47 - Build Your Own Mortising Machine , страница 4

T IPS & TECHNIQUES

Readers® Tips *

Vacuum Muffler_

Wood Plug Trim Saw

No. 47

EPOXY

waste

blade

Me" clearance

■ Cutting wood plugs is a snap with this simple trim saw, see photo. Ifs just a curved wood block that holds a cutoff hacksaw blade, see drawing.

To avoid marring the workpiece, the blade is recessed in a groove, see detail. (This leaves a nub sticking up, but it's easily sanded flush.) Also, a notch provides clearance as you saw.

Chris Forgacs North Benton, Ohio

ShopNotes

cutoff hacksaw blade

cut groove slightly deeper than blade (see detail)

■ Shop vacuums are great tools, but they sure make a lot of noise. My dog knows. As soon as I flip the switch, he bolts out of the shop.

To reduce the noise, I made a simple muffler using inexpensive PVC pipe and pipe fittings, see photo. As it turned out, the muffler cut the noise level in half.

Editor's Note: This muffler requires the shop vacuum to have an exhaust port that allows you to attach the hose and use it as a blower.

The basic concept of this muffler is simple. Air from the vauccum is exhausted through a layer of foam that fits between an inner and outer pipe, see drawing at left. Hie foam dampens the sound as the air passes through. (Foam is avabilable at most upholstery shops.)

To direct air into the foam, you'll need to drill a number of holes in the inner pipe and glue a cap on the top end. (I used PVC cement to attach the cap.) This forces the air through the holes, into the foam, and out of a reducer thaf s glued to the top end of the outer pipe.

There's also a reducer on the bottom end of the muffler. But to allow the inner pipe to fit through this reducer, youll need to file off the lip that's on the inside of the fitting.

To fit the muffler in the exhaust port on my shop vacuum, I added another reducer to the bottom end of the inner pipe. But first I cut off the expanded part of the reducer. Note: Don't file the lip on this reducer. It keeps the pipe from sliding through.

Chris Glowacki West Des Moines, Iowa