Mandrels

[dogcatcher]

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.

 

[mitch]

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.

 

[monk]

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.

 

[LVVP]

Cool, thank you for sharing

 

[John P. Anderson]

Excellent post.