Arc 16" wide and 9" high

[franksbedford]

Hi,

I'm trying to draw an arc 16" wide and 9" high. Nothing special, but I can't work out how to do it. When I use two points and height the arc goes past 180 degrees. It's the opening to a brick oven where the height is 1" taller than the radius of the width.

Thanks!

[CVH]

It's the opening to a brick oven where the height is 1" taller than the radius of the width.

An arc with 2 different radii is probably an ellipse arc.

See: menu Draw .. Ellipse .. Ellipse with radii (EI).
Once it is touching two verticals or a horizontal auxiliary line at the center one can remove the bottom half with 'Break out Segment' (D2).

Constructing it with 'Ellipse Arc' (EA) is also possible if you already have the proper reference positions.

Regards,
CVH

[franksbedford]

haha. Bad on me. Thanks!

[Husky]

Hi,

I'm trying to draw an arc 16" wide and 9" high.

It's the opening to a brick oven where the height is 1" taller than the radius of the width.

It is easier to build a brick oven opening with a radius instead of an ellipse.
If you want an arc with this measurments then you have to extend tangential the ends of the arc with 1" lines.

How?
Draw an auxiliary rectangle 16x9,
launch circle tool "3 Tangents",
Determine the tangents, left, top, right of the rectangle,
confirm the lower circle,
launch "Break out Segment" (D2) and click every line which needs to be deleted.

[franksbedford]

Thanks as always for the great input. In this case, it's a cast pizza oven, where the ellipse defines the curve of the mold that holds the casting material. Not an opening defined by discrete bricks. You helped me with that months ago, and it all worked very well.

I'm using the Ellipse Arc tool, where you define the center, the major radius and the top, and then draw the arc. Very easy (once you know it's there).

[CVH]

FB,

Similar advice as before:
Ensure that your mold is segmented for removal ... Most casting material like fire resistant concrete or mortar shrinks.
One should remove it very shortly after initial curing. Think of days, not weeks.

Regards,
CVH

[franksbedford]

Thanks for the advice. In this case, the mold is cardboard covered with vegetable oil to keep the cardboard from sticking to the castable. So getting it to drop away shouldn't be an issue. It's a cast in place system.