ER COLLETS RUNOUT TOLERANCE
DIN ISO 15488 specifies the dimensions, materials and manufacturing requirements, and designation of collets (of form A or of form B) for tools with cylindrical shanks and their corresponding holders and nuts. All Haas ER collets are manufactured to meet or exceed these requirements.
- Form A: 6 to 8 slots.
- Form B: 12 to 16 slots.
This International Standard also specifies collet runout tolerances. These tolerances are checked as is shown in the figure below, by the introduction of a test mandrel into the collet. The diameter of the test mandrel is the nominal diameter of the collet.
For the test mandrel, the following specifications apply:
a) diameter tolerance: h6;
b) cylindricity: 0.002mm;
c) parallelism: 0.002mm;
d) roundness: 0.002mm;
e) surface without longitudinal marks;
f) maximum surface roughness Rz = 4µm;
g) surface hardness: (58 +3/-0) HRC.

d H7 Nominal Diameter | L | Runout Tolerance (a) | ||
| Above | Up To (Included) | Class 1 (b) | Class 2 | |
| 1 (Included) | 1.6 | 6 | 0.01 | 0.015 |
| 1.6 | 3 | 10 | ||
| 3 | 6 | 16 | ||
| 6 | 10 | 25 | ||
| 10 | 18 | 40 | 0.015 | 0.020 |
| 18 | 26 | 50 | ||
a. Normal Style collets are designed with runout tolerance class 2. If class 1 is required, it shall be given separately. b. In the case of applications where runout tolerances class 1 are required, the accuracy of the whole system (machine tool spindle, holder, collet and tool) shall be observed. | ||||
ER Collets
ER Straight-Bore Collets – Features
NOTE: These collets have a clamping range. Use the tightest collet available for any given tool shank, to provide the greatest tool-to-collet contact area while minimizing runout.
In the case of a Ø12.2 mm tool, do not use a Ø12–11 mm collet. Instead, use a Ø12.5–11.5 mm collet. For general cutting applications, a Ø13–12 mm collet is usable.
- Can be used to hold any type of round shank tool
- Flexibility to clamp a wide range of tool shanks
- High accuracy and concentricity
Clamping Range:
ER8: 0.5 – 5mm
0.012 – 0.187"
ER11: 0.5 – 8mm
0.043 – 0.281"
ER16: 0.5 – 10mm
0.043 – 0.375”
ER20: 0.5 – 12mm
0.043 – 0.5”
ER25: 1 – 16mm
0.086 – 0.625”
ER32: 2 – 20mm
0.086 – 0.781”
ER40: 2 – 26mm
0.086 – 1”
ER Sealed Collets – Features
NOTE: Collet bore is the exact diameter of the tool shank. These collets have no clamping range.
- Fits all Haas ER collet chuck holders
- Ensures 100% of through-tool/spindle coolant gets to the tip of the cutting tool
- Approved for high-pressure coolant to 1100 psi
- Short rear collet slots provide a mechanical seal, blocking coolant flow
- Mechanical seal design is superior to silicone/rubber sealed collets
- Do not require a coolant ring or special ER nut
- To seal properly, the entire tool shank must be in the collet and cover all slots
ER Tap Collets – Features
NOTE: Collet bore is the exact diameter of the tool shank. These collets have no clamping range.
- Collet bore is the exact tool diameter, with a square drive
- Special design locks flat-sided tap shanks into the collet
- Provides maximum concentricity, with positive driving force
- Reduces tapping clearance requirements
