1. D-Lab 2: Spindle
March 17th 2008

2. Project Update

3. Gantt Chart

4. Spindle

5. Shaft

6. Turning Threads

7. Fitting the Bearings
Angular contact bearings lightly press fit to the shaft

8. Spindle Interior
Shaft with the preloaded angular contact bearings and the rear roller bearing

9. Exterior Components
The exterior consists of the headstock, end cap and housing

10. Creation of the Housing
Starting with a solid 3in rod of aluminum

11. Spindle Exterior
The finished product

12. Lathe Error Sources

13. Final HTM
Output:

14. Spindle Error Sources
Bearing errors (radial play, ball size, race profile, etc.)
Machining errors:
Concentricity of shaft features
Concentricity of housing features
Clearance fits
Uneven deformation due to interference fits, preload, etc.
Thermal gradients
Errors in chuck registration

15. Spindle Error Test

16. Bearing Calcs Front bearing Rear bearing Reaction force: 400 lbs
Desired life: 5000 hours
Desired speed: 4000 RPM
C10 = 4250 lbs
Select A/C bearing set with dynamic load rating = 6560 lbs
Rear bearing
Reaction force: 200 lbs
C10 = 2125 lbs
Select Conrad bearing with dynamic load rating = 3210 lbs

17. Shaft-Bearing-Housing Fits
From Barden literature for A/C spindle bearings
Bearing-housing fit
Normal accuracy, low to high speeds, moderate temperature = (nominal) clearance
Bearing-shaft fit
Inner ring clamped – very low runout, high radial rigidity = (nominal) interference

18. Tool Holder Joint Stiffness