There comes a time in the life of a Stearman when one or more Dzus fasteners do not engage the mating spring with enough tension, with too much tension, or not at all.

When this happens, it is clear that the spring needs adjusting up or down.  The tool of choice to make this adjustment, most often  is the “BHSD”.

You go to the tool box and pick out the appropriate BHSD, and move toward the malfunctioning Dzus fastener. You reach through the hole and put the end of the BHSD under the spring and pry it up.  The spring moves up a bit, but since you are prying at an angle, the spring also is forced to one side of the hole.

No problem! Just reach through the hole in the opposite direction and pry a little more. The spring comes up a little more and “voila”, it moves back nearer the center of the hole. 

Working from both sides in this manner, puts matching symmetrical dents in the sheet metal and gives you a leg up in winning the “Stearman Most in Need of Restoration” award.

OK, a BHSD is a Big Honkin’ Screw Driver.

MilSpec Products  has come up with a tool  that spoils all of this fun.

It has a base plate which either rests flush against  the front of the Dzus hole, for pulling the spring up, or rests against the rivets or screws on the back of the spring  for pulling the spring down.

The heart of the device is a hardened metal tool that is threaded on one end and has slots to engage the Dzus spring on the other. 

The base plate is positioned against the Dzus, front or back, and the tool is placed through the hole in the base plate where it engages the “S” spring.  A nut is threaded on to the tool and the spring is pulled toward the base plate by turning the nut. Just a turn or two and then you can retry the Dzus fastener and get it right where you want it.

MilSpec is located in Apopka, Florida, 407-814-8997.  They also have a web site with more information about their products at

The tools runs about $20, give or take, and looks like it should out last the BHSD