March 10, 2010

When things go wrong

I was on a roll, milling stock for drawers, when disaster struck. No matter what I tried, I was getting awful tearout on the maple. I had never experienced anything like it; time to sit down for a bit, take one deep breath, and plot a plan of attack:

  • Is there much variation from board to board that some planed well, and now they weren’t?
  • How is the grain running?
  • Am I getting distracted, and in the process reversing the feed direction, and causing the tearout?
  • Should I try a hand plane, and see how the boards behave vs. the planer?
  • Have I looked at the planer itself? Blades, speeds, spider webs, gremlins, what else?
  • Should I …

The following photo shows what I was dealing with – tearout like I had never, ever, experienced <gulp!…>:

tearout

On edge, many of the maple boards showed this kind of change in grain direction – but the DW735 had handled it beautifully, until now! Photo showing change in grain direction on the edge:

grain-direction-change

Down the checklist I went. A Stanley # 4-1/2 hand plane handled the grain beautifully. Now what? Blades!  Look at the blades on the planer, dummy! In almost 5 years, I had never (ever!) changed the blades. On this planer, the blades are double-edged, and can be rotated. It took exactly 15 minutes to rotate the three blades (each was secured with 8 machine screws). Indexing pins on the blade turret made the job a snap, as nothing more is required to set the blades properly.

Problem solved! The first board off the planer looked like this:

after-planer-blade-change

The moral of the story: If you are going along fine, and everything hits the proverbial fan, something has changed. Time to find the root cause!

.

—— Al Navas

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Fine furniture deserves great drawers

Drawers are a critical part of a project. Mario Rodriguez shared his insight into making and fitting drawers during a terrific session at the Woodworking in America conference in Valley Forge, PA. You can view a 19-minute video I shot and later edited, at this link.

As I work on the stand-up desk and prepare for the next step, Mario’s words have gained prominence. I extracted the following thoughts from that particular session, and I suggest you keep this list handy as you work on your next project:

  • What is the scale and size of the drawers relative to the size of the project?
  • Thickness of the drawer sides vs. front
  • Use of drawer slips, to minimize the risk of failure of the sides, at the groove where the bottom normally resides
  • Selection of suitable materials, with straight grain
  • Slips should be even with the bottom of the drawer sides, to increase the surface area bearing on the drawer support structure (frame, dust cover, etc.)
  • Use solid wood for drawer bottoms – and ensure the grain runs side to side, not front-to-back
  • Allow for wood movement – secure the drawer bottom using a screw inserted into a slot through the drawer bottom and into the bottom of the drawer back. Do not over-tighten the screws, or wood movement cannot take place

Now it is time to make four drawers that will fit the desk. If you follow my blog, you will remember that the drawer fronts and the front apron all came from one board of quarter-sawn white oak. This detail is important; I cannot afford to accidentally ruin any of the drawer fronts, as the grain on these is (almost) perfectly matched to the drawer fronts – in other words, I have exactly zero spare drawer fronts. I convinced myself that hand-cut dovetails would best suit this critical part of the project. For those of you who have asked in the past, I must repeat that I will not part with my Leigh D4 dovetail jig.

I spent time trying out various side and back board thickness, to get a better feel for the scale of the drawers vs. the size of the project. In the end I settled for 5/8-inch board thickness for the sides and back, vs. 7/8-inch for the drawer fronts. Drawer slips will be required to beef up and reinforce the sides; the use of slips will help minimize the risk of failure of the drawer sides at the groove that accepts the drawer bottom.

I normally am in the pins-first camp when it comes to hand-cutting dovetails; and, like Frank Klausz, I simply start cutting, eyeballing distances in the process. However, in this project I did something I have not done before: I first went through the steps of laying out the pins on the pins board, as I wanted a symmetrical look. And I also did the layout for the half-blind dovetails on the drawer sides. Then I started sawing.

I tackled the dovetail sawing with much concentration. For the back of the drawer I made a conscious effort to cut to the line on the pins board, and to leave the line on the tails boards (the drawer sides). And for the half-blind dovetails I cut to the line for the tails boards (the drawer sides), and left the marking knife line on the drawer fronts. Careful sawing resulted in very little or no paring required to assemble very nice, tight joints.

The following is my very-concentrated look, an actual action shot (!):

cutting-new-pins

The results, for the half-blind dovetails – before using any hand planes to smooth the sides:

drawer-box-half-blind-dts-front

The through dovetails on the drawer back – notice the straight-across cut near the bottom, to allow for bottom slips (in the photo after this one):

drawer-box-dts-on-back

I had a great feeling when I got to this point:

drawer-box-completed

This next photo shows a little more detail on the spacing available for the drawer slips – the slips will run the entire length of the sides:

drawer-box-awaiting-slips

I will write in a future blog entry some details of the preparation of the drawer slips, and on the machining of the solid wood drawer bottoms. In the meantime, three additional drawers await. I have milled sufficient stock, including some extras to match for color and appearance, just in case my saw starts to wander a bit:

drawer-side-boards

I hope to share with the client some of the recent progress on this desk.

.

—— Al Navas

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