Thrash drumming is fast, aggressive, and structurally simple — Slayer, Metallica, Megadeth, Anthrax, Exodus, Testament. The vocabulary is small. The execution is brutal. A typical thrash verse runs ♩=160–200 with the right foot grinding 8th-note double bass, the right hand on hat or ride bell, and the left hand snapping the snare on 2 and 4. The genre's ear is for density: the more notes per bar without losing the backbeat, the more thrash it sounds.
Lombardo built this template with Slayer between 1985 and 1990. Ulrich modified it for Metallica's longer-form material. Today it's the foundation under any band that puts "metal" in their genre tag without further qualifier. Get these four patterns into your hands and you can play a hundred thrash songs from instruments unknown.
Exercises
The basic thrash template: hat on every 8th, snare on 2 and 4, double-bass 8ths underneath (RLRL × 2). The hand and one foot fire on every 8th — this is constant percussion, no breathing room. ♩=160 is the entry tempo; Slayer's Reign in Blood sits closer to ♩=200, but at this speed the pattern is hard enough to be useful.
The right hand moves to the ride bell. Accents on every quarter — beat 1, 2, 3, 4 — produce the bright, ringing pulse Lars puts under Metallica's chorus sections. The off-beat 8ths are softer ride-body strokes (no accent). Snare on 2 and 4. Double-bass 8ths under everything. This is the signature thrash chorus voice: bell on the quarters, body in between.
Accent the bell on 1 and 3 only — beats 2 and 4 already have the snare and don't need the bell shouting over it. That odd-beat bell / even-beat snare alternation is what makes a chorus read as a chorus while the 8th-note kicks keep the floor.
Each beat is boom · boom-boom — an 8th plus two 16ths, feet sticking R · L-R (or R · R-L if your lead foot prefers). The whole gallop lives in one measurement: the gap between the 8th and the first 16th must exactly match the gap between the two 16ths.