Please note: Johann Brentrup passed away September 18, 2024. All instruments have been sold and no more will be built.

Here’s a tour of the shop. As you can see, it is very small, but as they say, “well appointed”. I have what you would call a working shop with no frills, fancy jigs, fixtures, CNC, just the right amount of machinery to hand build instruments.



Mandolin spruce top shelf, and a stash of Brazilian RW below. Jet 16-32 sander is just right for dimensioning tops, backs and sides.



6” X 89” belt sander and 12” disc are invaluable for shaping and straightening. Notice the ducting and air filtration upper right.



Oneida cyclone, downdraft sanding table and vent to outside are important for dust collection and fumes. Stickered Adirondack red spruce on shelving.



Workhorse Powermatic 14” bandsaw, radial drill press.



Clamps, binding, chisels, and lots of Dremel routers.



Workbench doubles as an outfeed table for the table saw.

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Much of the rest of this page is devoted to building techniques and jigs. It will be updated periodically, so enjoy the photos.

Thank you for visiting my shop!
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Here are the construction steps I took to make vintage ‘20’s purfling:



This is the purling on an old Stahl mandolin. I decided I liked it so much I wanted to copy it as close as possible.



After some experimentation with sizing, I cut, dimensioned, and glued up a block of holly, ebony and red heart.



After squaring up the block, a .080” slice was cut off.



Herringbone is split, and crossgrain slices are cut from the .080” slice and sandwiched between the split pieces of herringbone.



A couple of early attempts.

Binding and purfling the instrument.



Since this is a very wide purfling, I am starting out with this tool I use for oval hole mandolins. I’m cutting the innermost ledge.





Next I rout the binding ledge. That leaves material to be removed with a chisel.







I finish off with a small file and carefully even everything out.




Here are several variations of the pattern.