Making a Difference Engine with Difference Manufacturing

For those following along, we are cutting scaled up pieces of Babbage’s difference engine from a digitized copy of his actual drawings. When assembled, the pieces will be hung from the ceiling above the front desk. We’d cut a prototype in coroplast and took it over to check the fit. We are ready to cut the actual parts.

The best material for this project would be 3/4” sign foam. It is light and holds a nice edge, but it is expensive. A trip to Roddis Lumber got us the next best stuff. We went with full sheets of 3/4” 4C Meranti Epicor plywood which has nice plywood veneer layers sandwiched over a lighter weight core.

We already have the vectors for the parts ready. After some work in Aspire, we generated the toolpaths to cut our pieces. Symmetry in the design means many parts are duplicates. These parts are effectively gears so we could skip adding pockets to index alignment and just use the opening where the shaft would be.

Odd Sector Parts

Even Sector Parts

Figure Wheel