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Press jaw, master jaw, inserts & profile

Lost in the terms? Here you'll find in one overview how everything fits together, from press tool to fitting, plus a glossary and direct links to the right selection guide.

The chain at a glance

  1. Press tool / pressing machinedelivers the force, expressed in kN
  2. Master jawbase jaw, chosen by kN class
  3. Insertinterchangeable, determines profile + size
  4. Fittingthe part that gets pressed

If you know which step you're stuck at, you choose faster. That's why there are these short selection guides:

Which press jaw / master jaw?Choose by your machine (kN class). Which profile?TH, U, UP, M or V: by your fitting. Which inserts?Profile + size (TH16, M15…). Which master jaw?The base jaw per kN class.
STAHLPRESSE press jaw set: press jaw and 19 inserts TH, V, U and M in a case
In the set: 1 press jaw and 19 inserts (TH, V, U, M) in a case. UP is an add-on.

For sale: from €345, free shipping across the EU, dispatched within 24 hours.

View the sets →

Glossary

Press tool / pressing machine
The tool that delivers the force to press a fitting. The pressing force is given in kN (kilonewton) and determines which master jaw fits.
kN class
The pressing force class of the machine: 32 kN standard, 19 kN compact, 15 kN mini/MAP. Few people know the difference, yet it determines which jaw you need.
Master jaw also: base jaw · jaw holder
The base jaw that clicks into the press tool and holds the interchangeable inserts. One master jaw works with many inserts.
Press jaw
Collective term, sometimes for the master jaw, sometimes for the complete set (master jaw + inserts) together.
Insert also: press insert · jaw insert
The interchangeable part in the master jaw that gives the correct press contour and size. Designated as profile + size, e.g. TH16.
Profile also: press contour
The shape in the insert that matches the fitting: TH U UP (plastic/multilayer) and M V (copper/stainless/steel).
Size
The outside diameter of the pipe/fitting in mm (e.g. 16, 20, 25 mm). Together with the profile this determines the insert.
Fitting also: press fitting
The connecting piece you press. Its manufacturer prescribes the profile (Henco = TH, Viega = V, Geberit = M, Uponor = UP/U).

What does a code like "TH16" or "M15" mean?

Very simple: the letter is the profile and the number is the pipe size in mm. TH16 = TH insert for 16 mm. M15 = M insert for 15 mm. V15 = V insert for 15 mm.

With the complete set (1 master jaw + 19 inserts in TH, V, U and M, UP optional) you cover virtually all common profiles and sizes in one case.

Frequently asked questions

The master jaw is the base jaw in the press tool; the insert is the interchangeable part that determines profile and size. "Press jaw" is used for both (and for the set).
Start with your machine (kN → master jaw), then your fitting (→ profile) and the pipe size (→ insert). Use the checkers above.
The pressing force of the machine in kilonewtons: 32 (standard), 19 (compact) or 15 kN (mini/MAP). It determines which master jaw fits.
The letter is the profile, the number the pipe size in mm. TH16 = TH insert 16 mm; M15 = M insert 15 mm.