Reddit reviews Micro 100 QRR-039-16X Quick Change Retaining Ring Grooving Tool, Solid Carbide Tool, 0.039" (1.00 mm) Groove Width, 0.100" (2.54 mm) Projection, 0.370" (9.4 mm) Minimum Bore Diameter, 1.000" (25.4 mm) Maximum Bore Depth, 0.3750" (9.5 mm) Shank Diameter, 2.5" (64 mm) Overall Length
We found 1 Reddit comments about Micro 100 QRR-039-16X Quick Change Retaining Ring Grooving Tool, Solid Carbide Tool, 0.039" (1.00 mm) Groove Width, 0.100" (2.54 mm) Projection, 0.370" (9.4 mm) Minimum Bore Diameter, 1.000" (25.4 mm) Maximum Bore Depth, 0.3750" (9.5 mm) Shank Diameter, 2.5" (64 mm) Overall Length. Here are the top ones, ranked by their Reddit score.
Retaining Ring Groove ToolsQuick Change Tooling - Micro-QuickMade in USACoated AlTiN for extended tool life
Sounds like you're looking for an internal retaining ring (or O-ring) grooving tool. These have carbide cutting edges, and come in different profiles so you can cut the proper shaped groove for your O-ring or retaining ring, e.g., square shaped slot, v-shaped, half-round, etc. Try a Google search for "internal retaining ring grooving tool" and you'll find enough to help you get started finding what you need. Here's a link to one on Amazon as a start:
https://www.amazon.com/Micro-100-QRR-039-16X-Retaining-Projection/dp/B00Q8NR718/ref=sr_1_12?gclid=CjwKCAjwk7rmBRAaEiwAhDGhxBH-hio7eC3-DCH1OsZ3_IEoA2OA8NjA8M-hxPeznLraCYKp8uteNRoCcCQQAvD_BwE&hvadid=323144562441&hvdev=c&hvlocphy=9003944&hvnetw=g&hvpos=1o2&hvqmt=b&hvrand=13326339003767944250&hvtargid=aud-676677759484%3Akwd-527024404990&hydadcr=28602_10166550&keywords=retaining+ring+grooving+tool&qid=1557111657&s=industrial&sr=1-12