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That is a different way to drill those tiny brass allen set screws. I use a small drill with a drill bit adapter I got from Mcmaster and I hold the brass set screw with a set of needle pliers with tape on the pliers to not mark and ruing the threads on the set screw and gently drill them out. I will have to try your method. Thanks for sharing.
 

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Discussion Starter · #5 ·
That is a different way to drill those tiny brass allen set screws. I use a small drill with a drill bit adapter I got from Mcmaster and I hold the brass set screw with a set of needle pliers with tape on the pliers to not mark and ruing the threads on the set screw and gently drill them out. I will have to try your method. Thanks for sharing.
That's how I was told to do it back when i got into drilling bleeds, think it was Jmark or Tuner. I also have one of those small bit adapters that I got/use for custom squirters but it's a lot easier to break a tiny drill bit that way.
 

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Mark Goulette
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My two King Demon RS carbs are home built, going off Jmark's advice. Carbs were easy to tune and ran great. To drill air bleeds, I got a threaded block from BG (was old stock at a performance parts store), screw them in and use a pin vise to drill them. Takes a few min but works perfectly, and reduces the risk of breaking the small bits....
 

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Race it, Don't rice it!
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The most accurate and repeatable way of doing this is to secure the bleed in a fixture such as an old metering block, purpose built index block, or even a tube with threaded ends for fixturing. Drill on a mill, to within .005 of the final ID and ream to within .0005, debur, and wet flow check. After a production run, all flow matched sets are labeled and sorted. If needed the entry radius is cut to change the flow numbers and again, matched sets are sorted. This is how the top tier professionals are doing it manually, if they havent incorperated CNC yet to hold toleraces of .0002, even then, the parts must be flow checked as tool wear will have to be compensated for.
Coming from Holley and the like, their QC isnt as good so one set is with a range and another set is also in a range and the two ranges can overlap. That means you buy a set of bleeds or jets and if you go one number, there a chance you haven't actually changed flow characteristics at all. It important to stick to the brand name of the builder when experimenting because how they do things effects how you do things.
 
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