Question about Hand Cut DT's...

Re: Question about Hand Cut DT's...

Paul Kierstead

>Yes, cut on the waste side. As you can see, your saw cut has a 'width', called the kerf. If you cut dead down the line (pencil or marking knife), then half of that kerf will be over the line, resulting in a loose joint.

Re: Question about Hand Cut DT's...

Norman (Metcalfe, Ont.)

>This seems to be a confusing issue regarding dovetails.

We hear and read the term "splitting the line" very often and

it means precisely that, cutting down the middle of the knife mark.

There should be very minimal kerf width cut for this to work right.

The result should be a half a kerf of cut on both the waste side and pin side resulting in a good fit.

What I think is the issue with some woodworkers having success with this and others producing too narrow pins if doing tails first is :

It really does depend on the kerf produced by the dovetail saw. We are basing this technique/procedure on the kerf width. If the dovetail saw used has much set and produces a wide kerf, I can see too narrow pins being the result.

However, if a dovetail saw which has been tuned for a narrow kerf, the better likelihood of the pins fitting just right.

I tend to err on the waste side, but I feel that a DT saw with narrow kerf ( <= .022 ) should do it.

Anxiously waiting to hear from our resident

dovetail experts,

Norman

Re: Question about Hand Cut DT's...

Arw01

>Pick up the Rob Cosman video, Hand Cut Dovetails. You do leave the line when you cut to the wasteside. Rob cuts the tails first which leaves you with only 1 critical cut there, the pins are marked from the tail and you try to split the line. As you know, it can be done, but a smaller set on the dovetail saw helps.

Also taking one of Rob's week long training the hand classes will be an epithany.

Alan

Re: Question about Hand Cut DT's...

Dean J in MN

>Well -- I am no expert, but I'll give you my 2 cents.

Dovetails are simple! If you can cut away the part that doesn't belong and leave what does. That is the trick. :-)

I really don't buy into the fact we need a paper thin, 15 zillion tooth dovetail saw in order to cut dovetails. A chainsaw would be fine so long as you cut away the part that doesn't belong and leave the rest. It comes down to being able to saw well, and understanding how your marking technique works. Granted if you want to cut tiny pins that chainsaw will not work, but only because you wouldn't be able to initially cut the tails close enough together because the kerf is wider than the tiny pin you want.

There are other features of a dovetail saw that are more important in my mind. The handle being perhaps the most important in my mind. That funny angle assists in cutting away the part that doesn't belong.

I don't split the line, I leave the line. If you take any of that line away, you have a loose joint. At least that is the case for the way I mark out the pins. If you put the tail on the pin board and outline the tail, it stands to reason that any wood removed beyond or even on that line removes wood that needs to be there. If splitting makes it fit perfectly it would mean you somehow got that line (or that portion of the line) under the tail when you were marking them.

Go to the shop, knock out some tails on a scrap, and mark them onto a scrap pin board. Saw as close to that line (on the waste side, the part that doesn't belong) as you can without removing any of it. See how your tails fit. Repeat.

Someone once said you are born with "X" bad dovetails in you. Once you cut all "X" poor dovetails you are set. I say, go cut "X" bad dovetails on scrap and get them out of the way. :)

-Dean, who wishes he had all "X" bad dovetails out of his system...

Re: Question about Hand Cut DT's...

John Pappas

>Dean, I agree with your post. Ignore kerf width and focus on the edge of the kerf. That edge is as thin as your imagination will allow it to be.

Re: Question about Hand Cut DT's...

Adam Cherubini

>Joe,

I'm sorry to report, I think this is a situation that simply requires experience and lots of it. I can say the situation is a bit more complicated than you may have heard thus far.

I sometimes mark with a mechanical pencil or very very lightly with an awl because sometimes (and I know this sounds contradictory to my earlier remarks) I DON'T want the knifed like to guide my saw. Depending on the species of the two pieces, I change how I saw.

If that isn't complicated enough for you (and it shouldn't be) what if I were to tell you I often saw the pencil lines out? Now that contradicts what Dean has said. But I disagree with his ascertion that this is simple somehow so...

Since dovetails are wedges, the gaps are formed by EITHER the sides or the back of the wedge. So you may have sawed perfectly well, but under cut or too closely chopped to your base line. If you read my PW article on chisels, I made reference to Moxon discussing the under cutting effect of chopping with a chisel. So I never set my chisels in the gauged base line, but pull them out a 1/32 or more to account for the undercut. In any case, I recommend an undercut thru the thickness for tails only (its irrelevent for the pin side) regardless of where you set your chisel to begin that cut.

But know this- how you saw is directly related to how you chop. Over time you can get these in sync. But then you have to change things slightly with species.

Don't be discouraged. You can do it. I recommend working with softer, more forgiving woods than cherry for a while. If you continue to have problems, know that there are many factors causing that. You technique with pine won't work with cherry etc etc.

Good luck

Adam

Re: Question about Hand Cut DT's...

Paul Kierstead

>Dovetails probably have infinte complexity, like many things. I could learn all my life (an am!) how to good a steak to perfection, but this does not mean a beginner cannot cook a steak well.

Perhaps some more constructive help?

Re: Question about Hand Cut DT's...

Tom Ryan

>A couple of suggestions from another beginner. First, save some of the shavings you planed from the board. Then when you glue up the dovetail, rub the shavings over the joint (while the glue is still wet). Little bits break off the shavings and fill in the littly bitty faults, and it winds up looking great. (And, of course, they look much better after you've planed the joint.) I learned this trick at a Rosewood Studio course (which I recommend hightly).

Second, the marking of the pins from the tails needs to be almost perfect. If you have trouble holding everything in perfect alignment like I do, I've found that using small cheap corner clamps (like those used for picture frames -- $12 for a pair at Lowes IIRC) to hold the two parts in the correct relationship to each other. This is a suggestion of Chris Schwarz in Pop. Woodworking or Woodworking a few months or a year ago.

Re: Question about Hand Cut DT's...

Dean J in MN

>Adam --

My ascertion that this is simple somehow was with tounge planted in my cheek, hence the little smile face. We need a way to transmit humor a bit better... :)

I agree, it isn't simple, and there are a ton of factors to deal with. Your advise to start with soft wood is a winner, and I also agree you have to consider how you chop.

But I still hold by the 'remove what doesn't belong, leave what does.'

The trick is finding those two for your wood type, how you saw, how you chop, etc... Spending time cutting bad dovetails is the only way.

-Dean

The Baseline, and some other stuff

Wiley Horne--Glendora, CA

>Are you getting a good transfer of pattern from your tail board to your pins board? Figure out how to clamp the tail board pattern over the pin board end grain so that nothing is moving.

What Adam said below about chopping at the baseline is really important IME. Sawing correctly will get you a pretty good fit, and the advice from everyone to saw just outside the marks is exactly right. But to get an exact fit, the baseline has to be right. The final cut should be a paring cut, and you want to make it just a hair shy of the scribe line. If the chisel is registered in the scribe line, you'll get too deep a baseline every time (for the reason Adam gives). And the pins board will sink down too deep into the tails board, and the fit is a little loose.

I freehand about everything, but the one jig I use is a paring block clamped down just that one hair inside the baseline, to guide the final paring cut, and to keep the chisel from diving on you. If interested, I'll say more, but you can get a perfect baseline, and that combined with accurate sawing will give you dovetails that will go together right every time.

Wiley

Re: Question about Hand Cut DT's...

GolfSteve in Calgary

>Cutting dovetails isn't too complicated, but precision is required. Here's the simplified version what I've learned:

1. Mark out your tails and baselines (the Rob Cosman method is great, but you could freehand it if you wanted to). Use a fine ball-point pen for marking the tails, a marking guage to score your baselines, and a marking knife to mark your pins from your tails.

2. Since you're cutting the tails first, cut the tails. The important part of this step is to ensure that your cuts are perfectly square to the face of the board. The angle of the tails is not critical.

3. Saw and chop out the waste from the tails (good chiselling technique helps here).

4. Holding the two pieces perfectly square to each other, perfectly mark the pins from the tails using a marking knife. I disagree about using a pencil here.

5. Cut the pins. If you saw so that exactly half of the knife line is left on the pin board, and half of the knife line is sawn away, then when you hammer the pieces together you will have a perfect fit. If you sawed your tails perfectly square to the face of the tail board, then you must saw your pins perfectly square (ie. vertical) to the end of the pin board.

6. Saw and chop out the waste from the pins.

7. Apply glue and hammer together.

8. Have a beer and repeat until perfect.

The important points to remember: Saw your tails perfectly square to the face of the tail board. Saw your pins to perfectly match the tails. If you do this, the joints - by definition - will perfectly fit together. Reality is somewhere inbetween failure and perfection.

IME Softer Woods are More Difficult

Bot Hutchins in central TX

>Mind you, now, I'm no DT expert but I've cut and fitted enough that I feel competent to do the process. When I was practicing, I used poplar. It's a good species to work with primarily because it's cheap. I found the grain of cherry to be much easier to work with than poplar. I tried cutting some full-blind dt's in redwood 2-by material and found it too soft. I got 'em cut and fitted but doubt that they would ever hold in such soft wood the geometry of the angles notwithstanding. My favorites were clear yellow pine (not that white wood stuff at the borg) and doug fir for practising.

On another note, I made it my goal to achieve proficiency with poplar because that is the secondary wood I use for most drawers, ergo, most dt's. Haven't tried any of those large ones used for workbench vices and breadboard ends.

As for sawing and chopping, I imagine a plane where my saw must cut. When chopping out, I work about a 1/16" from the baseline until most of the waste is out (about 5 or 6 whacks alternating sides) then use a paring chisel sharpened as keenly as I can get it to fit them together. My goal is to creep up, always leaving the imaginary planes. My first attempts were too aggressive and my chisel control technique needed work, but with practice the fit gets better.

Cutting off is easy compared to putting back on.

My 2 cents and worth every penny you paid for it.

BobH

A good way to get better & make something...

Fritz In Mi

>Joe,

I think a good way to get some work done is to cut the pins close, not perfect, and fit them with a paring cut from a chisel. I have found that as I get better, I get closer & closer to the right saw cut fit. At least this way you can make something instead of just making practice joints (although I have made several of those as well).

I am sure that there is some downside to this idea...

Re: Question about Hand Cut DT's...

Jack Guzman

>Power tool people are always welcome over here.I like to think we'll convert em all.As to your dovetail problems. I agree pretty much with what has been said.You might take a look at Ian Kirby's book,The Complete Dovetail. One thing Kirby recommends and so do I is practice sawing to a line.Alot,repettitively,til you get tired of it.That is the hardest part of dovetailing for most people.Sawing to a line.Have fun with it.---Jack

woods: hard versus brittle versus...

Jonathan Kaplan (OR)

>I agree that soft-woods are sometimes harder to make good DTs in than are harder woods. On the one hand, soft woods give you more room to use "compression" to get everything to fit; on the other, I (at least) find it more difficult to make the accurate cuts necessary with them, and more diffcicult to get the joints looking perfectly clean (not that I succead in getting the joints to look perfectly clean in any wood, but whatever).

But too hard isn't good either -- and woods that are brittle are another matter entirely -- trying to cut DTs in brittle woods is awful, as any attempt to press together two parts that don't quite fit tends to result in a big chunk coming off from somewhere! DAMHIKT. :)

I agrre that cherry is a very nice wood to work with -- it is dark enough to hide small gaps :) hard enough to cut well, and soft enough to be a bit forgiving when it comes time to put the joint together...

Just my $.02.

Best,

jk

Don't say poplar

Adam Cherubini

>Its not poplar. Darn crazy homesick Englishmen are to blame for this and many other misnomers. Its tulip. Poplar are those tall things in Tuscany. Tulip is in the magnolia family.

I find tulip gummy to work with. I use a lot of it. It seems to compress before it cuts. It also moves like nobodies business, and its lack of stability was documented in the mid 18th century.

I have no point. Just bored out of my mind this morning!

Adam

Re: POPLAR!

paul womack

>

POPLAR

Neal (San Jose)

>

Darn Brits!

Adam Cherubini

>

Re: Question about Hand Cut DT's...

les winter

>One of the things that Bother me when cutting dovetails is that on the cuts where the line is on the far side of the saw, I cannot watch the cut progress down the vertical. With the line on the near side, there is no such probem.

Les

Re: Question about Hand Cut DT's...

Wiley Horne--Glendora, CA

>Les,

Saw down the two lines you can see--the one on the end grain and the one on the near side. Saw along these two lines simultaneously. If you track to those two lines, the line on the back will take care of itself.

Caveat: On the tails board (if you go tails first), the vital thing is that the kerfs across the top--across the end grain--be dead square to the long edge. So favor that line as you start the cut, and then start working along both lines. I like Ian Kirby's advice to make the initial cut with the saw vertical, then start the angle cut once you've kerfed across the end grain.

I apologize if I'm telling you what you already know.

Wiley

P. S. -- Actually

Wiley Horne--Glendora, CA

>There's no need to mark the back side.

Wiley.......Hoping we're talking about the same thing.

Even better,Popple.

Bob Hackett

>That`s what a notorious weed tree up here is called.

The rest of you probably know it as Quaking Aspen.

Everyone seems to agree it`s a major PITA.

Mainely,Bob

And DON'T say popUlar

Bill Houghton, Sebastopol, CA

>Another of those misspellings that's somehow crept in like a rabbit.