My friend Jason was in town, so I put him to work sawing some pieces of 7/16 threaded rod for spacing out the forward and aft halves of the F-704 bulkhead.

The instructions say to make this gap exactly 1.438 wide, but when I measured the thickness of the spars, I got as much as 1.446. I used these pieces of allthread and some washers and jam nuts to get the spacing exactly right. The piece of paper shows the different measurements I measured. I think I'm going to try to borrow some gauge blocks from work to check this gap since it's difficult to get the calipers between the forward and aft halves of the bulkhead to get a good measurement.