Coefficient of friction test - slip factor - query

[r4c3r]

Dear All please can anyone advice?
I have followed the guidelines given in the BS4604:1970 standard to establish coefficient of friction (slip factor) between the surfaces of our interest.
I am confused with regards to the interpretation of the calculation method provided by the standard;

Slip Factor = Slip Load/(2x specified proof load of one bolt x number of bolts)

The samples where prepared in accordance with the BS4604-1:1970 (Appendix A, page 8)

The slip occurred on one half of the tested system (sample) and the lowest value of the slip load has been taken in to account.
Does it mean that I shall use number of bolts equal to 2 as the slip occurred between surfaces on which only 2 bolts are providing clamping force?

I would greatly appreciate your advice or if you could provide me a contact details to someone you think will be competent in this field.

 

[r4c3r]

Hello,
I have investigated the subject and after consulting with two independent test houses I can confirm that the number of bolts to be used for calculations is 2 as the value of minimum slip load that has been taken for calculations load occurred only on the surface affected by clamping force provided from two bolts. Shall anyone require further information please get in touch.
Regards
Albert