Should I replace my lathe spindle bearings with angular contact bearings?

Alexander McGilton

Alexander McGilton

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As the title suggests I intend to change the spindle bearings in my 1440 lathe. Mainly because I'm spoiled by the mas turn and colchester lathe at work, surface finish and parallelism are at a different league from my home lathe. So I spent some time and did some research on the size of bearings needed. The grizzly equivalent uses the bearings listed below and I would for quoting purposes for myself assume that theses are the same, I will of course take the machine apart to confirm bearing sizes. Finding high precision bearings in tapered roller bearings is a challenge, online distributes frequently display on their web site class 0 or class K, bearings in the appropriate size having 10-20 microns of runout. Usable for say a counter shaft used for power transition, though hardly satisfactory for a lathe. It is also about the amount of free play I have in my spindle bearings, so it is suggesting that the manufacturer very well could have used these bearings.

So what are my options, ISO 492 Class 4 tapered roller bearings are hard to find listed let alone get a hold of, though equivalent Od and Id angular contact bearings are available from multiple manufacturers. The lost thickness can be made up by ground shims or modifying the head stock spindle retaining system. I would obviously need to take apart the head stock to see how best this be done, the shoulders of the bearings don't exactly match. The load limitations of these bearings is near equivalent. I'm just in the speculation phase of this.

Is it worth changing the spindle bearings to my lathe? Does the accuracy of the machine other sliding component take full advantage of the ABEC- 7 bearings.? This is the machine that I learned how to scrape dove tail ways, so the compound and cross slide are glass smooth with out wiggle. Scraping the bed ways would be on my short list, if successful I would then have a tool room lathe minus the ridged castings.

(The listed bearing dimensions are not confirmed to fit any lathe.)
30210
Dimensions - d (inside diameter) 50mm
Dimensions - D (outside diameter) 90mm
Dimensions - B (width) 21.75mm
$68.92 EACH

30212
Dimensions - d (inside diameter) 60mm
Dimensions - D (outside diameter) 110mm
Dimensions - B (width) 23.75mm



7212 CDGA/P4A
Dimensions - d (inside diameter) 60mm
Dimensions - D (outside diameter) 110mm
Dimensions - B (width) 22mm
$495.95 EACH


7210 CDGA/P4A
Dimensions - d (inside diameter) 50mm
Dimensions - D (outside diameter) 90mm
Dimensions - B (width) 20mm
$362.97 EACH


https://www.timken.com/wp-content/u...ion-Tapered-Roller-Bearings-Brochure_5722.pdf
20200413_194918.jpg
Capture bearing spindle.JPG
Capture bearing spindle 2.JPG
 
the way i see things....

if your intention is to rebuild your machine from the ground up, including scraping the non-hardened surfaces,
then by all means, go for installing the angular contact bearings.

if not, use the machine within its limitations and be happy with how it performs, or spend a lot more money on a better lathe.
(not to impune import lathes, i own 2 1236's and a 2040)
 
Well, maybe I have a similar question. I don't like the bearings on the spindle of my Grizzly G0602, I would like to replace them. Would there be options for an "upgrade" for it?If I just apply a little pressure to my chuck while I have an indicator on the part, it move far too freely. Everything is tight and over tightening isn't a solution...not for very long anyway. S, while I'm at it, might as well improve the bearings. With the VFD and depending what belt config I use, I COULD run this lathe faster if I wanted, granted, I wouldn't go to 4,000 rpm, but more than it originally went to.
 
I have a similar but 13x40 lathe (Kent USA model KLS-1340a, and accept it just the way it is. The difference in mass will not allow the same performance as the heavier Colchester lathe.
 
What kind of bearings are in the lathe now? Are they tapered rollers? I would think tapered rollers would be more robust than the angular contact style for lathe work. Some time back I did a (cheap) deep groove ball bearing to tapered roller bearing upgrade on a mini lathe and it made a really big difference, seemed like a different lathe, and that was with SKF automotive grade bearings. I have since moved up to a Clausing 5914 with the "zero precision" (essentially ABEC7) roller bearings.

You might want to try replacing the stock bearings with a decent name brand. The quality of Chinese and/or "no name" bearings tends to be rather crappy. Some of the better Grizzly lathes will advertise the use of name brand bearings; lower end ones likely have the cheapest available bearings in them.
 
I’d say if you have the capability the time and the money what can it hurt. It would be an improvement almost guaranteed. Like said stock bearings in a Chinese lathe are probably low quality at best.
 
My only experience with swapping bearings comes from my G0704 spindle which I took from tapered roller bearings to angular contact bearings.

I found that I didn't have the precision and cleanliness in my home shop to easily do the retrofit. Afterwards, I found the performance to be slightly improved but nothing to write home about. I feel that the bearings are very touchy to the amount of preload I applied. An extra 1/10 of a turn on the jam nuts took me from free play to bearings that would get burning hot.
 
Thanks for the advise everyone. My experience with bearing replacement is limited to changing the bearings in my Harig grinder, and doing so made the machine quieter and eliminated wheel bounce. I was hoping that doing the same would have similar results on my lathe. Just pulled out my receipt on those bearings, and do I wish that I could get those 2013 prices again. I'm thinking now that a thousand plus dollar experiments may not be worth while as there is the chance that the bearing seats to the head stock and that on the spindle may not be co-axial. Even with perfectly concentric bearings, they can't hold zero run out if the ball cage assemblies are running in a crocked and constantly varying clearance in the race ways.

I vary well could get the name brand class 0 bearings at a fraction the price. It won't hurt the existing run out, and it may well be more accurate as these will be clean bearings. When I did the first head stock oil change from the original oil from china, I looked inside of the dry head stock casting and found a few grams of metallic dust at the bottom. Likely from the three month break in period of running the lathe, I had washed out the dust with clean oil though the damage was done, knowing that this very well could be in the existing bearings, clean bearing could only improve the machine. I know that seeing the before and after runnout would be very interesting for the number of readers here that have a variant of this machine.

1586963160025.png
 
Alexander McGilton said:
Thanks for the advise everyone. My experience with bearing replacement is limited to changing the bearings in my Harig grinder, and doing so made the machine quieter and eliminated wheel bounce. I was hoping that doing the same would have similar results on my lathe. Just pulled out my receipt on those bearings, and do I wish that I could get those 2013 prices again. I'm thinking now that a thousand plus dollar experiments may not be worth while as there is the chance that the bearing seats to the head stock and that on the spindle may not be co-axial. Even with perfectly concentric bearings, they can't hold zero run out if the ball cage assemblies are running in a crocked and constantly varying clearance in the race ways.

I vary well could get the name brand class 0 bearings at a fraction the price. It won't hurt the existing run out, and it may well be more accurate as these will be clean bearings. When I did the first head stock oil change from the original oil from china, I looked inside of the dry head stock casting and found a few grams of metallic dust at the bottom. Likely from the three month break in period of running the lathe, I had washed out the dust with clean oil though the damage was done, knowing that this very well could be in the existing bearings, clean bearing could only improve the machine. I know that seeing the before and after runnout would be very interesting for the number of readers here that have a variant of this machine.

View attachment 321063
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What website did you order from? @Alexander McGilton
 
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