Found my pitch guage, and it is 28TPI which makes it UNF I believe.
well ive got a part restored belter sitting behind me.ive the screw in my hand but my thread gauge is in the ''shed of plenty''...ill update the ''thread'' with the tpi when i open up...
Found my pitch guage, and it is 28TPI which makes it UNF I believe.
It is 100% 28 TPI as the Cadet Major screw fits the 7/32" 28TPI Die perfectly except it's wobby loose inside even though it fits to the pitch very well. I therefore think that the screws are 13/64" 28TPI and NOT 7/32" 28TPI
For this reason I am hoping that a heavily squeezed down die will effectively make a thread of 13/64 28TPI and all will be well.
I'll let you know what happens...
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
Just to throw petrol onto the fire, what about the thread form? That may also make a difference.
I've just rechecked the thread diameter, and over a thread length of 11/32" and 28TPI, the leading thread diameter is 3/16" and the trailing thread is 13/64", so there appears to be a very slight taper.
These measurements were taken from a virtually brand new screw with an overall length of 1.3/64", with a pan head diameter of 11/32" and a depth of 5/32", followed by a waist of 5/32" diameter for 17/32", and a thread length of 11/32".
Hope this is of some help.
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
any one send me a pic of one i think ive got a full set.coddy.