Manual lathe chuck: selection and replacement
The information required to select the chuck and backplate, on a new machine or when replacing an existing chuck.
A manual chuck, whether self-centering, independent or combination, is selected starting from the machine spindle. What has to be checked depends on whether a new machine is being equipped or an existing chuck is being replaced.
Case 1
New conventional machine
Equip the customer’s machine with a self-centering, independent or combination chuck.
Case 2
Replacing an existing competitor’s chuck
What to check when replacing a self-centering, independent or combination chuck.
What do we need to equip a new machine with a chuck?
Information required to select the chuck and backplate:
01
Spindle nose type. DIN 55026, DIN 55027, DIN 55029, ISO 702, etc.
02
Machine spindle taper or nose size. For example sizes 4, 5, 6, 8, 11, 15, 20.
03
Dimension B max. Key measurement for correctly identifying the spindle nose.
04
Required chuck type. Self-centering, independent or combination.
05
Chuck diameter. According to machine capacity and the workpiece to be machined.
06
Mounting type and required backplate. Type A / A2, Type C (bayonet) or Type D (Camlock).
07
Spindle photos or drawing. To confirm compatibility before preparing the quotation.
The most important measurement: B max
Of all the items above, dimension B max is the one that confirms exactly which spindle nose the machine has. It is measured on the spindle nose, at the position shown in the drawing.
Spindle nose and mounting types
The spindle nose type also determines how the chuck backplate is mounted:
| Type | Standard | Mounting |
|---|---|---|
| Type A / A2 | DIN 55026 / ISO 702-I | Mounting with bolts or threads |
| Type C | DIN 55027 / ISO 702-III | Bayonet ring mounting |
| Type D | DIN 55029 / ISO 702-II | Camlock mounting |
Conclusion
To select the correct chuck and backplate, identify the spindle nose and verify dimension B max.
Replacing an existing competitor’s chuck
What to check before replacing a self-centering, independent or combination chuck:
01
Check the chuck type. Self-centering, independent or combination.
02
Check the mounting type. Direct mounting or chuck + backplate.
03
Identify the spindle nose. Refer to the machine manual or check the taper. It is always best to verify the taper.
04
Check whether the customer will reuse the backplate. If the backplate is reused, its main dimensions must be measured.
If reusing the backplate, take these measurements
When the existing backplate stays on the machine, the new chuck has to match it. The required measurements are shown on the drawing and in the table:
| Symbol | Required measurement |
|---|---|
| G (h6) | Locating diameter |
| F | Locating recess depth |
| D | Through-bore diameter |
| K | Hole center distance, bolt circle diameter |
| M | Hole size |
| P | Number and type of threads or threaded holes |
| A | Overall backplate diameter |
For what the h6 on the locating diameter means, see fits.
Conclusion
To replace an existing chuck, first identify the chuck type, mounting type and spindle nose. If reusing the backplate, its dimensions are essential to ensure compatibility.
We are the official BISON representative in Greece. Send us the information above, together with photos of the spindle, and we will propose the right chuck and backplate.
