# #7 drill bit . . .



## Kevin (May 18, 2015)

Can I get away with using a 13/64 drill bit instead of a #7 for a 1/4" x 20 tap . . . . into PVC? I've already done it and I know the 13/64 is a hair bigger but it seems snug. I just don't know about vibration and long term use though in PVC. Anyone done it?


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## Brink (May 18, 2015)

You're tapping pvc?


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## Kevin (May 18, 2015)

That's what I said.


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## Brink (May 18, 2015)

What feels snug? The tap in 13/64 hole?


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## Schroedc (May 18, 2015)

My tap chart actually list both bits as acceptable for 1/4-20

Reactions: Thank You! 1


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## Kevin (May 18, 2015)

No the modified carriage bolt seems snug but it's in PVC so I don't know what to expect after lots of use and vibration. Was just wondering if anyone has ever tapped PVC and threaded a carriage bolt into it. Won't see much torsion just lots of low grade vibration.


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## SENC (May 18, 2015)

2 thousandths of an inch difference? I haven't done it and don't know you're application nor utility, but suspect you'll still have plenty of thread.

Reactions: Thank You! 1


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## Brink (May 18, 2015)

When tapping plastics, the hole deflects slightly as the cutting flutes come around. You probably feel the tap dragging as it comes out. Metal doesn't deflect (or very little) so the flutes will cut the threads more fully. 

So, when you thread the bolt in, it feels tight.

Reactions: Agree 1 | Informative 1


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## robert flynt (May 18, 2015)

Heck, just wrap some teflon tape around the threads of the fitting or use some leak lock and your good to go.


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## Brink (May 18, 2015)

Is this a fitting, or a bolt?

Supposed to be leak proof?


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## Kevin (May 18, 2015)

I think I got it figured out. Not trying to be secretive just another one of my hair-brained ideas. I figured it out when the dogs took me for a walk. They always set me straight.

Reactions: Like 1


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## Schroedc (May 18, 2015)

I think he's making a lightweight whacking stick out of PVC and when he says "Modified carriage bolt" he means "sharpened to a point to inflict ouchies"

Reactions: Funny 1 | Creative 1


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