I've read several threads in the past re: the benchtop units and how one
should not expect much accuracy jointing a board over 3' long. I know
they have a shorter I/O tables than a full sized unit, but why is it
that they would not be accurate for anythihng over around 3'? It would
seem that if you kept the proper pressure in the same place as you moved
the board along (provided the table is set up properly) that you'd get a
good accurate cut on a boards say 6' long. How is my logic flawed -
I need a jointer (and table saw, BT3100? if I can figure out who the
hell sells them & where I can see one first) and most of the work I'll
do will be shorter pieces, however I may work on a few large display
cabinets, built-in bookshelves and kitchen cabinets so larger stuff is a
possibility. I'm very limited in shop space so the footprint is important.
There is no comparison between a benchtop and
a cabinet jointer. There isn't that much difference in cost and the
difference in performance is tremendous.
Several reasons why the benchtop jointers are not as good:
- too awkward when using boards much longer than 3', unless you
make or buy table extensions - which, in that case, you're
then taking up as much or more space as a cabinet jointer,
- cheaper construction
- motor is very noisy and not really strong enough to do a
good job on hardwood boards 5" or 6" wide,
- lack of rabiting feature
I think you pretty much hit it on the head when you said "keep the proper
pressure ". That is quite hard to do if one end of the board is drooping a long
way over the end of one of the tables. Having the ends supported certainly
increases the chances of a successful operation.
I have used my 6" jointer for long boards and it helps when I use extension
tables. It takes a bit of friggin to get the tables to the correct l height.
And for bench tops , are you not quite limited in the width of the wood?
The first time you use a benchtop jointer (motorized) with a curly or exotic
wood, you will find out why they are stopgap, temporary, first jointers, etc.
They will take tissue thin slices of wood only. Th ei/o bed is so short, even
if you can maintain an even pressure on the wood, well, you really can't.
If it's a money issue, get a 6" Grizzly, which is a pretty good machine. The
staionary model. Jointers are vey underappreciated, but really vital: without
flat square stock, you can't build anything.
Draw a sketch of a curved board running across a jointer. As soon as you
start the cut, you have established a line which the rest of the cut has to
follow if the edge is going to be straight. IF the curve of the board takes
the back end up, away from the table, you're going to tend to lower the back
to keep some weight ton the infeed table. You should now see that the front
end of the board will rise, taking your cut off the theoretical straight
line you want. Conversely, if your board curves down toward the back it
will lift the back end as you feed onto the table, which raises the back end
and takes the cut off the tatget line. We can push this a bit, but for a
jointer to truly work as we think of their doing you need for the infeed
table and the outfeed table to both be longer than the board. We get around
this tough requirement by keeping weight on the outfeed once the line is
started, but even this won't work in the case of the downcurving board!
To really straighten a board, I prefer to screw it to a straight carrier
board and run it through my radial arm saw. You can use a carrier on a TS,
but the fence is short and guiding something long can be a problem. I have
a six foot infeed on my RAS, so it's really easy to stay straight.
Most jointers are really good for picture frames and drawer parts! Big ones
can do cabinst parts.
Once I started making my own lumber, it was easy to see why the straight,
flat boards in the store are so expensive. I'd bet they are no more than a
third of most trees!
"Grandpa" <jsdebooATcomcast.net> wrote in message
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