What is the Width of the Square Part Under the Head of Thule Bolt 915-068-054

Question:

Hi, I am comparing two different Thule carriage bolts for specific application. What is the width of sq. section under bolt head? Replacement Bolt for Thule Sidearm TH594XT Item # 915-068-054 Bolt size: M6 x 80 Square section under bolt head: ??? Versus Carriage Bolt M6-1 x 75mm - Fully Threaded Item # TH10403 Size: M6-1 x 75mm Square section under bolt head: 0.3

asked by: Suzie

Expert Reply:

I went out to the warehouse and pulled Thule carriage bolt # 915-068-054 to measure the square part under the head for you. Using digital calipers I found that it is 0.23 inches square which just a hair less than 1/4 inch.

Like you said, # TH10403 by comparison has a 0.3 inch square part under the head.

expert reply by: Michael H