Big Bore – No Problem
The unique bi-lateral expansion of Watt-Flex cartridge heaters
eliminates the need for tight fits and makes them well-suited for
use in oversized bores where conventional cartridge heaters
cannot be used effectively – especially after heaters were drilled
out.
Cartridge heater fit is measured as the difference between the
inside bore diameter (I.D.) and the outside dimension (O.D.) of
the heater. The suggested fit for a Watt-Flex Cartridge Heater is
0.010″ greater than the nominal heater diameter.
For example, the ideal bore diameter for a 1/2″ diameter Watt-Flex
heater (0.495” nominal) would be (0.502” to 0.505″).
At the maximum tolerance dimension of the heater (0.497”) and the
minimum bore diameter (0.502), the heater would have a 0.005″ fit,
allowing easy insertion and removal.
Generally, smaller diameter heaters benefit from a tighter fit and fit
can be loosened for larger diameters and as length increases.