boring bar

This post is about making some very rigid holders for indexable inserts for use with Criterion style boring heads. This is a Criterion boring head with a typical set of low cost sweated carbide boring bars. A genuine Criterion like this comes in at around US $5/600 for a 2" version, but...

I made my first serious attempt at boring last week on a supremely under-powered and insufficiently rigid lathe. It took ~4 hours (yes, hours of listening to a belt slipping) to bore out a ~1.75" ID / 1" depth in 1018 (and I over ran my tolerance, so I get to make it again...). I started the...