Arched top exterior door

[john_hartman]

I have an opportunity to rebuild an exterior double door that a contractor botched. Six months ago, prior to the SB, I would have traced a template for top and middle rails and used a hand held router. I would obviously like to use the SB to cut these pieces from 10/4 Mahogany. How do I draw these curved parts so that they precisely fit into the contour of the arched door frame?

Also, you will notice that there is no door casing, which is also curved along the top. I believe the "extruder" feature is capable of producing such a piece using the profile of the straight casing. How is this done?



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[pro70z28]

Don't know if my method is the best method but it works for me when I tackle jobs similar to this.
Will you be building these doors from scratch or trying to match up & replace components?

I would set the door up in a position where you could get a straight on picture of it. I'd then load the picture on the computer & use it as a template. Blow it up to the actual dimensions of the door. Draw/trace the parts to create a vectorized replica of the doors. Then go back and make several measurements to tweak it to get the individual pieces dialed in to the original.

[magic]

I've put butcher paper down and run a pencil along the profiles.

Then using several scans - into the computer where it's stitched together,

Then into artcam - then cut the panels .15 oversize along the curves - the straight edges can be measured and cut correctly without all the extra fuss.

This would take up to two hour, until toolpathing is ready, for both sides but the parts would be a pretty tight fit.

[grandpaspastime]

You can also take that full size paper tracing to Kinkos and have them scan and put it on a CD for you. May have to clean up some on the scan or use the Poly line trace in Vcarv-pro or aspire to clean up the vector and then tool path directly. You can resize the pattern with the same tools. That way you do not have to stitch pieces from seperate scans

[john_hartman]

Thanks for the advise guys! I was thinking I could take a photo of it but also thought that that could leave a lot of variation if the camera isn't perfectly perpendicular. I guess this would just have to be a trial and error process..


Gary, the door will be rebuilt to look just like the one in the photo. I have some flexibility with the curved mid-rail, however the top rail will need to be a perfect match to the door frame.

I guess I was thinking there would a mathematical/geometric way to figure out the arch diameter and redraw in partworks. Is there such a technique?

Any thoughts on the arched door casing?

[rb99]

You can square the photo up in photoshop or equivalent photo program.

RB

[bob_s]

John;
Attached should be a version of your photo that is more square, although i do not know if the height width ratio is correct. The 50kb limit onthis site makes this difficult, but if you want to email me a larger file i could square it in a matter of just a couple of minutes. Let me know the exact height versus width, as well.
BUT- I would suggest that you shoot a better photo. To shoot one at the correct angle try the following.
attach a decent sized mirror - about 8 x 10" to the center of the subject.
It wants to be exactly flat to the plane of your subject.
Mark the center of the mirror with an X or + in grease pencil or indelible marker.
Line up the camera so the reflection of the lens appears centered around the X.
this will put you within less than 1/4 degree of dead on.
Please be aware that many "cheaper" cameras that take great pictures have pretty bad spherical distortion. Try and use a camera with a good glass lens, and make some marks on the subject near the edges that you know to be square as a good check.




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[john_hartman]

Thanks Bob... I will need to take a better photo. I might just have to unlist your help on the alignment.

Thanks!

[oddcoach]

You can do it with geometry easily
all you need are 2 dimensions width of the door and the difference of the 2 sides of the door
transfer these dimensions to a piece of cardboard
then draw the 2 yellow circles in the picture their radius does not matter as long as they are the same.
then draw the red line thru the 2 points where the circles cross each other take the distance from where the line crosses the centerline of the doors to the top of the doors
that is the radius you need


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[coach]

John, I don't know if this will help. I use the formula frequently.


step 1:::::::height of arc divided by 2
step 2:::::::width x width
step 3::::::: 8 x height

DIVIDE STEP 2 BY STEP 3 (3 INTO 2)
ADD STEP 1 TO ANSWER THAT IS YOUR RADIUS.

Ikeep this formula written down at the shop. I have no internet at the shop so I can't use the following.
http://www.handymath.com/cgi-bin/rad2.cgi?submit=Entry

David

[GlenP]

Could you use the bot with a template. Trace the arch onto a paper or some sort of template that can lay flat on the table of your machine. Place the template square on the table and across the width of the template make reference marks say at 6" intervals. With a small 1/6" bit or small pointer move the spindle over the arch at the 6" intervals and record the readings from your screen. You should now be able to recreate the arch in your cad software. Make a sacrificial template to before cutting good material. I have done this once and it seem to work well. I am not good at geometry and complicated math so I find other ways. Hope I didn't confuse you too much.

[beacon14]

If the top of the door is a true arc, which it appears to be, then all you need is the width of the frame and the rise, that is the height of the center of the arc above a horizontal line through the top left corner and top right corner. Use those dimensions to re-create the arc in PartWorks, then cut a test piece out of cardboard or 1/4" plywood to be sure.

[john_hartman]

This really is a great forum. I need to come up with challenges more often. The geometric approach was what I was looking for. Thank you all for the creative thinking.

[loriny]

That formula is awesome. The time I save now rather than templating is unbelievable as is the fit. Thank you
Lorin

[stevevarrow]

You could download Karona's Door program http://www.karonadoor.com/software.php,
Then configure all the dimensions of the door and export the finished drawing it will be scaled correctly.
steve

[navigator7]

Is this cheating?

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[bleeth]

I downloaded this handy calculating spreadsheet years ago from woodweb and still use it. (Tried to download the actual spreadsheet but it was too big for the forum so here is the link to it)

http://www.woodweb.com/knowledge_base/_Spreadsheet_Calculation_Program.html

I have not only used this in cabinets but for things like making curved arched casing, jambliner, baseboard, etc. by taking the numbers off the conditions in the field and then making the parts in the shop.

As far as remaking those doors: For the cost of the doors themselves a new jamb set or at least header should be minimal and by creating both yourself you have a much easier time of making sure you have a good fit. You certainly can use the shopbot extruder to do the arched casing. There is also a method for Arctcam or Aspire that works well.

[wberminio]

How would this be done if you had an irregular
opening?


Erminio

[jseiler]

You can do it from a picture, but I'd recommend using two rulers in the picture, one in the x direction, one in the y. If you get offcenter one way or the other (x or y direction), you can scale the x and y independantly. Also it seems to help to stand way far back and use the zoom on the camera. It helps to hide the edges and makes the template easier to trace accurately.

John

[bob_s]

John is correct, the longer, more telephoto, the lens is the less distortion.
If you want to be at exactly 90 degrees to the wall or door, just tape a mirror to the spot.
Be sure it is flat to the wall.
When you center the reflection of the camera lens in the center of the mirror, you will be less than 1/4 of a degree off.
If you don't want to bother with the mirror trick, just remember to keep the camera level, distortion is caused/corrected by the back/ film plane of the camera being in the same orientation as the subject. Even if the subject is then off center, it will have less distortion.
yes, this stuff was my world for 35 years.
Bob

[wberminio]

Thanks Guys

I might have a job were this information will be very useful.
Once you get the photo,what's the next step?

[bob_s]

Erminio;
What software do you use?
If you have Aspire, you can import the photo and trace it to create your vectors. If not you need to create the vectors in a program like Illustrator, Corel draw, photoshop, or one of many Cad programs. Then use those vectors to cut from. Depending on what you are cutting, you might want to cut some test parts from something cheap and light like 1/4 ply or 1/4 MDF, in my opinion this would be the safe way to go.
If you have problems making the vectors, email me and I'll see what I can do to help.
As with most jobs, I'm sure there are a lot of different solutions, some easier than others.

[wberminio]

Hi Bob
I use Partworks.I'll try your method and see how it works out.Beats tracing and templates.


Thanks again

Erminio