May 1, 2012

Homemade Shaving Brush

Continuing to groove on the straight razor thing, and having made shaving soap and a strop, it seemed natural to make a brush. I'm doing fine with the the horsehair brush I got for free off B&B, but I wanted to experience what badger hair has to offer.

Actually I bought the 22mm Super Badger Bulb from The Golden Nib, but I made the handle and did the assembly. The ferrule is laser etched titanium. The handle is maple finished with oil & wax, secured to an aluminum disk plug with an M4 stainless screw. The knot was installed with epoxy.

The ferrule tubing is 1" OD, 0.035" wall Grade 2 welded Ti tubing from McMaster, #89835K81. I cut some 25mm long chunks with the abrasive chop saw (Ti makes dazzling white sparks!), then cleaned them up with abrasives and a buffer. The tubing came with deep and regular marks in it, probably from the fabrication process. I didn't bother sanding them all the way out.

I ordered a 1" maple dowel, 97015K82 from McMaster, and chopped a piece off, then put it into the metal lathe. I freehanded the little groove using my microplane rasps, drilled and countersunk the end, then used the cutoff tool to turn down the end to press into the ferrule. I cleaned up the rasp marks with sandpaper, then cut the part free with the cutoff tool.

Next came a small aluminum plug, envisioned as a press fit into the ferrule. This was tapped for an M4 screw. I was a little worried about the maple maintaining its dimensions and thus a good bond to the ferrule. The idea with this plug was that it would be more stable and better connected to the Ti tubing. Plus I thought having a flathead stainless screw in the back of the handle would look nice. Much to the chagrin of some of my coworkers, I love flat head cap screws.

Unfortunately I was in a rush and turned the aluminum plug to a slip fit instead of a press fit, while the maple ended up being a press fit. I'm pretty sure epoxy will hold it together in any case, but we'll see.

We have a 1064nm fiber laser at work for cutting silicon wafers, so I used this to etch in the design to the ferrule, with the help of some ceramic laser marking spray from Ferro called Cermark. I am carrying on with the trident theme previously employed on my strop and shaving soap.

The parts were assembled using Loctite E-120HP epoxy and its associated static mixer and dispensing gun, again from McMaster. I used a bit too much epoxy to glue in the knot, so the first millimeter or so of the bristles is now saturated with epoxy, at least around the perimeter.

Finally, I covered the bristles and ferrule with plastic and tape, and finished the maple with 4 coats of Waterlox Original oil finish plus an application of furniture wax. Hopefully it can stand up to the wet shaving environment.

I also made a little travel case for it out of 1.5" diameter Ti tube from McMaster. I turned down some chunks of 1.5" OD, 1" ID aluminum tube to fit in the ends. On one side I pressed in an end retaining piece. On the other side I turned it to a slip fit and added an O ring groove so that it can be pushed in and out, but stays put once you push it in.

Once I tested it, I realized the handle would slip through the opening in the endcap. So I added an internal O ring to the fixed end cap, to prevent the brush from slipping out the back. This worked, but overall I think I'd design the second rev of the carrying tube to hold the handle somehow and have it not able to bang against the bristles inside the case.

Millie was playing around with it last night and sniffing it. I asked her what it smelled like. She said "Dead skin!". Now if that doesn't make you want to rub it all over your face I don't know what will :)

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