Calculating Bevels

[wdnboatbuilder]

The formula is a hacksaw blade , a rivet , and picking up each bevel on the loft floor in your case but on the boat in the builders case. . no calc that i know of, one end of the board (plank) the bevel could go out and on the other end the bevel could go in. A fillet is a great way to fasten. Cyclops you or PAR know of any calcs? sure would save some time. I know , I know , you computer boys don't use loft floors any more. I guess you could pick them off the comp.

[PAR]

I always loft new construction, it helps me get intimate (okay, maybe I'm a little lonely) with the design and familiarize myself with the shapes. Then there's the mighty dividers and bevels of various sizes, templates of both sides, etc. for old work.

It's faster for me to pick up the bevels in real life then track down each cross vector. I've not used the software "Bevel Gauge" but have heard good things, it may be of some help.

I've just generated my first cut file, unfortunately it's an aluminum boat and just thin plate. I don't have, nor want the skills to compute out a cut file for a 5 axis machine. It is done, can be done and is reasonably common, so maybe some of the real computer folks will chime in.

[Raggi_Thor]

Ajmoair, there is no formula. As mentioned before, if you have a 3D model if the hull, a surface defining the inside of the skin or a solid model of the skin, you can section this model where you want a frame. If you make two sections for each frame, one in front and on on the back side, you have a 3D model of the frames, with the correct bevel.

[cyclops]

Ajmoir, what quanity are we talking about? Less than 3 ? You could build them in all likely hood, perfectly, by the time the Automatic cut ones are perfect. Automation is not cheap when it comes to complex 3 D shapes. The R & D costs are spread across large runs. I wanted to have a 1/72 model of the A-10 Warthog tank killer scaled up to 1/10 scale. The cost and different companies in a complete scale up made me stand in front of my bathroom mirror and ask. Did I think I was so much more clever? Laughed and hand made it from blue Styrofoam and 80 man hours. Passed all my standards on the first assy.

[chandler]

Why would you want to build a carvel plywood planked boat. The whole idea behind carvel planked boats is the planking swells squishing the caulking to make it water tight. Plywood is so dimensionally stable it would never close up,so you would be reliant on the caulking itself to keep the hull tight. Besides the fact plywood ripped into planks would be more expensive than conventional solid wood.

[ajmoir]

Originally Posted by cyclops

Ajmoir, what quanity are we talking about? Less than 3 ? You could build them in all likely hood, perfectly, by the time the Automatic cut ones are perfect.

To begin with it's just a single boat. But if the code is there for the CNC mill then there's no reason another cannot be built.

There is no way I can build a traditional wooden boat in a timely manner, it would take me years. I have not the skills or tools required and if truth be told am not that inclined to acquire either.

My idea is more towards the ability to build a wooden hull quickly and econmically.

[ajmoir]

Originally Posted by Raggi_Thor

Ajmoair, there is no formula. As mentioned before, if you have a 3D model if the hull, a surface defining the inside of the skin or a solid model of the skin, you can section this model where you want a frame. If you make two sections for each frame, one in front and on on the back side, you have a 3D model of the frames, with the correct bevel.

This makes sense. I have my hull surface from the offsets etc. I could subtract the depth of the planking. I could then plot the rib and I should be able to ask the software to fit the ribs to the hull. Obviously I am now at the mercy of the cad software. But I could probably script this to be done automatically.

Hmm, probably the best answer I have so far.

[cyclops]

That is why there are VERY GOOD kit boats of all types and prices. Go for it. Build and finish one boat. The next is pure pleasure.

[chandler]

Maybe you should just buy a cd of virtual boating save a buck and a few trees

[PAR]

Ajmoir, the "asking" and "trusting" the software aspect of the project is what I meant by debugging. You will have errors and it's best to make them virtually then on the planking or framing stock. This requires much time and skill, of which I don't personally think is cost effective on a one off hull.

Plywood hulls can be round, not have bevels to fool with and easy to build. Molding a hull from 1/8' or 1/4" stock ripped into widths that will take the curvature works great. Since there is more then one layer and plenty of goo, butt joints of less then perfect craftsmanship is all that's required. Stitch and glue or tape and seam construction doesn't need bevels, though good fits are something one should always shoot for. Epoxy (wood butcher's friend) can fix and hide a host of sins.

Take a look at "Bevel Gauge" or some of the AutoCAD plug ins to see if they can help.

[wdnboatbuilder]

Okay here's the problem and I feel ( I hope what ajmoir is saying) that I have hunted for kit boats and (Ireally don't want to insult anyone), but they are just not eye appealing. and I could see where some one would want to do what they know to build , his case a CNC machine. But on the other hand if you don't have the skills his building, mine confidence in the calcs, what choice do you have but to try to do it yourself. ajmoir it will still take the same amount of time to build the boat cuz even the bevels on the frames and every where else on the boat will be the same in the process of what your trying to achieve. you might try to find a set of plans and see if you can get some where close and build in stitch and glue. ( OH GOD, I did not say that stitch and glue thing)

[wet feet]

While I know how to extract the information from a surfaced model to generate frame shapes and bevels,I would not have any idea about determining developed planking shapes.Why not get the frames CNC cut and then employ a gang of boatbuilders to do the planking?You would get the accuracy of the initial model and you need somebody to attach the planks to the frames whatever approach is needed.

[chandler]

Is everybody in such a hurry that they have to employ cnc and cad designs. Isn't this about the love of designing something, our own creation, then building it.

[wet feet]

If the use of technology is what it takes to remain in business,people will use it.If one is pursuing a hobby,different objectives apply.