Technique problem? Removing waste with a chisel

[Frederick Skelly]

Good morning guys!
Im making a large storage box and decided to use what I think are called "box joints" - wide, interlocking joints like dovetails, only square. Ive been making practice joints on scrap to get the feel of it. Its going together pretty well, but Id like to improve the fit - I dont think Im using my chisels correctly. Basically, I saw the sides, remove most of the waste with a coping saw, and then use a chisel to cut along the line made by my marking gauge.

Heres where I need to improve: the chisel seems compress the wood at the line, making the joint slightly deeper than intended. That impacts the fit of the joint. I place the bevel of the chisel facing the waste side of the line. Then hit it with a mallet until it cuts about 1/8" deep. If I hold it vertically, I get the compression. If I angle it so that chisel's edge is cutting OUTWARD into the waste (overcutting?) it does pretty much the same thing. If I angle it so that the chisel is cutting slightly INTO the joint (undercutting?), its a bit better but then I get a V-shaped groove that Im concerned may not glue up well.

Can someone please describe how I should be handling this chisel?

Thanks very much.
Fred

[david charlesworth]

Fred,
You don't say what timber you are using?

My advice would be finer cuts with sharper chisel as you approach the line.

I like to mark a penultimate cut line, with a knife and square, close to the shoulder line. Something like 1/32 to 3/64 from line.

Fine cuts, with freshly sharpened chisels, cause less compression and hopefully this will be the same all the way across.

Best wishes,
David Charlesworth

[Brian Holcombe]

Howdy Fred,

My approach to this with dovetail joints is to cut forward the line about 1/8" inch, it'll compress back slightly. I split out the waste as I'm cruising through these cuts. I then clamp a heavy block along my mark to use as a guide and chop the line all the way through to the inside from the face. If your chisel is sharp you'll get a nice, cleanly sliced end grain. If the chisel is dull you will cause the center areas to split up.

Best Regards,
Brian

[Frederick Skelly]

David, Brian, thank you!

And yes, I should have noted that Im just using pine for now. When Im more skilled with hand tools, Ill switch to finer woods.

Best regards,
Fred

[Jessica Pierce-LaRose]

For chisel work like this, pine can actually be the hardest thing to work with, particularly if you're cutting into the face of some flat sawn stock. I like to work poplar for things that I care less about or experimenting with technique. With a lot of pines, you really need to make sure your edges are as sharp as they can be, because pine will easily compress or crumble before or as it cuts if it's not.

Make sure you're not trying to take too big of a bite, as well. If you've removed enough of the waste with the coping saw, then you can get by find with removing the last bit in one pass, but if you find the chisel drifting back, then you may need to do this in two passes.

Another thing that can help is making a deeper cut with a knife into the gauge line, and then chiseling or knifing a little sliver of waste from there. This gives the chisel something to register against, and if it's deep enough, also means that the "show" part of the joint will look nice, regardless of what happens on the end grain surfaces within the joint.

I would say, working by hand, I don't really see a need to do box joints - they're less strong than dovetails, and are going to take just as long to make using hand methods. Box joints like that shine when working quickly with machinery because they're so easily cut with a table saw or router, but unless you were going for a very specific look, I'd go with dovetails every time if I was working purely by hand, since the time spent is pretty much the same either way.

[Curt Putnam]

As has already been said, but with different words, there are three things to consider. 1st, chisels must be as sharp as you can make them. Secondly, carefully deepening your reference line with with either a knife or extra passes with the cutting gauge will sever the surface fibers. Lastly, you can carefully pare a small chunk from the surface to the gauge line. This last gives you a pristine surface for its mate.

You must pare back to the gauge line, slowly and carefully. You cannot just stick the chisel in the line and whale away. When you get to the point of putting the chisel in the reference line, you want the resulting chip to be so thin that there will be no "pushback" into the reference line. It's simple physics - you are forcing the chisel into the wood and something has to give, so the wood compresses. Different woods behave differently, with hardwoods generally exhibiting less compression that softwoods. You can use that compressability for you in the final fit.

[Steve Voigt]

For chisel work like this, pine can actually be the hardest thing to work with, particularly if you're cutting into the face of some flat sawn stock. I like to work poplar for things that I care less about or experimenting with technique. With a lot of pines, you really need to make sure your edges are as sharp as they can be, because pine will easily compress or crumble before or as it cuts if it's not.

Make sure you're not trying to take too big of a bite, as well. If you've removed enough of the waste with the coping saw, then you can get by find with removing the last bit in one pass, but if you find the chisel drifting back, then you may need to do this in two passes.

Another thing that can help is making a deeper cut with a knife into the gauge line, and then chiseling or knifing a little sliver of waste from there. This gives the chisel something to register against, and if it's deep enough, also means that the "show" part of the joint will look nice, regardless of what happens on the end grain surfaces within the joint.

I would say, working by hand, I don't really see a need to do box joints - they're less strong than dovetails, and are going to take just as long to make using hand methods. Box joints like that shine when working quickly with machinery because they're so easily cut with a table saw or router, but unless you were going for a very specific look, I'd go with dovetails every time if I was working purely by hand, since the time spent is pretty much the same either way.

+1 to everything in this post. Great advice.

[Prashun Patel]

Also, know that undercutting the base line is ok. It will allow te jojnt to come together tightly. Also, the strength of the glue joint comes from the fingers where its edge grain to edge grain. The base of the socket is end grain, and does not contribute significantnlyto the strength of the joint.

[Mike Henderson]

I would say, working by hand, I don't really see a need to do box joints - they're less strong than dovetails, and are going to take just as long to make using hand methods. Box joints like that shine when working quickly with machinery because they're so easily cut with a table saw or router, but unless you were going for a very specific look, I'd go with dovetails every time if I was working purely by hand, since the time spent is pretty much the same either way.

I agree. Box joints are a power tool joint. If you're going to do the joinery by hand, I'd sure do dovetails. Stronger and better looking.

Mike

[Mike Holbrook]

Some people may actually have specific chisels for "paring", removing fine small amounts of wood close to joint lines. The paring chisel may have a more acute bevel angle which may help in keeping it very sharp. Paring chisels are typically designed to be used with hand pressure vs a mallet. Although such chisels may not be necessary some of the design features can be incorporated into one or more regular chisel. Any chisel with a more acute bevel, sharper edge and handle that is easy to exert hand pressure with may work better when one is doing exacting work.

Although finger or box joints are more commonly made with machines, it has been my understanding that the joint made well is actually stronger than through dovetails. Finger joints typically run parallel to the grain of the wood, less "endish" grain, and their shape typically allows the woodworker to make more of them in a given distance, increasing the gluing surface. I believe getting better results with these joints requires clamping, which depending on how well it is done may improve or hinder how well the joint holds.

[Frederick Skelly]

Thanks for all the responses and help everyone! I get it now and the last test joints are much better!

FWIW, Im using the box joints because this is only my second project with handmade joints and I felt these would be a smidgen easier than dovetails. The joints are about 2" wide on a box thats about 6" high. I do intend to grow into dovetails - Im just taking baby steps while I learn to properly handle my saw and my chisels. I really do like the look of the wide box joints on this particular project - looks like some old wooden beer or pepsi cases I remember at my grandfather's house as a kid. Kind of utilitarian but not fancy (for THIS project :) )

Once again, thanks to all of you!
Fred

[glenn bradley]

David, Brian, thank you!

And yes, I should have noted that Im just using pine for now. When Im more skilled with hand tools, Ill switch to finer woods.

Best regards,
Fred

Common mistake IMHO. Trying to learn on soft woods that squash as opposed to shear off leads to bad results and possibly bad habits. I did the same thing early on and someone here helped me out of it. Pick up some inexpensive hardwood like maple, beech or cherry (what's "inexpensive" will vary with your region). As long as your cutters are sharp I think you will see a change in the result immediately. As to the technique, I do as others have stated; slicing away smaller bites to get to the scribe line. If you have an 1/8" or more of waste and set your chisel in the scribe line and give it a whack in soft wood, even the sharpest chisel is going to result in some compressed fibers. You're not mortising, your removing a final bit of waste. You should almost be able to do it by hand. That is; without a mallet.

[Winton Applegate]

I commend you for cutting finger joints by hand. Even though I am ALL ABOUT hand tools, especially these day, it would never have occurred to me to cut finger joints by hand.

Often they are many and small and symmetrical so I would have gone right to my dado blade stack on the table saw and the fun finger joint jig I made from a magazine article.

As far as the chisel not cutting where you want the others here have filled you in. Start your cuts inside the line and pare toward your finished joint. As far as cutting out the waste with the coping saw . . . it took quite a while before I learned when to do this. I used to go back and forth (on dovetails) some times I would not cut but just chisel all the waste and sometimes cut out the waste and then pare back. A satisfactory rule, in my view, that I FINALLY, FINALLY discovered from the old time pros is :
on the harder hard woods like maple, the rose woods (if you are brave enough to try) some of the walnut and other hard ones ; cut close to the line with the coping saw or jewelrer’s saw.

For the softer woods, walnut, the softer mahoganies etc., the secondary woods like pine and poplar; just start in with the chisel near but not on the line and chisel out the waste in layers without using a coping saw. That makes sense to me / the softer woods you can cut deeper and the chunks come out in a few large ones rather than endless little chips like the more hard stuff.

[Jessica Pierce-LaRose]

Although finger or box joints are more commonly made with machines, it has been my understanding that the joint made well is actually stronger than through dovetails. Finger joints typically run parallel to the grain of the wood, less "endish" grain, and their shape typically allows the woodworker to make more of them in a given distance, increasing the gluing surface. I believe getting better results with these joints requires clamping, which depending on how well it is done may improve or hinder how well the joint holds.

I suppose if you're looking at gluing surface as an indicator of strength, in theory box joints would provide a better long-grain gluing surface compared to the quasi-end-grain nature of dovetails - but unless you're doing radically dramatic dovetails on a board with wacky grain, I think the sloping grain is still "long grain" enough to get a perfectly great bond, not that far off from finger joints. I really only imagine there being a noticeable once you got to the super skinny skinny fingers cut from a shaper, like the types in old Jennings auger bit boxes (I'm thinking 1/8" fingers or something) - these obviously get you a massive amount of gluing area, more than you can get from handout tails anything. But dovetails have the mechanical advantage going for them - in a simple drawer, if the tails/pins thing is oriented correctly, you could probably get away with no glue, since the force is all against the mechanical fit, (dovetails can only be assembled/disassembled in one direction) rather than relying on glue. This is the advantage over finger joints.

As far as the pine thing - assuming you're going for cheap, and guessing you might be shopping from the box store, I'd really recommend poplar if there's not a suitable hardwood in the same price range for you (you'd be surprised at what you can get at a real lumberyard for the same price as the box stores) it'll be much easier to hone your skills on, and if you pick boards with the darker heartwood, can be quite attractive in it's own right. (Don't worry if it's got that wacky green tinge - a couple of days in the sun can make it a nice pleasing walnut-ty brown).

My big deal with box joints by hand is that you're either really relying on cutting perfectly vertical saw cuts to define the "fingers"; hoping to skip the "mark one piece from it's mate" aspect, and hoping you were accurate all around; or you're marking one piece from the other, in which case, why not get the added mechanical advantage of dovetails?

I know it's Jim K's job to throw this up here, (and usually we catch somebody before they get as much mileage out of the forum as you, Fred) but don't hesitate to add your location to your profile - there's plenty of us here who'd be more than willing to hang out for an afternoon and talk shop if that's helpful. Certainly if you're in the VT area, I'd be willing to check out what you've got going on.

[Daniel Rode]

I've done a fair bit recently with Eastern white pine from the home center.

I think it's the best stuff to start with for 3 reasons. First, it's cheap a plentiful, so I think it encourages practice and experimentation. Secondly, all wood at the home center is not equal. Careful choices can result in stock that is half decent. Last, home center construction pine is usually VERY soft and weak. It will tear, chip, splinter, dent and compress rather than cut unless the tools are very sharp and the technique is spot on.

The chisel as it's struck is forced back in the direction of the chisel back by the shape of the bevel. Pine is soft and compressible , so the cut is pushed back past the line unless the cut is very small.

Start with a good deep knife line. Before going to the line, make a cut about 1/32 away and at least 1/8" deep. Then place the chisel in the knife line and make your cut. Make it a t 90 degrees or 1-2 degrees undercut. The undercut helps make sure the middle doesn't stick up and helps protect the knife line a little.

[Jim Koepke]

Much good advice above.


The chisel as it's struck is forced back in the direction of the chisel back by the shape of the bevel.

This is the number one cause of your experience.

Someone chastised me recently for bringing physics theory into a discussion of what is going on when metal meets wood. Knowing the science behind what is taking place can lead to understanding the problem and help to correct errors before they happen.

Almost all of my work is done in pine or other soft fir. It can be a pain in the backside. It can sure teach one to have patience and be disciplined when joint cutting.

jtk

[Winton Applegate]

Someone chastised me recently for bringing physics theory into a discussion

Ha, ha, humans are a silly lot. It is what makes the Planet of the apes movies so belivable.
Humans jump through their _____ backwards messing around with witch craft and stuff like that . . . they want the "secret book" . . . "The Book of Secrets" . . .

They want to be able to fly through the air , to multiply their miniscule muscle power thousands of times in magnitude and to use the elements around them to do their bidding . . .

When you hand them a 1940's Physics book that cost three dollars and is full of really well done pen and ink illustrations by the way, they say " I don't want that ! That is BOOOORING. That is too hard to understand.

Ha,ha, ha, ha,
well guess what guys . . .
oh I give up
shame on you Jim, shame on you.

[Frederick Skelly]

Just to follow up - I got all the joints/ parts cut and fitted. Man oh man, did I learn alot about using my backsaw, coping saw and my chisels. (In addition to the box itself, I made 4 test joints to get a feel for it. So I got a LOT of practice. :) ) The joints all fit well, except 3 places where I cut to the wrong side of my line (inattentiveness), but even then the gap was straight and only as wide as my saw. I corrected them by gluing an shaving to the side of the joint causing a gap.

But everything else about the box joints was spot on, thanks to all of you and your advice!

If I get a chance, I may write up what I learned and what I did as "newbie note" for the archive.

What a great way to spend the weekend!
Fred

[Daniel Rode]

It seems that with every project I learn something new, I get a tiny bit better and something or I learn how to fix or prevent some mistake. Good advice and lots of practice.

A little physics helps too :)


Just to follow up - I got all the joints/ parts cut and fitted. Man oh man, did I learn alot about using my backsaw, coping saw and my chisels. (In addition to the box itself, I made 4 test joints to get a feel for it. So I got a LOT of practice. :) ) The joints all fit well, except 3 places where I cut to the wrong side of my line (inattentiveness), but even then the gap was straight and only as wide as my saw. I corrected them by gluing an shaving to the side of the joint causing a gap.

But everything else about the box joints was spot on, thanks to all of you and your advice!

If I get a chance, I may write up what I learned and what I did as "newbie note" for the archive.

What a great way to spend the weekend!
Fred