Mandrels

Awhile back someone asked about how to hold a bangle for engraving. Here is my version of a mandrel to hold bands for duck calls. The bands are nothing more than small bangles.

These are some of the mandrel designs I use to hold the duck call bands while I work on them.

A piece of aluminum turned to the correct diameter, then drilled and tapped for a lug bolt. Yes a simple lug bolt, they sell on Amazon 5 for about $7. As you tighten the bolt into the hole the cane shape expands the 4 "fingers" locking the band into place. It is like it is welded in place.





The next one uses a pipe plug, NPT threads, a natural expander. This is made for polishing on the lathe. This one uses a 3/4" pipe plug to expand the "fingers" It turns true when the lathe is under power, making polishing an easy job, slap some Brasso on a gun cleaning patch, Then hitting it with a clean patch. The patches are cheap, and throw away expense item, also very safe around lathes that are spinning a lot safer than a larger rag.

depending on the thickness of the material and how sturdy the 'ring' being engraved, if the ends are square/parallel one can very often get away with no fixture at all. tubes are extremely strong end-to-end and can easily withstand sufficient clamping force for engraving. however, for rings & bands with non-parallel ends and other structural irregularities, good expanding mandrel fixtures like these are indispensable.

interesting stuff you made there. an inspiration to those of us that enjoy "making stuff". thanks for the share. i've experimented with hardwood (oak) for a similar such device with a tapered pipe tap. the first ver. was a fluke. i became busy with other things and never went back to finish what i had started.

Cool, thank you for sharing

Excellent post.