Wanted: Tap for 7/8-20 heli-coil

[MrPontiac]

Please if anybody has one for sale let me know.rbudney@comcast.net

[lcaswell]

Like this? - British Tools & Fasteners: TAP BSC 7/8 x 20 B

[CarWiz]

You'll need an STI (Standard Threaded Insert) tap. These are different than standard taps as the actual cut size is larger than normal to accept the insert. (As is the tap-drill size.) The inside thread of insert would then be the called size. Good luck on finding that size though. What's it for? Are you sure it's not metric 22x1.25mm? Even that's not standard.

Note: The tap will be stamped "STI". If it isn't, it's not for inserts.

[MrPontiac]

Just for a project im working on, funny, i can buy the inserts but i cannot just buy the tap& drill to install them unless i buy a complete kit with drill bit and reamer!! Cannot afford all that. I cannot even aquire info on what size i need!

[MrPontiac]

Tryed a 56/64 drill bit and installed the heli coil and it was to loose but im close to the size.

[MrPontiac]

ok, seems like the 55/64 drill bit is a little to big so im moving down to a 29/32,s, heli coil go,s in but the fitting is just a tad loose!! Im gaining on it.Now i am using a 1 inch 20 tap but i think it will work but afraid its not exactly right.

[MrPontiac]

Had a tap made out of california, workd perfect, Im being told to drill carb. body out to 57/64 so far so good!! 128.00$ for the tap!! ouch!!