Cylinder Stud Thread Profile

[vibrac]

In Passing )) All my editions of KTB say 55 deg 9/16" CEI x 20 TPI. Whitworth form and Original Vincent Page 128 says the same.

oops Roger you are right I must have looked at wrong page 185 says 60 but thats 26tpi CEI next page gives 9/16 at 55 but doesn't say CEI and I note that on P70 he mentions neither CEI or 55 deg

 

[Bill Thomas]

Thats the one I sent off for, I was not happy. Cheers Bill.

 

[ogrilp400]

The works drawing specifies 9/16" CEI x 20 TPI. Whitworth form, with an effective diameter of .535".
Can`t be more positive than that.

The increase in effective over the chart earlier posted, is for the reason I gave you about the manufacture of the stud.
So the tap that Roger purchased will go through easily, given those figures.
I personally use a tap with .003 oversize to take care of the effective given on the works drawing.

Trev, if the works drawing says CEI, I would take that as being CEI thread form?

Phelps.

 

[ogrilp400]

Dear All,
The basis for the original question was to confirm the original correct thread form. From that I can get the correct taps made. I repair Vincents and if I am going to do these threads then I want to do it right. I don't want it causing me problems further down the line. As Glenn Bewley says, "If its almost right its wrong"

Phelps.

 

[clevtrev]

9/16" CEI x 20 TPI. Whitworth form, with an effective diameter of .535".

That information off the works case drawing, is all you need to tell your tap manufacturer.
If you look at the spec, earlier posted you will notice the difference in effective diameter. So with that information, you can deduce that the tap required is, in engineering terms, a special.