home depot boost controller question

[dj_jake]

i made a home depot boost controller identical to the famous one here
http://www.geocities.com/chmwatson/FAQs/mbc.html

except i have one problem. step 1-4 describe how to make that "cap assembly" however, when i saw that coupling in half, the bolt i bought (exact one specified), the bolt doesnt fit through. the hole is just too small. i tried enlaring it slightly, using like a 20 diff bits from my old man's work, i would go like this...
bigger... bigger... bigger... bigger.. damn bolt, still doesnt fit through... bigger... damn, too big! bolt just slides through now

am i using the wrong coupling or something? did i mess something up? ideas plz

 

[The_Oat]

I think i had the same problem. I think i saw 2 of those caps that you need to tap in order to fit the bolt into and they had different amounts of brass even though they were still both 1/4"size. Anyways, what i ended up doing was using a thricker bolt (3/8" i believe), then i tapped the cap to match the bolt size. We tested it in my friends Gst and it held 18.7psi fine.

 

[MikesDSM]

im sorry but that does look like a challenge. im sure u can cough up $50 for a joe p. or even cheaper from ebay or used

 

[RoasT BeeF]

What are you talking about?

Are you trying to drill the hole bigger after you cut it in half? You arent supposed to drill anything. All you do is cut it inhalf and tap it and the bolt should screw right in. Mine did.

 

[dj_jake]

how do i tap it?

 

[BUCK]

3. Since the hole thru the fitting is already slightly over .257" (required taps size for a 5/16-18UNC thread) drilling to the correct size to tap is not necessary. Tap the Cap all the way thru. Make sure the hole is tapped straight (concentric to the hole)

http://www.geocities.com/chmwatson/FAQs/mbc/images/tapcoupling.jpg

 

[TURFNNSURF]

Go back to Home Depot or LOWES and make sure you have ALL the tools from the VFAQ

the tools:
drill
1/32" drill bit (to drill vent hole in plastic straight thru coupling)
5/16"-18 UNC tap
hack saw
teflon tape

When you buy the Tap it will come with the proper size drill bit to use to prepare the brass fitting for threading with the tap..