Question of the Week: Are 3D-printed parts a fit for your ride?


When your car is stuck in the garage, awaiting parts that are thousands of miles away, it can be a stark reminder of our beloved machines falling victim to Father Time. But can modern technology ease the pain?

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2018/02/23/are-3d-printed-parts-a-fit-for-your-ride


If you own a vehicle, for instance that was a “one year only” design, or if a specific part was not/or has been in dealer stock for 25+ years, then I see 3-D printing as a viable alternative. For example, plastic grilles (e.g. 1970 Dodge Charger, one BIG piece of plastic!) are practically made of “unobtanium” now, and IF you find one, chances are it will be in a fragile, time worn state. When doing a “money is no object” concourse restoration, I’d say if the parts can be found, then by all means, use them. For a really nice driver class restoration, I’d have no problem with and would welcome a 3-D part, as long as the reproduction was up to OEM standards.


I’ve been 3D printing NLA or rare parts for my two Triumphs for about 4 months now. The parts are very nice, most are cosmetic parts such as switches and rubber gasket type parts (TPU) and in some cases I can improve on the original design. I’m currently making some real functioning parts that are showing great promise and that’s a part that is no longer produced anywhere. I see great promise for many parts that I’ve got on my list. I also have 20+ years using CAD systems so if I can put it on CAD I can print it.


I have printed a yoke for a Stewart Warner speedometer that might be usable as is made from ABS, or it could be used as a lost wax model for casting in aluminum or pot metal. Haven’t been able to get a speedo rebuilder to try to assemble it into a unit to test the design.

I have also made a first pass model of a piston for a 1924 Oakland. Got a quote from a local metal printing company, but it was about 10X the cast part from an established (but very slow) vendor. Again, the model could be used to do a cast part, but I don’t have a backyard foundry yet.


I’m 50 and I have a 1993 Miata, one of the ultra rare Red ones with a black top and black interior, so there are no parts out there that I can afford. Oh wait, I can buy whole cars for parts for dirt cheep based on my budget, combined with dead easy internet sourcing, 3D printing a part would not be my first choice today, mainly because it doesn’t have to be.

Now when I was 16 and driving a 1966 Plymouth Barracuda that was all kinds of brittle and broken and it could take months to find parts for it in that pre-internet diplopia called the 1980’s. The idea of the ability to print a part at home or at a local shop may have been my first choice. Then again, parts for a 1966 Plymouth aren’t all that hard to find today thanks to the internet.

In the end it comes down availability of usable parts, if I can source a new old stock or factory part that is serviceable and looks good, that will be my first choice, if I need an odd piece of trim that I can’t find but could 3D print and hand finish to look as good as the real thing I would do that with no problem with 3D printed. Also if the story of getting a part printed is better than the story of sourcing a factory part I’m totally in with 3D.


I can see your point, however, I print parts for English cars in my ownership that are 50 years old. One is a 1968 and the other is 1970. Although there are a few sources, there are many parts that are not reproduced, and the used parts on ebay are 50 years old so those rubber and plastic parts are also in poor condition. 3D printing is a great way to re-create those parts I can’t get anywhere and at a reasonable cost. The one glitch is you need the capability to create the part on a CAD system to create the STL. file. Fortunately I have that skill set. The 3D printing allows me to expand on this and make parts I wouldn’t attempt in my home machine shop. My prediction is that 3D printing will become a major force in restoring older cars in the near future.


@brian - Do you start with a scan of some type? Just curious as to how you create the part in CAD for it to then be sliced for printing.


No, 3D scanners are still too expensive and detail limited at this stage of the process. Commercial (very expensive) ones are pretty good but for our home use not practical. So at this point in time you have to be somewhat proficient using 3D CAD design programs. I use INVENTOR. Then you convert the file into a STL file, usually with a couple clicks of a keystroke. Then bring the STL file into the slicer. So in my case I take the part I want to create in hand from my car and create (reverse engineer) the CAD 3D model. In some cases I make design improvements on the part to improve function or appearance. That’s all part of the fun for me. I’ve made parts that are no longer available for my two Triumphs. Some are complicated and some not.


I needed a very rare clip for my 71 Dodge Challenger convertible. I looked everywhere without success. When my mechanical engineer friend found out, he took my one decent clip and created the specification for the 3D printer. A trip down to a local printer and voila! I now have the clips and rocker trim that I always wanted.


3D printed parts 10 years ago would result in a stepped surface (from layer to layer). Then you have to sand down that surface to smooth it out. Is that the same today with 3D parts or do they come out smooth now?


I can’t say what the quality was 10 years ago but now, the layers are pretty fine. Yes you can see them and catch them with your fingernail but it also has a lot to do on how you set up the slicer parameters. There are also epoxy coatings made for 3D prints which fill in the layers and really smooth’s the surface nicely and then they are smooth. If you are looking for glass smooth, you would still have to do some post processing like sanding. If you are looking for injection molded finishes, 3D isn’t there yet. The detail is still pretty nice for the parts I’m making.


Here is a pic. Black housing is 3d printed


My car is a driver so I was more interested in getting everything functioning over original/ factory parts.
My car didnt come with hood turn signals and I found the online but too expensive. So I bought just the lenses and 3d printed the housings and updated the bulbs to LED so they never have to be replaced.

There are many online services which will print the part for you and mail it.
Also you can share your designs online and other people can print them.
I used Shapeways for mine.


Nice work Michal, this is why 3D printing is going to be a fast growing opportunity for the older car hobbyists. I look frequently at Thingiverse and Shapeways but currently there are very few if any parts for the old British cars I work with. Fortunately I have over 20 years experience with 3D CAD design so I create the models I need and then print them on my printer. I like the challenge and it’s fun also.