Pull studs by taper
BT50 Pull Studs (Retention Knobs) – 45°, 60°, 90° and 15° Heads, M24 and 1" Threads
BT50 pull studs (retention knobs) screw into the back of a BT50 tool holder (shank to MAS 403 / JIS B6339, ISO 7388-2 type J) so the machine's drawbar can pull it into the spindle. PTP makes 27 BT50 pull studs: MAS-BT with 45°, 60° or 90° heads and JIS B6339 with a 15° head, with M24 and 1" threads, solid or with a coolant hole. Every stud is CNC ground, MPT tested (Magnetic Particle Testing) and proof tested at 2.5× the clamping force.
All 27 BT50 pull studs
Grouped by standard, then by head angle. Each ordering code opens its own page with the drawing and every dimension (mm).
MAS-BT (MAS 403): 23 BT50 pull studs
| Ordering code | Head angle (θ) | Thread (TH) | Knob Ø (A) | Overall length (D) | Coolant hole Ø (J) | Seal |
|---|---|---|---|---|---|---|
| PSI4B5001 | 45° | M24 | 25 mm | 85 mm | – | – |
| PSI4B5001R | 45° | M24 | 25 mm | 85 mm | – | – |
| PSI4B5001I | 45° | 1" | 26.17 mm | 85 mm | – | – |
| PSI4B5001C | 45° | M24 | 25 mm | 85 mm | 7.9 mm | – |
| PSI4B5001CI | 45° | 1" | 26.17 mm | 85 mm | 7.9 mm | – |
| PSI4B5001CO | 45° | M24 | 25 mm | 85 mm | 7.9 mm | Seal ring |
| PSI4B5001COOC | 45° | M24 | 25 mm | 85 mm | 7.9 mm | Seal ring, O-ring |
| PSI4B5001ICT | 45° | 1" | 26.17 mm | 85.2 mm | 7.9 mm | – |
| PSI4B5001ICOCT | 45° | 1" | 26.17 mm | 85.2 mm | 7.9 mm | Seal ring |
| PSI4B5001ICOCTSB | 45° | 1" | 26.17 mm | 85.2 mm | 7.9 mm | Seal ring |
| PSI3B5002 | 60° | M24 | 25 mm | 85 mm | – | – |
| PSI3B5002I | 60° | 1" | 26.17 mm | 85 mm | – | – |
| PSI3B5002C | 60° | M24 | 25 mm | 85 mm | 7.9 mm | – |
| PSI3B5002CI | 60° | 1" | 26.17 mm | 85 mm | 7.9 mm | – |
| PSI3B5002CIOCT | 60° | 1" | 26.17 mm | 85.2 mm | 7.9 mm | Seal ring |
| PSI5B5009 | 90° | M24 | 25 mm | 85 mm | – | – |
| PSI5B5009I | 90° | 1" | 26.17 mm | 85 mm | – | – |
| PSI5B5009C | 90° | M24 | 25 mm | 85 mm | 7.9 mm | – |
| PSI5B5009COOC | 90° | M24 | 25 mm | 85 mm | 7.9 mm | Seal ring, O-ring |
| PSI5B5009COOT | 90° | M24 | 25 mm | 85 mm | 7.9 mm | Seal ring, O-ring |
| PSI5B5009COOTT | 90° | M24 | 25 mm | 85 mm | 7.9 mm | Seal ring, O-ring |
| PSI5B5009CI | 90° | 1" | 26.17 mm | 85 mm | 7.9 mm | – |
| PSI5B5009ICOCT | 90° | 1" | 26.17 mm | 85.2 mm | 7.9 mm | Seal ring |
JIS B6339: 4 BT50 pull studs
| Ordering code | Head angle (θ) | Thread (TH) | Knob Ø (A) | Overall length (D) | Coolant hole Ø (J) | Seal |
|---|---|---|---|---|---|---|
| PSJIS5037 | 15° | M24 | 25 mm | 74 mm | – | – |
| PSJIS5037CI | 15° | 1" | 26.17 mm | 74.2 mm | – | – |
| PSJIS5037I | 15° | 1" | 26.17 mm | 74.2 mm | – | – |
| PSJIS5037C | 15° | M24 | 25 mm | 74 mm | 11.5 mm | – |
How do I choose a BT50 pull stud?
Taper. Check that the tool holder has a BT50 shank to MAS 403 / JIS B6339, ISO 7388-2 type J. Its dimensions are on the MAS-BT shank page.
Standard. Pick the pull stud type your machine's drawbar is built for: MAS-BT (MAS 403) or JIS B6339.
Head angle. MAS-BT 45°, 60° or 90° and JIS B6339 15°. Check that your drawbar gripper takes the head angle you order.
Thread. The BT50 shank table gives M24 for the holder's pull-stud thread. The 1" version is for holders made with that thread.
Coolant. For through-spindle coolant, order a stud with a coolant hole (J, Ø7.9–11.5 mm); seal ring and O-ring versions seal it.
Questions about BT50 pull studs
What thread does a BT50 pull stud have?
BT50 pull studs from PTP come with M24 (14 codes) and 1" (13 codes) threads. The BT50 shank table gives M24 for the holder thread.
Which head angles are there for BT50 pull studs?
45° (MAS-BT), 60° (MAS-BT), 90° (MAS-BT) and 15° (JIS B6339). Order the head angle your drawbar gripper takes.
Are there coolant-through BT50 pull studs?
Yes: 17 of the 27 BT50 codes have a coolant hole, Ø7.9–11.5 mm (J); 9 have a seal ring and 4 have an O-ring. The table lists the coolant hole of every code.