Cutting ListOverall dimensions: 32” x 24” x 4”

Lumber and Sheet Material

Part Part Quant. Dimensions

A side 2 24” x 4” x ¾”

B side 2 30½” x 4” x ¾”

C top 1 31¼” x 23¼” x ½”

D bottom 1 31¼” x 23¼” x ½”

PVCE air duct 1 6’ length of 2” pipe

F coupling 4 3” 90° elbow

G coupling 3 3” Tee

H coupling 1 4” to 3” reducer

Downdraft Sanding TableT h e s e p a g e s a r e p r e s e n t e d f o r p e r s o n a l u s e o n l y . N o w a r r a n t y i s e x p r e s s e d o r i m p l i e d . W o o d w o r k i n g i s a n e n j o y a b l e a n d e n t e r t a i n i n g h o b b y , b u t i t c a nb e d a n g e r o u s . I o f f e r o u r p r o j e c t s a n d t i p s i n t h e s p i r i t o f s a f e w o o d w o r k i n g a n d a r e n o t r e s p o n s i b l e f o r i n j u r y o r d a m a g e c a u s e d b y y o u r c a r e l e s s n e s s o ru n s a f e p r a c t i c e s . A l w a y s p r a c t i c e n e w t e c h n i q u e s o n s c r a p w o o d a n d S T A Y A L E R T A N D B E S A F E ! ! !

ConceptA downdraft sanding box captures a large portion of dust particles before it enters the air you breathe. This will keep your shop cleaner, andyour lungs healthier. A win-win situation.

CreditMany thanks to the fine people at the www.woodworking.org online exchange forum. Special thanks to Larry Layne for insightgained from his sanding box design, Paul Crifton, ‘Ron’, ‘Mango’, & ‘bobham’ for their technical assistance, and to the many otherswho took an interest and added their valuable advice and observations.

BOX CONSTRUCTION

• The sides of the box itself could be made with any sort of lumber or sheet good. I used old pieces from some melamine sidedparticleboard. But hardwood, pine, or plywood will work just as well.

• Join the box using any method you feel comfortable with, I used #20 biscuits and butt joints. Just be certain that the box is square andhas no gaps at the joints.

• Rabbet a 3/8” wide x 1/2” deep groove around the inside of the top and bottom of the box, then square the corners. For the bottom, Iused 1/2” hardboard that I glued and set into place with a few small brad nails.

• For the top I used a piece of 1/2” OSB board that I drilled 1/4” holes evenly spaced across the surface. I used a piece of scrap pegboardas a template for drilling the holes. This was a timely step and you can easily avoid it by securing two pieces of 1/4” pegboard together.I also drilled a 1 1/2” hole at one of the corners to use as a finger grip to easily lift the top up and facilitate cleaning the inside of the box.

• Drill a hole to allow the a piece of PVC pipe to extend through one end to give something for the reducer coupling (part H) to attach to.Use a hole saw or a router for this step, and remember to do this before you join the box. It will make life easier (hope you read ALL ofthe instructions before you started!)

• Use a basic rubber sanding mat to help hold the work piece on the top surface while sanding. Make sure it is porous so as to prevent theflow of air and prevent the downdraft.

• Optional step: I attached a clamping “rail” to the side of the box so that I could use spring hand clamps to quickly clamp the pieces to thetable. If you choose this option make sure the rail isn’t too thick to use the clamps in conjunction with a thick work piece!

PVC Duct Construction• The basic design is a figure eight, with 90° elbows at the four corners and Tee connectors at the sides and inlet. Start off by setting the

elbows and Tees in the box and then take the measurements for the sections between them.• Cut pieces of PVC pipe to these measurements and assemble. It’s that easy.• Begin drilling holes, smaller diameter (3/8”) toward the inlet and larger diameter (7/8”) as you approach the other end of the figure eight.• Drill holes sparingly at first, this is especially crucial since each dust collector will operate at different cfm, you will need to play around

with the amount and placement of the holes (see next section).• Drill holes on the top, sides and bottom of the duct work. Be sure to stagger their placement across from each other. If your drill too

many you can always cover them up with tape (that’s what I did).

Points to Remember & Helpful Tips• The vacuum pipe needs to be sealed to the box with silicone sealant or have anopening without noticeable gaps. The sanding box isn't a 'dust collector attachment'.You want a high volume draft moving through the vacuum pipe, not a high vacuum.The vacuum pipe should be drilled sparsely at first. After assembly, fire up the dustcollector and hold the hose close to the vacuum pipe. If the hose tries to 'grab' thepipe, you don't have enough holes or the holes aren't large enough. Drill extra holesuntil the hose no longer tries to 'suck onto' the vacuum pipe. Listen to the vacuumitself when you do this . . . it'll tell you when it's moving enough air and not trying tocollapse the pipe from vacuum.• The graduated holes are important to equalize the flow of air used to create thedowndraft. My 'test' for correct draft is done with a sheet of paper. Dropped flatfrom above the box, it should settle directly and not float off to one side. It shouldflatten out immediately, not 'eventually'.

• Lastly, the sanding box won't get "all" the dust, particularly the very finest sortc reated by finish sanding with 200 grit or finer paper. So don't expect it to turn the shop into a 'clean room'.

© w w w . w o o d w o r k i n g m a t t e r s . c o m

A

B

3/8” wide x 1/2” deep rabbet

F

F

F

F

E

E

E

E E

E

E

E

G

G

G H 24”

32”

You may alter the overall dimensionsfor your box, however, keep in mindthat this will necessitate a change inthe layout and number of holes to usein the PVC duct system. The top restsin the 3/8” x 1/2” rabbet.

H

E

E

F G

E

The photo on the left shows the individual pieces of the PVC duct system and a better view of the holes notice the tape over some of the holes (remember what I said about drilling sparsely at first). The photo on the right shows the entire system with the top off. You can see the rabbet along the inside edge of the box and the inlet cut through part B to the right.

These pages are presen ted for persona l use on ly . No warran ty i s expressed or imp l i ed . Woodwork ing i s anen joyab le and en t e r ta in ing hobby , bu t i t can be dangerous . I o f f e r our p ro j ec t s and t i p s i n t he sp i r i t o f sa f ewoodwork ing and are no t r e spons ib l e f o r i n jury or damage caused by your care l e s sness o r unsa fe p rac t i ce s .A lways prac t i ce new t echn iques on sc rap wood and STAY ALERT AND BE SAFE! ! !

Here you can see an assembled box. The photo on the left is a good shot that shows the clamping strip attached to part B and a handle I attached to the end opposite the inlet on part A. The photo on the right shows the inlet and the finger hole used to lift the top off.

A

C

B

C

B

H