Purpose: This article compares the fit accuracies of the swing lock metallic frameworks constructed with two different double casting techniques. Material and methods: An experimental mandibular acrylic model with the only remaining 6 anterior teeth was constructed. 4 partial metallic frameworks of S/L RPD were constructed using two methods of the double casting technique. For standardization 4 lingual parts of S/LRPD was constructed to be used with the 2 groups. The 2 groups differed in the method of construction of the labial part either with or without reduplication of the master cast. A standard measure scope was used to measure in micrometer the fit of the labial part of each of the S/L RPD metallic framework to the model. The SPSS program was used for data analysis. Shapiro-Wilk test was used to test the normality of the data. Paired samples t-test was used to compare the fit of the two groups. P was significant if < 0.05 at confidence interval 95%. Result: No significant difference was present between the two different methods for double casting technique of S/L RPD where P = 0.062. Conclusion: The two methods for double casting technique results in an accurate casting, but the one without reduplicating the cast saves time. Clinical implication: The double casting technique without reduplicating the cast saves the time.