This is instructable on turning big box home center construction lumber into functional furniture you could be proud of.
To follow this instructable you will need some intermediate level woodworking tools and a lot of patience.
Step 1: Materials and Tools
- To make two of these tables I used 15 - 2 X 6 X 12' boards.
- You'll also need about a quart of glue per table
- 4 X 3/8" X 5" carriage bolts + nuts and washers per table.
- 1 quart of your favorite finish (I used a semi-gloss water based poly)
- 24 plate joiner biscuits per table are optional
I used 2 X 6 lumber instead of 2 X 4 so I could more economically use material and I wanted a top that was more than 1.5" thick.
Longer boards are usually higher quality than the 8' boards because they take more mature trees to make. The longest pieces are 6' so I bought 12' boards and cut them in half.
- Table Saw
- Wood Chisels
- Circular Saw
- Hand Saws
- Assorted measuring tools
- Router with 1/4" roundover bit
- Drill Press
- Miter Saw
- Biscuit Joiner
- Band Saw
- Oscillating Spindle Sander
Step 2: Patience & Stress
Patience is key to using construction lumber. Even if it says the lumber is kiln dried it will usually have a much higher moisture content then what is recommended for wood working. As the wood dries it will shrink creating internal stresses on the boards. Depending on the grain orientation this may cause the board to twist, bend, cup and or check.
To help combat the effects of the excess moisture you'll need to let it dry for a long time, more than a month most likely. You can help this a little bit by picking light boards (weight not color) since they have less water weight. Buying larger sizes also help because are not sold as often staying on the shelves longer drying out. 2X4s sell quickly so they are "fresher" and therefore have a higher water content.
Stack the lumber so that there is good air flow between the boards so they dry evenly.
Once the wood has had a good chance to dry you'll want to start cutting it to the rough shape.
You can see the effect of drying in the 2nd picture how the internal stresses in the board were released when it was ripped half. This may be due to there still being a higher moisture content in the middle of the board.
I found out the hard way I should have let these ripped boards dry some more before moving on, but I was able to make it work with a little more time on the jointer.
Step 3: Glue Time!
When it came time to start gluing up the boards I did 4 boards at a time because my jointer is 6" wide and to get a flat tabletop you really need a jointer.
I book matched the ripped boards for 2 reasons.
- It looks cool
- The bends in the wood will counteract each other normalizing the stresses to pull them straight.
Use a liberal amount of glue since the faces have not been jointed or planed.
Use lots of clamps to keep even pressure and straighten any bent boards.
When the glue has set up for about an hour scrape off the excess. This will reduce the wear and tear on your jointer blades later.
Step 4: Straighten Up!
The key to getting a good flat laminated table top is a good Jointer. The longer the in-feed / out-feed tables the better. These 6' long 6" wide glue laminations are are about the limit for what my old Delta jointer can handle.
The technique I use when using a jointer are listed below
- Make sure your machine is setup properly: The fence is square with the out-feed table. The knifes are set properly and at the exact height of the out-feed table.
- Run boards with the concave face down making multiple shallow passes alternating the leading edge end for end.
- When you have a twist in the board I put pressure as far back on the board as possible until a clean flat edge has established contact on the out-feed table then make sure that fresh cut edge remains in contact with the out-feed table.
- Keep repeating using shallow 1/32" cuts (until you're comfortable with the technique then you can make more aggressive passes.
- When you have the face smooth and straight it's time to joint the edge making sure your fence is set exactly 90 degrees to the out-feed table (it should be both if you're machine is nice and tight and has those adjustments but if you have an old machine like mine, align the fence to the out-feed)
- Same technique applies but now you'll have the added task of making sure the freshly flattened edge is tight against the fence as well.
Once you have one flat face and edge you'll want to make sure the glue lamination is parallel.
You can get away without a planer for this step if you jointer is setup properly but there is still a chance it might not be perfectly parallel.
The 1st step is going back to the table saw and setting the fence to cut off the opposite sides that are most likely crowned or convex.
One more pass through the jointer (or Planer) will clean up the saw marks and you're ready for then next step!
Step 5: More Glue Please
I made two tables for this project. Both are roughly the same size 6' Long 30" deep and 29" tall but one of them have a 12" X 24" cutout for a sewing machine.
This is the only difference between the two tables. The process to glue up the 4 board laminations into a 20 board lamination is the same.
It's not necessary to use a plate joiner, but it does help with alignment. Even if your boards are straight the process of gluing and clamping multiple boards together can easily slip causing misalignment. The use of a plate joiner and biscuits will prevent the boards from slipping during the gluing and clamping process.
This careful alignment will prevent you form having to smooth and flatten the entire table top surface and limit it to only a minor amount of sanding.
The sewing machine cutout was done prior to glue-up because the thickness of the top (2.25") was too much for my jig saw so I cut the radius-ed corners with a band saw cleaning up the straight sections with table saw plunge cuts and my oscillating spindle sander for the corners. A rasp would also work if you don't have the sander.
Step 6: She's Got Legs
The leg design for these tables are a K brace style. They turned out very strong and provide enough clearance to move in and around freely.
The wood used is two 2 X 6 boards laminated together then ripped to different widths to minimize waste.
The angled braces were laid out using stair gauge blocks and a framing square.
Mortise and tenon joints are used for all joints with normal wood glue (no fasteners or wedges.)
Mortises are 1st laid out with a marking gauge then roughed out on the drill and finally cleaned up with a chisel.
Tenons were cut primarily on the table saw and cleaned up using hand saws.
The 1/2" relief cut on the bottom was made by clamping two feet together then drilling a 1" diameter hole 3" from each end. The middle was cut out using a plunge cut on the table saw (yes I know it's not safe) and a handsaw to cut the remainder.
All exposed surfaces were hit with a 1/4" round over bit and everything was sanded prior to glue-up.
Step 7: Brace Yourself
The cross brace for the back was made from 2 X 6 material was well. It was planed and jointed to make everything smooth and straight.
I screwed 2 boards together exactly in the middle then spread them apart to find the exact angle needed to connect the two legs.
Once that angle is laid out it's transferred to all four boards and the material between the lines is half removed. I used a circular saw and chisels to remove the material but a router could do the trick too.
I made sure to stay inside the line and used chisels to pear off material to the line.
The 1's pass was about 1/8" too shallow so I made another pass until things lined up perfectly.
Normal wood glue is used for the joint and it dried before I use a straightedge and saw to trim the ends to they line up with the legs.
Step 8: Sewing Machine Tray
The last bit of construction is a tray to support the sewing machine
I had some scrap 2 X 4 s and 1/2" plywood I used to make the tray.
The 2 X 4 s are ripped, jointed and planed so the depth of the tray matches the exact height of her machine.
To counteract the expansion and contraction the top will experience (~ 1/8") due to seasonal changes the tray was attached with long screws where only the head section of the screw went through an 1/8" diameter hole, but the rest of the screw went through a larger 1/2" diameter hole. This larger hole allows the screw to move as the wood moves.
The screw heads were counter bored to prevent snagging on your legs / pants.
After the tray is screwed in place I prepared a ledge for the insert to rest on. I used washer head screws and over sized holes in these as well so I could adjust the insert height to match the table surface.
The inserts are made from some 1/2" cherry veneer plywood I had left over. Fortunately my wife had an acrylic surface that already had the machine cutout so I just traced the profile and now everyone's happy!
Step 9: Finishing
For the finish I used a common water based semi gloss polyurethane.
The legs, braces and table bottoms received 3 coats each.
The table tops received 4 coats each
After the 1st and 2nd coats I sand with 220 grit paper.
If you want to stain a project like this you would 1st use a sanding sealer or wood conditioner prior to staining. This will even out how the stain is absorbed by the wood and prevent blotchy spots. You'll also have to be a lot more careful when sanding. any imperfection in the wood surface gets magnified by stain. This is why I use clear finishes on all my projects ;p
I hope you enjoyed this instructable.
You can make great looking furniture with big box store lumber you just need to be patient in letting it dry thoroughly. Have a jointer / planer to straighten makes a world of difference but not 100% necessary.