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1/2" Drive Speed Brace
- 1 1/2" Drive Speed Brace / Speed Wrench
- 2 Abstract
- 3 Bill of Materials
- 4 Tools needed for fabrication of the OSAT
- 5 Skills and Knowledge Necessary to Make the OSAT
- 6 Technical Specifications and Assembly Instructions
- 7 Cost savings
- 8 References
1/2" Drive Speed Brace / Speed Wrench
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
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 ($)|
All STL files as well as source files can be found at youmagine.com 
Tools needed for fabrication of the OSAT
- MOST Delta RepRap or similar RepRap 3-D printer
- Hobby knife for print cleanup
Skills and Knowledge Necessary to Make the OSAT
Technical Specifications and Assembly Instructions
Recommended Print Settings
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
- Clean all mating edges with a hobby knife. Be careful not to take too much off.
- Test fit parts while prepping the matting edges.
- If parts get stuck together use a 1/2" wrench and hammer to separate them.
- Parts should fit snugly together so that small taps with a hammer will seat the parts together.
- Approximate Assembly Time: 30 Minutes
- After all parts are prepped lay them out as in the figure to the right.
- (Optional) Apply JB Weld or similar two part epoxy to all joints.
- Make sure the fat end of the handle is away from the drive end.
- Seat all parts with a hammer.
Common Problems and Solutions
- 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.
A 1/2" drive speed brace can be purchased for $41.08 from 
Savings in Dollars
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
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
- The following website was used to obtain dimensions for the 1/2" socket drive .