Aside from the obvious time & energy saving, is there any other factor that makes the machine cut joint where stile meets rail superior to a mortise and tenon joint? I’m not a production shop and kind of like the idea of more traditional techniques. Being that M/T is used in big beefy main door construction I’d assume it’s a better joint, but you know what assuming does.
Also, would a pinned (dowelled) lap joint be adequate for cabinet doors? Not tall doors, but up to about 18×24 or 30 inch. Coffee table door size.
And how critical is it that the angle on dovetails be at exactly their respective ratios of 1:6 and 1:8? Is it close enough to lay out with a machinists protractor at 8 degrees for a hardwood board? I’d also guess that a single dovetail joint should not be any more than a few inches wide. As with mortise and tenon, anything over three inches wide should be split into two or more joints?
I could probably keep going, but I’d be way too far off topic. Thanking you all in advance.
Replies
15Broad:
A M&T joint is superior to the router joint you are talking about, it simply has more glue surface and additional mechanical strengths.
As for your lapped doors, how long do you want your doors to hold together? I have not seen half-laps used on doors. Like drawers, doors have to handle unpredictable stress and shock. Go at least with a bridle joint, they're not more complicated to make than half-laps, and pin it if you like.
Thank you very much. I've just started joining and am having some trouble. Cutting mortises deep enough to hold is tougher than I thought.
How easily should a chisel "glide" through softwood end grain? Should I be using a slicing motion when paring out the waste from a mortise? Should I start out by making through mortises before trying to make blind?
I don't mean to pummel you with questions, but I want to make sure my technique is right before I tell my wife I need better tools. Sears can only take you so far, right? I appreciate any help at all.
Your chisel should be very sharp for softwoods, else you'd be mushing the fibers and destroying your mortise. In fact, one test of a sharp chisel is the ability to easily slice shavings off softwood endgrain.
To speed up the blind mortise cutting, drill out most of the waste first. Start with holes at both ends of the mortise, then continue to drill out as much of the waste in the center as you can. Finish by cleaning up with a chisel, use a mortising chisel if you got one. The square sides will help guide the cut.
You will find that there is no end to the quality of tools a woodworker will lust over. But these first steps in learning to use a tool properly is crucial; you have the right attitude. It's breadth and scope are far greater than can be handled in a forum like this. Learn to really sharpen you chisel, proper technique is independent of tool quality.
You can get started here for sharpening http://home.earthlink.net/~kvaughn65/scary.html
My personal opinion: Everyone starting out should use bottom tier tools. This would force proper techniques and cultivate appreciation for better performing tools later on.
You can continue to find a ton of information on techniques by Google-ing it. And yes, Sears is the Rodney Dangerfield of power tools.
Welcome to the craft, it'll be a long journey :)
15 broad,
A typically sized lap joint in a cabinet door wouldn't be adequately strong if it were only pinned, for strength the joint would also have to be glued. With glue, the joint wouldn't need the small added strength of a pin, but you could add a pin, or two, primarily as a decorative element.
The ratios for dovetails have been found, over time, to work well and look good, but they aren't sacred. As long as you use an angle that falls into the general vicinity of the traditional ratio for the wood you are using, the joint will be fine. Individual dovetails aren't terrifically strong, a dovetailed joint will be stronger, and look better, with a number of moderately sized pins and tails rather than a few overly large ones.
I'm not sure I understand your last question, but dovetail joints can be any length, a long row of dovetails is often used to join the edges of a chest with 18 inch wide sides for instance. There are a couple of good reasons why long mortise and tenon joints are split into shorter sections, but those reasons wouldn't apply to dovetails. For a short explanation about why mortises are split, see my posting at 15167.3
Hope this helps, John W.
Edited 12/14/2003 7:48:16 PM ET by JohnW
Edited 12/14/2003 7:55:30 PM ET by JohnW
The angle the pins and tail in a dovetail joint are not critical, but there are some basics principles to follow. The steeper the angle, the less likely for the tips of the tails to break off. However, if steep (narrow) pins are used with softwood , the joint will loose pull-out strength in one direction because softwood can be compressed more easily.
The extreme would be a box joint where there is no taper at all. By adding some taper (dovetail) you provide mechanical pull-out resistance in one direction. The softer the wood, the more taper needed. But if there is too much, the tips of the tails can break off.
I would not obsess over it. Most joints probably look better with pins and tails that are more narrow. If the joint will not be subject to excessive abuse, it may not matter much.
Thank you all for your helpful responses. So much to learn! I'm kind of surprised that brand new chisels aren't sharp, but I guess a chisel set that's sold to a guy who's going to use it to bang a mortise into a doorframe with a claw hammer doesn't need to be terribly sharp. Having closely examined the cutting edge I've noticed some of them actually have a cabinet scraper type burr folded over. They'd likely cut better with that removed. Thanks for the link, I'll check it out.
Everyone new to woodworking seems to have the same pair of false assumptions about edged tools:
1. The tools will be sharp enough right out of the box to work with.
2. The tool will stay sharp for a long, long time and there is no need to learn how to sharpen until after you've made a few pieces of furniture.
Assumption #1 is almost never the case and probably never has been. It takes time, precision tools, and skilled workers to put a razor sharp edge on a tool, the manufacturers aren't interested in making the investment because it has no return for them. The reality behind the second false assumption makes putting on a razor edge at the factory pointless anyway.
Assumption #2, if it were true, would be woodworker's heaven. Unfortunately a sharp edge has a very limited life span. How long an edge stays sharp will vary, but if you are chopping out mortises in hardwood, the edge will need to be touched up after a few mortises and probably resharpened at least once before the job is over.
Any serious woodworking program starts out by teaching students how to sharpen early in the course. Learning to sharpen is the first "hands on" skill a woodworker needs, it comes before you start to cut wood.
The rolled over burr you are describing would certainly make chopping mortises very difficult. If it keeps occuring after you properly sharpen the blade, it could be a sign that the chisels are too soft either because of the steel used or how they were heat treated. It is a fairly common problem with some of the British made chisels.
Hope this helps, John W.
15Broad,
You are at the bottom of a not too steep, but very long learning curve. It's interesting (a little disheartening) that knowledge about some common little things is gone from our culture and most of the populace is faced with relearning these things before taking even baby steps in this craft. Often, the novice never gets to realize that he or she doesn't know facts that are necessary for simple operations to work well.
Chisels. No they are NOT sharp when you buy them. They are only ground to an approximation of the shape they MAY need to work on one kind of wood or another. They must be properly prepared by the worker or they will give abysmal results. The do-it-yourselfer, often without the tutilege of craftsman who used to be in abundance, but whose ranks are very thin now, often becomes discouraged. The needed skills, tips, tricks, methods are logical, easy, straightforward and satisfying to master, but many, many are surprisingly NON-INTUITIVE. It's a shame that so many novices are forced to re-invent the wheel. And that wheel is a poor model compared to the refined one that an experienced worker could show you how to make, very quickly.
Yes, chisels need to be ground and honed to a particular set of angles. The face (incorrectly called the "back" by newcomers) must be flattened (lapped) and polished to a mirror finish as well as the bevel surface.
Here's the non-intuitive part of the project you're tackling. Cutting mortises and tenons (especially the mortises) in softwood is harder than the same project in a hardwood. It takes much more skill to do it right and to maintain the razor edge that a chisel must have. The softwood tissue crushes rather than slices. It doesn't hold its shape for the craftsman to pare or chop, the wood easily becomes dirtied with skin oils, looks ugly, and the whole job goes south, resulting in discouragement. Very poor feedback.
You MUST learn to sharpen your tools, and a myriad of other basic skills. Without sharp tools you will be able to do nothing right or satisfying. You must learn how to make parts truly square. And you need to gain basic knowledge of joint strength, and the myths of this topic. There are many basic tutorials on this site. and elsewhere. Don't be bashful about asking questions. Tons of them. The only dumb question is the one that isn't asked. We've ALL been there at some point. Welcome to the craft.
VL
Edited 12/15/2003 11:22:29 AM ET by Venicia L
Venecia,
Well said.
John W.
Thanks again everyone. I hear what you're saying about a lack of craftsmen/craftsmanship in the world today. I had the same discussion with a friend this past weekend. What has been lost in our quest for instant gratification? As far as cutting square, etc., I've beaten my head against the wall over that one - until I realized that they don't true the equipment up before sale any more than they sharpen it.
Fortunately for me I do have access to this wealth of information. Still, it's a craft of it's own and takes time and experience to learn. Basics first! I've picked up a few books on the subject, but it seems the more I "know", the more I've still to learn. All I can say I know for sure is the intense pride I felt after cutting the M/T for the chisel rack I made... AND IT WAS TIGHT! Not pretty, perhaps, but the joints were snug and relatively straight. Frustration is a lack of knowledge, discouragement is not an option.
I found someone today who's willing to help with the finer points (no pun intended) of tool sharpening. I've also seen a few different sharpening setups (see "Scary-Sharp earlier in this thread), but as always, I think technique is at least as important as your materials. Hey! Does anyone wanna come over and stand at my shoulder to say "Not like that, like this"? Ha-Ha.
Anyhow, I find myself rambling, so I'll leave you all with the only thought I know to be true.
Wood burns.
Edited 12/15/2003 6:26:30 PM ET by 15Broad
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