flange 35 thereon fits between the top of head body 25 and the bottom of spacer 10 when spacer 10 is screwed on and insert 22 u2032 is in place flange 35 will be sandwiched between the lower rim of the spacer and the upper rim of the body this is illustrated in fig3 a u2032 and the groove 24 aligns with ridge 26 note that insert 22 u2032 must be placed on the body before spacer 10 is screwed on fig8 a 9 b 9 c 9 d 9 e 10 and 11 illustrate a second preferred embodiment of applicant 39 s insert here insert 22 u2033 applicant 39 s insert 22 u2033 is seen to comprise ring 37 to which is attached a pair of bodies 39 to the inside face of ring 37 bodies 39 are integral with and include ridges 26 and include locking portion 39 a extending below the lower tip of a pair of ridges as well as a cutout portion 39 b which is created when the ridges extend above central portion 39 c of body 39 thus it is seen with reference fig8 and fig1 how insert 22 u2033 may be placed or sandwiched between the upper portion of body 25 and spacer 10 when the spacer is screwed on it is seen that locking portion 39 a is dimensioned to fit snugly between the inner edges of the.