Here's an assortment of noseblocks I have made over the years...
Sky9pilot

Another noseblock/propblock type is the radial engine on one of my biplanes the New Standard D21.  Here the whole enging became the propblock and  it was drilled with down thrust of 3 degrees.

The noseblock can be constructed in many different ways.  You can build a box from balsa sheet, solid block of balsa, laminated sheets of balsa. 
Or you can make a round/cylindrical noseblock from a block of balsa or laminated sheets of balsa that is turned on a drill press, lathe, or variable speed hand drill. 
There are also adjustable propblock/noseblocks that can be purchased from Free Flight Suppliers such as Volare, Peck Polymers, Easy Built etc.

This first noseblock is very simple construction using a thin 1/32" ply disc with a laminated balsa block on the back of the ply disc which will fit into the nose of a radial engine cowling.  I think the picture of the noseblock will be pretty self explanatory.  The prop bushing is a brass tube and the hole for the tube is drilled at an angle to give approximately 3 degrees down thrust.  Side thrust is achieved by shimming the sides of the block in the needed direction.