What kind of thread is this?

[tcncj]

I'm trying to find out which thread is being used.

The outside diameter of the thread is 14mm
Inner diameter is 10,8mm


I was expecting it to be trapezoidal 14. But trapezoidal 14 should be 14,5mm outside diameter
So it's something else

Besides when I measure the pitch it's not 3mm or 4mm.
It's something like 3,6mm

Anyone familiar with this kind of thread?

 

[Lewie]

Sounds close to 5/8 - 8 Acme.
...lew...

 

[tcncj]

Thanks for your reply

But 5/8 seems to have a outside diameter of 0.625" that's 15,875mm. The thread on the part is 14mm

The tread pitch is 3,6mm.
That's pretty close to 0.14286...which means it's 7 TPI (acme)

But the outside diameter doesn't fit any standard ACME size?

 

[Phil in Montana]

A worn out acme...Phil

 

[CAMasochism]

Thanks for your reply

But 5/8 seems to have a outside diameter of 0.625" that's 15,875mm. The thread on the part is 14mm

The tread pitch is 3,6mm.
That's pretty close to 0.14286...which means it's 7 TPI (acme)

But the outside diameter doesn't fit any standard ACME size?

It could be a worn 9/16, that is pretty close to 14mm.

 

[gregormarwick]

It would have to be an extremely worn 5/8 acme, which it does not appear to be in the photo at least.

TR14 is 14mm major dia. not 14.5mm...
7TPI is 3.629mm
9/16" is 14.2875mm

It could be a 9/16-7ACME, but the minor diameter for that would be max. 10.15mm
Minor diameter of a 9/16-7 STUB ACME is min. 11.2mm...

Min. minor for a 14mm x 7TPI STUB trapezoidal is 10.9mm...

If it's a leadscrew off of a machinetool don't be surprised if it's a 14mm x 7TPI with some modified thread form. Stranger things have happened.

 

[Limy Sami]

If it's a leadscrew off of a machinetool don't be surprised if it's a 14mm x 7TPI with some modified thread form. Stranger things have happened.

+ 1 on that ;- My Induma turret mill's leadscrews are 30mm OD x 5TPI.

 

[mark costello]

Could be a bastard size, nothing is set in stone anymore.

 

[winger]

the cross slide lead screws on our 2 DoAll (Harrison) lathes are metric od and inch pitch acme. so a mix is not out of bounds.

Dave

 

[Mark Rand]

7TPI isn't unheard of in non-metric machines. It is actually 22DP, so useful if there is a worm gear somewhere in the system.

That probably doesn't apply to this thread though!

 

[MetalCarnage]

Doesn't look like an acme to me, more of an old square thread - Square Thread Precision Leadscrews - Rempco | Rempco

JMHO

-Ron

 

[Bill D]

the cross slide lead screws on our 2 DoAll (Harrison) lathes are metric od and inch pitch acme. so a mix is not out of bounds.

Dave

Their m300(rebadged over the years as doall, colchester, wilton etc) designed around 1972 and still being made today was designed that way. The base machine is all metric but the native English machines just changed the thread pitch on the lead screw and cross slides. They did not change the diameter.
Bill D