Thread sizes

KREW2

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I am just about to fit a Delphi 296 cav filter to a club boat. The ports for the hose tails are 1/2 inch UNF I have mistakenly bought 1/2 inch BSP hose tails. Will 1/4 inch BSP fit into the UNF thread.
Thanks in advance
 
Thanks, just googled it and found someone who has stock.
Don’t think they are unF but an American pipe size
trying to remember but will need to dredge memory
They are also available in metric

BSP can be forced in but it’s not a safe practice and just causes problems sooner than later
 
Don’t think they are unF but an American pipe size
trying to remember but will need to dredge memory
They are also available in metric

BSP can be forced in but it’s not a safe practice and just causes problems sooner than later

They are 1/2" UNF or M14
 
Thanks, sorted now, and Google only showed up one supplier gael force marine and they only had one in stock, found loads with BSP threads but wasn't sure if they would fit. Tried a few different searches and found the right ones.
 
Thanks, sorted now, and Google only showed up one supplier gael force marine and they only had one in stock, found loads with BSP threads but wasn't sure if they would fit. Tried a few different searches and found the right ones.
BSP ( and NPT ) are miles bigger than UNF ( and a coarse thread )

Pipe thread sizes are based on the nominal bore of iron pipe That means that 1/2" BSP and NPT are in fact 0.825" OD whereas 1/2" UNF is 0.5"

As already said NPT and BSP can sometimes be made to fit each other. The pitch is the same from 1/2" upwards but the thread form is different ( 60° vs 55° )

Ask Santa for a copy of Zeus thread tables
 
For the cost of the fittings and copper washer or dowry seals you might as well buy the Chinese Katsu filter units complete with all the fittings. See Ebay.
 
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