Torque measuring lever with bearing pivot

prusaprinters

<p>Remix of [A_R_B's]{<a href="/A_R_B">https://www.thingiverse.com/A\_R\_B</a>} torque measuring arm which has a pivot which can be attached to a board. Uses a 6903 30x17x7 cartridge bearing for the pivot. Sized to work with a Park Tools [DS-2]{<a href="https://www.parktool.com/product/tabletop-digital-scale-ds-2">https://www.parktool.com/product/tabletop-digital-scale-ds-2</a>} digital scale which is 26mm high.</p> <p>The plan is to mount the pivot to a board and have the scale to the right with the pointer in the center of the tray. Then a 13mm socket on the hex can be turned to read the breakaway force.</p> <p>Also adjusted the length of the arm slightly - A_R_B's version is 200mm which is based on the conversion 1kgf = 10N. While that's close and more than close enough for the accuracy of this setup, mine is sized to 204.1mm based on 1kgf = 9.8 N. In practice you'll never really see that level of accuracy but I figured since I could, I'd do it anyway.</p> <p>Sized to the 6903 bearing as that's what I had on hand that would clear the 13mm hex. Fusion 360 files included if you've got a different bearing on hand.</p> <h3>Print instructions</h3><h3>Category: Hand Tools Summary</h3> <p>Remix of [A_R_B's]{<a href="/A_R_B">https://www.thingiverse.com/A\_R\_B</a>} torque measuring arm which has a pivot which can be attached to a board. Uses a 6903 30x17x7 cartridge bearing for the pivot. Sized to work with a Park Tools [DS-2]{<a href="https://www.parktool.com/product/tabletop-digital-scale-ds-2">https://www.parktool.com/product/tabletop-digital-scale-ds-2</a>} digital scale which is 26mm high.</p> <p>The plan is to mount the pivot to a board and have the scale to the right with the pointer in the center of the tray. Then a 13mm socket on the hex can be turned to read the breakaway force.</p> <p>Also adjusted the length of the arm slightly - A_R_B's version is 200mm which is based on the conversion 1kgf = 10N. While that's close and more than close enough for the accuracy of this setup, mine is sized to 204.1mm based on 1kgf = 9.8 N. In practice you'll never really see that level of accuracy but I figured since I could, I'd do it anyway.</p> <p>Sized to the 6903 bearing as that's what I had on hand that would clear the 13mm hex. Fusion 360 files included if you've got a different bearing on hand.</p> <h3> Print Settings</h3> <p><strong>Notes:</strong></p> <p>0.2mm layer height is fine, even 0.3mm should give good results. Increase shells to at least 4 or 5, that way infill can stay low. I also upped the top and bottom thickness for the arm to 2mm, and have measured 5Nm with no issues. I did more shells with the bearing holder and realized print time wasn't dramatically increased by upping shells until the part was solid. Probably doesn't need to be that strong but remember it will see the equivalent force indicated on the scale as upward force so needs strength in tension most at the sides of the bearing hole.</p>