Buying task · Collets and collet nuts
Collets and collet nuts: ER11, ER16, ER20 and router collets
Which collet your CNC spindle or router takes: the ER system or the router's own collet, the shank range makers list, the nut thread, and how to read precision claims.
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Picks that fit
- Genmitsu 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
- Genmitsu ER20 router collet set, 14 pieces (1/16 in to 1/2 in)Check price on Amazon
- Genmitsu ER11‑A collet clamping nuts, 4‑pack (M14 thread)Check price on Amazon
Short answer
Buy collets in the system your spindle nose or router takes, in the exact shank sizes you run. ER11 tops out at 1/4 in in the catalogs we read, ER16 stops short of 1/2 in, and ER20 reaches 1/2 in; a router's own collet fits only the models its maker names. Then match the nut thread, because standard and mini ER nuts differ.
Picks that fitAll picks and how to choose
- Genmitsu 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
- Genmitsu ER20 router collet set, 14 pieces (1/16 in to 1/2 in)Check price on Amazon
- Genmitsu ER11‑A collet clamping nuts, 4‑pack (M14 thread)Check price on Amazon
What a collet does
A collet is the slotted sleeve that grips the bit's shank; the collet nut squeezes it shut. Spindles take ER collets, a standard family, and some routers do too. Other routers take a collet made for that router: Makita supplies the RT0701C with its 1/4 in collet, part 763637-1.[1] Getting the system, the size and the nut right is the whole job.
The decisions, in order
1. Your spindle nose or router model. The spindle or router decides the system, not the bit. Carbide 3D's precision collets fit only its Carbide Compact Router, not its ER-11 Compact Router or its VFD spindles.[2] Elaire lists its standard DeWalt router collets for the DW616, DW618 and DW621, not the DWP611, which it sends to its DWP series.[3]
2. The collet system. The number after ER names the collet size, not the shank.[4] An ER11 collet does not hold an 11 mm shank: the ER11 catalogs we read stop at 7.0 mm, about 1/4 in.[5] Galaxy lists ER16 collets from 1.0-1.5 mm up to 9.0-10.0 mm,[6] and its largest ER20 range is 12.0-13.0 mm.[7]
3. The shank sizes you run. Somma lists ER11 at 1/16-1/4 in and 1-7 mm, ER16 at 1/16-13/32 in and 1-10 mm, and ER20 at 1/16-1/2 in and 1-13 mm.[5] A 1/2 in (12.7 mm) shank is outside the ER16 ranges Galaxy, Command Tool and Somma publish.[8] A 1/4 in shank is 6.35 mm, so a 6 mm collet is the wrong size for it.[9] REGO-FIX advises against clamping a shank larger than the collet's nominal size and says to use the next larger collet instead.[10]
4. The nut thread. PreciseBits lists ER11 standard nuts at M14 x 0.75 and mini nuts at M13 x 0.75,[11] ER16 at M22 x 1.5 and M19 x 1.0,[11] and ER20 at M25 x 1.5 and M24 x 1.0.[11] A nut labeled only "ER20" does not tell you which spindle it fits. Router nuts are specific too: PreciseBits says its DeWalt 611 nut and wrench work only with PreciseBits collets, not the stock collet.[12] See ER collet nut threads and mini nuts.
5. The precision claim and how it is measured. Runout figures are makers' claims, and they depend on where they are measured. The runout guide shows how to read them.
How to choose
Pick the system first, then the set or single collet in your shank sizes. Four approved parts state their system.
Picks that fit4 products
Genmitsu ER11 set: choose the 15-piece variant (101-63-ER11) if you run inch bits, since it adds 1/8 and 1/4 in; the 7-piece set is metric only.
More on choosing
Genmitsu ER20 set: 14 collets, 1/16 to 1/2 in, ER20 noses only. Genmitsu ER11-A nuts: standard ER11 nuts with a 14 mm thread per SainSmart; check your spindle takes a standard, not mini, ER11 nut. Makita 763637-1: the 1/4 in collet cone for the RT0701C, not an ER collet. On Amazon, check that 'Ships from / Sold by' shows Amazon.com or the brand.
ER11 set with metric and inch sizes
Genmitsu ER11 precision spring collet set, 7 or 15 pieces (1‑7 mm; 15‑piece adds 1/8 in and 1/4 in)
ER20 set up to 1/2 in
Genmitsu ER20 router collet set, 14 pieces (1/16 in to 1/2 in)
Genmitsu ER11‑A collet clamping nuts, 4‑pack (M14 thread)
Makita 763637‑1 1/4 in collet cone for the RT0701C and RT0700C
Every page on collets
Guides
- ER11 vs ER16 vs ER20: which shanks each collet system holds
- ER11 collet sizes and the 1/4 inch limit
- ER20 collets for 1/2 inch bits
- ER collet nuts: standard vs mini threads
- Seating an ER collet and bit: what the makers say
- Collet runout claims: TIR, measuring points and what studies show
- Makita RT0701C and DeWalt DWP611 collets, nuts and wrenches
- Carbide 3D 65 mm VFD spindle: ER11 (V1) vs ER16 (V2)
- Carbide Compact Router vs ER-11 Compact Router: collets that fit
Finder
Collet systems
Key terms
Nominal collet size, clamping range, mini nut, nut thread, TIR, 1/4 in shank and 1/2 in shank.
Everything in this topic
Guides
- Collet runout claims: TIR, measuring points and what studies showHelps you compare collet runout claims only where the makers state how they measured them.
- ER collet nuts: standard vs mini threads, and finding yoursHelps you order the ER nut whose thread matches your spindle nose.
- ER11 collet sizes and the 1/4 inch limitShows which ER11 collet sizes exist, which one your bit needs and which nut thread your spindle takes.
- ER11 vs ER16 vs ER20: which shanks each collet system holdsTells you which ER system your spindle uses and which collet size holds your bit shank.
- ER20 collets for 1/2 inch bits: sizes, makers and spindle limitsHelps you choose the right ER20 collet and nut for 1/2 inch bits without overstepping the spindle or bit maker's limits.
- Seating an ER collet and bit: what the makers sayWalks you through changing an ER collet and bit in the order the makers and safety agencies describe.
- Makita RT0701C and DeWalt DWP611 collets, nuts and wrenchesHelps you buy a replacement or aftermarket collet that fits your exact trim router.
Shortlists
- ER collet sets and single collets with the range statedHelps you buy an ER collet set in your spindle's system that covers the shank sizes you actually run.
Tools
- Collet system finderShows which shank sizes and nuts your collet system takes, so you buy collets that hold your bits and fit your spindle or router.
Common questions
What is a good runout number for a hobby CNC collet?
No source we found sets one for hobby routers. Compare claims only when the makers state the same measuring method, such as PreciseBits' readings at the collet face and 1 inch down a blank. More in Collet runout claims: TIR, measuring points and what studies show
Are precision collets worth it?
Research on industrial and micro milling links runout to unequal tooth load and wear, but we found no controlled study of hobby wood routing. A precision collet is a maker's claim you can check on your own machine. More in Collet runout claims: TIR, measuring points and what studies show
How do I check runout on my machine?
PreciseBits recommends a dial test indicator on a smooth calibration blank, read at the collet face and at least 0.80 inch (20.3 mm) out. Do it with the power disconnected. More in Collet runout claims: TIR, measuring points and what studies show
Why do two collets with the same TIR claim perform differently?
The claims may not be measured the same way. REGO-FIX and Haas publish a TIR figure without stating where it is measured, while PreciseBits states two measuring points. More in Collet runout claims: TIR, measuring points and what studies show
Are all ER20 nuts the same?
No. PreciseBits lists standard ER20 nuts at M25 x 1.5 and mini ER20 nuts at M24 x 1.0. A nut labeled only ER20 does not tell you which spindle thread it fits. More in ER collet nuts: standard vs mini threads, and finding yours
What is an ER16M nut?
A mini ER16 nut. Carbide 3D's 65 mm ER16 spindle uses an ER16M nut with an M19 thread, which matches the M19 x 1.0 thread PreciseBits lists for ER16 mini nuts. More in ER collet nuts: standard vs mini threads, and finding yours
Do I need a torque wrench for an ER nut?
REGO-FIX recommends tightening its nuts with a torque wrench and publishes torque values separately. PreciseBits cautions that its torque values may not always be required, preferable or even possible, and treats maximum torque as a warning. Follow your spindle maker's instructions. More in ER collet nuts: standard vs mini threads, and finding yours
Why does the collet come out with the nut?
Carbide 3D explains that the off-center lip inside an ER nut traps the collet so it leaves the spindle taper with the nut. More in ER collet nuts: standard vs mini threads, and finding yours
Questions
What size collet do I need for 1/4 in bits?
A 1/4 in collet in your spindle's or router's own system. In ER11, the catalogs we read stop at 7 mm or 1/4 in, so 1/4 in is the top size. A 6 mm collet is not a 1/4 in collet: 1/4 in is 6.35 mm.[5][13][9]
Can ER16 hold 1/2 in?
Not in the catalogs we read. Galaxy and Command Tool list ER16 up to 10 mm, Command Tool's largest inch ER16 is 0.375 in, and Somma lists ER16 to 13/32 in, all below 1/2 in (12.7 mm). ER20 reaches 1/2 in.[6][8][5][9]
Are ER20 nuts all the same?
No. PreciseBits lists standard ER20 nuts with an M25 x 1.5 thread and ER20 mini nuts with an M24 x 1.0 thread, so a nut labeled only 'ER20' does not tell you which spindle it fits.[11]
Do Makita collets fit DeWalt routers?
Treat router collets as model-specific. Elaire lists its standard DeWalt collets for the DW616, DW618 and DW621, not the DWP611, which it directs to a separate series. Buy the collet whose maker names your router model.[3]