GG

Greg Guarino

02/04/2019 7:36 AM

How should I make this curve?

https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/

It will be 34.5" long, with a 32" radius according to Sketchup. I imagine s=
ome of you might do it with a band saw and a spindle sander, but that's not=
an option for me.=20

I have done pattern routing in the past, with success. But I wonder if with=
this large a curve it might be easier to whip up a jig with a pivot point =
34" from the router bit. I would of course roughly cut out the shape with a=
sabre saw before routing in either case.

Advice?


This topic has 17 replies

Dt

DerbyDad03

in reply to Greg Guarino on 02/04/2019 7:36 AM

06/04/2019 11:33 AM

On Saturday, April 6, 2019 at 12:14:46 PM UTC-4, Leon wrote:
> On 4/5/2019 11:57 AM, [email protected] wrote:
> > On Fri, 5 Apr 2019 11:09:57 -0500, Leon <lcb11211@swbelldotnet> wrote:
> >=20
> >> On 4/5/2019 6:30 AM, Greg Guarino wrote:
> >>> On Wednesday, April 3, 2019 at 11:22:27 AM UTC-4, Leon wrote:
> >>>
> >>>>
> >>>> Yex, I do not cut close to the line, I let the router take a full wi=
dth
> >>>> cut and go deeper with each pass.
> >>>
> >>> What size bit do you typically use? And another ignorant question:
> >>> As the bit will have wood on both sides, which direction do you move =
the router?
> >>> I'm going to guess that it doesn't matter, but that I should keep it =
consistent.
> >>>
> >>
> >> IIRC I used a 1/2" bit. I went counter clockwise for a lazy Susan pie=
ce
> >> that I did a couple of years ago. In your case I would go clockwise.
> >> You typically want the bit to be cutting away from the piece you want =
to
> >> keep.
> >=20
> > Shouldn't that be leading cutter rotating into
> > the piece you want to keep ?
> > .. experiment on a scrap piece to be sure ..
> > John T.
> >=20
> >=20
> >=20
>=20
> OK, so with the router bit facing down the bit spins clockwise. When=20
> cutting a circle and you want to keep the circle, you want to keep the=20
> convex part of the cut, the router should go counter clockwise.
>=20
> When keeping the concave side of the cut the router should be going=20
> clockwise.
>=20
> Going in the direction described above the bit will resist feed. If you=
=20
> go in the opposite direction for both operations above the bit will try=
=20
> to climb into the cut.
>=20
> Basically you want the bit to be cutting/pulling away from the keeper sid=
e.

And that fits with the "right hand rule". [ I think ;-) ]

With the palm down of your right hand facing down and the thumb and=20
index finger held at 90=C2=B0, your thumb points at the edge that you want=
=20
to rout (or in this case, keep) and your index finger points in the=20
direction that you should move the router.

To keep the circle, your thumb would point towards the center of the=20
circle therefore your index finger would point to the right, which
would be counter-clockwise.

Dt

DerbyDad03

in reply to Greg Guarino on 02/04/2019 7:36 AM

05/04/2019 5:12 PM

On Tuesday, April 2, 2019 at 10:36:09 AM UTC-4, Greg Guarino wrote:
> https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
>=20
> It will be 34.5" long, with a 32" radius according to Sketchup. I imagine=
some of you might do it with a band saw and a spindle sander, but that's n=
ot an option for me.=20
>=20
> I have done pattern routing in the past, with success. But I wonder if wi=
th this large a curve it might be easier to whip up a jig with a pivot poin=
t 34" from the router bit. I would of course roughly cut out the shape with=
a sabre saw before routing in either case.
>=20
> Advice?

How about a long trammel?

Sorry for the lousy image, but the top part of the page might give you=20
an idea...

https://i.imgur.com/MWhWROV.jpg

GG

Greg Guarino

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 7:44 PM

On Tuesday, April 2, 2019 at 5:02:56 PM UTC-4, Dr. Deb wrote:
> On Tuesday, April 2, 2019 at 9:36:09 AM UTC-5, Greg Guarino wrote:
> > https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
> >=20
> > It will be 34.5" long, with a 32" radius according to Sketchup. I imagi=
ne some of you might do it with a band saw and a spindle sander, but that's=
not an option for me.=20
> >=20
> > I have done pattern routing in the past, with success. But I wonder if =
with this large a curve it might be easier to whip up a jig with a pivot po=
int 34" from the router bit. I would of course roughly cut out the shape wi=
th a sabre saw before routing in either case.
> >=20
> > Advice?
> Are you cutting an opening or a table top? How this is approached will b=
e very different, depending on the form. The best thing is the old two nai=
l and a string trick to make the pattern, once you have that refined then =
transfer, saw and pattern rout. All that assuming you are working on a tab=
le top.

The drawing was in the original post. Here it is:

https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/

GG

Greg Guarino

in reply to Greg Guarino on 02/04/2019 7:36 AM

03/04/2019 4:57 AM

On Tuesday, April 2, 2019 at 10:57:04 PM UTC-4, J. Clarke wrote:
> On Tue, 2 Apr 2019 19:43:19 -0700 (PDT), Greg Guarino
> <[email protected]> wrote:
>=20
> >On Tuesday, April 2, 2019 at 1:39:34 PM UTC-4, Leon wrote:
> >> On 4/2/2019 9:36 AM, Greg Guarino wrote:
> >> > https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
> >> >=20
> >> > It will be 34.5" long, with a 32" radius according to Sketchup. I im=
agine some of you might do it with a band saw and a spindle sander, but tha=
t's not an option for me.
> >> >=20
> >> > I have done pattern routing in the past, with success. But I wonder =
if with this large a curve it might be easier to whip up a jig with a pivot=
point 34" from the router bit. I would of course roughly cut out the shape=
with a sabre saw before routing in either case.
> >> >=20
> >> > Advice?
> >> >=20
> >>=20
> >> I have a piece of plywood that I attach my router on to and I pivot t=
he=20
> >> router and plywood piece as you are mentioning. Just make the cut in=
=20
> >> 3~4 passes.
> >>=20
> >> When I have a ellipse type arc I print the ark at full scale on=20
> >> Sketchup, tape the pieces together, glue the drawing to the board and=
=20
> >> cut out with either a band saw or jig saw. Then smooth with a spindle=
=20
> >> sander.
> >
> >In my case, I will definitely be using a router. I doubt that I could ap=
proach the accuracy I'll get with a router with any other method that is cu=
rrently available to me. The question is should I make a template or make m=
yself a circle jig.=20
> >
> >The template I certainly know how to do. I was curious to see if anyone =
here used a "jig" - as you mention, just a piece of ply with a couple of ho=
les in it. I may give that a shot. Do I understand you correctly that you d=
o not even cut out the curve roughly beforehand? You make the entire cut wi=
th the router, getting deeper with each pass? I do have a plunge router, bu=
t I had not considered that.
>=20
> If you can make a template then why not just cut the curve the same
> way you would have cut the template?

You have a point, I guess. When I have done this before I was making multip=
le identical pieces. I still think I could "fair" a 1/4" MDF template to th=
e curve more easily than 3/4" oak though.=20
>=20
> Personally if I didn't have the tools I have, I'd make a spline, use
> it to draw the curve, rough it out with a jigsaw (or coping saw if I
> didn't have a jigsaw), and smooth it down with a sanding spline. This
> isn't one of those deals where you have to have absolute precision, as
> long as it's a smooth curve nobody's going to notice if it isn't a
> perfect arc of a circle.

ww

whit3rd

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 3:31 PM

On Tuesday, April 2, 2019 at 7:36:09 AM UTC-7, Greg Guarino wrote:
> https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
>
> It will be 34.5" long, with a 32" radius according to Sketchup. I imagine some of you might do it with a band saw and a spindle sander, but that's not an option for me.

In solid wood, it's easy to kerf near the curve, then... just carve the thing with a wide chisel.
A drawknife is good, too, but chisel is fast, and a spokeshave can finish it just fine.

Minimal tools for this job would be a crosscut saw and wide chisel, and layout is a matter
of string and pencil work. Power tools, while nice, aren't required, unless it were
in plywood; can't chisel that well at all, and the spokeshave will clog badly...

I'd want to consider non-circular curves, too; freeform is a side benefit of leaving
motorized tools shelved.

Sc

Sonny

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 8:02 AM

On Tuesday, April 2, 2019 at 9:36:09 AM UTC-5, Greg Guarino wrote:
I would of course roughly cut out the shape with a sabre saw before routing in either case.
>
> Advice?

I suppose you know.... Got a wood vise? Or find a way to clamp your board vertically, to more easily cut with the saber saw.

Also, might want to make a few/several radial cuts, before rough cutting the arc.

Sonny

GG

Greg Guarino

in reply to Greg Guarino on 02/04/2019 7:36 AM

05/04/2019 4:30 AM

On Wednesday, April 3, 2019 at 11:22:27 AM UTC-4, Leon wrote:

>
> Yex, I do not cut close to the line, I let the router take a full width
> cut and go deeper with each pass.

What size bit do you typically use? And another ignorant question: As the bit will have wood on both sides, which direction do you move the router? I'm going to guess that it doesn't matter, but that I should keep it consistent.

h

in reply to Greg Guarino on 02/04/2019 7:36 AM

05/04/2019 12:57 PM

On Fri, 5 Apr 2019 11:09:57 -0500, Leon <lcb11211@swbelldotnet> wrote:

>On 4/5/2019 6:30 AM, Greg Guarino wrote:
>> On Wednesday, April 3, 2019 at 11:22:27 AM UTC-4, Leon wrote:
>>
>>>
>>> Yex, I do not cut close to the line, I let the router take a full width
>>> cut and go deeper with each pass.
>>
>> What size bit do you typically use? And another ignorant question:
>>As the bit will have wood on both sides, which direction do you move the router?
>>I'm going to guess that it doesn't matter, but that I should keep it consistent.
>>
>
>IIRC I used a 1/2" bit. I went counter clockwise for a lazy Susan piece
>that I did a couple of years ago. In your case I would go clockwise.
>You typically want the bit to be cutting away from the piece you want to
>keep.

Shouldn't that be leading cutter rotating into
the piece you want to keep ?
.. experiment on a scrap piece to be sure ..
John T.


k

in reply to Greg Guarino on 02/04/2019 7:36 AM

03/04/2019 10:46 PM

On Wed, 3 Apr 2019 04:57:04 -0700 (PDT), Greg Guarino
<[email protected]> wrote:

>On Tuesday, April 2, 2019 at 10:57:04 PM UTC-4, J. Clarke wrote:
>> On Tue, 2 Apr 2019 19:43:19 -0700 (PDT), Greg Guarino
>> <[email protected]> wrote:
>>
>> >On Tuesday, April 2, 2019 at 1:39:34 PM UTC-4, Leon wrote:
>> >> On 4/2/2019 9:36 AM, Greg Guarino wrote:
>> >> > https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
>> >> >
>> >> > It will be 34.5" long, with a 32" radius according to Sketchup. I imagine some of you might do it with a band saw and a spindle sander, but that's not an option for me.
>> >> >
>> >> > I have done pattern routing in the past, with success. But I wonder if with this large a curve it might be easier to whip up a jig with a pivot point 34" from the router bit. I would of course roughly cut out the shape with a sabre saw before routing in either case.
>> >> >
>> >> > Advice?
>> >> >
>> >>
>> >> I have a piece of plywood that I attach my router on to and I pivot the
>> >> router and plywood piece as you are mentioning. Just make the cut in
>> >> 3~4 passes.
>> >>
>> >> When I have a ellipse type arc I print the ark at full scale on
>> >> Sketchup, tape the pieces together, glue the drawing to the board and
>> >> cut out with either a band saw or jig saw. Then smooth with a spindle
>> >> sander.
>> >
>> >In my case, I will definitely be using a router. I doubt that I could approach the accuracy I'll get with a router with any other method that is currently available to me. The question is should I make a template or make myself a circle jig.
>> >
>> >The template I certainly know how to do. I was curious to see if anyone here used a "jig" - as you mention, just a piece of ply with a couple of holes in it. I may give that a shot. Do I understand you correctly that you do not even cut out the curve roughly beforehand? You make the entire cut with the router, getting deeper with each pass? I do have a plunge router, but I had not considered that.
>>
>> If you can make a template then why not just cut the curve the same
>> way you would have cut the template?
>
>You have a point, I guess. When I have done this before I was making multiple identical pieces. I still think I could "fair" a 1/4" MDF template to the curve more easily than 3/4" oak though.

Yes, and when you slip and screw it up, you won't cry as much over
ruined MDF. You can probably repair it well enough to continue using
it as a template, too.

DD

"Dr. Deb"

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 2:02 PM

On Tuesday, April 2, 2019 at 9:36:09 AM UTC-5, Greg Guarino wrote:
> https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
>=20
> It will be 34.5" long, with a 32" radius according to Sketchup. I imagine=
some of you might do it with a band saw and a spindle sander, but that's n=
ot an option for me.=20
>=20
> I have done pattern routing in the past, with success. But I wonder if wi=
th this large a curve it might be easier to whip up a jig with a pivot poin=
t 34" from the router bit. I would of course roughly cut out the shape with=
a sabre saw before routing in either case.
>=20
> Advice?
Are you cutting an opening or a table top? How this is approached will be =
very different, depending on the form. The best thing is the old two nail =
and a string trick to make the pattern, once you have that refined then tr=
ansfer, saw and pattern rout. All that assuming you are working on a table=
top.

Ll

Leon

in reply to Greg Guarino on 02/04/2019 7:36 AM

03/04/2019 10:22 AM

On 4/2/2019 9:43 PM, Greg Guarino wrote:
> On Tuesday, April 2, 2019 at 1:39:34 PM UTC-4, Leon wrote:
>> On 4/2/2019 9:36 AM, Greg Guarino wrote:
>>> https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
>>>
>>> It will be 34.5" long, with a 32" radius according to Sketchup. I imagine some of you might do it with a band saw and a spindle sander, but that's not an option for me.
>>>
>>> I have done pattern routing in the past, with success. But I wonder if with this large a curve it might be easier to whip up a jig with a pivot point 34" from the router bit. I would of course roughly cut out the shape with a sabre saw before routing in either case.
>>>
>>> Advice?
>>>
>>
>> I have a piece of plywood that I attach my router on to and I pivot the
>> router and plywood piece as you are mentioning. Just make the cut in
>> 3~4 passes.
>>
>> When I have a ellipse type arc I print the ark at full scale on
>> Sketchup, tape the pieces together, glue the drawing to the board and
>> cut out with either a band saw or jig saw. Then smooth with a spindle
>> sander.
>
> In my case, I will definitely be using a router. I doubt that I could approach the accuracy I'll get with a router with any other method that is currently available to me. The question is should I make a template or make myself a circle jig.

Make a circle jig if your arc has a continuously same radius, IOW not an
ellipse. Sorry if I was unclear on that.



>
> The template I certainly know how to do. I was curious to see if anyone here used a "jig" - as you mention, just a piece of ply with a couple of holes in it. I may give that a shot. Do I understand you correctly that you do not even cut out the curve roughly beforehand? You make the entire cut with the router, getting deeper with each pass? I do have a plunge router, but I had not considered that.

Yex, I do not cut close to the line, I let the router take a full width
cut and go deeper with each pass.

Ll

Leon

in reply to Greg Guarino on 02/04/2019 7:36 AM

06/04/2019 11:14 AM

On 4/5/2019 11:57 AM, [email protected] wrote:
> On Fri, 5 Apr 2019 11:09:57 -0500, Leon <lcb11211@swbelldotnet> wrote:
>
>> On 4/5/2019 6:30 AM, Greg Guarino wrote:
>>> On Wednesday, April 3, 2019 at 11:22:27 AM UTC-4, Leon wrote:
>>>
>>>>
>>>> Yex, I do not cut close to the line, I let the router take a full width
>>>> cut and go deeper with each pass.
>>>
>>> What size bit do you typically use? And another ignorant question:
>>> As the bit will have wood on both sides, which direction do you move the router?
>>> I'm going to guess that it doesn't matter, but that I should keep it consistent.
>>>
>>
>> IIRC I used a 1/2" bit. I went counter clockwise for a lazy Susan piece
>> that I did a couple of years ago. In your case I would go clockwise.
>> You typically want the bit to be cutting away from the piece you want to
>> keep.
>
> Shouldn't that be leading cutter rotating into
> the piece you want to keep ?
> .. experiment on a scrap piece to be sure ..
> John T.
>
>
>

OK, so with the router bit facing down the bit spins clockwise. When
cutting a circle and you want to keep the circle, you want to keep the
convex part of the cut, the router should go counter clockwise.

When keeping the concave side of the cut the router should be going
clockwise.

Going in the direction described above the bit will resist feed. If you
go in the opposite direction for both operations above the bit will try
to climb into the cut.

Basically you want the bit to be cutting/pulling away from the keeper side.

Ll

Leon

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 12:39 PM

On 4/2/2019 9:36 AM, Greg Guarino wrote:
> https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
>
> It will be 34.5" long, with a 32" radius according to Sketchup. I imagine some of you might do it with a band saw and a spindle sander, but that's not an option for me.
>
> I have done pattern routing in the past, with success. But I wonder if with this large a curve it might be easier to whip up a jig with a pivot point 34" from the router bit. I would of course roughly cut out the shape with a sabre saw before routing in either case.
>
> Advice?
>

I have a piece of plywood that I attach my router on to and I pivot the
router and plywood piece as you are mentioning. Just make the cut in
3~4 passes.

When I have a ellipse type arc I print the ark at full scale on
Sketchup, tape the pieces together, glue the drawing to the board and
cut out with either a band saw or jig saw. Then smooth with a spindle
sander.

GG

Greg Guarino

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 7:43 PM

On Tuesday, April 2, 2019 at 1:39:34 PM UTC-4, Leon wrote:
> On 4/2/2019 9:36 AM, Greg Guarino wrote:
> > https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
> >=20
> > It will be 34.5" long, with a 32" radius according to Sketchup. I imagi=
ne some of you might do it with a band saw and a spindle sander, but that's=
not an option for me.
> >=20
> > I have done pattern routing in the past, with success. But I wonder if =
with this large a curve it might be easier to whip up a jig with a pivot po=
int 34" from the router bit. I would of course roughly cut out the shape wi=
th a sabre saw before routing in either case.
> >=20
> > Advice?
> >=20
>=20
> I have a piece of plywood that I attach my router on to and I pivot the=
=20
> router and plywood piece as you are mentioning. Just make the cut in=20
> 3~4 passes.
>=20
> When I have a ellipse type arc I print the ark at full scale on=20
> Sketchup, tape the pieces together, glue the drawing to the board and=20
> cut out with either a band saw or jig saw. Then smooth with a spindle=20
> sander.

In my case, I will definitely be using a router. I doubt that I could appro=
ach the accuracy I'll get with a router with any other method that is curre=
ntly available to me. The question is should I make a template or make myse=
lf a circle jig.=20

The template I certainly know how to do. I was curious to see if anyone her=
e used a "jig" - as you mention, just a piece of ply with a couple of holes=
in it. I may give that a shot. Do I understand you correctly that you do n=
ot even cut out the curve roughly beforehand? You make the entire cut with =
the router, getting deeper with each pass? I do have a plunge router, but I=
had not considered that.

Ll

Leon

in reply to Greg Guarino on 02/04/2019 7:36 AM

05/04/2019 11:09 AM

On 4/5/2019 6:30 AM, Greg Guarino wrote:
> On Wednesday, April 3, 2019 at 11:22:27 AM UTC-4, Leon wrote:
>
>>
>> Yex, I do not cut close to the line, I let the router take a full width
>> cut and go deeper with each pass.
>
> What size bit do you typically use? And another ignorant question: As the bit will have wood on both sides, which direction do you move the router? I'm going to guess that it doesn't matter, but that I should keep it consistent.
>

IIRC I used a 1/2" bit. I went counter clockwise for a lazy Susan piece
that I did a couple of years ago. In your case I would go clockwise.
You typically want the bit to be cutting away from the piece you want to
keep.

GG

Greg Guarino

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 8:00 PM

On Tuesday, April 2, 2019 at 6:31:45 PM UTC-4, whit3rd wrote:
> On Tuesday, April 2, 2019 at 7:36:09 AM UTC-7, Greg Guarino wrote:
> > https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
> >=20
> > It will be 34.5" long, with a 32" radius according to Sketchup. I imagi=
ne some of you might do it with a band saw and a spindle sander, but that's=
not an option for me.=20
>=20
> In solid wood, it's easy to kerf near the curve, then... just carve the t=
hing with a wide chisel.
> A drawknife is good, too, but chisel is fast, and a spokeshave can finish=
it just fine.
>=20
> Minimal tools for this job would be a crosscut saw and wide chisel, and l=
ayout is a matter
> of string and pencil work. Power tools, while nice, aren't required, un=
less it were
> in plywood; can't chisel that well at all, and the spokeshave will clog b=
adly...
>=20
> I'd want to consider non-circular curves, too; freeform is a side benefit=
of leaving
> motorized tools shelved.

Wow. I'm afraid that my efforts with chisels would yield a very freeform re=
sult indeed. I did however consider non-circular curves (and for that matte=
r, non-curves. Any shape with no concave parts that are smaller than the di=
ameter of my router bit are possible using a template, especially one print=
ed directly from the drawing, as Leon suggested. But I like the simplicity =
of a true arc.

JC

J. Clarke

in reply to Greg Guarino on 02/04/2019 7:36 AM

02/04/2019 10:57 PM

On Tue, 2 Apr 2019 19:43:19 -0700 (PDT), Greg Guarino
<[email protected]> wrote:

>On Tuesday, April 2, 2019 at 1:39:34 PM UTC-4, Leon wrote:
>> On 4/2/2019 9:36 AM, Greg Guarino wrote:
>> > https://www.flickr.com/photos/gdguarino/46549143805/in/photostream/
>> >
>> > It will be 34.5" long, with a 32" radius according to Sketchup. I imagine some of you might do it with a band saw and a spindle sander, but that's not an option for me.
>> >
>> > I have done pattern routing in the past, with success. But I wonder if with this large a curve it might be easier to whip up a jig with a pivot point 34" from the router bit. I would of course roughly cut out the shape with a sabre saw before routing in either case.
>> >
>> > Advice?
>> >
>>
>> I have a piece of plywood that I attach my router on to and I pivot the
>> router and plywood piece as you are mentioning. Just make the cut in
>> 3~4 passes.
>>
>> When I have a ellipse type arc I print the ark at full scale on
>> Sketchup, tape the pieces together, glue the drawing to the board and
>> cut out with either a band saw or jig saw. Then smooth with a spindle
>> sander.
>
>In my case, I will definitely be using a router. I doubt that I could approach the accuracy I'll get with a router with any other method that is currently available to me. The question is should I make a template or make myself a circle jig.
>
>The template I certainly know how to do. I was curious to see if anyone here used a "jig" - as you mention, just a piece of ply with a couple of holes in it. I may give that a shot. Do I understand you correctly that you do not even cut out the curve roughly beforehand? You make the entire cut with the router, getting deeper with each pass? I do have a plunge router, but I had not considered that.

If you can make a template then why not just cut the curve the same
way you would have cut the template?

Personally if I didn't have the tools I have, I'd make a spline, use
it to draw the curve, rough it out with a jigsaw (or coping saw if I
didn't have a jigsaw), and smooth it down with a sanding spline. This
isn't one of those deals where you have to have absolute precision, as
long as it's a smooth curve nobody's going to notice if it isn't a
perfect arc of a circle.


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