Patching a Poorly Cut Dovetail
I've been practicing by making boxes with half-blind dovetails and frame and panel bottoms. Although I was taught to cut near the line and approach slowly and carefully, I know it is faster to cut perfectly with the saw. So I've been cutting right to the line and dealing with the consequences, knowing I will spend more time now for reduced time in the future.
The first two joints came out quite nicely, but on the third joint my hope for the best didn't work so well. I wrote last week about cutting on the wrong side of the waste line. The good news is that my practice of cutting to the line meant I was only one saw's width too wide instead of more. But there was a saw's width gap.
I didn't think that could be fixed with a simple wedge (as I plan with the bottom side of the same tail), so I decided to patch it with some of the waste generated while cutting the pins.
The first step was to identify a waste piece that would fit, and make sure it fit snugly. I chose to patch the pin rather than the tail, because end grain is less likely to show noticeably. Then I made sure the side and corner of the tail were square and flat.
Even though my chosen waste piece had a flat section, there was a notch where I had started the chop. I needed a safe way to flatten this, and a chisel was definitely not that way. While puzzling over this, I remembered a miniature plane that might work. It looked to be just right for this application, so I tuned gave the blade a quick flattening and sharpening. Then I clamped it in the vice and ran the intended patch over it until it was flat.
Note: Looking at the picture, I realize this probably is not safe for the ends of my fingers. I was lucky and did not make finger shavings. Let me know if you have a safer idea for how to do this in the future.
Then I used a chisel to cut a matching angle for the bottom edge and test fit the patch to the tail.
Glue up was next. I used Tightbond II and a small c-clamp to attach it.
After letting that sit for a day, I trimmed the patch flush with the pin.
Then marked it for a new cut.
And trimmed to the line with a chisel. Actually, I trimmed past the line on one end (insert a favorite string of curses here) but the result is much better than I started with. The remaining gap can be wedged during glue up or hidden by peening the end grain.
The first two joints came out quite nicely, but on the third joint my hope for the best didn't work so well. I wrote last week about cutting on the wrong side of the waste line. The good news is that my practice of cutting to the line meant I was only one saw's width too wide instead of more. But there was a saw's width gap.
I didn't think that could be fixed with a simple wedge (as I plan with the bottom side of the same tail), so I decided to patch it with some of the waste generated while cutting the pins.
The first step was to identify a waste piece that would fit, and make sure it fit snugly. I chose to patch the pin rather than the tail, because end grain is less likely to show noticeably. Then I made sure the side and corner of the tail were square and flat.
Even though my chosen waste piece had a flat section, there was a notch where I had started the chop. I needed a safe way to flatten this, and a chisel was definitely not that way. While puzzling over this, I remembered a miniature plane that might work. It looked to be just right for this application, so I tuned gave the blade a quick flattening and sharpening. Then I clamped it in the vice and ran the intended patch over it until it was flat.
Note: Looking at the picture, I realize this probably is not safe for the ends of my fingers. I was lucky and did not make finger shavings. Let me know if you have a safer idea for how to do this in the future.
Then I used a chisel to cut a matching angle for the bottom edge and test fit the patch to the tail.
Glue up was next. I used Tightbond II and a small c-clamp to attach it.
After letting that sit for a day, I trimmed the patch flush with the pin.
Then marked it for a new cut.
And trimmed to the line with a chisel. Actually, I trimmed past the line on one end (insert a favorite string of curses here) but the result is much better than I started with. The remaining gap can be wedged during glue up or hidden by peening the end grain.
Labels: Dovetails, Fixes, Mistakes, Techniques
posted by rookster at
10:33 AM
5 Comments:
A method for planing thin stock using an inverted plane is given in Hand Tools - Their Ways and Working by Aldren Watson (page 272). He avoids finger tip shavings by using a notched stick to push the work. He says: "The cutter iron must be sharp and set for a very fine cut. Lay the work on the toe of the plane [from the drawings he appears to be using a Jack plane but later says a jointer is a good plane to use] and set the notched stick on top, the notch caught on one end of the work. Bear down on the stick and slide it until the work catches the edge of the cutter iron. Keeping plenty of pressure on the stick, push the work through. Lift the work and the stick at the end of each pass and repeat the sequence." Pieces of stock as thin as 3/16" can be planed this way.
I can thoroughly recommend the book. Written in 1982, it has dated in certain specifics, such as its list of well known tool makers, but on the whole it offers great advice on hand tools and how & when to use them, especially for the beginner (like me), with good clear drawings. And Chapter 1 contains a timeless take on the relationship between woodworker and his tools.
I have not yet reached the level where I can even attempt dovetails, so I have bookmarked your blog entry for future reference!
Thanks for stopping by, resare. And thanks for the book recommendation and excerpt. I'll have to see if the library has it! The notched stick is a great improvement to the process, especially for using a full-sized plane.
I finished cutting the dovetails and planing the bottom panel last night. I'm now finishing the bottom and inside of the box before glue up. We'll see, but so far the box is looking better than my last one...
P.S. When I dry fit the box last night I had to look closely to determine which of the sides had the repair. I don't guess anyone else will notice if that's the case.
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