What's the threading on the fuel inlet fitting ?
- Thread starter christian
- Start date
Joe K
Well-known member
Also keep in mind that the threaded portion is "short" inside the boss of the carburetor.
Most hardware store taps you buy are "plug" taps.
But taps are available in three different graduations of "taper."
"Taper" taps gradually cut the threads from one end of the tap to the other. Each tooth takes a gradual bite beyond the tooth that preceded it. Taper taps are used on difficult to tap materials that tend to clog the tap or present other problems in tapping.
"Plug" taps are the commonly found version like at the hardware store. The taper portion of these amounts to about four threads at the leading edge of the tap. The remainder of the tap is "full size" and serves only to guide the front four turns where all the cutting occurs.
"Bottoming" taps may be the one you choose to use. These taps are straight full size teeth nearly the length of the tap and only the first tooth or two actually do the cutting. A bottoming tap serves after tapping with either taper or plug taps to bring the tapped thread nearly to the bottom of a threaded hole.
Larger machine tool houses such as MSC or even Enco or McMaster will have higher grade taps in bottoming configuration. They may even be a bit more expensive, this being the result of lesser market demand/production or limited sourcing.
You can convert a plug tap to be a bottoming tap by using a thin grinding wheel and cutting off the first third or so of the tap where the taper teeth are. Or at least good enough to do what you have in mind.
Hope this helps. DON'T cut into the ferrule seating surface at the bottom of your compression bushing tapped hole. A small 90 degree countersink that will fit to the bottom of the tapped hole can be used to "clean up" the ferrule seating surface if it seems defective.
Joe K
Most hardware store taps you buy are "plug" taps.
But taps are available in three different graduations of "taper."
"Taper" taps gradually cut the threads from one end of the tap to the other. Each tooth takes a gradual bite beyond the tooth that preceded it. Taper taps are used on difficult to tap materials that tend to clog the tap or present other problems in tapping.
"Plug" taps are the commonly found version like at the hardware store. The taper portion of these amounts to about four threads at the leading edge of the tap. The remainder of the tap is "full size" and serves only to guide the front four turns where all the cutting occurs.
"Bottoming" taps may be the one you choose to use. These taps are straight full size teeth nearly the length of the tap and only the first tooth or two actually do the cutting. A bottoming tap serves after tapping with either taper or plug taps to bring the tapped thread nearly to the bottom of a threaded hole.
Larger machine tool houses such as MSC or even Enco or McMaster will have higher grade taps in bottoming configuration. They may even be a bit more expensive, this being the result of lesser market demand/production or limited sourcing.
You can convert a plug tap to be a bottoming tap by using a thin grinding wheel and cutting off the first third or so of the tap where the taper teeth are. Or at least good enough to do what you have in mind.
Hope this helps. DON'T cut into the ferrule seating surface at the bottom of your compression bushing tapped hole. A small 90 degree countersink that will fit to the bottom of the tapped hole can be used to "clean up" the ferrule seating surface if it seems defective.
Joe K
christian
Senior Member
BILL WILLIAMSON
Well-known member
Most tap & die sets, even cheep ones, come with a thread gauge, very handy if your eyesite is still good. Bill W.
Bruce Lancaster
Member Emeritus
Remember that the actual sealing is between the ball ferrule on the line and the surface at the bottom of the hole in the carb/surface at bottom of the line nut. The threads serve only to press the sealing surfaces together.
mot
Registered User
when ever you use a tap and die , you actually cut into the metal making a loose fit
the proper tool is a rethreading tap and die set
it just cuts whats buggered up and does not make the threads oversize
they are not for cutting new threads ,just for cleaning up bad threads
snap on ,sears and others make them in various sizes
this is the large snap on set ,I also have two small sears craftmen sets
tom
the proper tool is a rethreading tap and die set
it just cuts whats buggered up and does not make the threads oversize
they are not for cutting new threads ,just for cleaning up bad threads
snap on ,sears and others make them in various sizes
this is the large snap on set ,I also have two small sears craftmen sets
tom
