Speed Brace Print Finished.jpg

This project stems from the OXFAM equipment catalog and attempts to make a 3D printed version of a speed brace. The purpose of this tool is to quickly remove fasteners after they have been broken loose using a breaker bar or ratchet. This tool is meant to be used with 1/2" drive sockets.

Bill of Materials[edit | edit source]

Here is a bill of materials. Costs are based on a $20.00 / Kg of PLA filament price:

Quantity Part Name Material (grams) Cost ($) Total ($)
2 Corner Joined 57.00 1.14 2.28
1 Coupling 21.00 0.42 0.42
1 Coupling Handle 14.00 0.28 0.28
1 Drive 11.00 0.22 0.22
1 Handle 31.00 0.62 0.62
1 Handle End 59.00 1.18 1.18
1 Key Long 4.00 0.08 0.08
1 Key Short 2.00 0.04 0.04
Total Cost $5.12

All STL files as well as source files can be found at youmagine.com [1]

Tools needed[edit | edit source]

Skills and knowledge needed[edit | edit source]

Technical Specifications and Assembly Instructions[edit | edit source]

Recommended Print Settings[edit | edit source]

All STL files are orientated for printing. Print all objects according to the quantities listed in the BOM (Two "Joined_Corner" pieces are required).

  • Layer Height: 0.25 mm
  • Infill: 100%
  • Support Material: None
  • Shell Thickness: 2 lines
  • Print Temp: 210 Degrees Celcius
  • Print Time: Approx. 10 Hours

Part Preparation[edit | edit source]

  1. Clean all mating edges with a hobby knife. Be careful not to take too much off.
  2. Test fit parts while prepping the matting edges.
  3. If parts get stuck together use a 1/2" wrench and hammer to separate them.
  4. Parts should fit snugly together so that small taps with a hammer will seat the parts together.

Assembly[edit | edit source]

Speed Brace Assembly.png
  1. Approximate Assembly Time: 30 Minutes
  2. After all parts are prepped lay them out as in the figure to the right.
  3. (Optional) Apply JB Weld or similar two part epoxy to all joints.
  4. Make sure the fat end of the handle is away from the drive end.
  5. Seat all parts with a hammer.

Common Problems and Solutions[edit | edit source]

  • If 100% Infill does not provide enough strength there are a few options.
    • Epoxy all joints
    • Try an alternate print material
    • Future consideration: may redesign with an overall larger cross section area.

Cost savings[edit | edit source]

Commercial Equivalent[edit | edit source]

A 1/2" drive speed brace can be purchased for $41.08 from [2]

Savings in Dollars[edit | edit source]

Given the print cost of $5.12 shown in the BOM and the cost of the commercial equivalent being $41.08, the savings are $41.08 - $5.12 = $35.96 Savings

Savings in Percent[edit | edit source]

Given the dollar savings of $35.96 calculated above and the cost of the commercial equivalent being $41.08, the percentage savings are ($35.96 / $41.08) *100 = 87.54 % Savings

References[edit | edit source]

The following website was used to obtain dimensions for the 1/2" socket drive: Engineers Edge - Standard Square Drives for Socket Tools, ASA B5.38 (1958) Available: http://www.engineersedge.com/hardware/square-drive-tools.htm

Discussion[View | Edit]

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