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AccessoriesMade in USA

ER16-M4-L

ER Style Integrated Collet and End Mill Extension Holder

ER16 Metric End Mill Extension Holder, 4mm Hole Diameter, 9.5mm Extension Diameter, 25mm Extension Length

ER Style Integrated Collet and End Mill Extension Holder — ER16-M4-L
Series photo — representative of the ER-M family
Dimension diagram of an ER solid mill extension: body diameter, extension length, and hole diameter
Dimension reference — labels match the specifications below
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Cutaway of a RobbJack ER solid mill extension showing the precision-ground ER taper and triangular set-screw grip

Solid ER-mill extensions

  • Reaches micro tools past fixturing that a standard holder can't clear
  • Holds exceptional runout at extended reach — TIR under .0002″ at full extension
  • Beats deflection and chatter on long, small-diameter work
  • Set screws grip the shank in a triangular arrangement for repeatable accuracy
  • Internal stop adjusts from both ends with a standard hex key
  • Precision-ground ER taper twists and snaps into most standard ER clamping nuts — available ER8 through ER25
  • Coolant-Thru versions available in ER16

From the RobbJack Applications Guide.

About this series

ER Solid ER-Mill Extensions

Reach deep into fixtures without giving up accuracy.

Integrated ER collet-and-extension holders that let miniature and standard end mills clear fixturing and run at extended length while holding exceptional runout — solving the deflection and chatter that come with long, stacked tool assemblies.

  • Precision-ground ER taper — available in ER8, ER11, ER16, ER20 and ER25
  • Internal stop adjusts from both ends of the holder with a standard hex key
  • Set screws clamp the shank in a triangular arrangement for excellent accuracy
  • Coolant-thru versions available for ER16

Twist and snap into most standard ER clamping nuts — RobbJack recommends HiQ® by REGO-FIX for best results.

Headline spec

TIR < .0002" at full extension

Best for

  • Deep-pocket & fixture clearance
  • Micro tools at reach
  • High-accuracy finishing

Specifications

US machining terms with ISO 13399 codes.

Accessory Type
ER Holder
ER Size
ER16
Hole Diameter
0.1575″
Body DiameterDMM
0.374″
Extension LengthOAL
0.9843″
Series
ER-M — ER Style Integrated Collet and End Mill Extension Holder

See it run

Starting at$317.75

Made & shipped in the USA · lead time confirmed at order. Buy at retail or through your distributor.

Performance guaranteed. Run it against the tool you use today — if it doesn't beat it, we'll make it right.

Adds Uncoated · $317.75 — our pick for your material. Choose another finish below.

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Download ISO 13399 data (.csv)

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Finishes (1)

  • Uncoated

    ER16-M4-L

    $317.75

    Available to order

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Starting at

$317.75

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More in the ER-M series

Same series, different size — what changes from this tool is shown in red.