The through dovetail joint is strong and attractive. It's the traditional joint of choice for joining boards at right angles. Here is how I went about setting out and cutting my dovetails using hand tools and with some practice you can too. As always make sure you take all necessary safety precautions and follow all the safety instructions provided with your tools.
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Step 1: Terminology
Just to keep things easy I have labelled the key areas of the through dovetail joint.
Step 2: Tools
These are the tools I used. Mallet, Bevel Edge Chisels, Marking Gauge, Cutting Gauge, Dovetail Saw, Dividers, Marking Knife, Hard Pencil, Dovetail Square (or adjustable bevel), Try Square, Ruler, Smoothing Plane, Coping Saw
Step 3: Face Side, Face Edge
Make sure your material is cut to an accurate dead length, apply face side faced edge marks and reference the corners.
Step 4: Baseline
Set your cutting gauge to create the base line. Set it to the exact thickness of the timber to be joined. In this case the timber is of equal thickness. If the thickness of the stock varies apply the thickness of the tail board to the pin board and pin board to the tail board. For best results use the timber to set your gauge. Don’t be too aggressive with the gauge. We just want to create a nice edge for a chisel to pare from later.
Step 5: Half Pins
Dovetail joints start with a half pin located on the outside of the joints. Typically on fine work this would be 6mm > 9mm on larger work like a tool chest 10mm > 18mm would be acceptable. Set your marking gauge to the half pin size of your choice and mark the half pins onto the tail boards.
Step 6: Spacing
The space between half pins is divided between pins and tails. Fine work the pins 4mm > 6mm, larger work 7mm > 12mm. To have a desirable appearance the pins smaller than the tails.
Your tails should be around 18mm > 35mm for fine work like drawers and 35mm > 55mm on larger work like a chest.
Decide on your tail size remembering “One more tail than pin”.
Example: With experience we would know what we want to do but let’s experiment with this example
I have a distance between half pins of 330mm and I have chosen a pin size of 10mm.
15 x pins of 10mm = 150mm
330mm between half pins -Total pins 150mm = 180mm
180mm total tails divided by 16 (One more tail than pin) = 11.25
AWFUL, the tail is so small. This joint would be really strong but it would take ages to prepare and would have machine cut proportions. Lets try again
10 x pins of 10mm = 100mm
330mm between half pins – Total pins 100mm = 220mm
220mm total tail divided by 11 (One more tail than pin) = 20mm
Better, this would be OK for a drawer
6 x pins of 10mm = 60mm
330mm between half pins - Total pins 60mm = 270mm
270mm total tail divided by 7 (One more tail than pin) = 38mm
Good, this would good on a chest
Set dividers to 1 tail +1 pin. Start from the half pin marks walk them across the work leaving a light pin mark.
Step 7: Square
Using the square mark a pencil line across each divider mark.
Step 8: Slope
A 1:6 angle is typical for softwood a 1:7 or 1:8 angle is typical on hardwoods. Use the dovetail square or a bevel set to the right angle to mark your slopes. It’s good to mark your waste here. It will help you remember what you should be removing.
Step 9: Preparing to Cut
Clamp the tail board in the vice. To make the cutting easier set the board to the tails become a square cut rather than an angled cut
Step 10: Sawing
Using your dovetail saw cut to the line with the saw kerf within the waste section and cut all the way down to the base line
Step 11: Remove Waste
Use the coping saw to remove the waste. Don’t try and cut to the base line, leave a little for paring. Trim the half pin waste with the dovetail saw. Cut to the baseline or leave a little to trim
Step 12: Paring
Clamp the board down. Use a bevel edge chisel remove the waste by paring down just over half the thickness of the timber. Work back to the base line with the final trim on the base line. Flip the tail board over and repeat from the other side. Undercut very slightly to allow the shoulders to pull up nicely
Step 13: Marking Pins
The tail board is the template for the pin board. Secure the pin board in the vice. Use the plane to level the pin board. Rest the tail board on top. Use the plane to support the far end of the tail board. Line up the base line of the tails with the pin board and make sure the ends of the tails are flush with the pin board. Secure the tail board by applying downward pressure (use clamps if you want). Use the marking knife to create the outline of the tails. Remove pin board, square the lines, mark your waste.
Step 14: Sawing
Use your dovetail saw to rip down the pin with the saw kerf in the waste
Step 15: Removing Waste
Use the coping saw to remove the waste, as before don’t try and cut to the base line with a coping saw leave a bit for paring
Step 16: Paring
Clamp the pin board down and using a bevel edge chisel remove the waste by paring down to just over half the thickness. Work back to the base line with the final trim on the base line. Flip the pin board over and repeat from the other side. Undercut very slightly to allow the shoulders to pull up nicely
Step 17: Preparing
Use a chisel to remove a little edge to the inside face of the tails. Make sure it does not extend to the end of the tail. This makes it easier to line up and prevents damage to the ends of the pins during assembly. Check that the base line shoulders are square on both boards.
Step 18: Dry Fit
Offer the boards up and tap together with a mallet and waste piece of wood. If the joint feels tight separate the joint before going to far and trim as required. The joint should be firm but not over tight. If the joint is to tight it will split the timber
Step 19: The Finished Article
All ready to fit into my tool chest.