A swirler for a combustor of a gas turbine engine includes a swirler outer body with a swirler threaded section defined around a swirler central longitudinal axis. A bulkhead support shell for a combustor of a gas turbine engine includes a swirler boss with a boss threaded section defined around a swirler central longitudinal axis. A combustor of a gas turbine engine includes a bulkhead support shell with a swirler boss. The combustor also includes a swirler mountable to the swirler boss at a threaded interface defined around a swirler central longitudinal axis.