Thread ID?

[Welderpaul]

Anyone know what this thread is likely to be?

Its from the 1950's so not metric.

 

[mike os]

1INCH UNC?

 

[mtt.tr]

What's that 14tpi

 

[brightspark]

whats your thread pitch gauge say and a zeus book

 

[Welderpaul]

whats your thread pitch gauge say and a zeus book

There isnt a pitch that it aligns with.

 

[Welderpaul]

Given that the thread is mullered, you sure it isn’t M24x3 ?

Not from 1950's, unlikely.

 

[brightspark]

whats it off

 

[Welderpaul]

whats it off

Tractor crank bolt

 

[Shox Dr]

That’s mullered. More than likely the wrong thread. What’s the internal thread look like

 

[brightspark]

here may beCRANK PULLEY BOLT 32162318, 32162331, 376184X1, 376197X1, 747267M1, 3118221R1, 02/101586, EM6419 | Emmark UK, Tractor Parts

 

[Agroshield]

You are not doing us any favours by showing the pitch of the male thread and not its OD.

Similarly, you are showing us the tapping size of the female thread without showing its pitch.

Screw a wooden dowel into the crank and try to measure the pitch of the female thread from the impression left on the dowel.
Measure over five pitches of the bolt instead of two.
Measure the OD of the bolt.
Measure the A/F size of the bolt.

Mr brightspark has maybe hit the nail on the head. It does look approximately like 5/8 - 14 BSP (see the URL) .

 

[RonA]

7/8” UNF that’s 14 TPI RonA

 

[brightspark]

might be 24mm

 

[Kram]

Edit.. Adding a rough guess of the pitch depth I get 7/8" 14tpi.

 

[Welderpaul]

You are not doing us any favours by showing the pitch of the male thread and not its OD.

Similarly, you are showing us the tapping size of the female thread without showing its pitch.

Screw a wooden dowel into the crank and try to measure the pitch of the female thread from the impression left on the dowel.
Measure over five pitches of the bolt instead of two.
Measure the OD of the bolt.
Measure the A/F size of the bolt.

Mr brightspark has maybe hit the nail on the head. It does look approximately like 5/8 - 14 BSP (see the URL) .

The OD of the male thread doesn't exist anymore, its been chewed off my some cackhanded spanner holder at some time in the past
There aren't 5 pitches to measure on the male thread - the last few are very flat.
There's no AF on the bolt as it just has a large head and recess to start it with a cranking handle.
The ID I have measured is unadulterated so is about the only precise thing to go off.

 

[Welderpaul]

might be 24mm

It ain't metric

 

[mechman]

Any clue from the makers? Brit or USA?

 

[Agroshield]

The OD of the male thread doesn't exist anymore, its been chewed off my some cackhanded spanner holder at some time in the past
There aren't 5 pitches to measure on the male thread - the last few are very flat.
There's no AF on the bolt as it just has a large head and recess to start it with a cranking handle.
The ID I have measured is unadulterated so is about the only precise thing to go off.

An OD measurement of what you have will nonetheless be useful: we can safely assume the correct one will be no less than what you measure. If, for example, it is bigger than 7/8", that would rule out the 7/8" UNF suggested above.

There are six clear and shiney (from flash reflection) thread crests in your second photo, which define five thread pitches.

ID does not tell you much, only tapping drill size and there is a range of possibilities for any particular thread.

A print of the female thread on some soft material is your best and most reliable chance of success.

 

[zzr1200]

Could it be 7/8, 15/16 or 1 inch SAE National Fine 14tpi?

It could even be an Perkins Inhouse purpose cut thread....

 

[pressbrake1]

Manufacturers like to use their own thread standards. I have boxes of odd bod taps
Beauty of cnc machining means you can Make non standard thread forms once produced to cause nuisance
The make of tractor would be useful