Money Saving Shop Hack, or a Waste of Time? #lathe #tool #metalcasting #diy #machining #handmade

I recently got a bigger boring bar, but I didn't have a proper toolholder for it. I thought I should cast one to see if it was useable. My only hard costs for this project were a little bit of propane and 5 Allen set screws, about 5 dollars total. This video documents my experiment to see if a large "CA" size lathe tool holder can be successfully cast out of scrap aluminum and machined into a useful part, despite conventional wisdom from machinists warning that cast aluminum is too soft for the job. If you enjoyed the build or have tips on how to improve the process, drop a comment below! I’m learning as I go on this journey to build cool stuff, and your feedback keeps the shop moving forward. Don't forget to like and subscribe for more DIY machining and shop therapy! If You want to try out this crazy experiment for yourself you can download the 3d model for free over on my Patreon page. https://www.patreon.com/c/MacGarvins As an Amazon affiliate I earn from qualifying purchases, links below help support the channel at no extra cost to you! Products used in this video Creality 3d printer https://amzn.to/4fZ3yP3 Creality pla https://amzn.to/4hhKMER Vevor 12kg furnace https://amzn.to/4fByzIF Rigidizer for ceramic wool https://amzn.to/4wlkoys Satanite refractory coating https://amzn.to/4hznIRY Ingot molds https://amzn.to/4gUS1Ta Aluminized gloves https://amzn.to/4wf0jtG Makeup Brush https://amzn.to/46DkF4N Talc Powder https://amzn.to/4dpYbYI Shars Dovetail cutter https://amzn.to/4wZJOBR Speed Tiger endmill https://amzn.to/4wkb5Pk Cobalt drill bits https://amzn.to/4ftZQwz Key Steps & Process 1. CAD Design & Mold Preparation Contraction & Draft Angles: The CAD model accounts for thermal contraction as the aluminum cools, along with draft angles on vertical faces so the pattern pulls cleanly from the green sand mold without collapsing the walls. 2. Melting & Casting Material Selection: Previously cast scrap was used for the melt, to give us the best shot at success. Casting Failures & Success: My first attempt failed because I got excited, and forgot to cut a feeder into the mold, keeping the mold from filling and spilling molten aluminum all over the driveway. My second try was more successful , I had a partial failure due to a blocked flow and pulled the part to early, which caused a defect near the riser. But when life hands you lemons, you make lemonade. 3. Machining We put our lemon through its paces on the milling machine and come out with a precise fit on the lathe tool post, achieving a tight, slop-free sliding fit. Boring & Tapping: Holes are drilled and tapped directly into the aluminum block for a 3/4-inch steel boring bar, height adjustment, and clamping set screws. Testing Results Light Cut (0.010" depth in steel): Performed effortlessly with a clean surface finish and minimal vibration. Medium Cut: (0.025) It handled the load smoothly without chattering, but was starting to squeal. Heavy Stress Test (0.060" depth in steel): Too much flex and chatter occurred to be useful at this cut depth, but the holder did not crack, the dovetail did not slip, and the tapped threads held tight. I also noticed later that I chipped the insert, probably from the tip dropping too much below center while cutting. Raising the tool above center a little bit may allow for better cutting performance in the future. Final Verdict While cast aluminum is generally too soft for heavy, long-term industrial use, it works remarkably well for light to medium home-shop tasks or non-ferrous materials—provided you avoid overly aggressive depths of cut. I think this design has some promise, if it was cast in Bronze or Cast Iron. I'm particularly intrigued with Cast Iron as it has great dampening properties and might make for smoother cuts with the boring bar. #backyardmetalcasting #foundry #machining #macgyver