Cutting longish curve in plywood.

On 3 Oct, 14:57, "Kerry Montgomery" <[email protected]> wrote:
> "HeyBub" <[email protected]> wrote in message
>
> news:[email protected]...
>
>
>
> > dadiOH wrote:
> >> WonderMonkey wrote:
> >>> I'm making some yard items for youth activities. One of them is a
> >>> football. Here is a picture of somethig real close to what I will
> >>> be doing:http://www.henrynet.com/stuff/yard/football1.jpg. I've
> >>> used the
> >>> search function here for advice but didn't find anything that fit.
> >>> If you know of another thread, please give me a hint and I'll go
> >>> there. OK, right now I plan on drawing my template, and using my
> >>> jigsaw to cut the arc. My problem revolves around making a smooth
> >>> curve instead of what I usually do. Any advice for using the jigsaw
> >>> for this?
>
> >> You can forget about the template if...
>
> >> 1. You determine the radius of the arc you want to cut.
>
> >> 2. Take a 2-4" wide piece of ply a bit longer than the radius
>
> >> 3. Attach your jigsaw to the end of #2
>
> >> 4. Nail the other end of #2 to the ply you want to cut (one nail only)
> >> so distance blade<>nail equals desired radius. Enlarge the nail hole
> >> in #2 so it is the same diameter as the nail and so the nail will slip
> >> thru it easily.
>
> >> Now you have a compass and can happily cut smoothly away :)
>
> > Works for Rugby balls (which, I think, have arcs of circles). American
> > footballs (again, I surmise) have arc of an ellipse. For the latter,
> > you'll need two nails.
>
> And a string. I think you're correct, that an American football is an
> ellipse, but the one in the OP's photo has arcs that are so close to being
> circles as to not be noticeably different.
> Kerry- Hide quoted text -
>
> - Show quoted text -

And he's gonna need a really strong needle to add the stiches.

On Oct 3, 2:24 pm, "HeyBub" <[email protected]> wrote:
> dadiOH wrote:
> > WonderMonkey wrote:
> >> I'm making some yard items for youth activities. One of them is a
> >> football. Here is a picture of somethig real close to what I will
> >> be doing:http://www.henrynet.com/stuff/yard/football1.jpg. I've
> >> used the
> >> search function here for advice but didn't find anything that fit.
> >> If you know of another thread, please give me a hint and I'll go
> >> there. OK, right now I plan on drawing my template, and using my
> >> jigsaw to cut the arc. My problem revolves around making a smooth
> >> curve instead of what I usually do. Any advice for using the jigsaw
> >> for this?
>
> > You can forget about the template if...
>
> > 1. You determine the radius of the arc you want to cut.
>
> > 2. Take a 2-4" wide piece of ply a bit longer than the radius
>
> > 3. Attach your jigsaw to the end of #2
>
> > 4. Nail the other end of #2 to the ply you want to cut (one nail only)
> > so distance blade<>nail equals desired radius. Enlarge the nail hole
> > in #2 so it is the same diameter as the nail and so the nail will slip
> > thru it easily.
>
> > Now you have a compass and can happily cut smoothly away :)
>
> Works for Rugby balls (which, I think, have arcs of circles). American
> footballs (again, I surmise) have arc of an ellipse. For the latter, you'll
> need two nails.

Those look like circular arcs on that photo. It looks like the center
point
of each arc lies on the midpoint of the other arc.

"WonderMonkey" wrote

> My
> problem revolves around making a smooth curve instead of what I
usually do.
> Any advice for using the jigsaw for this?
<snip>

1) Make your template from 1/4" hardboard, doubled to 1/2".

2) Layout curve, then trim template proud with jig saw.

3) Sand to the line using a fairing board and checking your work with
a fairing batten.

What is a fairing board?

A fairing board for this application will be a piece of 1/4-3/8
plywood about 3"W x 36LG with a handle at each end,

Use rubber cement and glue strips of 3"W, 24 grit sand paper to the
plywood.

Stroke the fairing board across the curved jig saw cut line until
smooth. (Change paper frequently).

A fairing batten for this job will be a 3/4"x3/4"x1/16"x96" aluminum
angle.

Use back side of angle to check for high spots.

TIP: Rub the back side of the angle back and forth against the
template surface. The aluminum will leave black marks on the high
spots.

When your arms feel like they want to drop off, your template is
fair<Been there, done that>.

When complete, you will have served your apprenticeship to fair out
boat hulls<Grin>.

Have fun.

Lew

dadiOH wrote:
> WonderMonkey wrote:
>> I'm making some yard items for youth activities. One of them is a
>> football. Here is a picture of somethig real close to what I will
>> be doing: http://www.henrynet.com/stuff/yard/football1.jpg . I've
>> used the
>> search function here for advice but didn't find anything that fit.
>> If you know of another thread, please give me a hint and I'll go
>> there. OK, right now I plan on drawing my template, and using my
>> jigsaw to cut the arc. My problem revolves around making a smooth
>> curve instead of what I usually do. Any advice for using the jigsaw
>> for this?
>
> You can forget about the template if...
>
> 1. You determine the radius of the arc you want to cut.
>
> 2. Take a 2-4" wide piece of ply a bit longer than the radius
>
> 3. Attach your jigsaw to the end of #2
>
> 4. Nail the other end of #2 to the ply you want to cut (one nail only)
> so distance blade<>nail equals desired radius. Enlarge the nail hole
> in #2 so it is the same diameter as the nail and so the nail will slip
> thru it easily.
>
> Now you have a compass and can happily cut smoothly away :)

Works for Rugby balls (which, I think, have arcs of circles). American
footballs (again, I surmise) have arc of an ellipse. For the latter, you'll
need two nails.

WonderMonkey wrote:

> I'm making some yard items for youth activities. One of them is a
> football. Here is a picture of somethig real close to what I will
> be doing: http://www.henrynet.com/stuff/yard/football1.jpg .

Easiest way to get football shape is to layout a camber.

See Fred Bingham's book, Practical Yacht Joinery, for details.

Been there, done that.

Lew

"HeyBub" <[email protected]> wrote in message
news:[email protected]...
> dadiOH wrote:
>> WonderMonkey wrote:
>>> I'm making some yard items for youth activities. One of them is a
>>> football. Here is a picture of somethig real close to what I will
>>> be doing: http://www.henrynet.com/stuff/yard/football1.jpg . I've
>>> used the
>>> search function here for advice but didn't find anything that fit.
>>> If you know of another thread, please give me a hint and I'll go
>>> there. OK, right now I plan on drawing my template, and using my
>>> jigsaw to cut the arc. My problem revolves around making a smooth
>>> curve instead of what I usually do. Any advice for using the jigsaw
>>> for this?
>>
>> You can forget about the template if...
>>
>> 1. You determine the radius of the arc you want to cut.
>>
>> 2. Take a 2-4" wide piece of ply a bit longer than the radius
>>
>> 3. Attach your jigsaw to the end of #2
>>
>> 4. Nail the other end of #2 to the ply you want to cut (one nail only)
>> so distance blade<>nail equals desired radius. Enlarge the nail hole
>> in #2 so it is the same diameter as the nail and so the nail will slip
>> thru it easily.
>>
>> Now you have a compass and can happily cut smoothly away :)
>
> Works for Rugby balls (which, I think, have arcs of circles). American
> footballs (again, I surmise) have arc of an ellipse. For the latter,
> you'll need two nails.
>
And a string. I think you're correct, that an American football is an
ellipse, but the one in the OP's photo has arcs that are so close to being
circles as to not be noticeably different.
Kerry

WonderMonkey wrote:
> I'm making some yard items for youth activities. One of them is a
> football. Here is a picture of somethig real close to what I will
> be doing: http://www.henrynet.com/stuff/yard/football1.jpg . I've
> used the
> search function here for advice but didn't find anything that fit.
> If you know of another thread, please give me a hint and I'll go
> there. OK, right now I plan on drawing my template, and using my
> jigsaw to cut the arc. My problem revolves around making a smooth
> curve instead of what I usually do. Any advice for using the jigsaw
> for this?

You can forget about the template if...

1. You determine the radius of the arc you want to cut.

2. Take a 2-4" wide piece of ply a bit longer than the radius

3. Attach your jigsaw to the end of #2

4. Nail the other end of #2 to the ply you want to cut (one nail only)
so distance blade<>nail equals desired radius. Enlarge the nail hole
in #2 so it is the same diameter as the nail and so the nail will slip
thru it easily.

Now you have a compass and can happily cut smoothly away :)


--

dadiOH
____________________________

dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

Thanks for all the suggestions. I'll take them into consideration when I
start on this project tonight.

I'm going to be making several of these. I'm going to end up making a
template.

Phisherman wrote:
>>I'm making some yard items for youth activities. One of them is a football.
>>Here is a picture of somethig real close to what I will be doing:
>[quoted text clipped - 15 lines]
>>have some nicer equipment in for but now it's me, my jigsaw, a circular saw,
>>and a jug of water.
>
>There are several ways to draw a curve, although I don't think that's
>your question. I probably would not make a template unless I would be
>making more than one item, but a template and router will work just
>fine. If the ply is thick, make more than one pass. If you are
>making just one football, draw, cut /w jigsaw (leaving the line), then
>sand to the line.

--
Message posted via http://www.craftkb.com

"WonderMonkey via CraftKB.com" <u37947@uwe> wrote in message
news:7932c49e96c29@uwe...
> I'm going to be making several of these. I'm going to end up making a
> template.
>
As others have said, a router will just make a mess of it.
If you want to use a template, run the jigsaw along it.

"WonderMonkey" <u37947@uwe> wrote in message news:7924a321faba9@uwe...
> I'm making some yard items for youth activities. One of them is a
> football.
> Here is a picture of somethig real close to what I will be doing:
> http://www.henrynet.com/stuff/yard/football1.jpg . I've used the
> search function here for advice but didn't find anything that fit. If you
> know of another thread, please give me a hint and I'll go there. OK,
> right
> now I plan on drawing my template, and using my jigsaw to cut the arc. My
> problem revolves around making a smooth curve instead of what I usually
> do.
> Any advice for using the jigsaw for this?
>
> If these go well and I want to make more I was planning on using a ( to be
> purchased ) router to make the cuts. I'd make a template for the edge of
> the
> router to ride along, position my piece of plywood, and whammo, I'd have a
> nice cut. Sound ok?
>
> And for some background.... I'm not a TOTAL idiot when it comes to
> woodworking, but I'm inexperienced in the best (or even close) way to do
> things at times. I'm in the process of building a small shop in which
> I'll
> have some nicer equipment in for but now it's me, my jigsaw, a circular
> saw,
> and a jug of water.


And don't forget to put masking tape on area to be cut to prevent
splintering along the cut edge if using plywood. W W

"WonderMonkey" wrote in message

>
> If these go well and I want to make more I was planning on using a ( to be
> purchased ) router to make the cuts. I'd make a template for the edge of
the
> router to ride along, position my piece of plywood, and whammo, I'd have a
> nice cut. Sound ok?

A good jig saw, with a sharp blade suitable for cutting plywood, would be my
first choice for doing this.

You may find that a router will have a tendency to tearout most plywood ...
ymmv.

With a jigsaw, go slow, take your time, cut just outside the line, use a
wood rasp sander, to "fair the curve".

The more time and carefularity you take making the cut, the less
cleanup/fairing you'll have to do.

... just my tuppence.


--
www.e-woodshop.net
Last update: 9/30/07
KarlC@ (the obvious)

On Wed, 3 Oct 2007 11:49:36 -0500, "Swingman" <[email protected]> wrote:

>
>The more time and carefularity you take making the cut, the less
>cleanup/fairing you'll have to do.
>
>... just my tuppence.

Carefularity....excellent!
ROY!

On Wed, 03 Oct 2007 16:25:03 GMT, "WonderMonkey" <u37947@uwe> wrote:

>I'm making some yard items for youth activities. One of them is a football.
>Here is a picture of somethig real close to what I will be doing:
>http://www.henrynet.com/stuff/yard/football1.jpg . I've used the
>search function here for advice but didn't find anything that fit. If you
>know of another thread, please give me a hint and I'll go there. OK, right
>now I plan on drawing my template, and using my jigsaw to cut the arc. My
>problem revolves around making a smooth curve instead of what I usually do.
>Any advice for using the jigsaw for this?
>
>If these go well and I want to make more I was planning on using a ( to be
>purchased ) router to make the cuts. I'd make a template for the edge of the
>router to ride along, position my piece of plywood, and whammo, I'd have a
>nice cut. Sound ok?
>
>And for some background.... I'm not a TOTAL idiot when it comes to
>woodworking, but I'm inexperienced in the best (or even close) way to do
>things at times. I'm in the process of building a small shop in which I'll
>have some nicer equipment in for but now it's me, my jigsaw, a circular saw,
>and a jug of water.


There are several ways to draw a curve, although I don't think that's
your question. I probably would not make a template unless I would be
making more than one item, but a template and router will work just
fine. If the ply is thick, make more than one pass. If you are
making just one football, draw, cut /w jigsaw (leaving the line), then
sand to the line.