Mine is bolted onto a folding sawhorse. The sawhorse has locking bars to keep it solid. I put the rear locking bar through a concrete block so the whole rig can't tip forward. When I first used, it, without the block, a K&B 4011 tipped it forward toward my crotch. Fortunately, I got it under control without bloodshed. I put the block on before running another engine.