Simple Dome for the Domeless Person

[bill south]

Bobcad!!! What great software. Just wish I knew how to use it better!!

I've been trying to draw a simple dome shaped object but can't seem to get things to smooth out. I've tried to merge part of a sphere and a small cylinder but have not been successful. The following are the design criteria.

Round object 3.1" OD. I want the bottom to be a 1/8" cylinder with a dome on top of that which will yield a total thickness of 3/8" at the highest peak. I'm going to machine this out of a 3/8 or 1/2 inch flat stock aluminum. It's going to be a new engraved point cover for my Harley.

Any help will be appreciated. Hope I've listed enough info.

Happy Holidays.
Bill

[bill south]

Bump - Happy Holidays.

[erase42]

can you send me what you have so far so i can understand? i maybe able to help

[tobyaxis]

Bill,

Please post a sketch or a CAD File for everyone to look at. I'm confused as to what you want to do. Maybe a Tapered Cone with Radial Ends or two Arcs with Tangent Lines.

[eshreve]

This was done using a portion of an elipse with a short line attached to one side. I used revolve surface to make the surface. Hope it comes through.

[bill south]

Thanks Guys.
Not enough info, that's what I was afraid of. This is a simple disk with a base of 1/8 inch. The top of the disk will be dome which is .375" from the bottom at the highest point (dome section will be .25"). I'll attach a simple dwg which is a side view sketched in bobcad with the rectangle function and the arc through 3 entities function. Hope this clarifies my request a little. I know it's simple to do (most likely) but I can't seem to find the right combination. My goal is to take this drawing and project different images/engraving on it to give it a custom look to show off to all my harley buddies. I'm going to tell them I did it all by hadn which is true. I just used a cnc machine as a tool!!!
Sketch attached and thanks again.
Bill from Spartanburg

[erase42]

hi. is this the right idea not sure about the edge thickness? select it all then render it. look on the solids menu if you arent familiar with render

[bill south]

Thanks for the dwg. The cover I'm invisioning does not have a lip as shown on your drawing. It's basically a flat disk 3.2" in diameter with a domed top approximately 3/8" thick at the top of the dome. If I could figure how to take a 3.2" piece of round stock, placed vertical in the vise, cut a dome on the top of the cylinder (this is where I'm struggling), then part of the dome to make the disk. Sounds simple doesn't it???
Thanks again.
Bill from Spartanburg.

(love the fro)

[erase42]

is it creating the g code from the drawing thats difficult? what version of bobcad do you have? for this item you would probably want a spiral or radial toolpath. let say you have the exact item you want to machine on the screen in 3d, are you able to create a toolpath? Do you know how to turn the toolpath into g-code? At which point do things get trickey for you im sending a radial toolpath of a shape similar to what you describe. when they open you need to turn on 3d view or rotate them manually otherwie you cant see the dome aspect of it since the view defaults to straight above.

[turmite]

Bill this is not Bobcad but is this what you are looking for? Rhino in just a few seconds.

Mike

ps projecting on the surface in Rhino is quite easy as well. If you need anything else let me know.

[Kiwi]

Bill
I have a program that is still in development but should do what you want.
If you wish to try, use the Arc-Convex Option and enter your radius figures as positive numbers. You will also need to enter a radius figure.
I've entered some figures to help. Pic attached to help explain.

[bill south]

Mike;
Your spot on!!! This is what I'm having difficulty trying to generate in Bobcad. Seems simple but I can't do it for some reason. Wish I had a copy of Rhino to play with. Thanks.
Kiwi,
Nice program. A little later (I'm moving my brother today), I'll play with it and get back to you. I know it will work for me. Your example is very impressive.
E42,
Thanks for all the help. I'm not haveing the troubles you mentioned just can't draw the part in 3D as mike did above. Simple but why can't Bobcad do it. Sorin, where are you when your needed??? (Most probably working and on the road).
Thanks again Guys.
Have a happy new year and be safe.
Bill from Spratnaurg.