In my design I have a 220 ksi bolt with hex captive head place inside a counter bore hole of size 1" dia and 3.5" deep.
The torque that i need to apply is 1250 inch pounds.
What should be the hex head size that i need to provide. Is there any torque wrench tool available with <1" OD?
1250 lb-in is 104 lb-ft, which is well within the range of any 1/2 inch drive socket wrench. What is the bolt (head) size? Different toolmakers have different standards, so sockets ODs vary. Snap-On has some of the best and thinnest wall sockets available. Or perhaps use a hex socket head cap screw and torque it with a hex key.