Sinews of Steel is a 1927 American silent drama film directed by Frank O'Connor.
| Actor | Role |
|---|---|
 Alberta VaughnHelen Blake | Helen Blake |
 Gaston GlassRobert McNeil Jr. | Robert McNeil Jr. |
 Anders RandolfRobert McNeil Sr. | Robert McNeil Sr. |
 Paul WeigelJan Van Der Vetter | Jan Van Der Vetter |
| GGreta von RueElsie Graham | Elsie Graham |
| NNora HaydenMartha Jenkins | Martha Jenkins |
| CCharles WellesleyDouglas Graham | Douglas Graham |
| JJohn H. GardenerElmer Price | Elmer Price |
 Robert GordonThe Office Boy | The Office Boy |