BOLTON CSK 24-XG · CLOSED DIE · 300 t PRESS

3/4" countersunk lockbolt, 150 mm pin

Hydraulic-press simulation of the first blow. Load, fill, and temperature come from the billet volume and the 100° cavity.

ERSCSK24-32G window

0.00 s · APPROACH

Approach — no metal contact

Closed-die section — ram down, cavity fullScale schematic · mm · pin axis vertical
9.8 headØ35.0Ø19.8 boreshank cavity 140.2 deeppunch · 100° CSKH13 inserts · parting at under-head faceBillet Ø19.1 × 160.1 cold · stick-out 19.9 · ejector stroke 160Calculated blow 39 t · set the press limit at 80 t of 300 t100°

The lower insert is a solid bush. The countersink lives entirely in the punch, so the parting face is the under-head plane. Volume of the Ø19.1 billet fills the head with no trim web. After the ram returns, the Ø16 ejector lifts the pin clear of the bore.

  1. 1Saw Ø19.1 bar to 160.1 mm. Ends square within 0.3 mm. Deburr the leading end so it enters the bore.
  2. 2Induction-heat the upset end to 1100°C. The shank can run 50°C cooler. Check with a pyrometer, not colour alone.
  3. 3Brush scale. Graphite-spray the bore and the 100° punch. Die face at 220°C before the first blow.
  4. 4Stand the bar in the Ø19.8 bush, 19.9 mm proud of the parting face.
  5. 5Close the 300 t press on an 80 t limit (the blow itself is about 39 t). Dwell 0.8 s. Contact time under two seconds.
  6. 6Raise the ram. Fire the lower ejector (20 t, 160 mm) and lift the blank clear.
  7. 7Check head Ø34.7–35.3, height 9.6–10.0, length 148.5–153, and the 100° cone.
  8. 8Next dies, not this one: roll five lock grooves, the breakneck, and the pintail; quench and temper to 178 kN tensile; zinc plate 10 μm.

Press envelope this tool needs

Daylight at least 680 mm. Ram stroke at least 200 mm. A hydraulic cushion under the bed, 20 t and 160 mm, ejects the 150 mm pin. Inserts are H13 at 46–50 HRC in a 1045 holder. The finished pin drawn to the side of the press is the reference after groove rolling — this blow leaves a plain shank.

Catalog strength on the finished, heat-treated pin: 178 kN tensile, 144 kN shear, 127 kN clamp, hole 20.5 mm max.