31 replies to this topic

[tjallen]

Hi, hope I'm posting this in the right spot.

 

I'm just getting started on a project of making 3D printed replicas of a few famous vintage slot car chassis. I know how ridiculous this might sound to some people, but it is a fun project for 3D printing, and who knows what will come of this.

 

To begin, I have carefully copied a vintage Brian Warmack "jail door" chassis from the first Car Model Road Race in Feb. 1967. There is a picture of the chassis in the Car Model race report. In addition, Steve Okeefe has made a detailed drawing of the Warmack chassis at Slotblog's own The Independent Scratchbuilder, which I used as a guide.

 

I made two versions using the free software at TinkerCAD.

First, a static model with non-rotating wheels, axles, (and in the future, maybe a motor.)

 

 

Second, I made an almost practical version, to which you could, in theory, add wheels, axles, and a real motor, and maybe try to drive the thing.

 

 

I have sent my design to Shapeways, and ordered my first sample in plastic, which should arrive in a week or so.

 

I hoped to be able to order a brass version, but the chassis exceeds the size limits for brass (about 3.5 x 3.5 inches is the max), and some parts like the bracket, are listed as too thin to print in brass. I could order an aluminum version for about $275. Stainless steel is almost reasonable $50 to $60, and nylon might work too, at approx. $40. The plastic version that I ordered will be about $20. (These are prices for the raw materials, and excludes any shipping, designer profit, etc. )

 

Already I have learned a few lessons to share, and found many questions I could use help on.

So, any comments or suggestions, so far? Thanks.

[Pablo]

I have three comments:

1) You posted in in the right place.
2) It's not ridiculous at all.
3) I love it.

[Bill from NH]

Jim, having your collection made in nylon accomplishes two things.

1.) The collection will be relatively light weight when you have to move it around in the future.

2.) Nylon doesn't tarnish. Any cleaning/dusting could be done with water, dish detergent, and paper towels.

[SlotStox#53]

Superb idea! Very much look forward to seeing the printed version when it arrives.

[MSwiss]

A static model of a slot car chassis.

 

I love it.

[Dennis David]

A static model in nylon will be your best bet. You need to read a little more about how they print in metal and you'll see there is nothing to be gained by the use of any of these materials to really justify the expense. Personally I don't really think any of the designs are appropriate to the 3D printing technology but that's only my opinion...

[tjallen]

Regarding the practicality or appropriateness of 3D printing for this project that's what I'm trying to discover. Find out by doing. Trial and error.
 
Maybe a little background and this will make more sense:

1. I have a pre-existing interest in vintage scratchbuilt slot car chassis,
2. I was intrigued by the idea of 3D printing and wanted to learn to do something,
3. A friend told me that her kids were learning 3D printing in high school,
4. I saw Kirk DuQuette's 3D-printed Super Modifieds on the facebook Slot Car Builders group, and so I knew it was possible!

... and here we are.
 
Here is Kirk's work that inspired me (thanks!):

[havlicek]

While this is all very cool, I have to agree with Dennis about how well suited these designs are for an actual "runner." Of course, 3D slot car chassis meant to be run, but not to emulate old scratchbuilt designs have been done and apparently work well. Then again, there have been molded "plastic" type chassis done way before 3D printing and those also worked well, and were durable as well as pretty light.

Even things like endbells, which are well suited to 3D printing and fairly short runs, are still limited by the types of resins available for the most common/less-expensive 3D printers. The technology (3D scanning and printing) is moving forward fast though, so I expect big changes/improvements in the near future. It's pretty neat to see this stuff evolve right before our eyes though.

[Samiam]

Jimmy,

I'm intrigued by all this 'puter controlled scratchbuilding you, Dennis, and others have brought to the table. You guys are bringing slots into the 21st century. Masters like Steve Okeefe, with his detailed computer drawings, have brought us out of the dark ages. No longer do we have to look at grainy black and white photos from 50-year old magazine articles for build details.

Very cool stuff happening.

[chaparrAL]

I wish I had your CAD skills. Eat my heart out!
It is possible to create an investment mold and have it cast like a partial denture frame. Just have it printed in jewelers wax.

[Dennis David]

Just to be clear i really like what you are trying to do even if i think it's nuts. LOL. 👍👍👍

I would love to try what you are doing with an SLA printer If i had one. I bet Marco at Area 71 could do this. He has access to printers that Shapeways could only dream about.

[n.elmholt]

Some years ago, when German Olaf Wachsmuth stopped producing the White Point nylon injected chassis, we were in trouble in Denmark as we used the chassis for our Danish Championship CanAm class as well as "The Secret Lige" (yes) using 60's GT clear bodies.
I designed a copy for 3D printing at Shapeways and this has later been improved with small details and it carried the class on for some years.

 

 

you can se more here:

https://get.google.c...p0RZ2tC3bfKQ_OH

 

 

NIels, DK

 

[MSwiss]

I have these that another local raceway makes up.

 

I haven't run one here, yet, but they are successful at his raceway.

 

I sell them for only $12.

 

[Tom Katsanis]

This is probably a stupid question to ask but is there any plausibility in making a jig for these vintage pro chassis designs like the jail door above.
3d print a piece that would be like a mold bottom that you can cut & bend your brass pieces to fit into so you just slot all your pieces in & solder the top pull it out then solder the bottom & you have the same chassis everytime.

[Dennis David]

Jigs are a good subject for 3D printing but in this scenario I would think a machined ceramic tile with properly drilled holes and steel dowels would be better.

[MSwiss]

If you come up with a way to easily machine ceramic, please share.

[Dennis David]

I think you can do it but it's not something I would do with my machine. Some other people have actually done it.

[Dave Crevie]

Micro-grain carbide with TiALN coating. But they only last until the coating wears off, about ten to fifteen minutes

of machine time. Use low RPM and about .006 chip loading.

 

Make the jig from aluminum or corian.

[Dennis David]

I have that end mill but I wasn't going to try it and now you've saved me the effort. LOL 

[tjallen]

My prototype is back from the 3D Printer. Here are several views.

 

There are a number of issues, but overall, I am really happy with the results.

1. The whole thing seems about 2% smaller than my dimensions. Calibration? Shrinkage?

2. The Printer's software reports that my motor bracket, both axle tubes and hinge tube are too thin to reliably print in many materials.

3. The axle tubes and hinge tube are filled with powdered plastic. I clean then with a drill bit. After cleaning, the 1/8 axle still does not fit.

4. The pinhole body mounting tubes are impossible. Too thin, and the hole is too small.

 

I am busy fixing the issues, and will report back more when I have a better result.

 

 

 

[MattD]

It's an amazing process.    Doesn't look like it is ready for prime time racing, but the technology is really something.

[tjallen]

Here is my jail door chassis replica, with some improvements, in Nylon.

 

 

This type of nylon, which Shapeways calls "HP Nylon Plastic," is too flexible to make a slot car chassis in the jail door design. This material may be appropriate for other slot car designs.

 

Shapeways says, "HP Nylon Plastic is Nylon 12 (PA12) printed on the new HP Jet Fusion 3D 4200 printer."

 

Image shows the chassis easily flexes. I'm holding the rear end flat, and rotating the front end. Not like brass at all!

 

I mentioned that this design has "improvements." The improvements all have to do with Thickness Requirements for the various materials that are offered for 3D printing. Is anyone interested in more detail about this topic? I had lots of problems getting my design to pass both computer and human inspectors, who will terminate your print and cancel your order when features of your design are judged to be unprintable. Here are the changes:

• Doubled thickness of motor bracket.
• Thicker front and rear axle tubes.
• Thicker hinge tube.
• Added more virtual solder blobs to the guide holder.
• Eliminated the pin tube body-mounting system, and added tabs with screw-holes for body mounting.

So I continue to look for the right material to print this chassis. I am trying to use the plastic called PLA, but I cannot get my designs to pass the human inspectors, who judge that it is impossible to clean out the axle holes. I'd like to tell them that I will clean it, but this material does not offer the "print it anyway" option.

 

I may also try the "acrylic plastic" and the "Acrylate" - but my budget is being strained by all the prototyping necessary to make this work!

 

Finally, a runner or a shelf queen? So far, my prototype is probably okay as a cheap jail door look-alike to put under your period bodies. However, every person who sees it asks the same thing - "Runner?" "Will you make a runner?" "I might want a runner." etc, so I am trying to see what I can do.

[Bill from NH]

Jimmy, those screw hole body mounting tabs could probably used with body clips too. As an aside, you could make the tabs with no holes. Then drill them to fit pins, body clips, or screws. You might be able to use velcro pieces on them for body mounting,

 

The thicker thin brass parts is a good idea.

 

At some point, you may want to replace the plastic droparm weight with a brass one. Maybe make a plastic mounting plate on the droparm for a place to secure the brass one.

[SlotStox#53]

As a static replica under a period body it's amazing

Good luck in passing the inspectors to get the tube sorted! Either way this printing lark is superb, it'll work eventually, just like printed endbells for 26Ds etc.

Just finding or waiting for a high melting point filament. Although a blogger does a shapeways endbell for Velociraptor drag motor

[n.elmholt]

Jimmy Allen,  I have had good experience with the material that Shapeways call "Black and flexible"  - other colours is also available. Is that the material you used for the yellow chassis ?

 

BTW this material is formed by bombarding a bath of powder with laser beams, building up layer by layer - therefore the powder residue in your axle tubes.

 

Niels, DK