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Discussion Starter #1
One of the first things I needed to take care of on my new 65 Sprint GT was to somehow fix or replace the bracket holding the inside rearview mirror. After 47 years, the old metal bracket had all but fallen apart. What I didn’t realize was how rare and hard to find these early mirror brackets with the 3 screw base were. I got one or two responses on the BB for used parts but the asking prices were kind of steep. So I decided to try my luck and print (yes, print!) one myself!

Additive manufacturing (aka 3D printing) has been around for a while but in the last year or so this amazing technology has really entered the consumer / hobbyist space in a big time. I’ve been meaning to try it out and this was the perfect opportunity.

Every 3D printed object starts with a 3D model. There are two ways to make one: Take the real part and scan it, or make one from scratch with suitable 3D software. In my case I was hoping to be able to scan my old bracket (our local TechShop has a good laser scanner that would have been perfect) but upon closer inspection I realized I wouldn’t be doing myself any favors. The old part was badly warped, cracked and flaking.

old_bracket.jpg


So I decided to start from scratch and model one myself. I took a couple of pictures of the old part to use as reference, imported them to Autodesk’s Maya
and started working on making the model. Most people will use more design-oriented software like AutoCAD or SolidWorks but I’m pretty comfortable with Maya and never used the other two so I decided to go with that.

It did take me a few iterations to get the shape right but in the end I was pretty happy with the result and it very closely resembled the original part!

Screen Shot 2012-10-17 at 9.46.13 PM.jpg

And here comes the fun part. Once the model is ready, all you need to do is export it in a compatible format (STL or OBJ), open your browser, go to one of a handful of sites that offers priting services and upload it. I used Shapeways (www.shapeways.com). I picked them mostly because their site and overall process is really well designed and user friendly and they offer a wide variety of materials.

Once the model has been uploaded, it gets processed on their servers where they check if it is indeed printable (meets some basic criteria for size, structure, etc) and you instantly get a quote of how much it would cost to print it with any of the materials they offer and what the expected delivery date would be.

I chose to print in plastic using their black “Strong & Flexible” material as it looked sturdy enough for what I needed and the price was definitely low enough (in the $30's) that I didn’t have much to lose even if it were a flop.

A couple of weeks later the actual print arrived home well packed in a cardboard box. I was excited to open the box and find inside the really cool looking part. It had a smooth, almost velvety, look and felt pretty sturdy.

Screen Shot 2012-10-17 at 10.11.16 PM.jpg

The last thing that needed to be done was to put some threads for the anti-vibration screw and the mirror. They both used M6 1.0 threads which was convenient. Not knowing what to expect from the material, I was prepared with a couple of different options for making the threads including directly tapping the plastic, a helicoil insert and a thread insert specially designed for plastic (all bought from McMaster-Carr). Since I didn’t know what size hole I would up needing to drill, I had just added relatively small guide holes in the 3D model which I could then drill to the right size.

It just so happened that the plastic material was really easy to tap directly and the resulting threads were nice and smooth. So I went with that.

Overall, I’m really happy with the end result. The bracket fit perfectly in the car. It’s ever so slightly flexible so there is a small vibration in the mirror but nothing too bad. The definitive solution would be to print the model in Stainless Steel (it’s about $130, still a lot less than the used parts I found) which I may try for kicks as well.

Screen Shot 2012-10-17 at 10.17.51 PM.jpg
Screen Shot 2012-10-17 at 10.18.30 PM.jpg

What excites me the most about this little adventure is that 3D printing could spell the end of NLA parts for our cars. I highly recommend giving it a try for your next project if you get a chance to do so.

PS. If you are curious what the model looks like or if you are looking for this mirror bracket for yourself, you can find it and even order one (it will be shipped from shapeways directly to you) here:

Shapeways | SprintGT by vangos
 

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This is great Vangelis! - I can confirm how difficult it is to find the original stuff - even in used form !
 

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Rock on! Having a background in industrial design, 3D printing facinates me. I always tend to think of its use in rapid prototyping, but you're right in that NLA may become a term of the past given the materials now available. Sounds like a great business venture to me!
 

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Discussion Starter #5
Excellent work! Now you just need to treat it with the silver nitrate spray to make it look completely original.
Thanks! I kind of like the black.. It matches nicely the rest of the mirror. I will be giving the stainless steel print a try as well to see how that feels.
 

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I had NO idea you could 3d print in metallic materials. Thank you tons for the tips. I actually have been thinking of making some parts...but being able to do it in metals is huge!
 

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I nominate this for the coolest post of the year. What an opportunity! Thanks for sharing!

I suggest it be moved to the Product/Vendor Reviews thread as it has broader utility and visibility there perhaps??
 

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Wonderful! Thank you .. I have been thinking of investing in these 3 d printers.
The use seems endless.. fantastic . Thanks again for a great post.
 

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Blast - that unobtanium widget type 133.456 I've been squrilling away for 30 years just became worth...$130....

What amazing technology and how brilliantly accessible.
 

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yes this technology is moving fast. Like when you paid $300 for 4 meg of ram and now... Still in its infancy regarding consumer level 3d printers but it won't be long before we all have one. I am glad my 15 years of 3d modelling skills can now cross over into the Alfa domain!
 

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one of the great and interesting draws of the alfa is and always has been their use of new technology in creative ways.
 

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A mirror bracket like this is pretty easy to fabricate, as I once did for my Super, but there are many other cast parts for which this technology is perfect. There is real potential here.

barry
 

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I carved and cast my own in bronze then had it plated.
Shapeways recently was asking for input on future materials that users wanted. One of the leading suggestions was wax, for lost wax casting. So you could design your 3D model, have it printed in wax, then have that cast in the metal of choice.
 

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Shapeways recently was asking for input on future materials that users wanted. One of the leading suggestions was wax, for lost wax casting. So you could design your 3D model, have it printed in wax, then have that cast in the metal of choice.
This is impressive technology thanks for posting Vangos.

Wax yes or for making patterns to sand cast parts in aluminum, iron, bronze. Not sure what this pattern would be made from. Wood was traditionally used, but a good plastic should work as it did for Yoska in his post above.

I have been using original parts as patterns for aluminum parts but you lose something in dimension due to shrinkage of the metal from liquid to solid. About 1/8 inch per foot for Aluminum if I remember.

Regards

Ken
 
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