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Meanwhile In The Next Room: Tuning Up The Ripple Molding Machine

While I was occupied with the Roubo bench slab in the center hall of the barn John was a dozen feet away in the classroom tinkering with the Winterthur ripple molding cutter.  When we gathered earlier as a group we identified a number of modifications that might serve to transform it into a reliable, precision machine.  I ordered all the materials and supplies we thought we needed for this undertaking so everything was ready to go for John to dive in to making these modifications a reality.

As a moment of review, the ripple molding machine is simply a contoured scraper being drawn across a length of wood, with either the scraper or the workpiece being undulated by some sort of linear pattern.  In short, a ripple molding is the result of controlled chatter.

In the case of this machine it is the cutter that remains fixed relative to the length of the frame, but which undulates up-and-down via a horizontal “follower” rod affixed to the cutterhead frame, pressing down on the pattern running the length of the machine frame.  We found in our earlier efforts that either the pattern or the follower ere being degraded and even destroyed by the very process of creating the moldings.

I do not know how this problem was dealt with historically, but for our applications we decided to replace the extant follower rod with a new rod and tiny roller bearings to instead ride along the pattern, transferring the up-and-down impulse without friction to the cutterhead.  John spent extensive time retrofitting the cutterhead to accommodate this modification without damaging or changing irrevocably the machine as it was presented to me.

After installing the new follower system John reported to me with a grand smile that it as a perfect solution to the problem, and would guide our design considerations as we move forward with new machines in both our futures.

 

 

Completing Workbench Mortises (a semi-misadventure)

When I last left the oak Roubo bench 4+ years ago it was still quite  ways from being done (one of the great benefits of building a bench a la David Baron is that it can get done in a week).  The leg tenons were all cut, but only two of the dovetailed mortises and none of the rectangular mortises, so clearly a lot of drilling and chopping was in store.  There was nothing exceptional about the task or process other than it required flipping the top a couple of times to get the job done.  The last two dovetailed open mortises took about an hour to knock out.

Drilling and chopping the closed mortises went smoothly.  For three of the four.  And the fourth?  Grrrrr!  For some inexplicable reason I switched from a Forstner-style bit to a long auger bit for my drill, and it went astray.  Not just astray but bound tighter than a drum and would not move forward or backward (a theme that was not yet fully played out).  After a lot of fussing and fuming I was eventually forced to drive it through the other face using my sledge hammer.  Sheer brute force.  I was reminded of my late friend Mel Wachowiak’s quip, “With enough force you can pull he tail off a living cow.”  Or drive a 7/8 auger bit through an inch of solid oak.

This blew out a chunk of the face adjacent to the mortise, leaving me less cheery than you might expect, my anger being tempered only by the fact that all this damage took place on the underside of the slab. An hour later I had knitted together all the splintered wood and glued it back in place to leave overnight.  In the end it was a patience-expanding experience.

The good news is that the repaired place (epoxy and shavings filled) held up perfectly when chopping the mortise in that area.  The repair felt just like the adjacent wood and held a nice crisp corner with no chipping or fracture.

So now the mortises were all done and seemed to provide a nice snug fit, and I was looking forward to driving the legs home in the morning.

Oh, about that…

Virtuosity At A Whole Different Scale

My acquaintance Bill Robertson, maker of astonishing miniatures, is featured in a new TED Talk.  Watch, and prepare to be astounded.

Repairing the Underside of the FORP Bench

With a little logistical cogitation John and I, both 60-somethings and neither of us mesomorphs, managed to maneuver the 300+ pound top of the French Oak Roubo Project workbench out into the light.  Immediately I was struck by both the magnificence of the 240(?) year old white oak slab, and the waney void adjacent to a glue line on the underside of it.  I suppose at one time I was just going to leave it as-is, an admittedly foggy memory going back four years, but given that one of the leg mortises needed to go right through the flawed region I decided instead to fill it.  I could have grafted in another piece of oak but instead fell back on a tried-and-true method of repair that I have employed several times in the past as it was especially well suited for a repair of this size.

I first sized (primed) the margins of the effected area with standard West System epoxy, thinned about 25% with acetone to get deep penetration.  One of the reasons for any potential epoxy failures, whether in adhesion, consolidation or filling, is that the epoxy does not penetrate adequately to knit the entire construct together nicely.  What then often happens also is that the density differences between the high density inelastic epoxy and the less dense, much more elastic wood, may result in a fracture at their margin when they are intimately bound together in a cyclic stressful environment.  The diluted epoxy addresses the first of these problems, the filling of epoxy with large wood flakes addresses the second.

 

In this case I ran a scrap of oak through the power planer to yield the typically large shavings you would expect from the machine.  I took handfuls of these shavings and packed them down into the void that had been previously primed with the thinned epoxy.

I then drizzled un-thinned epoxy on top of the wood flakes, then sprinkled on more shavings and packed them again through some wax paper.  I let the entire fill to harden overnight.

An additional feature of fills like this is that when the volume is large enough, the exothermic reaction of the epoxy hardening causes the adhesive to actually boil in place, aerating the  fluid as it hardens, reducing further the density of the hardened fill.  This is a very good thing.

The resulting repair is much closer in density to the wood, thus reducing the risk of a system fracture at their interface, and yields a repair that can be easily smoothed with a rasp or Surform tool.

The success of the repair can be clearly seen in the edges of the mortises I drilled and pounded through the slab and the repair (next blog post).  It held together wonderfully and had working properties nearly identical to the adjacent oak.

Insect Infestation and Salvaged Lumber

With our ambitious agenda awaiting us for the Man Week at the barn, our first task was to begin the Tetris game that always seems to be on tap for any type of reorganizing the shop.  The ripple molding machine was easily accessible for John but I had to move a ton of stuff to get to the FORP I workbench parts that were behind the parts for all the other workbenches that are not yet finished, and a large pile of old oak salvaged from the shack deconstruction that we were working on when I crossed paths with the cranky wheelbarrow that put me out of commission for the better part of a year.

The first thing I noticed from the pile of salvaged oak was the presence of frass in between each piece of the stack.  It might have been old frass from a no-longer-active infestation or it might not.  It was not an extreme amount but I was not going to take a chance as I was going to be making furniture for the cabin from it.

I mixed up my typical batch of insecticide with a gallon of marine anti-freeze and two 8 oz. cups of dry borate-complex powder (Disodium Octaborate Tetrahydrate), then mixed with a paint stirrer in my cordless drill.

I used a cheap garden sprayer to saturate the boards and stacked them under plastic to let it all soak in thoroughly.  After 36 hours I set them against the barn to dry, and two days later moved them inside and will put them to use when that project moves to the top of the pile.

Working Wood in the 18th Century

If you’re paying attention you might know by now I will be one of the presenters at the upcoming Colonial Williamsburg annual conference Working Wood in the 18th Century, January 25-28, 2018.

I have two time slots, the first being a discussion of the acouterments of a Parisian woodworking atelier in the late 18th century, including Roubo workbenches and ripple molding machines.  If all goes well we will be demonstrating these machines, making ripple molding right there on stage.  My second session will be the concluding presentation of the conference IIRC, reviewing and demonstrating the practice of woodfinishing of the era.

I hope to see you there.  Say “Hi” if you make it.

Varnishers of The World, Unite!

The Desk Project – The Wood

This post is in great part my celebration of a grand circle of friends who provided me with the wood I needed for the project.

In correspondence with the client for interpreting the c.1820 writing desk, it was clear that he wanted something made in the manner of craft technology of the period, and if at all possible, using wood of the period, or at least very old wood.  Since the task of acquiring verifiable 200 year-old mahogany was at best an iffy proposition I simply determined to find the oldest, best wood I could find.  In fact I already owned about half the wood necessary for the project thanks to my own acquisitional proclivities.

Among my inventory was a superb piece of dense, lightly figured mahogany I needed for the veneers that would wrap the box of  the desk.  It was one of the three critical pieces I needed.

The desk writing surface was a second vital component and I sent out requests to everyone I knew who might be able to supply my needs.   Before long a UPS truck bearing the piece I needed showed up in the driveway.  Then a second.  And a third.  And a fourth.  Sean, Ben, and Alf all contributed spectacular pieces to the venture.

One last look through my inventory uncovered the final piece of this particular puzzle, a wildly figure slab of flame crotch that was needed for the veneers on the outer leg elements.

But that was not the end of it.  My friend John brought  a small pile of vintage mahogany with him to the next MWTCA gathering, and I took it off his hands.  Josh emailed me about a stash he had, and delivered it to me.

Then my orthopedic surgeon told me he had a storage unit full of pre-WWI era lumber including some prized mahogany.  I loaded all that was there and headed for home.

In the end I would up with enough vintage, unused dense swietenia to make at least two additional desks and, thanks to the willingness to part with some of their holdings by my circle of friends, I probably will.

Plans done?  Check.  Wood in-hand?  Check.  Ready to dive in?  Uh-h-h-h-h.

Stay tuned.

Man-Week at the Man Cave, er, Barn

My recently scheduled barn workshop, “Make A Traditional Workbench,” was mercifully “cancelled” due to the fact that all four of the scheduled registrants notified me they were not coming.  No students, no workshop.  I say “mercifully” because it would have started the day after Barndaughter’s wedding weekend, and I was already worn to a nub.  Nevertheless, my friend John, who participated in the workshop last year and was scheduled to be my teaching assistant for the week, decided to join me anyway for a grand week of man-time in the man cave, a/k/a The Barn.

We had a delightful week of fellowship and working on projects; John concentrated on modifying and tuning up the Moxon-style ripple molding cutting machine while I emphasized bringing my FORP workbench from many years ago closer to completion.  In addition, John being a trained theologian and well-engaged citizen of The Republic, our conversations were vibrant and varied, and by the end of the week we were almost sentimental about our shared experiences.

The success of the week can be summarized in the observation that by Friday afternoon it looked like a tool-and-shavings bomb had been detonated there.  I’ll recount our adventures in greater detail in coming posts.  Stay tuned.

Saw Sharpening Demo at SAPFM-Blue Ridge

Recently I was a presenter at the SAPFM Blue Ridge Chapter on the topic of saw sharpening.  I would not call myself an accomplished saw sharpener mostly because my results are inconsistent, generally due to the lack of hours at the task.  But there are times when the result is excellent, for example my favorite old back saw that I last sharpened sometime in the 1980s and has cut hundreds of joints since, and remains sharp and the cuts crisp and clean.

Using some oversized props I reviewed the notions of tooth spacing and shape (rake, and fleam), and how these come into play for crosscutting and ripping at varying degrees of scale, precision and effectiveness.

I the moved through the nearly unlimited options for holding the saw during sharpening, and finally set up to actually doing some sharpening under less-than-ideal conditions of a large lumber warehouse with diffuse illumination.  I find that getting the lighting correct is perhaps the most important thing when sharpening a saw, and this setting wasn’t it.

My explanation of the process was certainly better than the actual sharpening during the demo, but I think the attendees got the idea.

As an aside, I was delighted I had my petite Roubo bench with me and realize that it has become a treasured part of my traveling side-show kit, as it fits neatly into the back of my S-10, is moved easily with a hand truck, and performs most excellently.

Plane-setting Hammer

Recently when I was visiting plane maker extraordinaire Steve Voigt I had the chance to use his Sterling plane setting hammer, and I liked it and said to myself, “Self, you gotta have one of those.  Right now.”  Since even in the era of the interwebs, on-line purchasing does not provide instantaneous delivery so I got up the next morning and made a plane setting hammer for myself, using scrap from my inventory of stuff.

My first step was to take a piece of brass and turn one end of the head on my wood lathe, which is easy enough to do when using turning chisels set up as scrapers rather than turning gouges (virtually all of my turning is with beefy scrapers with very rare use of gouges; it’s an old habit from my early years in the pattern shop).  I then turned a wooden end of the head from a scrap of lignum vitae, then drilled and tapped both sections and screwed and epoxied them together.

Then I grabbed a piece of exotic wood from the waste bin (probably bubinga) and made a handle in about ten minutes.  I drilled the hole in the head through which the handle passed, then used material from an ivory piano key as the wedges for the handle in the head.  All told I spend maybe 90 minutes on this hammer.

The result was immensely gratifying and its weight and proportions and performance have made it my “go to” tool for this purpose, and several folks I have shown it to have expressed interest in purchasing one.  Who knew?  I guess I will have to get set up to do it.  I might have to actually order some supplies.