In this instructable I will take you through a simple mortise and tenon based footstool. This is a good starting project for myself and others if you are interested in making something using the mortise and tenon joint. I am doing this with hand tools (minus the drill press) but it can be done with any mixture of hand and power tools.
-Chisels (im using 3/4", 1") and mallet
-Marking gauge - http://www.amazon.com/iGaging-Wheel-Marking-Gauge-...
-Tenon or dovetail saw (im using a Sears dove tail saw)
-Drill press, vise, and 3/4" Forstner bit
-Miterbox and saw
-Wood - I found the wood I am working with at home depot. Normally they have these poplar blanks that are 1.5x1.5x30 for something absurd like $8.00 but a few weeks ago they had these "special buy" 1.5x.1.5x32 blanks for $2.25! Look for the sticker on them, they might be mixed in.
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Step 1: Cutting Up the Wood
Start by cutting up your stool "chasis" pieces. We need:
4 - 5" pieces - these will be the pillars
2 - 7" pieces - these will be the short side pieces
2 - 11" pieces - these will be long side pieces
This is where having a chop saw would come in handy. I only have a miter box and hand saw and straight edges on the end cuts are a must to making good tenon.
Step 2: Marking Your Tenons
On the end of each of the 7" and 11" pieces we need to mark out the tenons we need to cut and chop out. I am going to make a .75" wide tenon that will eventually fit into a .75" wide mortise slot. The tenon is also going to be .75" long.
I recommend doing these next steps on a scrap piece of wood to make sure you have the right measurement and so you can index off it later.
First step will be set the marking gauge to .75 and scribe a line on all 4 sides to create a depth line on each end. In the above pictures I have marked it Step 1 and have edited the scribe lines to highlight what line is being created.
Second step is to set the marking gauge to make two sets up lines that make up the width of the tenon. This is done by a simple formula - Marking gauge measurement = (material width - desired tenon width) / 2
In this example my material is 1.5 x 1.5 and I want a .75 wide tenon so... (1.5-.75)/2 = .375 aka 3/8. So on the marking gauge I need to make sure the depth is set to to 3/8. Scribe two lines, one on each side, and check how close you got my putting your chisel in between the two lines.
*If lines do are too wide or are wider than your chisel the marking gauge depth needs to be set higher to bring each line in more.
**If the lines are too close to each other than the opposite applies, the depth needs to be set lower to bring the lines out farther.
This expert on youtube better demonstrates what the above steps are looking to do with making markings before cutting:
Step 3: Cutting and Chopping Tenons
The first step is cutting the shoulder depth cut. This is the line that was scribed around piece in the last step at .75". The cut should go down the 3/8" tenon line but not past. I do this step with a dovetail saw and as can be seen, I am not the straightest cutter. This can be remedied later on with some cleaning up with a chisel.
After making both depth cuts we can use a method that I took from Paul Seller's mortise and tenon joint video. Both my video and his are below and will show you how to finish off your tenon.
Step 4: Marking the Mortise Lines
I would, like most projects, mark your pieces so you know which pieces are going to what later on. On each pillar there will be two mortise slots created. One mortise's edge will be .75" from the bottom and the other mortise will be .75" from the top. Based on the above picture the 7" pieces will be going from 1-2 and 3-4. The bottom mortises will be using the 11" pieces going from 1-4 and 2-3
Each mortise will be .75" wide to fit the tenon and 1.5" long to fit the tenon as well.
I scribe the two 3/8" lines to get the width and then I come back and scribe a .75" line to get the first edge of the mortise and then scribe another line at 2.25" line to get the full length of 1.5".
For a more visual representation see John Bullar's video;
Step 5: Setting Up Drill Press
Start by clamping a drill press vise down to the drill press table fairly well centered under the drill bit. The idea here is to use the forstner bit to hog out most of the material to cut down on chopping with a chisel.
Start by getting a test scrap piece together. Using the scrap piece from the tenon step index your marking gauge to the proper 3/8" lines so that the middle portion is perfectly .75".
Put your scrap piece into the vise and turn on the drill press and bring the bit down to just kiss the piece so you can see where you are located. Make necessary back and forth and side to side adjustments until you can achieve a centered cut like above and lock your table in position. In the first cut you can see that the forstner bit is just a hair over the line towards the left. On the second cut I tapped the table to the left and locked it back down. As you can see the cut is within each line, so I know the bit is perfectly lined up for the next step.
I am doing a blind mortise so that means the .75" thick tenon will be fitting into a hole that is .75" deep. If you are doing this as well then a depth stop will need to be set on your drill press so that you only drill .75" into your piece.
Step 6: Drilling and Cutting the Mortise
Now that you have your mortise markings and your drill press is set up then start vising up pieces and cutting out the mortise. One each mortise I will make three cuts on the drill press. One cut is right on the edge of the mortise, the second cut is on the other edge of the mortise and then I come back to the center and make one more cut.
After all or most of the material has been hogged out by the drill press, use your 3/4" chisel to clean up the edges and sides of the mortise. The last picture is what a mortise will end up looking like. Notice there is still some loose pieces hanging there but the general shape is what you are after, a perfect square.
After you chop out each mortise joint, take a tenon and match it to it. This is where you will have to shave pieces off either off the tenon or widen the mortise. I cut my mortises very tight so I end up shaving some bits off the tenon and then using my mallet to pound them home.
Step 7: Bring It Together
After you have cut all your tenons and mortises fit everything together. I do not use glue on my mortise joints, at least not for this application. The mortise are so tight after striking them home I can not pull them apart. But, if you have more loose fitting joints, apply glue to mortise walls and tenon cheeks and clamp in place.
After doing this you should end up with the final stool "chasis". I take this opportunity to begin staining and clear coating.
The stain used is called ebony from Verathane and I then used a semi-gloss polyurethane.
Step 8: Cut Foot Plate
We still need somewhere to put your feet. I am using a 1x12 piece of poplar to match the chassis. 1x12 acutal dimensions are .75 x 11.25"
I marked off a piece that is 13.25" long so there is some overhang and cut it off the main board. I rounded off the edges of this piece using a drum sander on my drill press. I then stained it the same color as the chasis and finished it the same way. After everything was dried I used wood glue on the top of each pillar and then clamped the plate down. I left it over night and it was done.
Step 9: Finished
Step back and admire your work. This project is a great way to start with mortise and tenon joints. I am by no means a perfect mortiser yet so this is good practice.