Paper Crimper

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A rotary paper crimper with three different but not easily interchangable crimpers. I only printed full size of the medium crimp bar but they should work based on my small scale test. I printed 100% infill for the shafts and 30% with 3 walls for the remainder of the crimp bar and other parts. You may need to slice off or sand blobs on the edges of the crimp for super smooth results. I designed this to use proper ball bearings but see below for information The bottom is screwed in with 4mm x 20mm machine screws. I used a small sheet metal screw for the crank. There is a similar small hole for a screw to keep the knob on but the fit was tight on my printout so I did not use a scew there. This works well with thin paper. Copy paper is a bight tight. Thicker paper will probably break something. The crank shaft is the most likely source of failure in general but the system works ok just turning with the bar directly. The choice of bearings ultimately dictated the shaft sizes. Bearings with larger bore diameters get quickly expensive. If you know of any common and cheap bearings with 12-25mm bore diameters I'd be willing to rework the design. In the end I used inexpensive 608zz bearings I got on amazon for about $1 each. My local hardware store had similar bearings for about $10 each so they were not a good source. I did not check the local sporting goods store but this size is commonly used in skate board wheels. If you want to make your own bar, the tooth radius is 18.4mm on the medium bar. Shafts are 7.75 mm wide by 8mm on the short end and 23mm (13mm round, 10mm keyed) on the long end. The toothed part of the bar is 175mm.

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