And Finally (I put these in several replies due to the forum's character limit on thread replies):
My Reply:
Glen - You are welcome to use anything I've written in a blog enty/post, or even in a magazine article. That might actually make a pretty good topic for Woodwork Magazine. Something on the order of "Cross Grain Construction and Joint Failure - We Investigate the Real Story".
Please note that I didn't get on this topic to be argumentative, and especially not to critique your work. That wasn't the point - I just figured that you're going to have a lot of your more advanced readers question the absence of a discussion about cross-grain construction in the article.
From the standpoint of the questions you asked about pinned mortises - I've built a very limited number of case pieces with this type construction (and would guess that it's far, far fewer than you have). To date, 3 of them have one or more cracked side panels, and 2 do not. The 2 that do not are made of mahogany. The other 3 are made of cherry, maple, and walnut. The pins were usually made from the primary wood species, but one of the mahogany pieces and one of the maple pieces used riven white oak pins. Of the limited access to museum pieces I've had (mostly at MESDA, so mostly Southern pieces), almost all of them have either completely cracked, or partially checked, side panels.
However, I will most certainly acknowledge that there are instances cross-grain construction of furniture at MESDA that a modern woodworker would bet a paycheck on cracking, but are still in one piece. One particular one that comes to mind is a 1760 era fairly large drop leaf table made by Peter Scott that is in the anteroom of the museum (i.e., outside the period rooms). It's made of mahogany, and the table top has to be at least 35" wide. It is screwed to the table aprons with what amounts to pocket screws - very, very large handmade wrought iron screws in gouge-cut pockets from the underside. To say the least, humidity changes in Southern homes up until the 1950's were huge - I've personally experienced this, as I lived without air conditioning for the first 10 years I was in Raleigh, NC. My guess is humidity in the 85% range in the high summer, and as low as 15% in the winter. This experience, by the way, puts the lie to the adage that "modern homes are very dry compared to historic periods, and as a result antiques don't do well" - I can personally verify that the RH gets incredibly dry in a fire-heated, non forced air system.
There is, by the way, quite a bit of discussion about this particular joint in a number of books and on net forums. There was a significant discussion of it on a SAPFM thread a while back, and there's a couple of pages devoted to it in Jeffrey Greene's book.
Regarding PVA glue creep on the piece you built and wrote the article on - absolutely I've experienced creep with PVA, Epoxy, Polyurethane and Resourcinol-based glues, but only in the period that the glue is still curing - typically in the first 10 days or so. After that, it's been my experience that PVA glues get very hard and fairly brittle, so I would not expect that they would flex enough to allow a great deal of movement in a M&T joint. However, I simply do not have enough experience to categorically state that PVA will flex after a few years of being in place - I dropped PVA in favor of hide glue some time ago, and now only use it when I'm building something modern that will regularly be exposed to heat and wet, like an end-grain cutting board.
Again, Glen, the purpose of me writing this is that I approach some questions from the aspect of an engineer, and one that has been heavily educated in statistics and "zero defect manufacturing". Obviously, I don't apply that sort of thing to furniture building - perfection is neither achievable nor desirable, in my view. What prompted me to write was thinking "Well, perhaps quite a number of readers will build this piece, and a number of them will place them in a stable atmosphere where they will never see cross-grain construction stability issues. However, at least a few will probably wind up with cracked side panels, which they'll think of as a defect of design". In my view, such a result is not a defect, but after haunting the power tool side of internet forums frequently, I'm very familiar with the modern sensibility of perfect joints, surfaces sanded and finished inside and out, building dawers entirely of primary woods, and related viewpoints.
Because a great deal of your audience will tend to think this way (it's quite often that someone writes a thread on these forums about their table saw fence/table being out 10 thousandths of an inch), I figured it might be worth protecting yourself from criticism by addressing the issue ahead of time.
And, by the way - I agree with you on the "gloves" thing. When I do use the jointer or planer, I wear leather gloves - always. My justification for this is that loss of control of the stock is far more dangerous than the very low probability of the cutters failing to slice through leather (which, after all, is cured skin) and pulling an appendage into a spinning blade. Perhaps there are those with leather-like hands that don't lose their grip on polished maple as it goes through a machine, but I sure would without gloves!
Take care, keep up the good work - I think Megan/Chris may ahve forwarded my comments on the last Pop Woodworking issue to the contributors. It was, bar none, the best single issue of any woodworking magazine that I've read in the last 3-4 years.
David
And Glen's Reply:
Hey David,
I'm posting the exchange we had about case side cracks. I think it will make a nice discussion on the blog.
I was wondering if you have a photo of the side of one of your cracked pieces that I could use on the blog. It would explain what we are debating.
Could you help?
Thanks,
Glen D. Huey
And finally, my embarrassing response that I don't have much in the way of pictures of things I've built in the past (which readily speaks to my laziness!):
Unfortunately Glen, I do not. This is the case of "the cobbler has no shoes" - almost everything I build either gets sold, or given to relatives for Christmas or birthdays and embarrassingly enough I have almost nothing in my possession that I've built besides an oak bookcase. And despite having 30 years of photography experience and professional equipment, I'm really bad at making myself take photos of my work - the eastern white pine wall cabinet that I sent to Chris, a few Underhill-style tool boxes, a couple of miniature 6-board chests and a few jewelry boxes are all I've got pictures of.
It might have something to do with consistently finishing up pieces around midnight on the day before Christmas Eve. ;-)
However, I've a few suggestions - it may serve your purpose to e-mail the curator at Winterthur for historical perspective. You might get a few photos of 200-year old pieces, and perhaps some surprises - I may well be wrong about guestimating probabilities of this, and they'll tell you they've just a few pieces with cracked sides.
It may also be an idea to solicit comments on specifically on this - it may well be that many readers have constructed case pieces this way (either totally glued, or in my case, pinned) and can comment on whether they've had issues.
Finally, you might wish to contact Dennis Bork on this. I'm sure you know of him if you don't know him personally - he's spent a career making repro furniture (he received the 2009 SAPFM Cartouche award), and I know he had some opinions about this very subject a while back on the SAPFM forum. He's a very friendly guy, and I've no doubt he would return an e-mail or a phone call.
David
