Guide
Tool Holder Types Compared: ER Collet, Shrink Fit, Hydraulic and Weldon
A tool holder type is chosen by how it clamps the cutting tool. This guide compares PTP's holder types side by side: how each one clamps, which shanks and sizes it takes, its run-out and balance grade from the catalogue, and what else it needs.
Last updated 29 October 2026
How do the holder types compare?
Sizes are the range across BT, SK and HSK-A; run-out (TIR) and balance are as printed in the PTP catalogue for each family.
| Holder type | Takes | Accuracy | Also needs | Shanks |
|---|---|---|---|---|
| ER Collet Chucks | ER16–ER50 collets | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 25,000 rpm. | An ER collet for the shank size and an ER clamping nut | BT, SK, HSK-A |
| Mini ER Collet Chucks | ER11M–ER25M collets | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 25,000 rpm. | An ER collet and an ER-M mini nut | BT, SK, HSK-A |
| Weldon End Mill Holders | bore Ø6–50 mm | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 15,000 rpm. | A cutter shank with a DIN 1835-B (Weldon) flat | BT, SK, HSK-A |
| Face Mill Holders | cutter bore Ø16–60 mm | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 15,000 rpm. | A shell-type face mill with a matching bore | BT, SK, HSK-A |
| Combi Shell Mill Adapters | cutter bore Ø16–40 mm | Taper AT3 or better, TIR 0.005 mm max. | A shell end mill or face mill with a matching bore | BT, SK, HSK-A |
| Morse Taper Adapters | MT1–MT5 | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 15,000 rpm. | A drill or reamer with a Morse taper shank | BT, SK, HSK-A |
| Threaded Mill Adapters | M6–M16 thread | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 25,000 rpm. | A cutter with a threaded (screw-in) shank | BT, SK, HSK-A |
| Shrink Fit Holders | bore Ø6–32 mm | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 25,000 rpm. | A heat shrink machine; h6 carbide shanks | BT, SK, HSK-A |
| Slim Shrink Fit Holders | bore Ø6–20 mm | Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 25,000 rpm. | A heat shrink machine; h6 carbide shanks | BT, SK |
| Hydraulic Chucks | bore Ø6–40 mm | Taper AT3 or better, TIR 0.003 mm max. | HIS reduction sleeves for smaller shanks | BT, HSK-A |
| Heavy-Duty Hydraulic Chucks | bore Ø12–32 mm | Taper AT3 or better. | HIS reduction sleeves for smaller shanks | BT, SK |
| Boring Bar Blanks | blank Ø30–120 mm | Hardened AT3 taper, machinable HRc 28–32 body. | Machining into your own boring bar or tool | BT, SK, HSK-A |
When is an ER collet chuck the right choice?
Holds round-shank cutting tools in a DIN 6499 ER collet, closed by an ER clamping nut, for drilling, reaming and milling. Each DIN 6499 collet clamps a small range of shank sizes, so one chuck with a set of collets takes many tools: ER16–ER50 collets.
For small tools and deep cavities there are mini ER-M chucks with a slim nose.
Shrink fit or hydraulic chuck?
Shrink fit holders clamp h6 carbide tool shanks by thermal shrink fit; a heat shrink machine loads and unloads the tool. Bore Ø6–32 mm; taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 25,000 rpm. The slim version has a slim nose for deep cavities.
Hydraulic chucks (HYD) clamp the tool shank through a hydraulic membrane, for finishing, drilling and reaming: bore Ø6–40 mm; taper AT3 or better, TIR 0.003 mm max. Smaller shanks go in with HIS reduction sleeves. The heavy-duty hydraulic chucks (HYDH) are the milling version.
- Shrink Fit HoldersClamps h6 carbide tool shanks by thermal shrink fit, loaded with a heat shrink machine. bore Ø6–32 mm.
- Slim Shrink Fit HoldersSlim-nose shrink fit holder for h6 carbide tools in deep cavities. bore Ø6–20 mm.
- Hydraulic ChucksClamps the tool shank through a hydraulic membrane for finishing, drilling and reaming. bore Ø6–40 mm.
- Heavy-Duty Hydraulic ChucksHeavy-duty hydraulic chuck for milling that takes HIS reduction sleeves. bore Ø12–32 mm.
When do I need a Weldon end mill holder?
Clamps Weldon-flat (DIN 1835-B) cutter shanks with a side-lock screw, so it takes only cutters with that flat: bore Ø6–50 mm. Taper AT3 or better, TIR 0.005 mm max, balanced G2.5 @ 15,000 rpm.
Face mill, combi, Morse taper, screw-in adapters and boring bar blanks
- Face Mill HoldersCarries shell-type face mills on a pilot with drive keys. cutter bore Ø16–60 mm.
- Combi Shell Mill AdaptersCombi arbor that drives both shell end mills and face mills. cutter bore Ø16–40 mm.
- Morse Taper AdaptersHolds Morse-taper-shank drills and reamers in the machine spindle. MT1–MT5.
- Threaded Mill AdaptersDrives milling cutters with a threaded (screw-in) shank. M6–M16 thread.
- Boring Bar BlanksBlank with a hardened taper and a machinable HRc 28–32 body for making special boring bars and tools. blank Ø30–120 mm.
- Mini ER Collet ChucksSlim-nose ER-M collet chuck for small tools and deep cavities. ER11M–ER25M collets.
Questions about tool holder types
Which tool holder has the lowest run-out?
Among PTP's holders, the hydraulic chucks (HYD): 0.003 mm max TIR. ER and mini ER collet chucks, shrink fit and slim shrink fit holders, Weldon end mill, face mill, combi shell mill, Morse taper and threaded mill adapters are 0.005 mm max.
Which holders are balanced for high spindle speeds?
Collet chucks, shrink fit holders and threaded adapters are balanced to G2.5 at 25,000 rpm; end mill, face mill and Morse taper holders to G2.5 at 15,000 rpm.
Can a Weldon holder hold a plain round shank?
No. A Weldon holder clamps the DIN 1835-B flat on the cutter shank with its side-lock screw; for plain round shanks use an ER collet chuck, a shrink fit holder or a hydraulic chuck.