Found that the spindle bearings in my 2J head are not 7207s, but simple 6207's. With medical expenses lately, my rebuild budget is under the microscope. As a result I've been looking at options for spindle bearings. The $50 Chinese ones I know are garbage. H&N sells the NTN ones, and I have confidence those are solid and are $300/pair. The other brands I have seen are RHP, NSK, and SKF, typically in the $180/pair range. Are any of them any good?
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Opinions of spindle bearing manufacturers?
- Thread starter Solarbell
- Start date
- Replies 22
- Views 8,333
HWElecRepair
Hot Rolled
- Joined
- Dec 9, 2013
- Location
- Fort Wayne, IN
We sell two brands, one is American made (Timken, sealed, $340) and the other is Japanese (NSK, unsealed, $315).
Jon
H&W Machine Repair
Jon
H&W Machine Repair
Genuine NSK, RHP and SKF are all plenty good enough for a Bridgeport spindle. For anything important you realy want to stick with good name brand bearings, the cheap chinese i tend to use only in my own manually cranked equipment - experiments were there more of less disposable, some large rubber sealed chinese bearings had a visible gap on the rubber seals, but still plenty good enough for what they are in. For my bridgeport spindle i went with nachi,
7207-CSUP4 Nachi Precision Ball Bearing Single - BearingBoys.co.uk
Are what i have in my mill currently, (they are only listing singles at the moment, but the matched pair was right around £100 when i got them about $160 dollars at the time) are they perfect, who knows, but there certainly brilliantly usable for the price point and cause no errors that i can detect, measure or quantify. Very hard to see how spending double on them would improve things other than wallet hole size! Have been using them for a couple of years now and there still good. If i damaged them - they failed tomorrow i would just go for the same again. Really need to upgrade the surface grinder to a set as thats currently running non precsion NSK deep groves as i was stuck and had them to hand. With grinding spindle errors from bearings are a lot more noticeable.
7207-CSUP4 Nachi Precision Ball Bearing Single - BearingBoys.co.uk
Are what i have in my mill currently, (they are only listing singles at the moment, but the matched pair was right around £100 when i got them about $160 dollars at the time) are they perfect, who knows, but there certainly brilliantly usable for the price point and cause no errors that i can detect, measure or quantify. Very hard to see how spending double on them would improve things other than wallet hole size! Have been using them for a couple of years now and there still good. If i damaged them - they failed tomorrow i would just go for the same again. Really need to upgrade the surface grinder to a set as thats currently running non precsion NSK deep groves as i was stuck and had them to hand. With grinding spindle errors from bearings are a lot more noticeable.
Conrad Hoffman
Diamond
- Joined
- May 10, 2009
- Location
- Canandaigua, NY, USA
I've used ORS bearings (Turkish) in a high speed spindle with good results and at low cost. See if they make something suitable for the BP.
Clive603
Titanium
- Joined
- Aug 2, 2008
- Location
- Sussex, England
The Nachi bearings linked by adamant claim to be ISO P4 tolerance. According to this Bearing Tolerances and Precision Levels | AST Bearings ISO P4 and ABEC 7 tolerances can, for all practical purposes, be considered interchangeable.
$64,000 question is how well they are built. Is paying double the price for a "better name" brand getting you things that translate into longer good performance life. For a commercial shop paying twice the price for twice, or even a bit under twice, the life makes sense 'cos you have to pay for machine downtime and re-build work. Or, more likely, get more work out of the machine before selling it on. For DIY actual £sd on bearings is it as rebuild time comes free. Not to mention that home shop guy isn't going to put industrial hours on either.
My spindle is doing fine 10 - 11 years on after fitting a precision pair of P4's as advised by Bearing Service UK. Don't recall brand but about £150.
With the improvements in production technology since the Bridgeport head was designed I'd be unsurprised to discover that tolerance spread and overall performance of a modern relatively inexpensive bearing of equivalent specification would be rather better than ABEC 7 back then.
Clive
$64,000 question is how well they are built. Is paying double the price for a "better name" brand getting you things that translate into longer good performance life. For a commercial shop paying twice the price for twice, or even a bit under twice, the life makes sense 'cos you have to pay for machine downtime and re-build work. Or, more likely, get more work out of the machine before selling it on. For DIY actual £sd on bearings is it as rebuild time comes free. Not to mention that home shop guy isn't going to put industrial hours on either.
My spindle is doing fine 10 - 11 years on after fitting a precision pair of P4's as advised by Bearing Service UK. Don't recall brand but about £150.
With the improvements in production technology since the Bridgeport head was designed I'd be unsurprised to discover that tolerance spread and overall performance of a modern relatively inexpensive bearing of equivalent specification would be rather better than ABEC 7 back then.
Clive
Peter from Holland
Diamond
- Joined
- Jan 15, 2005
- Location
- The Netherlands
The best bearings are not gonna help you if the tolerances on your shaft and housing aren not to specs
Measure these and you might be in for a shock
Roundness of the bore is off most of the time Also the angle of the shoulder
Peter
Measure these and you might be in for a shock
Roundness of the bore is off most of the time Also the angle of the shoulder
Peter
rons
Diamond
- Joined
- Mar 5, 2009
- Location
- California, USA
I wouldn't even use a Chinese brand bearing for my bicycle.
Thanks for the clarification Jon. I couldn't find the brands listed on your site and the last set of bearings I ordered arrived all NTN.
HWElecRepair
Hot Rolled
- Joined
- Dec 9, 2013
- Location
- Fort Wayne, IN
@Solarbell I believe that our normal bearings (motor, endcaps, etc) are NTN. As far as the spindle bearings, we sell those.
But TBH, I had to get our head rebuilders to tell me. The only bearings I deal with are in powerfeeds and thrust bearings in CNC's.
Jon
H&W Machine Repair
But TBH, I had to get our head rebuilders to tell me. The only bearings I deal with are in powerfeeds and thrust bearings in CNC's.
Jon
H&W Machine Repair
JRIowa
Diamond
- Joined
- May 27, 2003
- Location
- Marshalltown, Iowa, USA
I bet those processor bearings get expensive! Probably almost as bad as the memory fluid.
JR
JR
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Peter's spot-on. Also, if you score the bores up a little when installing races you'll lose whatever accuracy was inherent in that expensive bearing.
Matt_Maguire
Stainless
- Joined
- Oct 17, 2011
- Location
- West-Central Illinois, USA
It’s tough to say, there are 200 (light) series radial bearings AND 200 series “angular contact” radial bearings. Both types can have (letters & numbers) + “207” in the number but they are different...
Your (runout & side thrust) numbers would likely be fine with the nachi 7207-CSUP4 on a small turret mill. They would be the lightest angular contact type that you can get (meant for lowest thrust loads but are intended for thrust). Could go a long time though.
With “angular contact” the angle was designated from low to high thrust load by prefix or suffix (ranging from 15-40°CA). The nachi above is 15°.
Never changed a B’port but Moore jig bore spindles had a 30° angular contact angle. I suspect that it’s when they are ordered in matched pairs that the cost goes up exponentially (you designate “DB, DF or DT depending on how they are arraigned and they are also match marked for max eccentricity point).
Good luck,
Matt
Your (runout & side thrust) numbers would likely be fine with the nachi 7207-CSUP4 on a small turret mill. They would be the lightest angular contact type that you can get (meant for lowest thrust loads but are intended for thrust). Could go a long time though.
With “angular contact” the angle was designated from low to high thrust load by prefix or suffix (ranging from 15-40°CA). The nachi above is 15°.
Never changed a B’port but Moore jig bore spindles had a 30° angular contact angle. I suspect that it’s when they are ordered in matched pairs that the cost goes up exponentially (you designate “DB, DF or DT depending on how they are arraigned and they are also match marked for max eccentricity point).
Good luck,
Matt
johansen
Stainless
- Joined
- Aug 16, 2014
- Location
- silverdale wa
I had heard that some of the early bridgeports were regular 6207 conrad style bearings under the older part number of 207, but bridgeport ground the races to set the preload. Another story is that they were manufactured with the ball groove not centered in one of the races.
Assuming the two spacers are equal distance then a new set of matched 7207 bearings will only preload the bearings if the bearings were ground such that they will be preloaded in a back to back application.
If your spacers are not the same length then you can't just throw new bearings in there and hope it works.
if you just want to get the mill working yesterday, buy some 6207 ball bearings and make new spacers or verify the ones you have produce an appropriate amount of preload. i think you will find they are good enough for a bridgeport spindle for most tasks.
If your bearings show the new part number of 6207 then someone replaced them before you and they may have modified the spacers to get some preload.. or too much preload and that might be why they failed.
some interesting information here
Bridgeport Spindle Preload
Assuming the two spacers are equal distance then a new set of matched 7207 bearings will only preload the bearings if the bearings were ground such that they will be preloaded in a back to back application.
If your spacers are not the same length then you can't just throw new bearings in there and hope it works.
if you just want to get the mill working yesterday, buy some 6207 ball bearings and make new spacers or verify the ones you have produce an appropriate amount of preload. i think you will find they are good enough for a bridgeport spindle for most tasks.
If your bearings show the new part number of 6207 then someone replaced them before you and they may have modified the spacers to get some preload.. or too much preload and that might be why they failed.
some interesting information here
Bridgeport Spindle Preload
^ New spacers are cheaply available, equally its not hard to measure there length accurately enough to prove there either the same or different. Please this is a profesional forum, stop with the hocus pocus, the bearing arrangement angular contacts are ground for can all be found in there full part number. Checking housing bore and shaft quality is just basic measuring.
Yets get rid of the old wives tales about spindle bearings, there a off the shelf item and fitted by mear mortal humans in a good clean accurate bore after being mounted on a good undamaged spindle under clean but not exactly silicon circuit lithography grade clean room conditions will work just fine. The spacing and arrangement details yes they need to be correct but its all out there for the googling and are both machine and bearing dependant, but if you follow my link you will see there U in there designation, that means the faces are ground correctly and in relation to the ball ways to work in any mounting arrangement.
If i can change mine and improve things, im sure most other people can too! Work clean check things and its not exactly rocket science.
Yets get rid of the old wives tales about spindle bearings, there a off the shelf item and fitted by mear mortal humans in a good clean accurate bore after being mounted on a good undamaged spindle under clean but not exactly silicon circuit lithography grade clean room conditions will work just fine. The spacing and arrangement details yes they need to be correct but its all out there for the googling and are both machine and bearing dependant, but if you follow my link you will see there U in there designation, that means the faces are ground correctly and in relation to the ball ways to work in any mounting arrangement.
If i can change mine and improve things, im sure most other people can too! Work clean check things and its not exactly rocket science.
JRIowa
Diamond
- Joined
- May 27, 2003
- Location
- Marshalltown, Iowa, USA
Agreed!
Also, it's a Bridgeport, not a SIP jig mill. Almost all of the bearings you'd find for this are more accurate than the tooling that you're going to use. Heck, on a lot of older mills, there is way more slop in the quill than any bearing is going to have. Make some chips. I'm going to today.
JR
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
I gotta disagree with you and Adama on this - good practice with bearings (especially spindle) is good practice. Sure, it's just a Bridgeport, and if all it matters to you is getting it running again, throw some radial bearings in there and have at it.
But if spindle life, surface finish, and smoothness of operation matter, then you should approach this as with any other precision repair, and do it correctly.
JRIowa
Diamond
- Joined
- May 27, 2003
- Location
- Marshalltown, Iowa, USA
I don't disagree with that. My meaning is that most of the people on the board (me included) would never know the differnce between $300 bearing and $1,000 bearings. If they meet the specs, they meet the specs! Most any decent quality bearing set that is installed correctly and maintained will perform very well. There is so much hype out there about bearings that it's pathetic.
If there would really be that much difference, then you should go to the scateboard sites and buy some grade 11 bearings. Yep, go look, they're out there and there are idiots that buy them. I can't remember how to do the roll eyes this morning.
JR
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
I call them "scatboards", but then, I'm a jerk.
Sure, but remember that those bearings are made from Mil-Spect billet. I'm a little surprised nobody's released Tactical Bearings yet, those would be better still!
JRIowa
Diamond
- Joined
- May 27, 2003
- Location
- Marshalltown, Iowa, USA
I love it. That's right up there with "rocket surgery", for which I have the tee shirt.
I was out thinking over the last of the morning coffee about what we spent to do spindle PMs. It wasn't all bought at once and there were upgrades, but I'm guessing well over $100K to check CAT 40,50, DIN 68 whatever, and the big HSK. The masters were over $5K each. IIRC, the indicator head was $15K plus the software. Every spindle was "supposed" to be checked once a year or after a crash. The problem is that both guys that were schooled on the equipment and reading results have left and I don't think were replaced. Somebody will open one of the Pelican cases with a master in it and say "a new tool blank".
I like retirement a lot better than work.
JR
Hay im not saying don't do it properly, just use bearings that are the correct spec (not fucking deep groves please!!!), use spacers that are the right length (the same if you use universal angular contacts) and make sure the locating features are good, true and its clean, there's just no more too it. Bridgeport's are total loss lubrication on the spindle so you don't need no snazzy grease just work clean and make sure things are good before reassembly.
if you want to improve the results of a $150 spindle bearing set, spend the rest on some better cutters, switch that old TPGT face mill to a high shear SEHT or similar and you can really notice the difference unlike dropping twice as much for bearings.
One sad regrettable certainty if your using your mill to earn a crust chances are the bearings are going to want changing again in less than 2 decades!! Mill spindles see some nasty random loadings and unlike even trailer bearings theres not much in the system to take the edge off any shocks!
Am not a fan of sealed bearings on a Bridgeport, theres going to be oil dribbling down there for the quill and also the splined drive bit at the top of the spindle, thats going to cause you issues with sealed bearings at the bottom of the spindle.
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