OldTools Archive

Recent Bios FAQ

273593 Andrew Heybey <ath@h...> 2021‑05‑05 Re: flattening a large slab
The “techniques” topic.  Tomorrow will be the “wood” topic :-).  Thanks again to

> On May 4, 2021, at 9:19 AM, Kirk Eppler via groups.io
> What little slab work I have done has greatly benefited from using a 5 or
> 5-1/2 diagonally, alternating diagonals. I’ve used my winding sticks and a
> longer straightedge to figure out the highpoints, remove them, and repeats.
> ( I have a friend who built a router device for this, kills me to see his
> FB feed). The extra mass if the -1/2 is a nice touch.  A big wooden plane
> could be used as well.

> On May 4, 2021, at 2:04 PM, James DuPrie  wrote:
> back when I was doing surfacing by hand, I used a combination of #5 and #7
planes. start at one end, cutting on a diagonal (45 degrees to grain), and work
your way to the other end. Go back to the start, and do the same thing, but on
the other diagonal (90 degrees from your first pass). When you start, the high
spots are obvious, and I'd hog them off with scrub, then switch to coarse set
bench planes. As you make progress, start using winding sticks and a straight
edge. When you get to the end, start tightening up the throats of your planes,
and they'll do the rest...

> On May 4, 2021, at 4:03 PM, scottg  wrote:
> A Handyman #4 will do if you have to.
> A more solid jack plane with a goodly camber on the razor sharp iron will hog
more chips faster though.
> Use your winding sticks to see where its the worst.
>  Go diagonal or even straight across to start.
> No time to squinge along and look at shavings etc. Dig in with a will and hog
some thick chips fast!
> When you get closer its time to slow down and use a longer plane.

There is a consensus! And yes that is my basic plan:
Use my “scrub” plane, straight edge and winding sticks to more-or-less flatten
one face, then use the #5-1/4 and/or #7C diagonally to do a final flattening.  I
will use my “good” #4 with the grain (and perhaps scrapers or scraping plane) to
finish.  Though the #5-1/4 is smaller than a #5, not larger like the #5-1/2.

I dug out the winding sticks I made 20 years ago, and they are no longer
straight, so I guess that is the immediate project.

> On May 4, 2021, at 2:04 PM, James DuPrie  wrote:
> I never flattened the bottom. I'd knock off really high spots, but instead of
flattening the whole surface, I'd plane 'slots' (I guess technically they'd be
dados) for the stretchers to sit in. To keep the top from sliding around too
much, I'd drill a 1" dowel into the center of each stretcher, and bore a hole in
the bottom surface to match it. Keep it loose so It's easy to get on (and off if
you ever need to disassemble). Keeping the slots in plane, and parallel to the
top is pretty easy if you do the top surface first. Then you just flip it over
(bottom up), mark out the slots, and using a level and winding sticks lay out
the areas to cut out and mark the depth. You can attack it with planes, or hog
it out with chisels then clean it up with planes or chisels. My method was to
cut the shoulders of the slots with a  back saw, but cutting about 1/4" shallow.
Hog both slots out with a big chisel, then start sneaking up on the final line
with planes - FREQUENTLY checking to make sure you're keeping both slots at the
same depth and parallel. I always worked both slots at the same time because I
found it easier to make sure they stayed at the same depth and parallel that
way. I didn't have a specific "final thickness" target, so I'd just work the
slots until they both had clean surfaces and were in line.

> On May 4, 2021, at 10:08 AM, yorkshireman@y... wrote:
> Next thought - Old time folk wouldn’t necessarily flatten the underside.  If
it is to rest on bearers across the top of the unit - then just provide trenches
/ rebates where the bearers run, and leave the excess timber in place.

> On May 4, 2021, at 4:03 PM, scottg  wrote:
> Richard is absolutely right of course.
> Flattening both sides is a machine approach.
>  You can shim up / relieve the bottom easy enough.
> There is no bonus at all for a finished bottom.
> If you are doing it by hand let it look a little like it was done by hand.
> There is no bonus in copying K-Mart with hand tools.

Thanks, I had not thought about just flattening the bottom enough to sit on the
cabinet.  The base of the island is a standard (USA) kitchen base cabinet, open
with the carcase of the cabinet making a rectangle that the top sits on.  There
are blocks in the corners to put a fastener up into the top from below.

I have several constraints with trying to put an uneven bottom on that kind of
- It is bowed by 1/2”, if I put a groove in it to make a level spot to sit on
the base, then will it hang down and interfere with the drawers (if the concave
side is down).  Or if the convex side is down, will it hang down and interfere
contents of the drawers on the inside?
- The base is actually 2’x3’ while the top is almost square, 3’x3’ (it will
overhang so a stool or two can be parked under the overhang).  Will have to
figure out how that affects the bottom.
- I do not want the top to be too thick because I don’t want the finished island
to be any taller than it is with the current temporary plywood+2x4 top which is
2.25”.  In fact if it only ends up 2” above the top of the cabinet that would be
fine.  So adding battens or other supports on top of the cabinet is not really
going to work.
- Aesthetically, what will SWMBO approve of?  I expect that she will be in favor
of a non-machine-made look, but I need to discuss.

> On May 4, 2021, at 5:32 PM, Darrell  wrote:
> Thicknessing, well, for my purposes I just needed it to sit level on the
> frame of the table. I used a scrub plane to hog off most of the stock
> and then a jack plane to bring it down to the line.  Ah yes, the line.
> I used a Stanley #78 rebate & fillister plane to cut a rebate with the
> fence registering on the Face side.  That means I simply plane the
> off side down to the bottom of that rebate.  Easy to see, that's for sure.
> I only scrubbed for 30 minutes or so at a time, otherwise I would have
> ended up a broken man, trying to accomplish the entire work at once.

I like the rebate idea, and I even have a #78.  At this point, it is more like
10 minutes of scrubbing before my computer programmer arms get tired, but by the
time I am done maybe I can get to 30!


Recent Bios FAQ