Very good stiffness:weight ratio
Low wear
Medium-low cost
Always used with M2, M3, and M4 threads.
Often used with M5

Medium-high thermal coefficient

Best stiffness:weight ratio
Lower thermal coefficient
Minimal wear
Used on some M5 styli
Preferable to Ceramic extension body (slightly higher weight, crash-proof, excellent stiffness)

Higher cost
More difficult machining

Very good stiffness:weight ratio
Reduced cost
Good for diameters over 0.7 mm
Perfect electrical conductivity
Stem diameter max length
0.7 - 1 20
1.5 - 3 40
4 - 6 80

Under 0.7 mm diameter the stem bending is not acceptable

Base and stem machined from one single steel part (integral)
Higher stiffness
Better stiffness:weight ratio
Ideal for scanning (M5)

Higher cost
Available only for M5 range

Offers best stiffness versus other metal stems
Necessary for diameters under 0.7 mm.
Necessary for balls under 1 mm diameter

Highest density = highest weight for same diameter and length
Higher cost compared to stainless steel

Lighter than the solid carbide stem for the same diameter
Lengths from 50 to 118 mm
Ball size from 5 to 10 mm
Ideal for lengths over 80 mm

Not available for ball diameters smaller than 5 mm
Higher cost
Available only for M5
Adhered ball

Low weight and resistant to crashes
Minimal thermal coefficient
Good for styli over 100 mm lengths with stem size over 6 mm
Ideal for extensions over 200 mm
stem length diameter
20 – 40 3
40 – 70 4
75 – 100 8

Lower stiffness than ceramic
Not to be used for stems under 3 mm diameter
Higher cost

Best absolute ratio stiffness / weight
(E-module > 450 GPa)
The lowest total thermal coefficient (body + base or fittings) due to mutual compensation between metal and fiber parts (negative coefficient of the fiber, positive of the base/fittings)
Used on high-end CMMs on shop floor
stem length diameter
20 – 40 2
40 – 80 3.5
90 – 100 6

Higher cost than traditional Carbon Fiber
Stem diameters are available in sizes 2 mm and above
Extension diameters are 11 mm and 20 mm only

Low weight
Best stiffness for same weight and diameter size
Low thermal coefficient
Good for styli over 100 mm lengths with stem size over 4 mm
Ideal for protection of probe head against crashes (e. g. CNC machining centres)
Adhered balls with stem size over 3.5 mm
Drilled balls for stems under 3.5 mm

Higher cost than traditional Carbon Fiber
Stem diameters are available in sizes 2 mm and above
Extension diameters are 11 mm and 20 mm only

Best ratio features/price
Diamond-like hardness (9 for Ruby, 10 for diamond on Mohs scale)
Very high roundness/roughness features for very small sizes (down to 0.3 mm)
Excellent resistance to wear
Ideal for point to point and scanning on steel parts

Attracts Aluminum particles for continuous scanning applications (heavy and repeated cleaning procedures)
Available sizes up to 13 mm

Smoother surface (lower friction)
Ideal for scanning on Aluminum parts (no build up of material particles)

Higher cost
Diameters sizes limited (from 1 to 10 mm only as standard, larger diameters are possible upon request)

Low weight
Possible to obtain the ball from stem machining
Better shock absorption
Normally used on articulated arms

Surface and dimensional features lower than Ruby
Rapid loss of dimensional tolerances
Very low roundness and roughness for ball sizes under 1 mm diameter

Very good surface features (comparable to Ruby)
Ideal for scanning on Cast Iron parts (lower friction, lower wear)

Higher cost than ruby