Once I've jointed an edge, I'd like to know that there are no hills or
valleys in the edge over the length of the board. For example, it's
hard for me to know if there's a concavity a 16th deep if it's spread
out over half of an 8' board. How can I tell how straight an 8' edge is
without an 8' straightedge?
-Tom
"nireedmot" <[email protected]> wrote
: Once I've jointed an edge, I'd like to know that there are no hills or
: valleys in the edge over the length of the board. For example, it's
: hard for me to know if there's a concavity a 16th deep if it's spread
: out over half of an 8' board. How can I tell how straight an 8' edge is
: without an 8' straightedge?
A very sensitive spirit level will do the trick.
Jeff G
--
Jeff Gorman, West Yorkshire, UK
Email: username is amgron
ISP is clara.co.uk
www.amgron.clara.net
On 11 Dec 2004 06:23:16 -0800, "nireedmot" <[email protected]>
wrote:
>Once I've jointed an edge, I'd like to know that there are no hills or
>valleys in the edge over the length of the board. For example, it's
>hard for me to know if there's a concavity a 16th deep if it's spread
>out over half of an 8' board. How can I tell how straight an 8' edge is
>without an 8' straightedge?
>
>-Tom
Sighting down the board is probably the easiest method, although not
quantitative. Winding sticks are also useful. You could also use a
laser. A board can be out-of-whack in other ways too: cup, bow,
crook, and twist. A well-tuned long-bed jointer should give you a
straight edge.
Back to the reality that two edges to be joined need only be complementary.
Then there's the reality that 1/16 inch is clamp closeable over three feet.
"Rumpty" <[email protected]> wrote in message
news:[email protected]...
> Buy a long straight edge, but then you are subject to the slave labor in
> china that makes the straight edge. Or do as the rest of us do, sight
down
> your jointed edge to check. Also place against the other piece to be
joined
> and you'll see any problems.
> "nireedmot" <[email protected]> wrote in message
> news:[email protected]...
> > Once I've jointed an edge, I'd like to know that there are no hills or
> > valleys in the edge over the length of the board. For example, it's
> > hard for me to know if there's a concavity a 16th deep if it's spread
> > out over half of an 8' board. How can I tell how straight an 8' edge is
> > without an 8' straightedge?
> >
> > -Tom
> >
>
>
"nireedmot" wrote in message
> Once I've jointed an edge, I'd like to know that there are no hills or
> valleys in the edge over the length of the board. For example, it's
> hard for me to know if there's a concavity a 16th deep if it's spread
> out over half of an 8' board. How can I tell how straight an 8' edge is
> without an 8' straightedge?
Often, you can just sight down it with a practiced eye, Or, lacking that,
there is generally a surface in your shop that is "flat" (a relative term),
i.e, your table saw top, a bench top made "flat" (a relative term) for the
purpose, a wing of a jointer, a factory cut plywood edge, etc, that can be
used for comparison.
Flat enough is relative, and generally perfect enough for woodworking.
--
www.e-woodshop.net
Last update: 11/06/04
Buy a long straight edge, but then you are subject to the slave labor in
china that makes the straight edge. Or do as the rest of us do, sight down
your jointed edge to check. Also place against the other piece to be joined
and you'll see any problems.
--
Rumpty
Radial Arm Saw Forum: http://forums.delphiforums.com/woodbutcher/start
- - - - - - - - - - - - - - - - - - - - -
"nireedmot" <[email protected]> wrote in message
news:[email protected]...
> Once I've jointed an edge, I'd like to know that there are no hills or
> valleys in the edge over the length of the board. For example, it's
> hard for me to know if there's a concavity a 16th deep if it's spread
> out over half of an 8' board. How can I tell how straight an 8' edge is
> without an 8' straightedge?
>
> -Tom
>
Stretch a piece of colored monofilament fishing line?
If you cannot see it how would it matter?
If you are edge glueing 2 pieces together then hold the 2 together
looking for gaps.
"nireedmot" <[email protected]> wrote:
>Once I've jointed an edge, I'd like to know that there are no hills or
>valleys in the edge over the length of the board. For example, it's
>hard for me to know if there's a concavity a 16th deep if it's spread
>out over half of an 8' board. How can I tell how straight an 8' edge is
>without an 8' straightedge?
>
>-Tom
On 11 Dec 2004 06:23:16 -0800, "nireedmot" <[email protected]>
wrote:
>Once I've jointed an edge, I'd like to know that there are no hills or
>valleys in the edge over the length of the board. For example, it's
>hard for me to know if there's a concavity a 16th deep if it's spread
>out over half of an 8' board. How can I tell how straight an 8' edge is
>without an 8' straightedge?
>
>-Tom
I use my bench... if that isn't flat enough, I use the cement garage
floor..
If you need a higher level of accuracy, build an 8' outfeed table for
your jointer... *g*
On Sun, 12 Dec 2004 07:55:33 -0000, "POP_Server=pop.clara.net"
<[email protected]> wrote:
>
>"nireedmot" <[email protected]> wrote
>
>: Once I've jointed an edge, I'd like to know that there are no hills or
>: valleys in the edge over the length of the board. For example, it's
>: hard for me to know if there's a concavity a 16th deep if it's spread
>: out over half of an 8' board. How can I tell how straight an 8' edge is
>: without an 8' straightedge?
>
>A very sensitive spirit level will do the trick.
>
>Jeff G
That is the most accurate. This is how they make those huge machines
flat. It takes longer than other methods, but works. Just use a level
that is calibrated and write down the numbers as you move it along.
Once you have a good straight board, keep it upright in a dry area to
use as your standard. Check it once in awhile.
BTW, you can also plot a large panel this way.
Hold the board up to an identically jointed board; there should be
little or no daylight visible between the two.
David
mac davis wrote:
> On 11 Dec 2004 06:23:16 -0800, "nireedmot" <[email protected]>
> wrote:
>
>
>>Once I've jointed an edge, I'd like to know that there are no hills or
>>valleys in the edge over the length of the board. For example, it's
>>hard for me to know if there's a concavity a 16th deep if it's spread
>>out over half of an 8' board. How can I tell how straight an 8' edge is
>>without an 8' straightedge?
>>
>>-Tom
>
>
> I use my bench... if that isn't flat enough, I use the cement garage
> floor..
> If you need a higher level of accuracy, build an 8' outfeed table for
> your jointer... *g*
>
Joint 2 8ft pieces, flip one over and butt up the jointed edges
together, If they are NOT flat, it will show up like a sore thumb
John
On Sat, 11 Dec 2004 09:53:07 -0500, "Rumpty" <[email protected]>
wrote:
>Buy a long straight edge, but then you are subject to the slave labor in
>china that makes the straight edge. Or do as the rest of us do, sight down
>your jointed edge to check. Also place against the other piece to be joined
>and you'll see any problems.