ER25 collets
ER25 body dimensions, bore ranges, nut compatibility and product-specific clamping limits.
Tags: tooling, collets, toolholding
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Identity and dimensions
Techniks lists two ER25 nuts with different holder threads and tightening torques. Its 41925 slot nut is M32 × 1.5 at 77 ft·lbf. Its 23125 mini nut is M30 × 1.0 at 28 ft·lbf. Use the tightening torque for the matched holder and nut. EROGLU's ER25 430 E-13 collet separately lists a 12–13 mm shank range. Techniks catalog, printed pp. 62–63, EROGLU capacity and size table.
EROGLU identifies its ER25-B collets as DIN 6499 B / ISO 15488-B, order family 430 E.
REGO-FIX lists these body dimensions, distinct from holder nose diameters. REGO-FIX main catalog, printed p. 295
| Size | Outside diameter D1 | Overall length L | Catalog scope |
|---|---|---|---|
| ER16 | 17 mm | 27.5 mm; 26 mm variant | 9.5–10 mm bores include a shorter version; availability up to 27.5 mm depends on production |
| ER20 | 21 mm | 31.5 mm | Listed bores 1–13 mm |
| ER25 | 26 mm | 34 mm | Listed bores 1–17 mm |
| ER32 | 33 mm | 40 mm | Listed bores 2–22 mm |
ER25 and ER32 require different mating holders and nuts even at the same bore.
Bore size and collapse range
EROGLU specifies 0.5 mm collapse for its nominal 1–2 mm bores and 1 mm for nominal 3–16 mm bores. Thus its 430 E-13, nominally 13 mm, covers a 12–13 mm shank interval; its 2 mm size covers 1.5–2 mm. A family-wide capacity is the union of multiple collets, not the travel of one collet. EROGLU capacity and size table
Worked diameter example: 1/2 inch × 25.4 mm/inch = 12.700 mm. This falls within the stated 12–13 mm interval, with 13.000 − 12.700 = 0.300 mm diametral collapse. That arithmetic establishes nominal range membership; it does not establish assembled runout or cutting performance. A 13.2 mm shank exceeds that collet's 13 mm upper limit.
Catalog coverage differs: Techniks' metric ER25 set 04204MS contains fifteen collets, 2–16 mm in 1 mm steps, for a stated aggregate 1–16 mm shank range. That set's 16 mm maximum does not contradict REGO-FIX's separate 17 mm catalog entry. Techniks collets catalog, printed p. 46
Nuts, engagement and torque
Techniks lists these two ER25 nut products. The common collet designation does not make their holder threads interchangeable. Techniks catalog, printed pp. 62–63
| Product | Holder thread | Nut outside diameter | Listed torque |
|---|---|---|---|
| PowerCOAT slot nut 41925 | M32 × 1.5 | 42 mm | 77 ft·lbf |
| PowerCOAT mini nut 23125 | M30 × 1.0 | 35 mm | 28 ft·lbf |
REGO-FIX specifies 24 N·m for 1–3.5 mm and 104 N·m for 8–17 mm standard/ER-UP ER25 bores with ER/ERC nuts. Assembly requires nut-ring engagement before mounting and tool insertion of at least two-thirds collet length. REGO-FIX catalog, printed pp. 290, 293
Check clearance, coolant sealing and assembly speed for the specified nut and holder.
Accuracy and coverage limits
Techniks describes its ordinary metric ER collets as averaging 0.0002 inch TIR. Conversion gives 0.0002 × 25.4 = 0.00508 mm, or 5.08 µm. An average is not a guaranteed maximum, and a collet figure is not a measured spindle–holder–collet–tool assembly result. Techniks catalog, printed p. 46
This reference covers the named manufacturers' ordinary collets and selected nuts. It does not establish limits for sealed, tapping, extended-nose or pullout-resistant variants, nor installed equipment condition, tool overhang, cutting loads or a particular shop's acceptance criteria. Those properties remain specific to the actual assembly and application.
The EROGLU page and Techniks catalog provide no issue date in the cited material. REGO-FIX's cited main catalog carries document code 0362.00251 / ENG.1; no issue date was established. URL directory dates are not edition dates. The reviewed date records this article's research review, not publication of the source documents.