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Screw thread finder - .133x40
Posted: Wed May 14, 2014 2:28 pm
by ovenpaa
I have some machine screws here with a major diameter of .133" x 40 TPI, can anyone identify them please. They are off an American produced set of 'scope rings. Closest I can find is .138x40 (No6x40) and these are too big, equally No5x40 is a tad small.
Can anyone help please?
Re: Screw thread finder - .133x40
Posted: Wed May 14, 2014 3:50 pm
by R.G.C
ovenpaa wrote:I have some machine screws here with a major diameter of .133" x 40 TPI, can anyone identify them please. They are off an American produced set of 'scope rings. Closest I can find is .138x40 (No6x40) and these are too big, equally No5x40 is a tad small.
Can anyone help please?
David,
Are they not simply M3:5 x 0,60?
They are so close to #6-40 that thy are easily cpnfused.
Qualified as 'limited use' , they were and are probably still widely used in german optic industry.
R.G.C
Re: Screw thread finder - .133x40
Posted: Wed May 14, 2014 4:02 pm
by ovenpaa
Robert, I tried a couple of M3.5x0,6 screws and they are too tight. As they have come off a set of rings of USA origin I suspect they might be No6-40 screws that are at the bottom end of limit on the major diameter.
Re: Screw thread finder - .133x40
Posted: Thu May 15, 2014 3:24 pm
by Alpha1
6 UNF
Re: Screw thread finder - .133x40
Posted: Thu May 15, 2014 3:29 pm
by ovenpaa
Yes 6x40TPI, I am really chuffed, I ordered them last night and they arrived today, are fitted and will head off to the customer in the morning ready for him to shoot a competition at the end of the month.
Re: Screw thread finder - .133x40
Posted: Thu May 15, 2014 3:35 pm
by Alpha1
Nice one.