Tuckpointing Grinder

The depth guard is the key feature: it lets the grinder cut a joint out to a controlled, consistent depth, deep enough to remove all the failed mortar and give new mortar something solid to bond to, without the blade wandering into the brick faces on either side. Hand tools like a plugging chisel still finish the corners and any header joints too tight for the grinder to reach cleanly.

Using a grinder without a guard, or rushing the cut, is a common way repointing jobs go wrong: it chips brick edges, widens joints past what new mortar can properly fill, and can leave a repaired wall looking worse than the joints it replaced. On older or handmade brick especially, that soft brick edge damages easily, so a controlled grinder pass paired with careful hand work is what keeps a repointing job clean.