Here's a small introduction of my "private" life... I'am not a fan of throwing away things especially when they are so called "defect", I also love the "good" ol' quality and design of the products from back in the days. Sadly we quickly moved into the consumer throw away world, we have so many product made from plastics which makes barbie even jealous! I'd rather have a product that lasts a decades instead of those 5 year plans.
Anyways... I also love the looks of the 60's ~ 80's products and yes I still love modern products, but the 70's / 80's is just something special... As we already know those products aren't being made anymore so this is why I started to repair those products since the parts are not available anymore.
These two render below are from the final product.
While I was thinking about how I'am going to reverse engineer this part I had two options... The hard way using calipers and measure everything or 3D Scan it and use it as a reference model in a CAD Program. 3D Scanning can be hard for some parts, or the dimensions wont be always exact so I still use the calipers to measure crucial parts from this object. As you can see in the images below I 3D Scanned the broken part, fused the course scan data for exportation so I can import it in a CAD Program.
Coating The Object...
The images below shows a RAW Scan (left) and the Fused Solid (right). Also note the rough structure of the object, this is because the part was glossy black and does not show up on the scans, in this case I had to powder coat the part so it would not absorb the light patterns.
I Imported the Scan Data into in a CAD Program and started sketching the rough geometry over the original scanned model. After I finished the rough lines I started to constrain them with the right dimensions. The reason I created the original one first is because I'd like to have the original part too. After finishing up the original part I started to work on the revision with mayor improvements for strength including a angled notch so the spring is not going to slip over the extruding pegs.
To see the Before & After just slide the slider in the middle of the images below.
This was not necessary for this project but I was curious if my revision was really improved over the original one, and also fun for demonstration purposes. So as you can see at the image below the results were perfect! On the left the original lever which has been snapped were the spring puts the notch under stress and on the right the same but without any weak spots.
3D Printing The Parts
It's really easy, just print them! Well... some sort of easy but parts like these are better of printing on high resolution machines and printing with FDM isnt really the option. You need SLA , DLP or PolyJet Fusion Printers to print these since accuracy and the fine details are really important with these complex designs.
Reverse Engineering & Replacing Broken Gears
Here is another example of Reverse Engineering and 3D Printing, in this case these were tiny clutch gears from another Cassette Deck. I Reverse Engineered the Gear in Inventor and did some minor improvements. 3D Printed the Clutch Gear in Strong Transparent Resin at a 0.025 Layer Height, and replaced the original ones!
The Cassette Deck is currently working a couple of days without any problems, It's mechanism is silent and no WOW & Flutter is introduced.
Below are pictures of the Technics RS-TR333 Stereo Double Cassette Deck Clutch Gears . The yellow gear is the original Clutch Gear with chipped off teeth (also known as Cheese Gears because they chip off easily).