BM Size 20 Technical Specifications

Compact Choice for Light-Duty Applications

Rail Types BM S 20

BM S 20-N	BM S 20-NU	BM S 20-C

Standard Standard	Tapped Holes at Bottom Tapped holes at bottom	Cover Strip Cover strip

Rail Dimensions BM S 20

BM S 20 Rail Dimensions

Rail Specifications BM S 20

Parameter	BM S 20-N	BM S 20-NU	BM S 20-C
Rail Width B1 (mm)	20	20	20
Rail Height J1 (mm)	19	19	19
Max Single Piece Length L3 (mm)	3000	3000	3000
Mounting Hole Pitch L4 (mm)	60	60	60
First/Last Hole Position L5/L10 (mm)	28.5	28.5	28.5
Weight per Meter (kg/m)	2.2	2.3	2.1

Carriage Types BM W 20

BM W 20-A / B	BM W 20-C / D

Standard / Standard Long Standard / Standard long	Compact High / Compact High Long Compact high / long

Carriage Dimensions BM W 20

BM W 20 Carriage Dimensions

Carriage Specifications BM W 20

Parameter	BM W 20-A	BM W 20-B	BM W 20-C	BM W 20-D	BM W 20-H	BM W 20-J	BM W 20-K	BM W 20-L	BM W 20-N
System Height A (mm)	30	30	30	30	28	28	28	28	30
Carriage Width B (mm)	63	63	44	44	59	59	44	42	44
Reference Surface Distance B2 (mm)	21.5	21.5	12	12	19.5	19.5	12	11	12
Carriage Height J (mm)	25.5	25.5	25.5	25.5	23.5	23.5	23.5	23.5	25.5
Carriage Length L (mm)	72.5	88.5	72.5	88.5	72.5	48.7	48.7	72.5	48.7
Steel Body Length L6 (mm)	51.5	65.5	49.5	65.5	49.5	25.7	25.7	49.5	25.7
Lateral Mounting Hole Pitch N (mm)	50.5	50.5	32	32	49	37	32	32	32
Reference Surface Height O (mm)	4.4	4.4	4.4	4.4	4.4	4.4	4.4	4.4	4.4
Carriage Weight (kg)	0.5	0.6	0.4	0.5	0.4	0.3	0.3	0.4	0.3

Rigidity Curve and Load Ratings

BM W 20 Rigidity Curve and Load Ratings

Load Ratings

Carriage Type	C₀ Static Load (N)	C₁₀₀ Dynamic Load (N)	M₀Q Static Cross Moment (Nm)	M₀L Static Long. Moment (Nm)	MQ Dynamic Cross Moment (Nm)	ML Dynamic Long. Moment (Nm)
A / C / H / L	31,400	14,400	373	292	171	134
B / D	41,100	17,400	490	495	206	208
J / K / N	13,100	8,400	150	58	99	37

Load Rating Definitions

C₀ = Static load capacity
C₁₀₀ = Dynamic load capacity - 100km travel life
M₀Q / MQ = Cross moment (lateral)
M₀L / ML = Longitudinal moment

Available Options

Accuracy Classes

Accuracy Class	Carriage/Rail Tolerance A/B2	Matched Carriage Max Deviation ΔA/ΔB2	Standard Carriage Max Deviation
G0 Highly Accurate	± 5 µm	3 µm	10 µm
G1 Very Accurate	± 10 µm	5 µm	20 µm
G2 Accurate	± 20 µm	7 µm	40 µm
G3 Standard	± 30 µm	25 µm	60 µm

Preload Classes

Preload Class	Preload Force (% of C₀)	Application
V0 Extra Light Preload	0-2%	Extremely low friction, uniform load, minimal vibration
V1 Light Preload	3%	Low friction, uniform load, slight vibration
V2 Medium Preload	8%	High rigidity, moderate variable load and vibration
V3 High Preload	13%	Maximum rigidity, impact loads, highly variable loads

Lubrication as Delivered

Code	Type	Description	Application
LN	Oil Protect	Light oiling	Applications with continuous oil supply after installation
LG	Grease Protect	Thin grease layer	Applications with continuous grease supply after installation
LV	Full Greasing	Complete grease fill	Manual lubrication applications

Surface Treatment (Coating)

Code	Type	Features
—	Standard (No Coating)	Standard steel surface
CN	Hard Chromium	Excellent corrosion protection, high wear resistance, good emergency running properties
CH	Black Oxide	Enhanced rust protection

Reference Side

R1 - Reference at Bottom R2 - Reference on Top

Order Code Examples

Rail Order Code

BM S 20-N-G1-KC-R1-500-28.5-28.5

BM S 20 = MONORAIL Ball Profile Rail Size 20
N = Standard (top mounting)
G1 = Very Accurate
KC = Countersunk mounting holes
R1 = Reference at bottom
500 = Rail length 500mm
28.5-28.5 = First/last hole positions

Carriage Order Code

BM W 20-A-V1-S11-LV-CN

BM W 20 = MONORAIL Ball Profile Carriage Size 20
A = Standard carriage
V1 = Light preload
S11 = Lubrication port position (top center)
LV = Full greasing
CN = Hard chromium coating