Straightedges, Rules and Small gauges
ULTRA aluminium straightedges, flat and assembling
Aluminium straightedges are light and handy; approx. 2/3rd of the weight is saved in comparison to steel straightedges.
A hard coat provides for high wear and corrosion resistances.
Coat properties:
- Coat thickness approx. 50μ
- Hardness 500–550HV
- High electrical insulation / 4 Ω 1015 mm2 / m
- Minor thermal conductivity
- Good sliding property
Flatness tolerances for straightedges according to DIN 874
The calculation is done according to the formulas given in the table; the tolerances are rounded off.
The tolerances specified in the table are valid only if the straightedge is suspended on its bearing points according to the drawing below. Double values apply for the parallelism of the measuring surfaces to one another.
| Length Reading = mm | Grade 00 (1 + Reading/150)μm | Grade 0 (2 + Reading/100)μm | Grade 1 (4 + Reading/60)μm | Grade 2 (8 + Reading/40)μm |
|---|---|---|---|---|
| 300 | 2 | 5 | - | - |
| 500 | 4 | 7 | 12 | 21 |
| 750 | 6 | 9,5 | 17 | 27 |
| 1000 | 8 | 12 | 21 | 33 |
| 1500 | 11 | 17 | 29 | 46 |
| 2000 | 14 | 22 | 37 | 58 |
| 2500 | - | 27 | 46 | 71 |
| 3000 | - | 32 | 54 | 83 |
| 4000 | - | 42 | 71 | 108 |
| 5000 | - | 52 | 87 | 133 |
| 6000 | - | 62 | 104 | 158 |
Scale accuracy and straightness of rules according to DIN 866, form A and B
The straightness refers to the lower measuring surface.
Form A–10 mm protective ends on both sides of rule
Form B–Rule begins on the left with 0 point; right with 10 mm protective end.
| Form A | Form B | |||
|---|---|---|---|---|
| Length Reading = mm | Straightness μm | Scale accuracy μm | Straightness μm | Scale accuracy μm |
| 500 | 35 | 30 | 70 | 75 |
| 1000 | 60 | 40 | 120 | 100 |
| 1500 | 85 | 50 | 170 | 125 |
| 2000 | 110 | 60 | 220 | 150 |
| 3000 | 160 | 80 | 320 | 200 |
Length tolerances
Length tolerances of folding rules, measuring tapes and roller tapes, are as per EC accuracy classes.
| Length m | 0,5 | 1 | 2 | 3 | 5 | 10 | 15 | 20 | 25 | 30 | 50 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| EG I / mm | 0,2 | 0,2 | 0,3 | 0,4 | 0,6 | 1,1 | 1,6 | 2,1 | 2,6 | 3,1 | 5,1 |
| EG II / mm | 0,5 | 0,5 | 0,7 | 0,9 | 1,3 | 2,3 | 3,3 | 4,3 | 5,3 | 6,3 | 10,3 |
| EG III / mm | 1 | 1 | 1,4 | 1,8 | 2,6 | 4,6 | 6,6 | 8,6 | 10,6 | 12,6 | 20,6 |
Special scales and verniers:
We can supply all types of special scales and dials made of steel, stainless steel, brass, aluminium, etc.
