazon.com/Parker-Majestic-Surface-Grinder-Manual/dp/B00OVJECB4

When mounted as drawing number two I do not see how the spindle even worked.
The spring moves the assembly back and unloads the front set, now running on the part of the race you never want to touch.
Key here is the back set floats and moves in the housing. The front set is fixed the back moves in/out all day long as needed.
When mounted this way, it is maybe easier if you just view both ends as single bearings.
Double facing sets like this act the same as a single bearing, just stiffer and averaging each others errors.
"H" preloaded seem strange to me..... but if the spring is big enough? (somewhere in the 200-300lb range)
Only problem with a "H" in this mounting is enough spring pressure to get them tight and they run a bit hotter.
Generally small SGs like "L" bearings.

Spindles like this care a lot about finish on the back bore.
The back single or pair must be free to move in it's OD bore as temp changes take place on the spindle shaft.\
A standard check in the Harig manual is to place a DTI in front and pull the wheel and bearing towards you.
The spring is supposed to pull it back into the races when you let go.
Bob

Wow, Thanks for the responses! I learned a lot.

Richard, I have the "Parts Manual" and it does have some diagrams but it does not get into the spindle bearings, mostly about the lifting screw, x axis tape etc... The seller provided all paper work he had, including the original Parker Majestic quote. for a No.2 or No.2z. There was way more then 30% fill of grease in the bearings. More like 90%.

Thank you for the PDF I will take a look for any markings like it showed. This would help settle my mind.


Alex, You harig spindle is completely different. How do you like the Nachi bearings? The Bardens are like $230 each, but I can find Nachi bearings for $29 each new old stock.

The Spindeln_Typenreihen_TSA.PDF is almost exactly mine, looks like I have confirm the bearing orientation and do it like that.

The link about spindle-types, Mine is a Direct motorized spindle, air cooled.


Thanks CBlair,


CarbideBob, I am not sure how its working either but,.. my drawing doesn't show this, but, don't some angular contact bearing have slight ball bearing characteristics. Similar to this drawing I have seen better drawings that show the balls captured in small grove, not only held by the race. Maybe I am just confused on that.

Does the H in 107H mean H pre-load? The spring is not putting anywhere near 200-300lbs of force, maybe only 30-40lbs.



Thanks Everyone for all the information.

On a surface grinder you need bearings to be Abec 7 or higher. Here is my receipt. I wouldn't trust a $30 bearing in an angle grinder. Also you need 15 degree contact not the 45.

jmanatee said:

Does the H in 107H mean H pre-load? .

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Not when the "H" is in that location. Where it is, straight after the bearing bore code of 07. It just means normal contruction. The cage is inner ring mounted. Preload comes much latter in the full part number after the arrangment. DU, DT, DF, BD etc.

Your spindle will only run in your first example drawing. The springs are applying preload to the outer ring. The other way is just arse about face.

Easy way to tell what the face or the back is. Look at the outer ring. The face will have a noticbly smaller land, the back will have a wider land.

Regards Phil.

Thank you machtool,

I miss spoke earlier, the pre load is more then 30-40lbs I remembered last night I had the weight of the Spindle Nose helping to compress the spring so maybe 70-90lbs of pre load, total guess.


I am assuming because these bearings are installed backwards they are probably trashed. I will clean them grease them and install them correctly and test it.

So I am searching for new bearings but like most things, my wife will need a lot of convincing for me to spend $1k on bearings.

The Barden 107H bearing is a 64mm 32mm 14mm 15* bearing I am not sure how to know the precision or abec level or if they did that then. It looks like the 107H is the old part number and has been replaced by 7007C ??? (??? = something something something)

I think what I need is a B7007C.T.P4.UL or B7007C.T.P4S.UL does this look correct?


Another thing a lot of bearings are rated to crazy spindle speeds up to 19k+ rpm etc..
My spindle is one speed 3500rpm does that matter in the choice of bearings?

Also what grease would be required for these RPMs?



Again thanks everyone for all the help.

Give these guys a call. I buy my bearings from these guys.
Bearings Inc. - Bearings Online: Roller, Cylindrical, Spherical, Contact, Angular & A1 bearings,bearing, miniature bearings, instrument bearing, instrument bearings, precision bearings, precision bearing, ball bearings, ball bearing, spindle bearing, spindle bearings, aircraft bearing, aircraft bearings, machine tool bearings
micro sometimes buys tool cribs of bearings and can sell them for 1/2 the price of new. I would tell them "No Chinese made bearings" to be safe. Rich

jmanatee said:

The Barden 107H bearing is a 64mm 32mm 14mm 15* bearing I am not sure how to know the precision or abec level or if they did that then. It looks like the 107H is the old part number and has been replaced by 7007C ???

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I hope there's a few typo's in there. Barden 107 or ISO 7007. That's a 62 x 35 x 14mm bearing. OD x ID x Thickness. The metric / ISO system is really good once you get past 20mm ID bore. The 07 in 107H or 7007. Just multiply that by 5mm, you have the I.D nominal bore. 7 x 5 = 35mm I.D. OD's just very by series, 70, 71, 72 etc.

jmanatee said:

Another thing a lot of bearings are rated to crazy spindle speeds up to 19k+ rpm etc..

Click to expand...

Don't get sucked into rated speeds out of a catalogue Those ratings are Max, for ONE bearings, under seating preload, with oil lubrication. Start stacking them together, Correction factor for grease lube. Its not uncommon to come up with a factor of 20% - 25%, on a quad set, running in grease. Yours would be on the higher side, being spring preloaded.

jmanatee said:

Also what grease would be required for these RPMs?

Click to expand...

In all your hunting through bearing catalogues, Have you come across something called the speed mean, or Factor Dn. Your actually very slow at Dn 169,750. Its not exactly high speed by a long margin. You can use anything from Red Mobile 28. I'd stick Kluber NBU 15 in it, only because that's one of the 3 spindle greases I keep .

Update, I pulled the spindle and turned the bearings around. I didn't take the time to repack them because I was anxious to see if they would squeal.

Hooked it back up and its almost silent. I can still hear the wrr of the motor but almost zero bearing noise. There is still some this machine is not silent, so I will now pull it and clean the bearing and grease with Kluber NBU 15.

After that I am going to run it this way for a bit and see how it does.

Thanks you everyone for all the help

Jon

machtool said:

I hope there's a few typo's in there. Barden 107 or ISO 7007. That's a 62 x 35 x 14mm bearing. OD x ID x Thickness. The metric / ISO system is really good once you get past 20mm ID bore. The 07 in 107H or 7007. Just multiply that by 5mm, you have the I.D nominal bore. 7 x 5 = 35mm I.D. OD's just very by series, 70, 71, 72 etc.

Click to expand...

I dont know what I was doing when I type the sizes out... Long day looking at bearing numbers. You are correct the bearing is 62mm x 35mm x 14mm, I am not sure if I can edit my original post.

machtool said:

Don't get sucked into rated speeds out of a catalogue Those ratings are Max, for ONE bearings, under seating preload, with oil lubrication. Start stacking them together, Correction factor for grease lube. Its not uncommon to come up with a factor of 20% - 25%, on a quad set, running in grease. Yours would be on the higher side, being spring preloaded.


In all your hunting through bearing catalogues, Have you come across something called the speed mean, or Factor Dn. Your actually very slow at Dn 169,750. Its not exactly high speed by a long margin. You can use anything from Red Mobile 28. I'd stick Kluber NBU 15 in it, only because that's one of the 3 spindle greases I keep .

Click to expand...

Ok great and you would stick with 30% fill?

Kluber recommends 15% pack. It's good grease...but so is the Mobil and cheaper. I eyeball it...

Rich

Richard King said:

Kluber recommends 15% pack. It's good grease...but so is the Mobil and cheaper. I eyeball it...

Rich

Click to expand...

Doesnt one of the bearing suffixes tell you how much fill the bearing is supposed to have? I know I have seen a bearing part number chart that shows that.

Charles

Grease overfill leads to heat buildup (churning) which will then kill the bearing. A bearing's first choice would be oil lube, but if lubricant can leak away and can't be replenished, grease is the second choice to at least make sure SOME stays there. At lower speeds heat isn't as much an issue and IIRC for this grinder application it's not running anywhere near its speed capability so shouldn't be so critical, but there's no point in giving it more than necessary.

Charles I have never heard of that. I took a Bearing class at SKF years ago and they are the ones who told me 30% and always have had luck with that using the Mobil #32 grease. I rebuilt a double disc grinder a few years ago and the owner wanted to use Kluger. I checked the Kluber website and it said 15%. I added a bit more and the bearings got hot, so I learned my lesson. I ended up running them a while, shutting them off to cool off, run again shut off, etc. The grease eventually worked it's way out and ran at a normal temp. I don't remember the exact temp, but I think it was around 100 F using a laser temp gun. My Dad used to say if you lay your hand on the housing and it is hot, but you can hold you hand on it, your good. Here is what SKF says. Running-in of grease lubricated bearings
Rich

Richard sent you an email, you will see it soon.

Charles