Mornin'all
Does anyone know what thread the stud is which secures the left hand front footrest on an early (60/61) c15. The stud is part 40-4807.
I got a frame a little while ago to rebuild the box of bits that was once a bike and realised yesterday that the stud had been snapped off in the frame and powder coated over. I know its left hand thread and taper easy-out wont shift it so will need to drill out and re-tap.
I have ordered a new stud/nut but does anyone know of a supplier who might be able to supply the correct left hand thread tap?
Hi,
Try Tracy Tools.
Dave.
They look promising Dave, now just need to know the thread and size
Both of mine have 1/4 x26tpi bolts (cie) ,
7/16" 20 tpi lefthand
Rather than drill it out completely as it's left hand thread would it be possible to drill a pilot hole and screw in a self tapper and keep tightening until the left hand thread undoes?
Just thinking out loud!
Regards
Woops my post of saying 1/4 x 26 should have gone into the rear brake pedel post ,sorry
Quote from: Stubaker58 on 10 Aug, 2025, 20:20 Rather than drill it out completely as it's left hand thread would it be possible to drill a pilot hole and screw in a self tapper and keep tightening until the left hand thread undoes?
Just thinking out loud!
Regards
Good plan and I tried it, including freezer spray down the pilot hole and warming the lug with hot air gun but it didnt budge at all :D
Quote from: Rupert on 10 Aug, 2025, 18:48 7/16" 20 tpi lefthand
so i definitely need a 7/16" 20tpi left hand thread tap, is that a CEI thread?
Yep, CEI
My old B40 from years ago had a snapped-off stud too, and I got the stud out by tapping it round with a centre pop.
Funny thing was I never did use the replacement stud even though it was so hard to source.
Quote from: V500 on 11 Aug, 2025, 21:41 My old B40 from years ago had a snapped-off stud too, and I got the stud out by tapping it round with a centre pop.
Funny thing was I never did use the replacement stud even though it was so hard to source.
I hadnt thought of trying that but I did try drilling out centre of stud to slightly smaller size then tapping a few turns of rh thread into hole and screwing in bolt with a bit of heat and impact wrench....the bolt just kept on cutting its own thread but didnt shift stud. There isnt really enough thickness in the remaining stud to to try & use a centre punch to move it
so, I have been searching for a supplier for a 7/16" CEI20 left hand tap to retap my frame for the left footrest stud and have drawn a blank so far. I know there are other 7/16" 20tpi threads but they all have either different thread angle or crest/root shape so may not give a secure fitting if i try and bodge it.
does anyone know where I might be able to obtain a 7/16" CEI/BSC 20TPI left hand tap? if not then I guess plan B is to use maybe a UNF tap into the frame lug and make a stud to suit.
an update,
I emailed Tracy Tools to see if they could supply a 7/16" cei20 left hand tap even though they don't list this size.
Extremely quick reply and advised that this size was not generally available & would be expensive to get made but UNF tap would work ok as they are both 20tpi with a 60 degree thread angle and they had supplied a number of these for CEI20 studs. The CEI thread has a rounded root and crest & UNF is flat but hopefully it will be good enough & will probably loctite it in ;D