Collet system
ER11 collets: shank range, the 1/4 in limit, nuts and spindles
ER11 collets top out at 7 mm or 1/4 in in the catalogs checked, not 11 mm. Ranges by maker, nut threads, the spindles that use ER11 and kit sizes.
Also listed as ER-11, ER 11 collet
We may earn a commission if you buy through links on this page. How we make money
Short answer
An ER11 collet does not hold an 11 mm shank: the number names the collet size, and the ER11 catalogs checked stop at 7.0 mm, or 1/4 in. ER11 is the collet on many 65 mm and 52 mm spindles and on Carbide 3D's ER-11 Compact Router and Sienci's AutoSpin. Its standard nut thread is M14 x 0.75 and its mini nut M13 x 0.75, per PreciseBits.
What fits
- Collet setGenmitsu ER11 precision spring collet set, 7 or 15 pieces (1‑7 mm; 15‑piece adds 1/8 in and 1/4 in)Check price on Amazon
- Collet nutsGenmitsu ER11‑A collet clamping nuts, 4‑pack (M14 thread)Check price on Amazon
Key facts
- Type
- ER spring collet with an 8-degree setting angle, held in the spindle taper by a threaded nut[1][2]
- Standard
- ISO 15488, Collets with 8 degree setting angle for tool shanks: collets, nuts and fitting dimensions. It defines Form A (hard bore, h10 clamping range) and Form B (extended clamping range) collets.[1]Scope from the Standards Norway listing; we state no edition status.
- Collet dimensions
- D 11.5 mm, length 18 mm per Galaxy's drawing fields[3]Galaxy does not label D as the outside diameter.
- Shank range makers list
- Galaxy: 1.0-1.5 mm (ER11-015) to 6.5-7.0 mm (ER11-070), 15 sizes. Command Tool: 0.5-1.0 mm to 6.5-7.0 mm. Somma: 1-7 mm and 1/16-1/4 in.[3][4][5][2]The ER number names the collet size, not the shank: no ER11 catalog checked goes past 7.0 mm.
- Largest inch size listed
- 1/4 in (6.35 mm, calculated from 25.4 mm per inch): Command Tool's ER11-F250 clamps 0.231-0.250 in, and Somma tops out at 1/4 in[4][5][6]A 1/4 in shank is 0.35 mm larger than a 6 mm shank, so a 6 mm collet is not a 1/4 in collet.
- Range per collet
- PreciseBits: 0.020 in (0.5 mm) per ER11 collet. Somma: .019 in for ER8, ER11 and ER12.[7][5]This is the range of one collet, not the range of the whole series.
- Nut thread
- Hex, standard and UM nuts M14 x 0.75; mini nuts M13 x 0.75 (PreciseBits)[8]Check which nut your spindle takes before buying a spare.
- Spindles and routers that use it
- PwnCNC 65 mm motors; Onefinity Redline 65 mm 1.5 kW; Carbide 3D ER-11 Compact Router (1/4 in maximum cutter shank); Sienci AutoSpin (tooling up to 1/4 in); Genmitsu 300 W 52 mm spindle; Genmitsu 4040-PRO MAX 710 W compact router; Carbide 3D's earlier 65 mm VFD kit (V1); Genmitsu's V2 1.5 kW water-cooled spindle[9][10][11][12][13][14][15][16]Genmitsu's V2 kit page conflicts with itself on ratings; only the collet assignment is used here.
- Sizes supplied in kits
- PwnCNC ER11 kits: 1/16, 1/8 and 1/4 in. Onefinity Redline 65 mm: 1/4 and 1/8 in. Carbide 3D ER-11 Compact Router: 1/4 and 1/8 in. Carbide 3D V1 VFD kit: 1/4 in pre-installed. Somma sets: ER11-1SET (13 collets, 1-7 mm in 0.5 mm steps) and ER11-2SET (7 collets, 1/16-1/4 in in 1/32 in steps).[9][10][11][15][5]
- Runout claims (maker's)
- PreciseBits grades its ER collets by TIR at the collet face and 1 in down a calibration blank, for example Precision-Grade at 0.0004 in and 0.0008 in. REGO-FIX lists 10 um TIR for its ER standard line without a measuring point.[17][18][19]Maker claims, not measurements of ours. PreciseBits states that DIN6499 and ISO 15488 call for TIR read at the collet face and at least four times the clamping diameter out.
- Makers' clamping rules
- REGO-FIX: never clamp a shank larger than the collet's nominal size; use the next larger collet. Insert the tool over the full collet length where possible and never less than two-thirds of it. Carbide 3D: snap the collet into the nut before inserting the tool, because the nut's off-center lip traps the collet.[18][2]Carbide 3D warns a tool already in the collet can push it off-center and damage the spindle and collet.
- Not confirmed
- Not confirmed
Watch out for
- ER11 is not an 11 mm collet: the catalogs checked stop at 7.0 mm, or 1/4 in.
- 1/4 in is 6.35 mm, not 6 mm. Use an inch collet for an inch shank.
- ER11 standard and mini nuts use different threads (M14 x 0.75 and M13 x 0.75 per PreciseBits).
- Never run a collet or bit above its maker's stated speed or past its maker's shank range.
What fits
Product details below are the seller's own description unless a source is shown. Pick the variant named for each item.
Collet set
Genmitsu ER11 precision spring collet set, 7 or 15 pieces (1‑7 mm; 15‑piece adds 1/8 in and 1/4 in)Choose the 15-piece set, which adds 1/8 in and 1/4 in collets to the 1-7 mm metric sizes.
SainSmart sells it for machines with ER11 collets; it does not fit ER16 or ER20.
Collet nuts
Genmitsu ER11‑A collet clamping nuts, 4‑pack (M14 thread)Choose the 4-pack of ER11-A nuts (14 mm thread).
SainSmart gives a 14 mm thread without the pitch; ER11 standard nuts are M14 x 0.75 per PreciseBits. Check your spindle's nose thread first.
For larger shanks see ER16 and ER20. Spindles that use ER11 are mostly in the 65 mm and 52 mm records.
Questions
Does an ER11 collet hold an 11 mm bit?
No. Carbide 3D says the number after ER denotes the collet size, and the ER11 catalogs from Galaxy, Command Tool and Somma all stop at 7.0 mm, or 1/4 in.[2][3][4][5]
Can an ER11 collet hold a 1/2 in or 3/8 in shank?
Not in the catalogs checked: Command Tool's largest inch ER11 collet clamps 0.231-0.250 in, and Somma tops out at 1/4 in. For 1/2 in, ER20 catalogs list collets.[4][5][20]
What thread is an ER11 collet nut?
PreciseBits lists ER11 hex, standard and UM nuts at M14 x 0.75 and ER11 mini nuts at M13 x 0.75.[8]