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Jefferson Bookcases #2: Building the plinths

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Blog entry by Dave Polaschek posted 08-03-2020 02:06 AM 593 reads 0 times favorited 17 comments Add to Favorites Watch
« Part 1: Introduction Part 2 of Jefferson Bookcases series Part 3: Large case tail boards (sides) »

For this style of bookcase, there is a plinth, which serves as a base, supporting the stack of boxes. Since the plinths are mostly hidden, and the weight is mostly carried by the four glue blocks in the corners, I figured they were a good place to start. Half of the dovetails will be hidden, and only one of the four boards is very visible.

Here’s my checklist for building the plinths, along with some pictures of the intermediate steps:

  1. Cut all the boards to length. There are three different lengths of pine 1×4, and two lengths of ash 1×1 glue blocks. Two 1×4x12, two 1×4x31, one 1×4x29½, two 1×1x3⅜, and two 1×1x2⅝.
  2. Mark out and cut tails on side boards (no miters yet)











  3. Cut rabbets on side boards, using my kerfing plane with a fixed ⅜ inch fence, and clean them up with a chisel


  4. Mark and cut pins on front board, including miter. If you cut the miter on the tail board before this, you won’t have a full tail to mark the pin from, and you’ll have to guess where the pin edge should be.


  5. Cut miter on matching corner of side board
  6. Test fit
  7. Cut other corner pins on front board, including miter
  8. Cut miter on matching corner of side board
  9. Test fit and adjust
  10. Cut rabbet on front board
  11. Cut curved cutout on front board
  12. Smooth cutout with knife and spokeshave

  13. Cut pins on rear board, including miter
  14. Cut miter on matching corner
  15. Test fit and adjust
  16. Cut pins on final corner, plus miter
  17. Cut miter on final corner of side board
  18. Test fit and adjust
  19. Check for square
  20. Glue up, making sure to glue the front cross brace to front before clamping
  21. Double-check for square
  22. Unclamp after the glue has dried overnight
  23. Glue ash glue-blocks into corners, short ones under the cross-brace board. Note the spacers set in the rabbets so the glue blocks will be flush with the rabbets, giving good support to the cases.
  24. Plane smooth with a smoother plane and chamfer the top-outside corners of the boards with a block plane, such that I get a 3/16 inch wide chamfer. This should make the tops more durable as the cases are set into the plinths.
  25. Three coats of shellac, brushed on. I’m using a 1.5 pound cut of super-blonde shellac.
  26. Sand lightly with 320 grit to remove raised grain, dust, etc
  27. Final coat of shellac

If there are any steps you’re curious about that don’t have pictures, let me know.

Here’s a stack of three of the finished plinths. The middle one is my prototype and doesn’t have the mitered dovetails, so doesn’t look as nice as the others. I’ll hide it in the corner or something.

And note that while I’m working, I keep all the pieces on my benchtop laid out in order so I can more easily keep track of where I am.

And here’s a photo of a plinth with the first case sitting on it.

-- Dave - Santa Fe



17 comments so far

View Oldtool's profile

Oldtool

3026 posts in 3038 days


#1 posted 08-03-2020 03:05 AM

That’s quite a write up, well detailed. Looking forward to the next installment.

-- "I am a firm believer in the people. If given the truth, they can be depended upon to meet any national crisis. The point is to bring them the real facts." - Abraham Lincoln

View mikeacg's profile

mikeacg

1696 posts in 1905 days


#2 posted 08-03-2020 11:04 AM

Dave,

This is very interesting to watch! One question though… What is this board on the top front of the plinth (size, purpose, etc.)?

-- Mike, A Yooper with a drawl, http://www.artcentergraphics.com

View crowie's profile

crowie

3897 posts in 2798 days


#3 posted 08-03-2020 11:16 AM

Now that’s something I truly admire, not just the hand tools and the results but hand cut dovetail joints, nicely done sir.

-- Lifes good, Enjoy each new day...... Cheers from "On Top DownUnder" Crowie

View Don W's profile

Don W

19697 posts in 3415 days


#4 posted 08-03-2020 11:23 AM

Nice work and excellent write up

-- http://timetestedtools.net - Collecting is an investment in the past, and the future.

View Dave Polaschek's profile

Dave Polaschek

5839 posts in 1430 days


#5 posted 08-03-2020 12:28 PM

Mike, that board is a brace. It’s a 1×4x29½, and its purpose is to reinforce the front board which has some material cut away for decorative purposes. It’s probably not necessary, as I made a smaller cutout than Schwarz did in his version, but it won’t hurt anything, and it helps me ensure that the plinth remains square when clamped up. Plus, as I’m going to be stacking the cases 6 high at a minimum, there will be a fair amount of weight. I’d rather not find out I under built in the middle of some night as books and lumber come crashing to the floor.

Thus, the brace.

I also just realized that at step 24, I forgot, “chamfer the top of the boards with a block plane, such that I get a 3/16 inch wide chamfer,” which I’ll go back and add. There’s always something!

Thanks for the comments, guys. Some of my dovetails are a little gappy, but each plinth off the production line looks a tiny bit better than the last. Number 6 (the last in this batch) gets glued up today, and should be finished by the end of the week (have I mentioned I really need more clamps?) and I’ll post a photo showing the evolution from first to last.

-- Dave - Santa Fe

View Dave Polaschek's profile

Dave Polaschek

5839 posts in 1430 days


#6 posted 08-03-2020 04:30 PM

Bunch of updates today. A few new pictures, and a lot of details I only seem to remember when I have a tool in my hand or a glue bottle open.

-- Dave - Santa Fe

View JohnMcClure's profile

JohnMcClure

1074 posts in 1488 days


#7 posted 08-03-2020 04:48 PM

Dave,
This is a great project and I look forward to following along.
Thanks for your detailed notes!
Few people would be inclined to undertake such a large project using hand cut dovetails!

-- I'd rather be a hammer than a nail

View Dave Polaschek's profile

Dave Polaschek

5839 posts in 1430 days


#8 posted 08-03-2020 05:32 PM

Thanks, John! The notes are the result of taking a lot of pictures while working through things. With 6 plinths, 12 large cases, 18 medium cases, and probably 12, but maybe 18 small cases, I’ve got… carry the one… a LOT of dovetails to cut. But they go pretty fast. It’s about four strokes with my dovetail saw to cut each side of the pins or tails, and a dozen with the turning saw to remove the waste.

Plus I decided right out of the gate that I was going to make the dovetails “chunky” both because I don’t like the look of skinny pins, and because it’ll mean less cutting. And I’m getting enough practice that my dovetails are improving with every day’s session. The two sets I cut on the final plinth this morning went together straight off the saw, with no adjusting needed. The set yesterday were loose enough that I had to pack a couple gaps with shavings and then CA glue them in place.

-- Dave - Santa Fe

View duckmilk's profile

duckmilk

4331 posts in 2172 days


#9 posted 08-03-2020 10:26 PM

Good start Dave. I’ll be watching the progress.

-- "Duck and Bob would be out doin some farming with funny hats on." chrisstef

View MrWolfe's profile (online now)

MrWolfe

1055 posts in 971 days


#10 posted 08-03-2020 10:45 PM

Cool hand tool project Dave!
Glad to see your shop too. Great blog and I’m following it too.
Jon

View Dave Polaschek's profile

Dave Polaschek

5839 posts in 1430 days


#11 posted 08-03-2020 10:47 PM

Thanks, Duck! Two more plinths now have shellac on them, the final one has the glue drying, and I got boards for half of the largest cases cut to length today. I think I’ll finish the plinths tomorrow and get box number two built, which means writing that up later this week.

Thanks, Jon. 90% of my work is done either in that twin screw vise or on the bench just behind it. I don’t know how I’d work without it.

-- Dave - Santa Fe

View mikeacg's profile

mikeacg

1696 posts in 1905 days


#12 posted 08-04-2020 04:05 PM

Dave,

What keeps the piled boxes in place? Pins?

-- Mike, A Yooper with a drawl, http://www.artcentergraphics.com

View Dave Polaschek's profile

Dave Polaschek

5839 posts in 1430 days


#13 posted 08-04-2020 06:23 PM

Gravity, Mike. And friction.

Schwarz bolted them to the wall with some anti-earthquake setup. If they show any signs of moving I’ll add pins or a piece of moulding, but I’m pretty sure good old 9.8m/s^2 will do the trick.

-- Dave - Santa Fe

View mikeacg's profile

mikeacg

1696 posts in 1905 days


#14 posted 08-04-2020 09:48 PM

The plinth has that handy lip but then I got to thinking about the stacked shelves… I live in town now and the train comes by at all hours! Things have been known to move around a bit with the tracks so close by!!!

-- Mike, A Yooper with a drawl, http://www.artcentergraphics.com

View Dave Polaschek's profile

Dave Polaschek

5839 posts in 1430 days


#15 posted 08-04-2020 10:46 PM

Yeah, I thought about doing something like that, but other than high winds rattling the exhaust fans, we don’t have too much movement here.

-- Dave - Santa Fe

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