What is used to check the fit of the joint before brazing?

Using feeler gauges to check the fit of the joint before brazing is essential because these tools measure the gap between two surfaces with precision. For successful brazing, it is crucial to ensure that the fit of the joint is optimal, as too large a gap may result in inadequate capillary action, preventing the molten filler metal from properly flowing into the joint.

Feeler gauges come in various thicknesses, allowing for the assessment of tightness and uniformity in the joint fit. This checking helps ensure that the surfaces are close enough to allow for effective capillary action during the brazing process, which is crucial for achieving a strong, durable joint.

Other tools, such as calipers, are primarily used for measuring dimensions rather than specifically assessing the fit of a joint. Pressure gauges measure the pressure within a system and screwdrivers are unrelated to joint fitting. Therefore, feeler gauges are the most suitable tool for evaluating the fit before proceeding with brazing.