A slotted tapered collet is pushed by the nut into the tapered bore of the holder. The collet closes and clamps the tool shank. ER is the collet with the "8° setting angle" in ISO 15488.
Applications
Drills, reamers, finishing with small to medium end mills, taps (with dedicated collets)
Runout
Mitsubishi Materials(Taper collet chucks, general):0〜0.02 mm At 4D from the tip[4]
BIG DAISHOWA(CNC collet chucks, general):Less than 0.003 mm (guaranteed) 4×D (stated from the collet tip)[5]
BIG DAISHOWA(MEGA NEW BABY CHUCK (NEW BABY COLLET, AA grade)):0.00004" (approx. 1 μm) / 0.00012" (approx. 3 μm) At the collet tip / at 4×D. Every collet is inspected twice[6]
BIG DAISHOWA(MEGA ER GRIP):No figure on the product page. The announcement on the list page says "3 μm (0.00012") at 5xD" Each collet is inspected at 4D twice, at 0° and 180° (product page)[7]
NIKKEN(Slim Chuck (SK collet)):5 μm (standard collet) / 3 μm (precision A type collet) 4×D (guaranteed)[8]
NIKKEN(Slim Chuck P-class collet (for drills)):Within 3 μm 4D from the chuck tip[9]
REGO-FIX(ER holder body):TIR 3 µm (0.0001") No condition stated[10]
Seiwa Seiki(Micron Chuck):1 μm at the tip / 2 μm at the 3D point (search-result snippet only; the official page has not been verified) At the 3D pointSearch-result snippet only. Not verified on the official page itself, so no source is given
Pros
One holder can grip many diameters just by changing collets
Wide range of uses, from drills, reamers and taps to end mills
With a high-precision product, runout is a few μm
Cons
Gripping force and rigidity are lower than with milling chucks, shrink-fit and hydraulic chucks (Mitsubishi Materials, Kennametal)
Over- or under-tightening the nut, or dirt caught in the collet, worsens runout
Clamping
Mitsubishi Materials(Taper collet chucks, general):Gripping force approx. 29 N·m at ø6 and approx. 69 N·m at ø16 (the original gives gripping force in units of Nm; see README)[4]
NIKKEN(Slim Chuck):Gripping range ø0.7–25.4 mm. Twice the gripping force at a lower tightening torque than ER (manufacturer comparison)[8]
BIG DAISHOWA(MEGA ER GRIP):Uses ER standard Form B collets (the page gives no range values)[11]
How it works Turning the nut makes the slanted needle rollers press the thick-walled sleeve from outside, and the whole sleeve contracts to grip (schematic)
Standard
—Not confirmed in public sourcesNo standard specific to milling chucks was found
How it works
The nut is turned over inclined rows of needle rollers on the outside of a thick-walled sleeve. The whole sleeve deforms elastically and closes, clamping the tool shank (or a straight collet).
Applications
Roughing and heavy cutting with end mills, large-diameter end mills
Runout
Mitsubishi Materials(Milling chucks, general):0.005〜0.02 mm 100 mm from the tip[4]
NIKKEN(MULTI-LOCK milling chuck (C32 type)):Within 5 μm (T.I.R.) 100 mm from the tip[12]
NIKKEN(ZERO FIT TYPE milling chuck CZF20/25/32):Maximum 0.050 / 0.050 / 0.030 mm (appears to be values before adjustment; read from PDF text conversion, so visual confirmation is needed) At the 100 mm position[12]
BIG DAISHOWA(NEW HI-POWER MILLING CHUCK / MEGA DOUBLE POWER CHUCK):— The product page says only "Stable Runout Accuracy" and gives no figure[13]
Pros
High gripping torque and rigidity; suited to heavy cutting
With a design that lets cutting oil escape through slits, gripping torque is less affected by oil (NIKKEN test data)
Cons
Large outside diameter that is prone to interference; runout is larger than with collet, shrink-fit, or hydraulic chucks (guideline from Mitsubishi Materials)
Mitsubishi Materials(Milling chucks, general):Gripping force is stated as 25 Nm (be careful how the unit is interpreted; see README)[4]
BIG's HMC (NEW HI-POWER MILLING CHUCK) is a mechanical milling chuck (not hydraulic). The body has fine slits so that the clamping section deforms uniformly (bd-hmc).
Shrink-fit holderShrink fit chuck
How it works The clamping bore is slightly smaller than the shank. Heating expands the bore so the tool can be inserted, and as it cools it becomes an interference fit (schematic)
Standard
DIN 69882-8 (dimensions of Form G shrink-fit chucks, holders for HSK; the 2005-06 edition was replaced by the 2023-05 edition)
The gripping bore of the holder is made slightly smaller than the tool shank. The bore is expanded by heating, the tool is inserted, and on cooling it is held by an interference fit. This uses the difference in thermal expansion between the steel holder and the carbide shank.
Applications
Deep cavity milling in dies with small-diameter end mills, high-speed machining, finishing. Power / Heavy Duty types are also used for roughing
Runout
Mitsubishi Materials(Shrink-fit holders, general):— The table shows "-" (no figure). The text says "high runout accuracy"[4]
HAIMER(Shrink Fit Chuck Standard Version):< 0.003 mm Measurement position not stated[15]
HAIMER(Power Shrink Chuck):< 0.003 mm Measurement position not stated. Described with this value even for roughing[16]
MST Corporation(Shrink-fit holder Slim Line):3 μm or less Measurement position not stated[17]
Kennametal(Shrink Fit Toolholders GP):3 μm or less (search-result snippet only; the product page itself shows no figure) 3×D (search-result snippet)Search-result snippet only. Not verified on the official page itself, so no source is given
Pros
Low runout (many published values are 3 μm or less)
No moving parts, so a slim shape is possible (4.5° profile). Short overhang makes it suited to deep cavities and vertical walls
Gripping force is higher than a collet's (Mitsubishi Materials)
Cons
Needs a heating device (induction heating, etc.) for tool changes
Depends on the shank tolerance (h6, etc.)
Repeated overheating degrades the holder material (MST warning)
Clamping
MST Corporation(Slim Line):Low-temperature shrink fitting at 300 °C (max. 430 °C) using a special steel for shrink fitting (1.6 times the thermal expansion of other companies' steels). Minimum wall thickness at the tip 1.5 mm[18]
HAIMER(Power Shrink Chuck):Safe-Lock can be fitted from ø6 mm up. Cool Flash is ø6–25 mm[16]
HAIMER Standard has a "specification close to DIN 69893-1 and DIN 69882-8" with a 4.5° taper angle. SCHUNK TENDO Slim 4ax is hydraulic, but its profile is the DIN 69882-8 shrink-fit shape.
Hydraulic chuckHydraulic expansion chuck
How it works Raising the oil pressure with the clamping screw makes the thin inner wall expand evenly inward and press on the whole circumference of the shank (schematic)
Standard
DIN 69882-7 (dimensions of Form F expansion chucks, holders for HSK; the 2002-04 edition was replaced by the 2005-06 edition)
Oil is sealed in a closed chamber inside the holder. Turning the clamping screw raises the oil pressure, and the thin inner wall (expansion sleeve) bulges inward evenly and clamps the whole circumference of the shank.
Applications
Reaming and finishing, drilling, high-speed milling (high-torque types also for roughing)
Runout
Mitsubishi Materials(Hydraulic chucks, general):0.005〜0.015 mm 100 mm from the tip[4]
SCHUNK(TENDO E compact (HSK-A63 Ø12/Ø20, SK50 Ø32)):≤ 0.003 mm 2.5×D[21]
Sandvik Coromant(CoroChuck 930):Bores 6/8/10/12/20/25/32 mm, 1 and 1¼ inch. "Fulcrum technology": a thin brazed membrane grips at two points on each side[22]
Kennametal(HydroForce):Gripping bores 20/32/50 mm. Front wall 40% thicker[23]
TENDO Platinum / Silver have a profile conforming to DIN 69882-7. Balance G2.5 at 25,000 min⁻¹ (SCHUNK).
How it works A side screw presses on the flat on the shank. Rotation is transmitted by contact between the flat and the screw (schematic)
Standard
DIN 6359-1 / -2 (sleeves with a 7/24 taper shank, for cylindrical shanks with a side drive surface and an inclined clamping surface)
Shank side: DIN 1835-1 (cylindrical shanks for milling cutters), DIN 6535 (cylindrical shanks for hard materials)
[27][28][29][30]1 source · referenceConfirmed on the DIN Media title page. The correspondence to side-lock is read from the titles
How it works
The flat on the shank (Weldon flat) is clamped by a screw from the side. Rotation is transmitted by the contact between the flat and the screw.
Applications
Roughing and heavy cutting, drills (indexable insert drills, etc.)
Runout
Mitsubishi Materials(Side-lock holders, general):0.02〜0.04 mm It says "End of 10", so the measurement position is unclear[4]
HAIMER(Weldon style (comparison)):Maximum 0.05 mm Not stated[31]
Pros
Simple construction and inexpensive; resists slipping and pull-out, so it can be used for heavy cutting
Cons
Because it presses from one side, the tool sits off-center and runout is large (Mitsubishi Materials 0.02–0.04 mm; HAIMER states up to 0.05 mm)
Requires a shank with a flat
The correspondence between the shape designations Form B (Weldon) and Form E of DIN 1835 and HB and HE of DIN 6535 has not been verified. Mitsubishi Materials states that "some products improve runout through the direction of the clamping bolt or eccentric machining of the bore."
How it works The cutter bore fits on the arbor's pilot section, a key transmits rotation, and a center bolt draws the cutter against the end face (schematic)
Standard
DIN 6357 (arbor with 7/24 taper shank for face mills centered internally)
DIN 6358 (arbor with 7/24 taper shank for milling cutters with longitudinal and transverse slots)
The bore of a face mill or shell end mill is placed on the arbor's centering pilot to locate it. A key (longitudinal or transverse slot) transmits rotation, and the center bolt pulls the cutter against the face to secure it.
Applications
Face milling, shouldering with shell end mills
Runout
Not confirmed in public sourcesNo published runout value was found on the manufacturer's official page
Pros
Holds large diameter face mills with high rigidity
Cons
An arbor matching the cutter's mounting standard (bore diameter, keyway) is required
BIG's Shell Mill Holder page only describes the increased rigidity from BIG-PLUS® (a registered trademark of BIG DAISHOWA; dual-contact) and gives no figures.
—Not confirmed in public sourcesNo standard was found
How it works
In synchronous (rigid) tapping, a very small internal axial float absorbs pitch deviation caused by synchronization error between spindle rotation and feed. It reduces the thrust load on the tap.
Applications
Synchronous tapping on machining centers
Runout
Not confirmed in public sources
Pros
Better thread quality and longer tap life
Cons
Requires a machine capable of synchronous tapping
Performance
BIG DAISHOWA(MEGA SYNCHRO Tapping Holder):Reduces thrust load from synchronization error by up to 90% (manufacturer's claim)[34]
Floating tapping holder (tapper)Floating (tension/compression) tap holder
Standard
—Not confirmed in public sourcesNo standard was found
How it works
Has a mechanism that extends and compresses widely in both tension and compression, absorbing the mismatch between feed and tap pitch. Can be used even on machines that cannot do synchronous tapping.
Applications
Tapping on drill presses and manual machines, NC machines without synchronization
Runout
Not confirmed in public sources
Pros
Allows tapping on machines without synchronization
Cons
Problems occur when the float limit is exceeded (NIKKEN marks the limit); overall length tends to be long
Float
NIKKEN(NZ32-12-105 straight shank TAPPER CHUCK):Compression 5 / tension 15 (read from PDF text conversion; probably mm; visual confirmation needed)[12]
NIKKEN(NZ32-16-125):Compression 8 / tension 20 (same as above)[12]
The table was read from a PDF text conversion. The column correspondence must be checked visually against the relevant PDF page before publishing.
Boring head (rough)Rough boring head
Standard
—Not confirmed in public sources
How it works
Two cutting edges (twin cutters) balance the cutting forces and remove a large stock allowance at a high feed.
Applications
Rough and semi-finish boring of cast pilot holes
Runout
Not confirmed in public sources
Pros
Up to 4 times the productivity of a single-point finishing head (BIG's claim)
Cons
Finished dimensional accuracy falls short of fine boring
BIG KAISER's TW series is discontinued. Its successor is the SW series (bd-twn).
Boring head (fine)Fine boring head
Standard
—Not confirmed in public sources
How it works
Single point. A micrometer screw adjusts the cutting edge radially in fine steps to set the hole diameter to the μm.
Bore diameter can be adjusted finely; types with a digital readout or automatic balance compensation are also available
Cons
Not suited to roughing (low productivity)
Adjustment
BIG KAISER(EWN 20-203):Adjustment within 1/100 mm on the dial (it does not state whether this is on diameter or radius)[35]
BIG KAISER(EWE 2-152 (digital)):LCD resolution Ø0.00005" (approx. Ø1.3 μm). Machining range Ø0.079"–6"[36]
Drill chuck (keyless)Keyless drill chuck
Standard
ISO 10888:1999 (specification for keyless three-jaw drill chucks)[37][38]
How it works
Three jaws are tightened by turning the sleeve by hand. Most tighten further automatically under cutting torque (self-tightening).
Applications
Drilling and center drilling, drill presses and manual machines
Runout
Albrecht(Albrecht precision drill chuck):0.04 mm (checked before shipment) Inspected after assembly with 4–6 test pins. Stated as "conforming to DIN ISO 10888"[38]
RÖHM(Spiro series / Supra series):Up to 0.05 mm / up to 0.12 mm Not stated[39]
Pros
Fast tool changes and a wide diameter range
Cons
Runout is tens of µm, one order of magnitude larger than collet or hydraulic chucks; not suited to high-speed rotation or end milling
All Albrecht chucks except the short AKL type are self-tightening (albrecht-faq).
The gripping bore is made in a polygon shape. When pressed from outside with a dedicated pressure device, the bore returns to a circle; the tool is inserted and, when the pressure is released, the bore returns to the polygon and clamps the shank (this explanation of the principle comes only from search-result snippets and has not been verified in the text of SCHUNK's official page).
Applications
Micromachining, electrodes, watch parts, small-diameter tools for dies
Runout
SCHUNK(TRIBOS-S HSK-A63 Ø25x95):< 0.003 mm 2.5×D[40]
SCHUNK(TRIBOS-S series):≤ 0.003 mm (permanent runout and repeatability) Not stated[41]
SCHUNK(TRIBOS SVL extension):< 0.003 mm Not stated[42]
1 source · reference
Pros
Runout and repeatability ≤ 0.003 mm
One-piece construction with no parts, slim and suited to high speeds (TRIBOS-RM / S up to 85,000 min⁻¹)
TRIBOS-Mini can grip from ø0.3 mm
Cons
Needs a dedicated pressurizing unit; TRIBOS-S is for light cutting. The manufacturer also notes "watch for radial forces"
Tools with Safe-Lock shanks can also be held in holders for DIN 6535 HA shanks (HAIMER FAQ)[31][30]1 source · reference
How it works
In addition to gripping by friction, these have a mechanism that stops pull-out and slipping by form. In HAIMER Safe-Lock, the holder's drive key engages a helical groove in the shank, preventing pull-out by drawing the tool in the direction of rotation. BIG MEGA PERFECT GRIP combines a milling chuck with a key-grip mechanism that engages the Weldon flat.
Applications
HPC and heavy cutting, Ti machining of aircraft parts
Runout
HAIMER(Power Shrink Chuck with Safe-Lock):< 0.003 mm Not stated[44]
BIG DAISHOWA(MEGA PERFECT GRIP):1 μm at the tip, 3 μm at 4D (search-result snippet only; not verified on the product page or in the instruction manual) 4DSearch-result snippet only. Not verified on the official page itself, so no source is given
Sandvik Coromant(CoroChuck 930 + collet for Weldon with mechanical lock):The chuck body is < 4 μm (2.5×DC). No value is given for use with the locking collet 2.5×DC[22]
1 source · reference
Pros
In roughing and high-load machining of difficult-to-cut materials (Ti, Inconel), prevents tool pull-out (micro-creep) and spinning in the holder
Safe-Lock secures the tool positively while keeping the runout accuracy of shrink fitting
Cons
Requires a shank with a groove (Safe-Lock) or a Weldon flat; Safe-Lock is for ø6 mm and up
Safe-Lock (Safe-λock®) is a registered trademark and patent of HAIMER, licensed to tool makers. The MEGA PERFECT GRIP instruction manual cautions "do not use a shank more than 0.02 mm smaller than the nominal gripping diameter" (bd-mpg-manual).
Press-fit collet holder (powRgrip)Press-fit collet system (REGO-FIX powRgrip)
Standard
—Not confirmed in public sources
How it works
A tapered collet is pressed into the holder with a dedicated hydraulic unit at a force of up to about 9 tonnes. The radial force produced by the press fit clamps the shank through the slotted collet. No heat is used.
Applications
High-precision milling, tool changes on automated lines
3 µm runout (at 3×D), transmitted torque up to 1,100 N·m, change in under 10 seconds (manufacturer's figures)
Cons
Needs a dedicated press-in unit; shank tolerance is h6
Clamping
REGO-FIX(powRgrip):Transmittable torque up to 1,100 N·m. Gripping range 0.0079"–1" (approx. 0.2–25.4 mm). Length repeatability < 10 μm[45]
powRgrip is a registered trademark of REGO-FIX.
Runout is measured at a different position by each manufacturer (2.5–4 times the tool diameter, 100 mm from the tip, etc.), so note that the figures cannot be compared directly.
📚Sources
Values with no mark agree across two or more independent publishers. The pros and cons are Kezuriba's summary of the manufacturers' technical documents.