Hose standards and crimping guide
What do 1SN, 4SH and R15 mean, are 1/2″, -8 and DN12 the same size, how is the crimp diameter found, how is a die chosen and what is checked after crimping? We explain the names you hear at a hose press and match each one to our METflex models, from MT 11 to MT 55.
What is hose crimping, and why do standards matter?
A hydraulic hose assembly has three parts: the hose, the fitting on its end and the crimp that secures the fitting. In crimping, the press closes the outer sleeve of the fitting evenly around its circumference through a die; the sleeve presses the hose onto the fitting stem. For the joint to stay leak-tight and not pull off, hose, fitting and die must match.
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Hose standards name that match: how many wires a hose has, at which diameter and pressure class it is made. The exact pressure class, fitting match and crimp size are in the hose and fitting maker’s catalogue, which always prevails.
What are the parts of a hose and a fitting?
A hydraulic hose has three layers from inside out: the inner tube that carries the oil, the reinforcement that carries the pressure (wire braid, spiral wire or textile) and the rubber cover. A fitting has two main parts: the stem (nipple) that enters the hose and the sleeve (ferrule or socket) that is crimped around the hose. In Turkish shop talk “rekor” means the whole fitting.
What do 1SN, 2SN, 4SP, 4SH, R1, R2 and R15 mean?
Hose standards come from two families: SAE J517 (names starting with R) and EN standards (names with digits and letters). The notes below describe construction, not pressure class.
SAE 100R1 and EN 853 1SN:
single wire-braid hose. R1 and 1SN correspond in construction; still check the catalogue for fitting and pressure match.
SAE 100R2 and EN 853 2SN:
double wire-braid hose, for a higher pressure class than R1/1SN.
EN 857 1SC and 2SC:
“compact” wire-braid hose with a smaller outer diameter.
EN 856 4SP and 4SH:
four-layer spiral-wire hose; 4SH is the higher pressure class. SAE 100R12 is also a four-spiral hose, similar in construction to 4SP.
SAE 100R13 and 100R15:
multi-spiral high-pressure hoses; R15 is among the highest classes.
Industrial hose:
wide-bore hose, usually 3″ and above, for low to medium pressure. For these hoses MT 30 crimps 3″–4″ and MT 35 crimps 3″–6″.
Which standards do our METflex models crimp?
These are the hose ranges of our models. For a name not mentioned above (2SN, 1SC, 2SC, 4SP, R12, R13), write down your hose and we will tell you if it fits.
- MT 11
- 4SH, 3/16″ – 1″
- MT 12
- 4SH, 3/16″ – 1″; 1SN, up to 1 1/4″
- MT 30
- R1-R2-4SH-R15, 3/16″ – 2″; industrial 3″ – 4″
- MT 35
- R1-R2-4SH-R15, 3/16″ – 2 1/2″; industrial 3″ – 6″
- MT 55
- Hose and pipe up to and including 10″
Are 1/2″, -8 and DN12 the same size?
Hose size describes the inner diameter and is written three ways: inch (1/2″), dash (-8, meaning 8/16″) and DN (nominal diameter, millimetres). All three point to roughly the same size; DN values are rounded millimetre equivalents.
- 3/16″
- -3 / DN5
- 1/4″
- -4 / DN6
- 3/8″
- -6 / DN10
- 1/2″
- -8 / DN12
- 5/8″
- -10 / DN16
- 3/4″
- -12 / DN19
- 1″
- -16 / DN25
- 1 1/4″
- -20 / DN31
- 1 1/2″
- -24 / DN38
- 2″
- -32 / DN51
In which notation are sizes written for the METflex models?
We write hose ranges in inches: 3/16″, 1″, 1 1/4″, 2″, 2 1/2″, 6″, 10″. For example the 1″ upper limit of MT 11 corresponds to -16 or DN25, and the 2″ upper limit of MT 30 to -32 or DN51. Machine values such as “outer diameter 120 mm” describe the outer-diameter capacity of the part to be crimped, not the hose inner diameter; do not mix the two.
What is the crimp diameter and how is it found?
The crimp diameter is the outer diameter the sleeve must reach after crimping. For each hose and fitting combination it is written in the fitting maker’s crimp table, with a tolerance. The die is chosen to close to this diameter, or the press is set to it.
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Do not confuse crimp diameter with the machine’s “maximum opening diameter”. Opening describes how far the die can open, which is machine geometry, not hose diameter. The opening is 200 mm for MT 30, 300 mm for MT 35 and 400 mm for MT 55. The crimp diameter is a value that changes with each job and is written in the fitting maker’s table.
How do I choose the right die?
Fix the hose standard and inner diameter, for example 4SH, 3/4″.
Find the fitting maker and code; the maker gives a crimp table for each fitting and hose pair.
Read the crimp diameter and tolerance from the table.
Choose the die set for that diameter; MT 11 has 6 die sets and MT 12 has 7.
Check that the press’s maximum opening and master die length allow the chosen die.
If no die exists, we make dies in the form and diameter you need; send us the size.
When is skiving needed?
Skiving removes the outer rubber layer, sometimes also the layer above the reinforcement, as far as the fitting needs. On spiral-wire high-pressure hoses (4SP, 4SH, R12, R13, R15) fittings generally ask for skiving; on wire-braid hoses (1SN, 2SN, R1, R2) it depends on the fitting type. The fitting maker’s table states which hose, how far and how.
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Our Hose Skiving Machine is bench-top, skives 3/8″–1 1/4″ hoses and has 6 dies. On MT 30, skiving dies for 3/8″–2″ are standard on the press.
What should I check after crimping?
Take the limit values from the fitting maker’s table; after crimping, check the following:
Crimp diameter:
with a caliper, measure the crimped zone of the sleeve in two directions at right angles and compare with the table diameter and tolerance.
Hose insertion:
confirm the hose sits fully in the fitting, up to the mark line.
Appearance:
no cracks in the sleeve, no hose pushed out and no exposed wire on the skived part.
Cleanliness:
cutting and skiving debris cleaned out of the hose.
Pressure test:
leak-tightness is tested at the test pressure set by the hose maker and the standard; the value depends on the hose.
Record:
in series work measure and note the first piece. On MT 35 and MT 55 the PLC screen can store hose sizes.
What safety points matter when crimping hose?
- Do not use a hose above its rated pressure; crimping force (tons) is not the hose working pressure.
- Use the approved hose and fitting combination of the makers; do not mix parts from different makers.
- Wear eye protection; keep hands away from the die area while it closes.
- Do not bend hose below its minimum bend radius or twist it during assembly.
- Do not reuse aged, cracked or damaged hose.
- For the machine’s operating and safety instructions, contact us.
What do the terms in the press specifications mean?
Crimping force (tons):
the force the press can apply; not the hose working pressure.
Maximum opening diameter (mm):
how far the die opens; machine geometry, not hose diameter.
Master die length (mm):
length of the die set in the crimping direction; 150 mm on MT 35 and 200 mm on MT 55.
Die set:
the die parts that work together for one diameter; MT 11 has 6 sets and MT 12 has 7.
Outer-diameter capacity (mm):
the outer diameter of the part that can be crimped; 120 mm on MT 30, 200 mm on MT 35, 300 mm on MT 55.
Frequently asked questions about standards
Are R1 and 1SN the same hose?
They correspond in construction: both are single wire-braid hose. MT 12 crimps 1SN, and MT 30 and MT 35 crimp R1. Check fitting and pressure match in the hose catalogue.
Which METflex models crimp 4SH hose?
MT 11 and MT 12 (up to 1″), MT 30 (up to 2″) and MT 35 (up to 2 1/2″).
Which standard does MT 55 crimp?
MT 55 crimps hose and pipe up to and including 10″. State your hose class (standard name and diameter) and we will tell you if it fits.
Does inch versus DN change the crimping die?
No. For the same inner diameter, DN or inch makes no difference; the die follows the crimp diameter. Give both in the quote to avoid misunderstanding.
Does crimping force (tons) set the hose pressure?
No. Crimping force is the force of the press; the working pressure of the hose is written in the hose and fitting maker’s catalogue. When choosing a press, look at the hose range, the dies and the maximum opening together.
What happens if I crimp a hose that needs skiving without skiving it?
The fitting does not seat properly on the hose and the crimp size does not hold. The fitting maker’s table states which hose is skived and how far.
What if I do not have the hose catalogue?
Read the standard name (for example EN 853 2SN) and size code printed on the hose and ask the fitting maker for the crimp table for that hose. If you have no information, attach a photo of the hose and fitting to your quote request.
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