STONES

1. STONES OPEN FORUM Aberdeen 2009-12-06

2. STONES New WCF stone consignments (384 stones + 10 spares) • 4A=   64+2stones       WCF 24001? to WCF 24066? • 4B=   64+2 stones      WCF 24101? to WCF 24166? • 5A=   80+2 stones      WCF 25001A to WCF 25082A • 5B=   80+2 stones      WCF  25101? to WCF 25182? • 6A=   96+2 stones      WCF  26001? to WCF 26098? All these stones have been printed and measured and the differences in measurements demand adjustments to the running bands

3. STONES New stone consignment 5A 80+2 stones Old stone numbers were WCF 30xx, 32xx and 35xx (Blue Hone inserts) New stone numbers are WCF 25001 to 25082 Important measurements for good stone quality Differences in: Old consignment New consignment running band inside diameter running band width running band area weight 4.5mm (120.6 to 125.1) 1.96mm (5.36 to 7.32) 8.46cm2 (21.54 to 30.00) 0.44kg (18.35 to 18.79) 1.4mm (122.4 to 123.8) 0.15mm (5.53 to 5.68) 0.62cm2 (22.35 to 23.00) 0.22kg (18.20 to 18.42) The “real” running band and the roughness are not yet possible to measure in a safe way

4. R&D STONES Today

5. R&D STONES

6. R&D STONES Tomorrow (today) Leif Öhman

7. R&D STONES Ny curlingsten Uppsala Leif Öhman

8. R&D STONES Running band roughness Leif Öhman

9. R&D STONES • Testing roughness meter

10. R&D STONES • Stone standing on hard surface (maybe hard ice) Leif Öhman

11. R&D STONES • Stone standing on softer surface (maybe soft ice) Leif Öhman

12. R&D STONE • Stone standing on even softer surface Leif Öhman

13. R&D STONES Stone standing on very soft surface Similar result as using rolling pin, but is this the stone surface towards the ice? Leif Öhman

14. R&D STONES • We need to develop a method to compare running bands and how they stands on ice • We also need to find a method to measure the surface structure (scratches) • When we know that we don’t need to match stones on ice any more The knowledge about the different parts involved is not sufficient yet Leif Öhman

15. STONES • Matching stones

16. STONES Stone thrower 8 stones (example) To throw stones on ice is still the best matching method

17. R&D STONES • Other matching methods possible, but not developed • Camera to see the stone movement (X;Y) • Using total station to see the movement in x;y direction • Measure the speed in two positions and calculate the friction coefficient to match the speed

18. R&D a camera method Using cameras for matching the curling stones

19. R&D a camera method • Camera

20. R&D a camera method • Automatic stone tracking • Records the position of the stones in the image • Translates to real world coordinates (X;Y) Camera

21. R&D a camera method (x,y)

22. Fitted according to eq(7)+eq(13) Good precision Estimated lambda = 2.49 Far away, precision 3 cm

23. R&D automatic total station • Automatically measuring the stone movement with total station

24. R&D Automatic total station Result of the measuring

25. STONES • Rubbing the running band? “Crystal Ice” for high level competitions demands special running band rubbing Should normal club stones be rubbed? Greenacres Curling Rink has played more than 3000 games with their stones and the movement is still 4 feet and 24 seconds without rubbing

26. R&D STONES What happens in the long term when rubbing the stones? A scratch in Granite A scratch in Calcite

27. R&D ICE This gives wet friction On the top of all ice crystals there is an extreme thin water-like film As colder as thinner A hair is approx. 50 um thick = 500-50 000 ggr thicker than the water film Thin watery film app. 0,002-0,1 um Hair Ice Crystal

28. R&D ICE • Wet friction is a prerequisite to have a curling stone to curl. • But why will a curling stone curl?

29. R&D ICE • On wet friction surfaces the friction coefficient changes with the speed and the temperature

30. R&D STONE CURL Stone curl Stone curl Stone speed Stone speed Curl

31. R&D STONE CURL Stone curl Stone curl Resulting Stone Speed Curl Resulting Stone Speed