# cnc machine



## longshore (Dec 4, 2008)

hello,

wanted to say hi to everyone here, this is my first post. 

what i am wanting to do is get a computer scan of an h.o. scale locomotive(baldwin rf-16 shark) and have the size multiplied to 1:29 scale, and then have a cnc machine, cut the shell out of a piece of billett aluminum. my further plans after this is done would be to build a frame. not sure if i am going to power it by battery, track power or make a live diesel. does anyone know who would do this, how to ask about it(technical terms), roughly how much it may cost etc.

thanks,

nick


----------



## Tom Lapointe (Jan 2, 2008)

If you're having this done as a "one-shot" unit, I would say be prepared to be *floored *







by the price! Even with CNC machining (I maintained CNC machine tools for 6-&-1-/2 years, working for a machine tool company), a *sizable portion of the machining costs will be the "set-up". *(Even computer controlled machines will have to have someone install the proper cutting / milling / drill bits in & *program *them - & skilled CNC machinists generally don't come *cheap!*)









One potential avenue to explore might be this site: http://www.emachineshop.com/ ; I guess you download their software, design the parts *yourself*







, then they give you a quote on production costs. *IF *you decide you actually want to do this, consider having them do a small *production run; *as a minimum, it would give you some *"spare parts"*







if anything get's damaged along the way. If you could afford to do a bit larger run, *consider making them available as kits!*







- You might see before hand if other modelers wouid have interest in a 1:29 th RF-16.







Another consideration might be to have the cab section machined *separately from the body; *you could then also see about producing Pennsy's much larger *BP-20 class Passenger "Sharks" (Baldwin model DR6-4-20), *which, as I far as I can tell from Al Stauffer's "Pennsy Power II" book, use virtally the *SAME cab. *(Might be quite a hit with PRR modelers!







). As a historical note, the "Sharknose" design was originated for Pennsy by Baldwin, emulating the noses of PRR's *GORGEOUS *







*(but unfortunately MAINTENANCE-intensive!*







*) T1-class streamlined 4-4-4-4 "Duplex" steam passenger locos.*


For the mechanical end, I'd keep things *simple - Aristo's Alco RS-3 trucks appear to be a close match for the RF-16's, * & should be readily available as a replacement parts from Aristo. I just bought an Aristo RS-3 in New Haven colors off eBay (it's my first Aristo diesel), *very impressed with it's smooth running qualities! *







Hope that gives you a few ideas.







Tom


----------



## Gary Armitstead (Jan 2, 2008)

Nick,

Tom is correct about the cost of this project. My trade before I retired was as a die sinker. I did this kind of work everyday. First thing you will probably have to digitize the surface and shape of the model. These tools are indeed not cheap! About twenty plus years ago, I was involved in a project to digitize the front swing arm for a 1987 Cadillac for GM. That process cost about 2K dollars THEN. Then the points generated need to be put into some software to get the surfaces to be cut. After this, you need to program the toolpath to cut this alum billet and then cut it. I have used software and NC mills for over 35 years and I would say just as an estimate for a one-off part, you would be looking at about 10K-15K dollars for your one locomotive! I don't know where you live but on the west coast, the digitizing, surfaced part in the software, programming, set-up and machining, would average 100 dollars per hour-maybe more. I hope you can find another way to do this.


----------



## ralphbrades (Jan 3, 2008)

Here in the UK there are several companies that specialize in PHOTO ETCHING -that is you provide the plans and then these are etched onto brass sheet. You then fold and solder the pieces together. It might take you a lot longer to build -but it should be vastly cheaper. Plus the fact that you can now sell any "spare" sheets you have made to recoup your costs....

Just a thought.

regards


ralph


----------



## DKRickman (Mar 25, 2008)

I'm just curious... 

Are you wanting to do this to say that you did it, or is there some specific reason why the more traditional kitbashing or scratchbuilding techniques are not viable options? I'm not trying to judge here, just asking a question. It seems to me that you could probably get satisfactory results for 1/50th the cost by building the model yourself. Even hiring someone else to build it would cost far less than having it custom CNC machined out of a solid block. Heck, I'm not sure it's even possible to machine an entire locomotive body out of a solid block. 

As for battery/track power/live diesel, again, why are you doing this? Live diesel is cool, but I don't think it really captures the essence of the real thing any better than an electric model, and it takes a great deal more time and money to get the same results. I'd go with track power or battery and a good sound system, and you'll never care that there isn't a real diesel engine in there.


----------



## Kovacjr (Jan 2, 2008)

Why all the trouble for have a exact model if its not even 1/32.....There are many units that you can start with, even the Marklin F7 units only because the bodies are brass. CNC unless you have the machine and can program it yourself its way out of budget in my eyes. 

For a drawing http://index.mrmag.com/tm.exe?opt=I&MAG=BOOK&MO=1&YR=1966


----------



## Jack - Freshwater Models (Feb 17, 2008)

Nick,

The RF-16 (NYC version) is one of my favorite diesels and would make for a nice model. That being said............

What you propose is VERY complex and expensive. On occassion I have had full scale parts 3D scanned to use as a pattern for mold making. An example was a complex shaped propeller for a model outboard. The price of the scan alone would be prohibitive. But there's more! Once you have the scan you will probably have to edit it in CAD or Solid Modeling software. If you get that far, you would be wise to have the shell "3D[/b] printed" rather than cnc milled. The printed model could be used to produce a RTV mold which could be used to cast production models.

Scanning others work is also questionable and there may be legal issues with the company that built the HO model. The end result may not be very nice since the HO scale model probably has a number of over size details which would stick out like a sore thumb in the larger scale.

The best way to get a model of a Shark would be to find some drawings and photos and just scratchbuild it. With the exception of the nose, the shape is relatively easy to develop in a model. Even the complex nose shape can be broken down into planes and simple curves. Scratchbuilding a Shark in styrene/wood/resin would be an interesting and fun project for the advanced modeler.

1:32 would be a better scale if power trucks are available.

Jack


----------



## Torby (Jan 2, 2008)

Also, when you just multiply an HO model by 3, the little details they didn't include 'cause you just wouldn't see them in 1:87 become noticable in 1:29, and your scaled up model would look much less detailed than the original.


----------



## Jack - Freshwater Models (Feb 17, 2008)

Nick, 

If you want to go ahead on this, possibly as a group effort, I would be willing to design/cast some of the detail parts at a reasonable price. Truck sideframes could be cast in metal. I might be able to design the nose and have it 3D printed for a cast resin nose. I would prefer to work in 1:32 since it makes a lot of the process easier. Theere are a lot of possibilities. 

Jack


----------

