Thread angle

[Firebird]

Hi

I need to make a number of fittings (brass mainly) for my Conway loco.

I have tried a die in the tail stock holder but I'm not really happy with the quality.

I'm going to try screw cutting, 40tpi and 32tpi

Does anyone know what the angle of the thread is? I have looked but can only find general info/tapping hole size etc.

Cheers

Rich

[Stuart]

It’s the same as BSW 55degrees

Hope that helps


IMHO the quality of the ME dies is not that great

I look after my HSS set and help the dies out by single pointing

[jadge]

If you're referring to the ME range of threads then they're Whitworth form, so the included angle is 55°. Can't say I've ever cut a 40tpi thread, but I've screwcut dozens of 32tpi threads ranging from 1/4" diameter to over 3". I'm too idle to grind a HSS tool so I use a full form 32tpi Whitworth insert.

Andrew

[Firebird]

Hi Stuart and Andrew

Yes that helps 

Do you know of a chart that lists thread depth etc.

Cheers

Rich

[Stuart]

If you do not mind mucky thumb prints

Pm me your email I will send you a pdf of the info

Stuart

[jadge]

Conveniently for 32tpi Whitworth the thread depth is 20 thou, if you ignore the odd one hundredth of a thou. I use the chart in an old Machinery's Handbook.
Andrew

[Stuart]

Rich

The files are to large to post please PM as above

[Firebird]

Hi Stuart

PM sent

Rich

[Dan Rowe]

Here is a good thread site:
http://www.gewinde-normen.de/en/me-thread.html

Cheers Dan

edit one with formulas:
http://johnandbecci.info/Engineering%20Thread%20Data.htm

[Stuart]

On its way

Stuart

[Firebird]

Hi

Thanks Dan 

Stuart, recieved and printed 

Cheers

Rich

[Stuart]

Rich

Sorry for the muck but they are my WS chart and do get used 
But mostly I use BA for fixing 8 BA and less ,with a small amount of metric but I make those as the standard metric heads are to out of scale so Jo will be happy nuts and studs are made


Stuart

[kvom]

If you're looking for the taper angle rather than the thread form angle, NPT has a taper of 1 degree, 47 minutes.