Twist-N-Lock NASA Handrail Clamp

grabcad

Update: 2/16/2015Twist-n-lock V6 support removal and testinghttp://youtu.be/zCld-aTrJ58------------------------------------------------------------------------------------------UPDATE: 2/15/2015My 3D printer has been print around the clock for the last week. Five Designs Later I have my final product! Twist-N-Lock V6 is:1) Easy to print2) Uses only 38 grams of ABS including support ( $59.28 cost to print on ISS)3) Self interlocks into one. No loose part floating in space)4) Reduced assembly to only two parts.5) Has two mounting locations for the T-Stud6) Provides an excellent holding force7) Holding force is adjustable with buttress screw design8) Easy to Slide on and off the Hand railCheck out my video going through all the designs from prototype to final product.http://youtu.be/FjpqPpqYXrcHere is what I have discovered in my design adventure:1) Printing thread in the Z direction is not that strong. Delaminate will occur between layers when screwing for is applied. Try printing threads in the XY plane for more strength and turn support on. 2) Avoid Applying moment stress on Screws. Once a crack propagates, it is all over.3) Stay away from infill. Instead of using infill increase shells to 10 or more. Think of shells as fibers and the more continues fiber you have the stronger the part is.4) K.I.S.S the design. Reduce the parts to the least amount possible. The more joints there are the more places it can fail. Stay away from small detailed parts. Easy to lose and easier to break.5) Built in features. Design features into the parts. Leave the manufacturing hand book in the car. If you can think it you can print it.6) Offset amounts for threads. I used 0.4mm offset for the threads and it turned out perfect. -----------------------------------------------------------------------------------UPDATE: 2/1/2015Videos of Twist-N-Lock V4 working http://youtu.be/Zyusg498S9Uhttp://youtu.be/DggLg6JFZEcJonathan on the forum pointed out my design extended past the 1" perimeter offset rules. With this information I redesigned the assembly with a small thread going from 20mm to 16mm Dia. Happy to report the new design had a better holding strength than V3 and uses 30% less material. The Lever has also been extended from 40mm to 50mm for better mechanical advantage. Side Note: It is possible now to print all the parts on one build tray (X: 50.15mm, Y: 66.95mm, Z: 51.51mm)Print Setting Suggestions:0.2mm Layer height90% Infill @ 45 DegreeThick Wall setting ( 3 Outer perimeter shells)Normal Print SpeedEstimated Time 04h : 28m : 57sEstimated 1.75mm abs used 18.458m (101,478 mm^3)Total mass 105g (Density of ABS: 0.00104 g/mm^3) Projected Cost to build in Space based on Falcon rocket : $163.8 ($1.56 per gram) --------------------------------------------------------------------------------------Update: 1/30/2015Design review on the Twist-N-Lock V3 3d model video:https://www.youtube.com/watch?v=_9wzYq3TM_U-----------------------------------------------------------------------------------The Twist-N-Lock Clamp is a simple design based using mechanical advantage with a Buttress thread pattern. ( http://en.wikipedia.org/wiki/Buttress_thread)My main design criteria:1) Must be able to be printed on a fused filament 3D printer2) Reduce the total amount of parts3) No small delicate parts that can break4) No support material required5) No post processing 6) Easy and simple operation 7) Reliable clamp every time