G4016 lathe Spindle Bearing Help

[kNucKlbustr]

The 14x40 grizzly manual shows the forward bearing is a 7212D. The large one.

Ordered both rear and front bearings. Received forward MRC 7212D angular contact bearing.

Today, removed the spindle and discovered the front is a tapered roller bearing w/ the raceway pressed into the main casting.

Whats up w/ this ? Should I use the angular contact bearing ?

This one piece bearing is going to be a real PITA to install.

[lakeside53]

You should use the tapered roller bearing as originally installed. The cup is pretty much always separate and pressed into the casting.... not sure what your issue is. It can likely be removed with a threaded rod and suitable sized block, or tapped out carefully.

[kNucKlbustr]

The issue is, grizzly manual has 7212D as the part number. That is an angular contact bearing number, not a tapered bearing, which was in the lathe.

[lakeside53]

The problem is likely the manual... not in sync with your serial number. I've yet to see a modern general purpose 14 inch lathe with anything but a tapered roller in the front, but griz calls it out if this is the manual - http://cdn0.grizzly.com/manuals/g4016_m.pdf

Is the other end the 30210? what are the part numbers on the front tapered roller and cone?

If you do use the angular contact (assuming it fits) you need to be very careful which way you push on the bearing - very easy to push/pull the outer shell off and all the balls fly out. Don't ask me how I know!

You can pull bearings into head-stock housings with threaded rod, spacers, and whatever. I made such setups for the the last two I did.

Griz may have given you part number but what they don't tell you is the fit tolerance or the precision class. You may need to heat one or more parts to get them placed.

[kNucKlbustr]

Yes, the rear part number is a tapered roller, which was in the lathe. i purchased a Timken 30210, separate race w/ bearing.
Yes, item 128 in the manual is the one for the front. Thats a huge discrepancy for a misprint.
I havnt punched out the front original race yet to see if a part # is on it. Do this tomorrow.

This 7212D angular bearing will fit on the shaft and in the housing. And its a good possibility I cant return it - $180
My next ques would be, can it be used in place of ? It seems good for axial/thrust loads, however what about its tolerance.

[lakeside53]

Not so much a misprint - just not in sync with your machines serial number. Call Griz and see if they can shed light on this and whether they have a parts list specifically for your machine - just in case the spindle are other parts are slightly different etc.

Two tolerances to be concerned with - fit and accuracy. Hard to say what adjustments they made in manufacturing or buy selection of a bearing fit to suit their manufacturing. But first - original bearing and cone numbers for comparison.

[darryl]

This kind of raises a theoretical question- which bearing would you rather have, or which would be best- the tapered roller or the angular contact?

[mikey553]

I have a similar Grizzly lathe, just 12 x 36. The spindle rides on two preloaded tapered roller bearings. I do not remember the sizes, probably the same as yours. You have to remember that you want 2 things from your bearings - accuracy and rigidity. Speed capability may be important for high speed machines, but manual lathe with top speed of less than 2000 RPM does not require anything special.

Accurate bearings cost way more than regular ones, so you have to make a choice here. In regards to rigidity tapered roller bearing wins without any questions. If it would be me in your place, I would never replace it with the angular contact ball bearing.

[lakeside53]

This kind of raises a theoretical question- which bearing would you rather have, or which would be best- the tapered roller or the angular contact?

For a lathe of this size, tapered roller at each end.

[mikey553]

I am back home, so I checked my spindle bearings. I have 30212 in the front and 30211 in the back (60 and 55 mm spindle journals under the bearings). The funny part is I also have a spare tapered roller bearing of unknown manufacture, identical in size to 30212, and marked D7212E. I also know that old Russian bearing classification reserves 72xx series for tapered roller bearings. Maybe Chinese follow the same classification.
So I would not say Grizzly made a mistake in their manual. It depends on how you look at it. It may be a user's fault to blindly trust the Chinese manual.
Get a proper tapered roller bearing for the front and be done with it.

[RichR]

A quick Google search returns angular contact for 7212D and tapered roller for 7212E. The E is right above the D on the keyboard. I bet the
typist fat fingered the entry and the proof reader was reassigned to quality control.

[kNucKlbustr]

"user's fault to blindly trust the Chinese manual". yeah, they got me.
Lesson learned.

Original bearings :
Front taper roller - 30212/P5
Rear taper roller - 30210/P6
SG manufacture - Philippines

Grizzly does sell these bearings, according to website, NSK-Japan.

or Ill try to exchange bearings from where purchased, w/out incurring a 20% restocking fee.

The absurd part about all this, is, the lathe is for sell.

[lakeside53]

P5 could get pricey. What do they want for it?

[kNucKlbustr]

Update:
Returned the 30210 Timikin rear bearing also. It wasnt P rated. Plain jane truck bearing.

So now I have Czech bearings. Both P5 rated. Figured Skoda live centers Czech made, why not.
KLF-ZVL 30210AP5
KLF-ZVL 30212AP5

Unfortunately, sold the 20 ton press last month, go figure.