Re: [CAD_CAM_EDM_DRO] Re: re:leadscrew bearings / machine design

>
>
> Smoke,
>
> Actually, I don't think any "GOOD" lathe headstocks use Timken type
> bearings. I'm pretty sure they all use angular contact bearings.
>
> I've been told tapered roller bearings are not made in the precision
> necessary for high end lathe spindles. Not sure if that's true. But
> I don't recall ever seeing any in high precision applications.
>
> doug

Hi guys,
Again quoting from Koyo's precision bearing catalog.

I. opposed tapered roller bearing (front) double row cyl roller (rear)
max dn = 1.5 E 5
grease lube

II. double row cyl roller, , double row cyl (rear)
opposed angular cyl (front)
max dn = 3.0 E 5
grease lube

III. double row cyl roller (front) double row cyl roller (rear)
high-speed angular ball (front)
max dn = 4.0 E 5
grease lube

IV. angular contact ball (front) double cyl roller (rear)
angular contact ball (front)
dn = 6 e 5 grease lube
dn = 7.5 E 5 oil and air lube

V. high-speed angular ball two pair(front) double cyl roller (rear)
high-speed angular ball two pair (front)
dn = 5.5 E 5 grease lube
dn = 8.0 E 5 oil and air lube

VI. high-speed angular ball (pair with spacing) (front) ditto (rear)
dn = 6.0 E 5 grease lube
dn = 8.5 E 5 oil and air lube

Lathes are listed thru example V.
Machining centers II thru Vi.

VII and VIII cover grinding spindles and integral motor/spindles

You pays your money and takes your choice.

Dave

p.s. someone else will have to define dn. I must be skipping over it in the book. :-( Essentially it is (I think) surface speed of the assembly.