"21st Century" something... Tranth

You posted a thread with link to a deck you made using CAD and a CNC machine. Replies said “doesn’t everyone have one in their garage”… or something like that. The post is gone due to recent database issues.

Can you post it again? It was an interesting glimpse into the possibility of using a laptop, with lite version of CAD (got both) and a used CNC machine* and tooling (from a place like eBay) to make a basic, “inexpensive” (today, $2K, tomorrow ?) process for computer generated hull plugs.

Maybe in the future, a CNC machine that I found at a garage sale, will be sitting in my shop next to the bandsaw, rigged up to my computer per somebody’s article on how to do so in Model Yachting magazine, and I’ll just turn out perfect one-off plugs as fast as I can design them. Anybody interested in this or has someone out there rigged up something like that?


Be sure and go big - something that can handle up to 10R or M Class boats at 50-5 inches or so. Look at the classes that allow development and hull design, as that is your customer base.

I’ve been looking for a heat/vacu-form press that can handle sizes that big, but can’t afford to build a shop big enough to hold one. If I did/could, I would be looking for CNC services for plugs.

Good luck - let us know if you get something.:wink:

This might be a bit beyond what you’re talking about, but my engineer (ME) friend Greg Jackson has developed this product & is getting alot of customers. The machines are quite impressive & are well suited to the entrepreneur/inventor/serious hobbyist/R&D startups etc. We used one to cut the runners for my rc iceboat.

The link is http://www.12metreyacht.com/images/gallery2/ and shows the deck plug for my new boat.
It shows the CAD model, through to a rough cut plug and then final finishing by the machine. The detail and accuracy are (obviously) far better than anything I could do by hand.
The hull is being cut as I type this and is coming out really well. The keel & wings look great IMHO. I’ll post some pics later on



I am actually working on a CNC machine, very slowly (multi year project), I say slowly because to do what I want is going to cost a significant chunk of change on the order of $5K to $7K. IM not going to bore you with specifics about the machine I’m working on.

The basic system is:[ul]
[li]CAD (creates the model)[/li][li]CAM (software that turns the model into a tool path this is a must for 3D work)[/li][li]controller (software that reads the CAM output and controls the machine)[/li][li]the actual machine[/ul]For the actual machine things that cost you are:[ul][/li][li]Size[/li][li]Power[/li][li]Speed[/li][li]Rigidity[/li][li]Accuracy (closely intertwined with rigidity)[/ul][ul][/li][li]Size - A larger machine, naturally weight more, thus everything has to be more powerful to move it. Size also costs because the distance supports increases, thus the cross members must be more rigid.[/li][li]Power - Once you reach a certain level all the electronics, become very specialized. For example 36 volts / 20 amps (I have seen several home machines that take this kind of power) this is not a continuous draw, but it can spike this high.[/li][li]Speed - Speed costs you indirectly. Just like in a race car more power equals more speed. To go fast, you have to accelerate, and decelerate fast, and this means your machine has to be more rigid, or you will lose accuracy because of machine flex.[/li][li]Rigidity – This pretty much comes down to the material used to build the machine. For example:[LIST][/li][li]Small/slow can be made out of MDF[/li][li]Midsize/average speed will be made out of aluminum plate.[/li][li]Large/fast your talking steel[/ul] [/LIST][ul][/li][li]Accuracy – A ton of cash gets eaten up here. It all comes down to what kind of tolerances you want to hold.[LIST][/li][li].1” - .01” - local hardware store[/li][li].01” - .005” - cheap mail order (cheap being a relative term)[/li][li].005” - .001” - mid grade mail order, you need to know what you are doing.[/li][li].001” - .0001” - premium mail order /need to consult some experts[/li][li].0001” or less – Time to call in a team of PhDs.[/ul] [/LIST] [/li] If you really want to get into it let me know I can hook you up with some links that should help you out, plus I can try and answer any questions you might have.

Dick Lemke, I took a plastics technology course in college (long ago) and the teacher had built a big vacuforming machine, about 2’x2’, for styrene, so smaller than you described yet all handmade. My uncle tells of the mammoth ones they use in the auto inductry for making fenders, etc. And dansherman, thanks for the specs and the confirmation that this is neither easy or inexpensive.
Bill Korsgard, the Personal CNC 1100 is impressive to be sure.

Hi Dan,

Some time ago I started looking into building a CNC machine, after reading a post on the MAKE website (actually guys if you have never seen this site you should definitely take a look at it…. www.makezine.com and click the Blog icon), but was sort of scared by the amount of pre-milling necessary in order to give stability (and accuracy) to that thing, you basically needed a 2D in order to build a 3D.

But Im still interested and still looking int the possibility of building one, although for 2000 dollars you could apparently buy a used one from E-Bay……. So I’m not really sure if building one would be really worth at this point…… But then again explaining the expense to the wife my bee a little more complicated then the actual build…

Anyway, what I wanted to say is that I would be interested if you could post more information and the web sites on your project.

Thank you


They’re talking about this topic over at SailingAnarchy, for RCs…


Bill, post your website there.


A quote of 1600 for a USOM hull, at this price buyiung a E-Bay used one starts to make actul sense, with one hull, deck and keel molds you have payed the cost of the machine.


Yeah, that guy’s dreaming with the quote of $1,600 to cut a hull (on the SA forum topic). What if he charged half that? Do you think he’d have any takers? If, so, you could pay off your equipment costs pretty fast.

I just dig the whole technology, yielding perfect lines in the part. Seems like the performance of the finished boat would have to be better than handmade. No?


Feel free to post it if you want, I don’t follow that forum. On another tangent, there’s always stereolithography, which is a pretty amazing process:
I ran into a local industrial designer who uses it to prototype shapes for vacuum forming. He told me he can email his design to a place out east & get the form back within 2 days.

The only problem might be the ability to do something 1m long, but I suppose it could be done in sections & joined together.


Its pretty interesting to see the cost figures that people throw around.
The machine I used to do this deck is used at work for cutting bulkeads, frames etc for the boats we build (essentially just flat, profile cutting) but can be used to generate full 3 dimensional shapes (like this deck).
The travel is 3600mm X 1800mm X 250mm and the accuracy is to .02 mm which is way more than is needed for model construction!
The deck in the photos was machined in four hours from 25mm MDF which was laminated together to give the required 50mm thickness.
An 8’X4’ sheet in 25mm cost $60ish AUD ($50ish USD) and one sheet is enough to do the entire hull of my new boat (i’ll psot some pics of the hull tomorrow), which about the same size as an EC12. If you allow another sheet for deck mould you’re still only talking around $100 USD for materials and a total of maybe 15 hours machine time for a hull plug and deck plug completely machined and ready for priming.
I think this technology is becoming more and more readily available and some of the people quoting jobs are gonna have to stop pulling fugures out of the air and realise that it is becoming a competitive industry.
Of course there are always going to be two kinds of people. For the first it doesnt matter how much something costs its always too expensive, and the second it doesnt matter how much something costs, they just want it. The trick is that you need to cater to both of these markets in order for the product/service to become readily available.
As far as I’m concerned (and this is just my opinion) the finished plugs when cut by a CNC machine are fairer, more accurate and much more quickly built so there is no way I’ll ever build a boat any other way.
Its like when I used to draw a boat by hand, use simpsons rule to calculate the station areas, then the displacement and centres, then go back and get out the battens again and re-fair the hull and do it all again. Now with CAD there is simply no need. This is the future of model building and any one thinking about exploring this technology should at least make enquiries and think about how quick and easy it is to go from a CAD model in the digital world to a MDF plug in the real world. If you consider the time involved you might be suprised how little it actually costs to get thing CNC machined.


I’ve added a few more pictures at http://www.12metreyacht.com/images/gallery2/
One of the real strengths of CAD/CAM is the ability to go back and add things later. I decided to add some more detail on the deck plug, the traveller and genoa tracks and the rear hatch enhenced the scale appearance. I didnt have to cut a new plug I just re-worked the existing one by cutting some slots for the tracks & hatch to go in then cutting the items from a seperate piece of MDF before gluing them in place.
You can also see the plug for the hull coming along, the rudder and keel wings were machined seperately but all join in place exactly where they should, once again something I could never do by hand!
If anyone is interested in this technology or would like to have a hull or something similar cut let me know.



I have to think the performance will be increased too.

Just getting better and better. I hope you post images of the hull when its gone through the machine. I am between boats yet want to do it this way next time but need to learn more about CAD first, get some practice in. As you said, “This is the future of model building”.


Here’s the image of the almost finished hull, all that remains to be machined is the deck edge flange then shes ready for painting & moulding


Here’s a link to the latest photos.

Its amazing how a coat of paint can change the look of something.


I think she’s coming along nicely…

That is nice!