A US provisional needs no claims. Why drafting some anyway helps, and why what the description supports matters more than the claims themselves.
A provisional application does not need claims (35 U.S.C. 111(b)(2)). It is never examined, so nothing in it is allowed or rejected.
A later claim gets the provisional's filing date only if the provisional describes and enables what that claim covers (35 U.S.C. 119(e)(1), which applies the requirements of 112(a); see New Railhead Mfg. v. Vermeer Mfg., Fed. Cir. 2002). The description is what counts, not the claims.
A draft claim set is a checklist. Each element of each claim names something the description must explain well enough for a skilled person to make and use it. If you cannot point to the paragraph that supports an element, the provisional does not yet protect it.
That is what iPatent's support map does: it matches every claim element to the numbered paragraph that shares its terms, and flags any element, or any number in a claim, that the description never supports. See it catch an invented torque range and material.
Describe the general idea and every variant you may later want to claim: other materials, ranges, configurations and orders of steps. A variant that is not described cannot be added later with the original date.
Draft a disclosure, freeSee a real run