Dovetails: Help please…
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Tagged: dovetails
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17 September 2014 at 8:22 pm #90363
I’m still trying to get my dovetails looking neater and to be able to make them faster in preparation for my final project in Summer 2015.
Yes, that is a year away, but I need to persuade a sceptical employer that I can make something with dovetails on the outside, neatly, in the ten working days allotted for the project.
I’m improving: the dovetails now fit, most of the time, and I take it for granted that the join will hold without glue. The gaps are getting smaller, but they won’t go away.
In particular I cn still see daylight at the bottom of both tails and pins: not a lot but enough to be annoying. I’m using Pauls method for the most part, but either I move the knifewall back or there’s something else causing trouble.
I’ve tried cleaning out the waste wood carefully, especially in the corners, which helped and I tried allowing the chisel to cut down into the wood, to allow space inside of the dovetail, and that seemed to make it worse. Any thoughts on how I could improve this?
Is there some cunning method to stop the chisel working backewards or is it now down to perfecting the method and getting the chisel to go where it is told?
17 September 2014 at 8:44 pm #90379I have that same problem with the gap at the bottom where the tail sits into the pin. I kept moving the knife wall..I think. I tried coping out the waste, and staying away from the knife wall, then chiseling the waste to the line. Concluding with the chisel directly in the line. Guess you could do Paul’s waste removal method away from the line, concluding with the chisel in the knife wall.
My dovetails have been a bit rough. I have been practicing but real quick. Not really squaring or marking. Just cutting a tail and pin in a few minutes. I changed to pins first too. Using a gents saw too, that I really like for now!
17 September 2014 at 9:58 pm #90521Best guess is that your hitting the chisel far too hard. Light taps to deepen the shoulder then pare out the waste. In soft wood try for 1mm depth at each pass, at the most. You can’t bash away at the waste wood. You have to coax it out. Sound is another thing that will help. You should never hear a dull thud when you hit the chisel when its on the baseline. If you hit it hard and deep enough to hear the dull thud, you’ve moved the baseline.
Here is a quick way to get an idea of how hard you can hit the chisel. Knife a line across a board. Now pare down from one side. Like you were going to cut the board to length. No place your chisel at the far end in a chopping position and give it a light tap. Move down the knife wall one chisel width and hit the chisel a little harder. Work your way across the board hitting a little harder each time. You’ll see when you’ve hit the chisel too hard. There will be an indent in the knife wall the width of your chisel.
I think Greg’s observation is right on the $. I had the same problem until I started cutting the waste out with a coping saw and then paring the bottom out without using a mallet; then fewer problems with the bottom of he joint, but still not perfect.
The OTHER thing I keep doing is not having my wood squared up properly. The other day, I found myself saying, “that’s good enough.” Well guess what? If the piece ain’t completely square, then all the care in the world will not produce square true lines, and crooked dovetails have gaps, as I know very well from my own work. If you are chasing a line around a piece and the lines don’t join w/in 1/64th “, stop, go back and re-true your piece [unless you’re making shop furniture]. Try cutting some practice dovetails with the ends out of square with the flat side of your board, and you’ll see what I mean…..using Paul’s methods are very rewarding, but they demand accuracy.
18 September 2014 at 2:46 pm #91767What jlmout said is a great way to go. I would sugest you do it twice #1 with pine and #2 with oak. You will learn a lot from it. My other point is what hammer are you using ? I would sugest aa 12 oz at most and see you always use the same one. The hammer is very importent. As a kid the boat shop I worked in the master gave me only one hammerr one set of chisels and one saw. I was not aloud to use other tools at all. After about 6 months the master said NOW you know your tools and how they feel. This was a very imporent lesson and it did make a lasting impression.
Your gents saw flatten a spot on the handel at about the eleven spot. This will help regester the saw in your hand every time you pick it up.
Its a simple thing but it means a lot. Getting to KNOW your tool will improve the tails and eveything else.Frankj
18 September 2014 at 3:31 pm #91814Another way to stop you going into knife wall is to clamp a 2″x2″ 50x50mm hard timber right on your knife line.
This actually dose two things stops you going into knife wall and keeps your chisel plumb.
Down side is that you will not acquire skill to do free hand and probably take longer as you have to deal with clamping timber.20 September 2014 at 7:25 am #93917Many thanks for the suggestions. this is the trouble with working in MachineWorld: the expertise has gone and even the master carpenters don’t really know how to make a decent dovetail.
I think I’m being too heavy handed in the knifewall so I’ll try and use that test on pine and hardwood and see what happens. I’ve wondered about using a coping saw to make a rough cut and speed things up -because in MachineWorld everything must be fast, fast, fast, so if I’m going to get permisssion to do this the way I want it has to at least be fairly quick- so I’ll try that as well.
@ Mark: I’ve tried the methosd you describe, but as you say, it is a faff to clamp the wood and this takes extra time. The other problem I found was that if you accidentally jog the edge of the wood and don’t notice you end up with all manner of problems, or maybe that’s just me.
Right, back to the workshop…
27 September 2014 at 9:55 am #118562So, here’s the results, warts and all. It annoys me that I’m not consistent, but I’m better than I was last year so that’s a step forward. Any suggestions how to improve on these results are welcome…
The dovetails are not glued: they are tighet but not really neat enough, and as the third image (which must qualify for the most boring photo in the world competition, I’m still getting gaps on the inside.
It possibly doesn’t help tha I’ve made the outside corners a 45 degree angle, but I have to do that on my final project for the apprenticeship, so that I can use a table router to make the groove for the infil. (If I don’t use a table router for this, I’ll barely use any machines at all which will get me in trouble).
Attachments:
You must be logged in to view attached files.What saw are you using? Maybe a very fine Japanese-style saw will make a neater cut. Also, is your wood perfectly square before you begin? This could be a problem area, effectively introducing difficulty before you’ve even begun. I use a very fine jewellers saw to cut out the waste as well, as I find it just leaves a much neater line.
To me the humble dovetail seems to have a number of pitfalls (moving while marking the pins/ brusing the wood/ cutting beyond the line) all of which can lead to undesireable results. Your not far off; I’m sure you’ll get there!
20 November 2014 at 5:46 pm #121229I use a fairly fine ‘Dozuki’ Japanese saw for these types of cuts, so I guess it is the usual rule that it isn’t the saw, but the user… I’ll try and get more oractice in before the exam…
28 November 2014 at 10:00 pm #121598I think you are cutting over the lines.
Anything pins or tails first, then the other you will mark according to the first pins or tails. After that it is better for you saw the second pins or tails with the lines remained just a little. In the corners, you have to remain the lines otherwise you cannot match the two. Even if you remained the lines in the corners the corners are not match, you have to align the bottoms of the pins and tails. check the bottom lines with square ruler if it is straight and match the knife line. I think you have remained some of wood in the bottom. Then the corners will not match well.Good luck
Shon
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