December 8, 2022

How to Make a Log Cabin Dovetail Jig

There are a lot of ways to make dovetail joints, but one of the most popular methods is by using a log cabin dovetail jig. This type of jig is simple to make and can be used to create some really beautiful joints. In this blog post, we will show you how to make your own log cabin dovetail jig. We’ll also provide some tips on how to use it effectively. So, let’s get started!

How to build a dovetail log cabin

  1. Use a jig to notch the logs. Make sure you have enough space to build your own if you want. To make your own, you need a custom set of jigs that will work for your log dimensions and end up with the gap between the logs you want. The plans are custom designed for whatever dimensions are specified. After you decide on the cabin dimensions, add 4 inches to each and use those numbers to cut the logs to length. The jigs for half dovetail notches take about 2-3 hours to make.
  2. Attach the first jig. Lay the log on a side and mark a line down the center using a chalk line. The jig also has a centerline with holes cut out that make it easy to align the jig with the log. It attaches to the inside face of the log. The log face will be on the inside of the cabin, facing upward. Leave about 2 inches between the end of the log, and the jig end piece. Attach it to the log with three sheetrock screws. Measure from the perpendicular edge of the jig.
  3. Calculate the cabin’s interior dimensions, align the other jig to the centerline of the log and attach it with screws. The jig plans have instructions for making and attaching the saw spacers to the chainsaw bar. They allow the saw to run along the jig without cutting into it.
  4. Saw the notches. Roll the log over and saw the notches using the jig to guide the saw. After making the two cuts for one notch, remove the scrap piece of wood and make a second pass. That will make the saw cut smooth for a good fit. It takes about 4 minutes to complete notching on one log. Use a dovetail jig to make box joints.
  5. Stack the logs.
  6. Chink the logs using perma-chink, a synthetic log-chinking product (Permachink.com). Install foam backer rods in the joints. Apply the chinking. Moisten with a spray bottle and smooth with a small trowel or modified putty knife.
https://www.youtube.com/watch?v=75RS0fF9d1o

Using a dovetail jig to make box joints

Nearly all dovetail jigs can cut box joints. Check the manual that accompanies your jig for the exact instructions. The setup is like cutting the tails of a dovetail joint, except that the bit would be a straight-cutting bit rather than a dovetail bit.

To assemble, apply a thin layer of glue on all joint surfaces, slip the joints together and clamp as needed. This type of joinery is for making box-like structures such as drawers. However, be more diligent about keeping the box square when clamping, than you might need to with dovetails. The box joint is strong and can be a lot of fun to build. It is not as elegant as dovetails.

The dovetail joint is a beautiful, strong method for connecting two stock pieces. However, there are times when the dovetail does not perform better. If you need to connect two pieces of plywood,  you might not use it as opposed to the hardwood. Using dovetails to connect plywood would increase the chances of delaminating the plywood when testing the joint while dry fitting.

An alternative to the dovetail is the box joint. A box joint is similar to a dovetail, with the difference being that the fingers in the box joint are rectangular rather than dovetail shaped.

There are a few ways to cut box joints. You could always do it with a dovetail saw and chisel. Pick a width for the fingers that will divide evenly into the width of the stock. If your stock is six inches wide, a half-inch wide finger allows for twelve fingers total, six on each piece of stock.

Steps

  1. Start by planning your board to the desired thickness. 
  2. Cut four sides, labeling each piece lightly in pencil: front, back, left, and right. Putting the label at the top of each piece helps in orientation later.
  3. Lay them out in the way they will be assembled.
  4. Stack two-piece on top of each other with one offset from the other. Raise the router bit until it touches the offset piece on top. Do not change the height. Take a flat scrap wood and clamp it to your miter gauge. You might need an additional scrap for a clamping surface on the rear of the miter gauge. The front piece is flush with the router surface table, and the clamping piece clears the router bit. Turn on the router and rout a rectangular hole in the front scrap piece. This hole will hold the jig finger. Cut a piece of wood, larger than your bit size. Fit the piece into the slot you cut in the jig board. File or sand it down to a tight fit. Sand the bottom down, so the finger is flush with the bottom of the jig board.
  5. Realign the jig board on the router table, against the miter gauge. Clamp the board offset from the bit by the width of the bit. Use a drill bit as a spacer between the jig finger and the router bit. Clamp the jig board into position, measuring against the widest part of the router bit.
  6. Start cutting fingers. Make some test fingers on a few pieces of scrap wood to test the alignment of the jig. If the fingers do not fit together, try the alignment. For the first cut: align one side of the side piece with the inside edge of the jig finger. Route a hole. For the second cut: move the piece so that the slot you just cut fits over the jig finger. Route a new hole. 
  7. Cut the fingers on the second piece.
  8. Fit your pieces. Do not be worried if the ends of the fingers are too long. If the finger ends are too short, your bit is not high enough. You may file the holes deeper to make a better fit.
  9. Cut fingers on all eight sides following the same procedure as the first two sides.
  10. Glue and finish.

Conclusion

Making a log cabin dovetail jig is a great way to connect two pieces of wood together. The process is simple and can be completed with basic tools. There are a few different ways to cut the joints, but we recommend starting with a dovetail saw and chisel. Be sure to test the fit of the joint before gluing and finishing.

David D. Hughes

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