Monday, October 13, 2008

Oxford Frame for Robin


Last week while my class of 7th graders was in the school library, one of the library chairs broke. All by itself - "I swear!"


Later, I spotted the chair pitched in the dumpster behind the loading dock. As if it wasn't enough that the chair was a middle school casualty, now the wood it was made of was going to be wasted. Finding this unacceptable I did what any good scrounge/woodworker would do - I climbed into the dumpster after school and shoved the carcass into the back of my truck.


Here's what was left of the chair when it arrived at the shop:



Now Robin, our school librarian, is amazing. She is always doing great things for our kids and school, so I wanted to use this salvaged wood to make some kind of thank you gift for her.


I took the chair apart to see exactly what I had to work with.



After picking two pieces with interesting grain, I cut of the ends to remove the dowels left over from the original joints.



I had been thinking about making some kind of box, but at this point I changed plans. The long, relatively slender pieces just didn't lend themselves to the kind of box I had in mind, so I decide to make a picture frame instead. I sketched up a rough plan for what I call an Oxford frame. I have no idea where I came up with that name, or why it is (maybe) called that.



Next I resawed the two pieces into four, and ganged them together for thicknessing with a scub (just for the few odd high spots) followed by a fore plane with a cambered iron and then a jack with an uncambered iron. (One of the screw hole cross-sections seen in the second picture is still visible on the back of the finished frame - a neat clue to the salvaged nature of this wood.)




After deciding which faces would show, I used a square, a marking gauge, and a marking knife to lay out the half-lap joints. I used a chisel, held by the blade (sort of an icepick grip) to cut vee shaped grooves for the saw to follow. The outside of each groove is the vertical knife cut, while the inside (waste) is the angled cut from the chisel. This really helps me make clean, square crosscuts by hand.



After that, it was just a matter of cross cutting (done with a LN dovetail saw filed for ripping...hey, it works!) and then using a mallet and chisel to pop out the waste, followed by paring it clean. I haven't gotten around to making a bench hook yet, so I am always just using two dogs to cut against. It has been working so well that I may never get around to making that hook.



A quick test fit, then it is off to the stopped rabbets for the glass, mat, picture and backer.



On the shorter pieces, rails in this case, the half-laps are cut in the back the same as the rabbets. This gave me enough room to drop a router plane into the gap created by the lap and then it was easy enough to plane the rabbet using the fence on the plane and lowering the blade after each pass.


On the stiles however, the laps are in the face so this technique wouldn't work. There may well be a way to cut stopped rabbets with a router plane, but I couldn't figure it out. So I reverted to the craftmanship of risk and did it with a chisel freehand. So much easier! Next time I am leaving the 71 on the shelf and just doing it with the chisel and marking gauge.




About this time I needed a break, and Teague came to my rescue!



Here's what the bench looked like at the end of the day. Times like this I am always glad I made the bench as big as I did.



A quick coat of Tried and True and it's done! I hope Robin enjoys it - and I'll try to keep my 7th graders away from it!




5 comments:

  1. Wow, this was a great post - thanks for sharing! Some of your joinery mirrored what I've had to do lately with one project or another. But I ain't got no [specialty] planes yet, just chisels - so I was doing my rabbets just like you did there.

    I like that frame saw there - I really need to make one of those myself. Especially because I am only resawing with a ryoba pull saw that is just right for small rips but too tiny for bigger jobs. (Oh, on a tangent, I use my shooting board for a bench hook, and flip it around for using my Japanese saw.)

    A clarification on technique. For the half-lap, you sawed down to the appropriate depth, and then you rotated the piece towards you 90 degrees and chiseled down (across the bottom of the joint)? There's no worry of the chisel going too far one way or the other? I dunno if I'm being clear or not.

    Anyway, thanks again for sharing!

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  2. Hey Eric,

    Glad you liked the post!

    Specialty planes are great, but honestly, sometimes it’s just faster and easier to use the chisel – and this was one of those times. The rabbets I did with the chisel (bevel down) hogging off wood with the mallet and then cleaning up with long smooth strokes by hand went just as fast or faster, and were virtually identical to the one’s done with the much more finicky router plane.

    As for the half-laps, I think you described it exactly – except I rotate it away from me – don’t know why, it just feels right. It all depends on the grain of the wood. This was quartersawn (perpendicular to my direction of chiseling) and very straight. It split off in almost perfect chunks. I could work very close to the line at the bottom of the lap and take it off all the way across, leaving just a little to clean up by paring to the line (working in from each side). To be safe, I tend to angle the chisel away from the bottom and chop in from both sides, leaving a slight ridge across the middle of the lap, which pares away easily. If the grain is not as compliant, I move further away for the line and angle even more. If the grain is really working against me, I might make a couple of extra saw cuts in the lap to help control the cleaving.

    I hope that makes sense.

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  3. Very nice work and a truly noble cause! Being a wood scrounger/salvager myself, I can totally relate to this project. Very nice job on the half laps as well. I have found these seemingly simple joints to be finicky to get right with hand tools only. The joint needs to be flat and level to fit correctly. Any convexity results in a joint that rocks and a visible gap. On the other hand, if the joint is concave or undercut like a bowl, you don't get good long grain contact and the resulting glue joint is weak. Nicely done!

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  4. 1. I hope that none of your 7th graders saw you dumpster diving. Second thought, I hope they did! hee hee

    2. Your boy is a cutie.

    3. The frame looks GREAT and bravo to you for saving some nice lumber from a landfill.

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  5. Bob - Thanks for the kind words. It always amazes me how much good wood just gets thrown away!

    I agree with you on the finicky opinion. To keep them tight, I cut them ever so slightly too narrow and then very gently opened them up by paring with a chisel. I am curious to see what happens when our humidity drops - I think it will be okay - small size and quartersawn.

    Kari -
    1. I don't think any of my students saw me - but my team teacher did. She was my backup/lookout :)
    2. Too true!
    3. Thanks!

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