Radius for the G. Benroy

[Tommy2tone_1999]

In building my teardrop, I probably should have made the front curve a 24" radius. 18" is almost too tight to bend most wood for the inside radius.

[KCStudly]

My front radius is 13-1/2 inches and although I have not tried to bend a full width panel yet, I was able to bend a 6 inch wide strip of 5 mm ply (grain running the easy way) with out any trouble. 5mm is 3/16 inch thick.

[Tommy2tone_1999]

I managed to bend 1/8" luan around the curve but it was iffy for a minute there

[dales133]

thought id post this here as its got what i should have ended up with previously!
the radius ive used 1200mm witch is close to the 48 inches.
what i think ive done but haven't really sussed it out yet is i made the 48 tangent to the top and imaginary back before i added on the xtra ply witch was giving me issues with the smaller 19 inch radius.
i havnt belt sanded it yet is just a rough cut but does this look alright to you?
my only other real option is to buy another sheet and add it on from where the galley starts so i can remark it correctliy , or shorten the back a few inches maybe.
because its so tall im wondering if it isnt ok as it is as there will be around the same virtical lenth as standard with the underfloor.
please give me your thoughts





i went with the inner most verticle line as it seemed to give me cleaner lines and accomodate the 19 inch radius better.

[KCStudly]

I don't understand the question. Do you have a sketch of the profile with the dimensions that you are trying to duplicate?

1200 mm is about 47.25 inch.

Is your ply metric in width (height)? If so what is the dimension? And what metric dimension do you plan to use in place of the 19 inch radius (about 483 mm... 482.6)

So you want the large top radius to be tangent with the top and rear, and the small bottom radius to be tangent with the rear and bottom? Any straight vertical in between, or do you want the two radii to be roll together continuously (depending on the height of the sheet)?

[dales133]

Hiya kc.
If you go to the first example on this thread it is what I have done instead of the second example.
You'll see what I mean when you look at those.
And I just rough cut my only option due to this mistake it's in the picture below.
What I'm realy looking for is does it look "right" to you guys

[dales133]

And its imperial sheet size 2440 x 1220 in metric

[Rick G]

it looks OK to me , it should work fine!

[dales133]

Thanks Rick I was kinda iffy on it...possibly the curve was to long

[KCStudly]

The only thing that matters is if it looks right to you.

Looks fine to me.

[Sheddie]

The only thing that matters is if it looks right to you.

Looks fine to me.

As he said, looks good to me too

[dales133]

Thanks guys.
Wasn't sure myself I just wanted some feedback as I was going to scrap it this time a week ago.

[DougN]

I shortened the rear top radius to 47" so my router jig would sit ON the side rather than 1/2 off.
I retained the 41.563" dimension but rounded it off to 41.0" .

The dowel in the center of the 2x2 was at the junction of the 47" and 41.5" when the arc was cut.

I love this jig! Was starting to work out how I was going to use my router to do the cut, but your picture is a thousand words!

Thanks,
Doug

[ChasCABQ]

I cut my sidewalls with 20" radius in the front and 36" radius in the back. They were easy to layout with string. I used Sketchup to compare various Benroy sidewall radii and checked other designers profiles. I even looked at 1/4 ellipses of various sizes but was worried about ease of accurate layout.

Modified Benroy profile

Screen Shot 2015-05-04 at 5.32.56 PM.png.jpg (73.43 KiB) Viewed 29306 times

[jsparrish26]

Back when I was working on submarines, a machinist boss came to me with a couple of his workers in tow and was trying to calculate the area of a circle. He refused to accept that the area of a circle is Pi x radius^2 (pi r squared), instead thinking that it was Pi x diameter. I was gentle with him, being younger at the time and not wanting to embarrass him in front of his guys (who were clueless to the math). Later he came around to my way of thinking and from that day on all of the machinist on the site started calling me by my new nick name "Piard" (from Pie-are-d).

Of course every one knows pie are round.

8th grade math, one of the things I rarely use, but will NEVER forget. Our teacher taught us that "Pie r squared, Cornbread r round."