what size hole

[TravisTractor]

444 IH tractor, the aux. port on front of rockshaft housing, could it be british paralell thread, as i am haveing trouble finding correct fitting, sae is not working. thanks

 

[beenthere]

Might be BSW (British Standard Whitworth) as the tractor appears to be made in England in the 70's.
Might be worth a google of a thread size chart. Might also try the national pipe thread, just by chance.

 

[Discount Hydraulic Hose]

Try this thread chart.

Fluid Port Size Charts > Discount Hydraulic Hose.com

 

[TravisTractor]

thanks everyone for the help