Talk:GrabCAD Backhoe Redesign for Fabrication

teeth

should we incorporate teeth into the bucket design? http://www.asbucketsteeth.com/ --Dorkmo 06:26, 9 September 2012 (CEST)

--- general redesign for easier fabrication questionable ---- Why?

1. Use of square tube 4x4x1/2" Is this commercially available? Doubtful. McMaster Carr supplies only 4x4 with maximum thickness of wall = 0.250" Nearest metric equivalent to 4x4x1/2" would be 100x100x12 mm. Did a quick search in catalogues/websites of leading German steel suppliers: 100x100 square tubes are only available with walls up to 8mm thick.

So what if you can't buy that stuff?

2. Strength of redesign Obviously the crabcad design is stronger than this redesign, just because the crabcad's has much larger crossections there where highest forces occur. Equal cross sections everywhere means either too much material everywhere except a few high tension areas or too weak design that will fail soon !

3. Drilled holes Bad idea to drill (unnecessary) holes in a part like this. Under high dynamic loads that are typical for an excavator, the boom will crack early at one of this points with an adjacent hole.

This redesign was wanted by Marcin; nevertheless this makes the backhoe unuseable and also impossible to build because You won't get Your hands on the raw materials. {Bastelmike Oct 30, 2013}