Log in

No account? Create an account
entries friends calendar profile Previous Previous Next Next
visitor, choosing more floorboards, cutting a board, mis-cutting a board - Rounding up the Usual Suspects
Steve's Livejournal
visitor, choosing more floorboards, cutting a board, mis-cutting a board

Today we had a visit from "A". She seems to be doing well.

Most of the day's work was flooring. I started with an easy task, cutting a single end board to length, Row 68 #0. (I had already cut Row 67 #0 and Row 67 #3 a while ago, but I still haven't nailed them down.)

Back on the first, I chose floorboards for Row 59 through Row 68, but skipped Row 68 #2 because it's adjacent to pieces that would fit around the furnace vent cover's frame. I also skipped Row 68 #4, because it's a short end piece that would probably end up as the cut end of the long Row 70 #0 end piece, and I didn't want to pick out the latter back then.

So, today I chose boards for the rest of the room, except for the narrow edge pieces that will be mostly hidden under the east wall baseboard trim. The tricky pieces were the ones around the vent frame. Row 69 #2 fits around the southwest corner of the frame, with just a little piece cut out, and Row 69 #3 will fit around the northwest corner of the frame, with a long rectangle cut out. (The difference between "fits" and "will fit" is intentional.*)

Row 70 #2 is actually two pieces, a long one abutting the south edge of the vent frame, and a short piece at the north edge of the vent frame. I chose two different boards for that: a piece with a defect in the part I'll cut off, leaving the longer section, and a small piece of scrap that I'll cut down even smaller on the other side.

Row 71 #2 will be really complicated: a piece with a rectangular chunk cut out of the tongue side, which will have to fit around both the northeast and southeast corners of the frame. Rather than attempt that sort of cut in the west bedroom, I cut it as three pieces (two end pieces and a side piece; only the side piece needed to be cut to precise length). Looking in the dining room, I see that I cut a rectangle out of the middle of a board's edge, but I don't clearly remember how I managed to get it right.

In addition to the boards around the edges of the vent frame, I chose end pieces for the same rows, and a few boards that I won't need to cut.

The next two tasks required quite a bit of precision: cutting pieces out of Row 69 #3 and Row 69 #2, to precisely fit around the southwest and northwest corners of the vent frame. Superficially, the frame looks like a 1213/16 × 79/16 inch rectangle (with a space for a removable 107/16 × 51/8 inch vent cover inside), but the pieces aren't cut precisely square. They're only off by about 1/32 inch (0.8 mm), but that's enough to leave a very conspicuous gap when the rest of the floorboards are fitted tightly. Fortunately, although I had to cut the corners a precise distance apart, I didn't need to worry about the angles much, because these cuts only remove about 7/8 inch (22.2 mm) of width, so the non-square corners wouldn't leave conspicuous gaps. Besides, I was cutting them approximately, with plans to adjust to the final distance by sanding.

Anyway, one of the corner cuts was simple – cutting away a 11/4 inch long, 7/8 inch wide piece from Row 69 #3.

However, Row 69 #2 was more complicated: about 11 1/2 inches of length (that I'd reduce slightly with sanding), the same 7/8 inch of width, plus the spline notch I described on the sticky note (below). And the cutting went wrong with the spline notch. For one thing, I should have cut the spline notch before the other two cuts. That deep edge cut turns a lot of bamboo to sawdust, and that much cutting of material as hard as this stuff heats up the cut to the point that it also generates smoke. That's why I made the length and width cuts first. But there are two reasons I should have done the notch first anyway: one, it's safer, because it leaves the spinning blade safely hidden within the thickness of the floorboard, and two, it's easier to cut the notch to a reasonably consistent depth.

But I did the width and length cuts first because I didn't think through the steps until there was a problem. Unfortunately, when I made the notch cut, I forgot to lock the table saw fence, so as I pushed the board through the cut the fence slid away from the blade. By the time I noticed the problem, the notch had shifted sideways toward the finished side of the floorboard far enough that the board was starting to crack. The board was ruined, at least for this purpose. (I can probably still use the rest of the board as an end piece in the next room.) It was too late for a do-over, both because the saw is a noisy tool and because I was getting fatigued enough to make mistakes like forgetting to lock the fence.

I chose a new board, and to make sure that when I cut the replacement I'd avoid repeating the mistakes. I thought through what went wrong (besides the obvious problem of leaving the fence unlocked) and how I could do the job better on the second try. And to make sure I won't forget anything when I continue working, I made a list while the corrected procedure was fresh in my mind, and wrote it on a sticky note that I stuck to the replacement board:

  1. Cut spline notch 7/32 [inch] from top to 13/32 [inch] from top.
  2. Rip 7/8 [inch] at 7°. [The 7°-from-vertical bevel allows the piece to meet touch the vent frame at the surface, and makes it easier to sand the joint smooth.]
    Add 1/16 [inch] slope allowance. [The table saw has a measurement guide, but it only works with the blade vertical, because the guide doesn't know the thickness of the piece being cut.]
  3. Cut at line, 15°. [I marked a line where the northwest corner of the vent frame goes. The deeper 15° bevel is easier to sand to the right size than a right-angle cut.]

* The reason for "fits" and "will fit" is that I cut Row 69 #2 correctly, so that the piece as cut fits the corner of the vent frame, but I screwed up Row 69 #3, so the replacement piece will fit.


Leave a comment