A: Yes, the JointPro should work in that application.
A: So the jig will work on a 2x4 if you provide additional blocks for spacing. The jig set up for 3/8 dowels will center for 3/4 stock. So placing your desired guide insert on the outer sections.. very top and very bottom. adding blocks/ shims on jig will allow you to customize the center point for your desired stock.. Wish there was a simple slip on insert for this . But if you were to just use the jig as is the dowels would line up on a 2x4 but be just 3/8 off center to the edge of the board. Hope that answers your question
A: Yes, this can be used for joining 2 x 4s. Please note that the dowel hole will not be exactly center, but slightly off center for 1.5" lumber.
A: The JointPro is made in China.
A: Proudly Engineer in the USA.
A: Try this link for an answer https://www.milescraft.com/about-us/history/ Their website says engineered in the US but doesn't say where manufacturing is done.