Straight Shank Collet Chucks & Extensions
Straight shank ER collet chuck extensions add reach: the straight shank goes in your holder and the ER collet holds the tool. 11 mini-nut extensions (ER8 to ER25) take a mini nut, for a small nose diameter in tight spaces, and 16 standard extensions take ER11 to ER40 collets with a hex or slotted nut.
All ER straight shank extensions feature:
- Collet pocket runout (T.I.R.) 0.0001"
- All surfaces precision ground
- PowerCOAT nut included
Extension length should not exceed a 4:1 ratio of length to diameter. For example, a 1/2" shank should not extend more than 2" in front of the holder. For shank sizes 1/8" (3 mm) or smaller, use our DNA (Dead Nuts Accurate) collets for best results.
| Shank | Mini-nut extensions | Standard extensions |
|---|---|---|
| 3/8" | ER8 (100 mm) | - |
| 1/2" | ER11, ER16, ER20 (140 mm) | ER11 (140 mm) |
| 5/8" | ER11 (140 mm) | ER11 (140 mm), ER16 (60 mm) |
| 3/4" | ER16, ER20 (140 mm), ER25 (100 mm) | ER16 (50, 100, 140 mm), ER20 (63.5 mm) |
| 1" | ER20, ER25 (140 mm) | ER20 (140 mm), ER25 (50 mm), ER32 (50, 140 mm), ER40 (50 mm) |
| 1-1/4" | - | ER32 (60 mm) |
| 16 mm | - | ER11 (140 mm) |
| 20 mm | ER20 (180 mm) | ER32 (50, 100 mm) |
Lengths are shank lengths.
Collets: ER collets by size, with DNA collets on the ER11, ER16, ER20 and ER32 pages. Shrink fit extensions: Shrink Fit Extensions.