Sunday, January 27, 2013

Marked for Death

OK, maybe not death, more like inconvenience…and Steven Seagal will not be featured anywhere in this blog entry.

It took a fair bit of time, but I’ve marked (for death) all of the dowel pin locations on each of the parts for the Rietveld Red Blue Chair.  I went over every piece, identifying the best surfaces and marked (for death), not only the dowel pin positions, but the orientation of each part as well…tops, backs, inside/outside, etc…
When it comes time to drill the holes for the dowel joinery I’ll be able to take advantage of Rietveld’s intention of making these chairs easy to mass produce.  Since most of the parts are 30mm X 30mm, the holes can be drilled with the same fence set-up on the drill press.  With that I reached for my trusty set of Forstner Bits and selected the 5/8 inch bit to match the dowel stock I picked up at Home Depot.

I marked (for death) the center, positioning line on a left-over piece of the Beech chair stock and aligned the bit and fence to drill the centered holes.

After drilling my first test hole I grabbed the dowel stock and tested the fit.  Uh oh…either this dowel is not 5/8 inch wide, or this is not a 5/8 inch Forstner bit!

I immediately began to curse Home Depot…those guys mis-marked (for death) these dowels!  A quick measurement of the hole’s diameter though revealed the true nature of the problem.  This is a 3/4 inch diameter hole!  I can’t believe I didn’t notice that before I started growling at Home Depot.  A trip over to the box of Forstner bits confused me even more, until it finally hit me…take a look at how these bits are marked (for death) in the box.  (Click to enlarge.)

That’s right…the 3/4 inch bit is sitting right smack-dab above the 5/8 inch marked (for death) slot!  Now in Craftsman’s defense, the bit sizes are clearly labeled on the shanks, and the plastic, protective covers for each bit are also labeled with the bit’s correct size, however the marking (for death) on the box is where my mind went when selecting the appropriate bit to use.  I sure hope I remember this the next time I pull this set out!

With the actual 5/8 inch bit set up and ready to go I drilled another hole in my scrap piece.  The test fit with the dowel stock was much better this time.  Funny what that extra 1/8 of an inch can do to mess things up.  Home Depot isn’t entirely off the hook though…their 5/8 inch marked (for death) dowel is just a hair under width, so the fit isn’t as tight as I’d like it to be.  I ran a caliper along the length of the dowel and the width does vary just a little as I worked my way down.  The kicker though…it’s never a full 5/8 inch wide anywhere along the length.  The dowel is Poplar, so it may swell a bit with glue, but I’ll definitely need to do a glue-up test to be sure.  If that test isn’t successful though, I’ll have to find another source for the dowels…and this time I’ll be packing my dial caliper to be sure I don’t fall prey to any more mis-markings (for death.)

On a less deadly note, I was able to find a picture of a Red Blue chair in the process of being built.  This fellow (G Najran) built several 1:20 scale models of the chair and made several jigs to aid in construction.  I would have to scale things back up to full size, but there may be some merit in the way he’s building these models that can translate to my full-sized reproductions.
I also found a great shot of the original prototype chair that led to the final Red Blue design.

Tune in next time to see if I can survive the continued construction of these “sillas de muerte!”


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