Hydraulic C Clamps

Hydraulic, Fixed Clamp Height, Sliding Style C-Clamp


Hydraulic, Fixed Clamp Height, Sliding Style C Clamp

“C” Clamps work in similar applications to our fixed height ledge clamps, but provided a different profile and customer preference. Using small Bolt-on guides, these clamps also work well in “slotless” press applications (bolsters with threaded holes only). Also, by reaching under and over the clamping plate and providing multiple ports, the clamp can be set “deeper” over the plate if needed, resulting in a lower installed profile.

Available in the single piston style Model 283 and double piston style Model 283D, “C” clamps require only 1.25″ to 1″ of die plate engagement, respectively, and may be modified at the nose to engage plates that have been pocketed to match clamp heights. Ledge brackets, bars, or ears may also be added to dies in some applications to accommodate the clamps. Clamp model and quantity should be selected to provide a total clamping force greater than the total (static and dynamic) force applied to the system during use.

Clamp sizing is done to provide a minimum .060″ clearance to the clamp plate and accommodate a wide range of slot neck height and clamp plate height combinations. For a given T-slot neck depth (N) and clamping plate height (CLH) the needed part number can be easily determined.

Standard Configurations
PFA C Clamp Hydraulic QDC SMED how to size
Model 283 Model 283D
Clamp Force at 5,000 PSI 6,700 lbs 6,900 lbs.


Clamp Height CLH Slot Neck Depth (N) Range
.50”-.75” .75”-1.00” 1.00”-1.25” .25”-1.50
¾” -50 -75 -100 -125
1” -75 -100 -125 -150
1¼” -100 -125 -150 -175
1½” -125 -150 -175 -200
1¾” -150 -175 -200 -225
2” -175 -200 -225 -250

*For a given N and CLH find the correct Dash No. or use H values (exact total clamp opening).
**Other sizes available. Please call PFA for details.


Dash No. H*
-50 1.560”
-75 1.810”
-100 2.060”
-125 2.310”
-150 2.560”
-175 2.810”
-200 3.060”
-225 3.310”
-250 3.560

Identify Your Part Number

Example:  Application requires clamps with 6,000 lbs. clamp force.  T-slot is 3/4 and has a neck (throat) depth of .875”.  Clamp height (CLH) = 1”.  Enter top of chart with Neck Depth of .875” (.750-1.00) and side of chart with CLH value (1”) to obtain (-100) with an “H” value of 2.06”

PFA C Clamp Hydraulic QDC SMED specifications for Part number