Introduction: Repairing Garage Sale Table Saw
Who doesn't love a garage sale! They say one mans junk is another mans treasure. Well it may not have been a treasure, but the Delta table saw I found was a steal at $40. It was dirty and the blade was dull, but the motor sounded good and the cord was in great condition. Only problem was that the height adjustment wheel was broken right where the crank handle once attached. So I talked the guy into dropping the price $10.....now the fun part started!
Supplies
Cleaning this thing up and getting a new blade was pretty straight forward, the hand wheel was going to be an Issue. So it was time to get to work.
Supplies:
- Digital Calipers
- Fusion 360
- 3-D Printer
- Durable Printer Filament
- 1/4 20 screw
Step 1: Design
Step one: take measurements. I only needed a few basic measurements of the shaft and clearances for the other controls:
Step two: Design the wheel. Design is always the toughest part of any project, and this was no exception. I use Fusion 360 for all of my design work. It may seem overwhelming at first, but there are many online tutorials that will have you up and running in about an hour. Did you know you can get a free version of it!
My original idea was to recreate the original crank type. I have always found the plastic cranks too vulnerable to heavy use due to the stresses where the handle meets the wheel. Considering that is exactly how the original one broke, why would I want to make the same mistake.
I wasn't loving my original design anyway, so.....
Back to the Fusion 360 drawing Board!
Step 2: Re-design
One of the great features of using Fusion 360 is the ability to go back in the timeline and change parameters and completely redesign your model. And that is exactly what I did. I decided to go with a handwheel design verses a crank design. Quicker to print, no moving parts or pieces to assemble and most of all, durability.
When designing 3D printed parts I have found avoiding sharp 90° interior corners makes the part more robust. Any mechanical stresses, especially torque, tend to end up in the part breaking at those intersections. using a wrench I tested the amount of force it took to adjust the height. It was a very stiff action on the shaft. Understandable since the crank is lifting the whole motor assembly. Taking this into consideration, I went with a very oversized fillet where the shaft meets the handle. I also added smaller fillets on all corners for aesthetics and comfort of use.
Modeling done, I export the design as an STL for printing.
Step 3: Print
I printed the part with a .04 nozzle, and in my slicer I put my settings at 40% cubic infill with 10 walls. I know it sounds counter intuitive, but parts with 20-40% infill and thick walls have better stability than solid. Combined with the reinforcement of the fillets on the stress points from the last step the part ends up extremely durable.
I ended up picking PLA+ from Inland as my filament of choice for this project. I have used PLA+ in place of PETG and ABS in other projects and find the formulation to be the best of all worlds when it comes to printing and holding up to abuse. It prints easily without warping, and have found it to hold up very well for tools and outdoor use. I have some plug's I made for my patio that have been through hot summers and below zero winters for the past 3 years. They have faded some, but they are still holding up.
All loaded up....I hit print!
Step 4: The Result
After 14 hours of printing, I had my replacement piece. It came out perfect with no needed sanding or trimming.
Using a 1/4-20 screw, I attached it to the saw and tested its operation. The oversized fillet I added into the design gives a solid hold on the shaft, and the wheel is comfortable to turn. the original crank wheel design would make for quicker adjustments, but I'll take durability over speed. I now have a fully functional table saw.
Step 5: Final Thoughts
Repairing, repurposing and reusing garage sale finds is fun. Especially when you get to flex your creativity and mechanical skills. I hope you found this Instructable inspirational. If you did, give it a like!
You can download my Fusion 360 and STL files at Printables. You can also check out my other designs while your there too...