Thread: FNi grinder

Originally Posted by chemfish

Just wondering if anyone has any experience with the FNi variable speed grinder. I've been using some of my chisels for house renovations that has resulted in edges best described as serrated (though I fear this description is like calling the grand canyon a ditch). This means I am looking for an edge restoration process that is faster than spending half an hour on a course diamond stone. My current thoughts are either a FNi variable speed or maybe a vicmarc slow speed grinder. Eventual upgrade path in either case would be to replace the wheels with CBN wheel.

Some things to think about/
Presumably you want the slower speed so as not to overheat the chisels?
The problem with FNi is that it is only 3/4HP to start with and I'm pretty certain it will use a basic speed controller meaning that at slower speeds it will have reduced power. This means it cannot grind as quickly at the slower speeds.
In contrast the slow speed Vicmarc is a full 2HP at 1450 RPM so it can be fully loaded although it costs about 30% more.
8" CBN wheels have which optimised grinding between 1450 and 2850 RPM. CBN usually grinds cool enough at the higher Rpm which is also the fastest grinding.
OTOH speed is not all its made out to be as slower grinding allows for better control of the grinding process.