Dovetail Practice

[Tom Bender]

Having made quite a few hand cut dovetails, my confidence is good, but the current project requires half blind. Time to get a little practice with that. Never in a hurry, always something new. This is a great hobby.

[Jim Koepke]

Same here, my next project uses some dovetails. A bit of practice beforehand has shown its value in the past. So far laid out and cut the tails. Other distractions got in the way. Will get it done eventually.

My dovetails tend to get better as they go. cutting a half dozen or so before cutting them for keeps is worth the effort.

jtk

[Michael J Evans]

I'm on my fourth official half blind dovetail and it was another one one those things where I watched some videos and thought "that ain't so bad". Jokes on me...

[Ben Ellenberger]

I think I was on my third or fourth drawer with half-blinds before I felt like I was getting the hang of them. For me, I didn’t get the back of the socket vertical, so the tails would get pushed out as i tried to seat them and I would end up with gaps. I had heard other people claim half-blinds are more forgiving than through-dovetails. At first that seemed ridiculous to me, but I think I’m coming around to agreeing with them.

I also agree with Jim about dovetails getting better as they go along. For future “nice” projects I may mill up extra stock to cut a practice joint or two before cutting the real pieces. There always seems to be little variations in how tight they need to be when you switch from one type of wood to another.

[Jim Koepke]

On the subject of half blind dovetails this is a worthwhile read > https://sawmillcreek.org/showthread.php?288626

Using a kerfing tool whether professionally made or shop adapted will save time and frustration.

jtk

[Mike Henderson]

I find the half-blind easier than the regular (through) dovetails. There's less showing so you can take a few liberties.

Mike

[Michael J Evans]

Well I'll be doing two more later this week. Both my attempts today / yesterday needed up being two loose. I'm thinking my problem may be I tried these two working to knife lines vs my normal pencil lines? I used the blue tape method and pared to right on the knife lines, but the pins ended up a shade too wide

[Bob Jones 5443]

Michael, the idea of offsetting the marks appeals to me. This is to mark the end of the pin board from the tails.

I kept hearing about this and trying to make sense of why it's being recommended. Then I drew it out to scale and I see why it works. This sketch uses 3/4" thick stock (width unimportant), 1" tail ends, 0.024" saw kerfs, 1/4" end pin (only one here), and 3/16" pins. Those latter two dimensions are from the narrow end of the pin.

kerf offset to mark pins single.jpg

Layout 1 (top in the drawing): you offset the tail board one (1) kerf width to the LEFT from the pin board and mark on the RIGHT sides of the tails (orange in the drawing).

Layout 2 (middle): you offset the tail board one (1) kerf to the RIGHT from the pin board and mark on the LEFT sides of the tails (green here). I labeled them as "cuts" because I will use a marker the same width as the saw kerf, so the mark is also the full kerf track. But see below.*

Layout 3 (bottom) shows how the pins and tails line up when the sides are flushed back up. (The precision with these small measurements overstressed the accuracy of PowerPoint, so try to see all the kerfs and cut lines as the same width.)



See if you can click on the sketch and enlarge it. The top rectangle in each layout is the tail board's end. The bottom rectangle is just the top inch or so of the vertically-oriented pin board's face. See how the pins fit into the voids created on the tail board (wood waste plus two saw kerfs)? Similarly, the tails fit into the voids on the pin board: wood waste plus two saw kerfs.

[I see that my labeling of "WASTE" is correct on the tail board but incorrect on the pin board. On the pin board, what's labeled WASTE should be called VOID. But you get the idea.]

I've never seen it explained visually before. After making the drawing I finally get it. Many creekers have known about this for decades. Can't wait to try my kerf-width marking knife when it arrives this month.

I only plan to use pencil for the lines on the board faces, not the ends. For the tail kerfs I'm hoping my saw-tooth marking knife will double as a kerf starter –– we'll see. This should increase my ability to saw square to the face! For the pin board I'll have properly angled end kerfs, so the crucial task will be to saw square to the end. Sounds easy, right? This will be my greatest challenge, I predict.

*If you're using a beveled and honed marking knife with a razor-thin slice, you'd knife flush against the sides of the tails, and nice and deep. Then you would make your saw cuts all the way up to the knife lines, just scarcely leaving the "cliff" of the line, but no more.

[Jim Koepke]

Over time one will tend to get used to sawing to the line without great complications.

A current project on my bench involves dovetails. Like Tom it is likely going to improve my finished project if a little practice or warm up is done beforehand.

The tail board was cut a couple days ago. Once the tails are trimmed and checked for square there shouldn't be any need for any more work on them.

Here is today's practice:

Straight Piece of Wood Trick.jpg

This is a simple version of the #140 trick. A straight piece of wood is clamped to the base line of the tail board to hold it in position for marking the pins:

In Place for Marking.jpg

After a quick cutting the waste with a fret saw, trimming to the base line and fitting of the pins it came out pretty good for my first practice piece:

Not Bad for First Practice Cut.jpg

My plan is to do at least one or two more warm up / practice cuts.

Here is an old post with more details on making a dovetailed box > https://sawmillcreek.org/showthread.php?259750

jtk

[Aaron Veres]

I am using a D4 jig from Leigh.
When I cut the pins I am cutting into the fingers of the jig. I killed 2 of them but stopped when I saw alum shaving flying off. My material is 9/16, but the scale goes down to 1/4 ". It seems like the bit needs to be deeper but that makes the fit loose. any ideas?
The angle of the bit hits the finger on the underside when cutting pins. It's an 8° bit 1/2 wide. And I am using a 7/16 guide bushing.

[mike stenson]

I'm not sure I prefer half-blind to through dovetails. For sure there are more places to hide things, but I do far more through dovetails. Just make sure to check everything for square. Even if you have a problem hitting square on a tail.