Drilling Lots of Holes in PVC Pipe

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lesrhorer

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I have to drill over 2000 holes, each 9/16" diameter, in 3/4" thin wall (class 200) PVC pipes. The pipes are a standard 1.050" OD. The best bit I have found for drilling moderately sized holes in PVC is a so-called step-bit, also known as a cone bit or a uni-bit. I don't have any that happen to have a 9/16" bore as the largest size, so drilling all the way through the pipes is not an option using these bits. I could easily machine a stop collar to prevent the drill from penetrating too deeply, but the main issue is using any bit that cannot be used to drill both sides of the pipe to the correct dimension will require boring one set of holes to depth, turning the pipe over, and drilling the other side, effectively requiring me to drill more than 4000 holes. Using a regular 9/16", 135 degree S&D bit will probably not yield good results, even if I drill a smaller pilot hole, plus then I am back to drilling 4000 holes, again.

I suppose I could partially sacrifice a step bit by hand grinding off all the lands larger than 9/16" by hand. In fact, I guess that is what I will do, unless someone here has a better idea.
 
There won’t be much pipe left! Definitely modify that step bit and extend the shank while you’re at it.
 
There will be plenty of pipe left. I have done it with 1/2" PVC, and there is plenty of pipe left, even then. Why would I need to extend the shaft? The bit can easily drill all the way through with the existing shaft.
 
Can you sharpen a normal 9/16"? Give it a sharp tip angle so it won't 'bite' on breakthrough and it'll drill about as fast as you can push the bit.

GsT
 
lesrhorer said:
There will be plenty of pipe left. I have done it with 1/2" PVC, and there is plenty of pipe left, even then. Why would I need to extend the shaft? The bit can easily drill all the way through with the existing shaft.
Click to expand...
I didn’t realize it was long enough!
 
lesrhorer said:
I have to drill over 2000 holes, each 9/16" diameter, in 3/4" thin wall (class 200) PVC pipes. The pipes are a standard 1.050" OD. The best bit I have found for drilling moderately sized holes in PVC is a so-called step-bit, also known as a cone bit or a uni-bit. I don't have any that happen to have a 9/16" bore as the largest size, so drilling all the way through the pipes is not an option using these bits. I could easily machine a stop collar to prevent the drill from penetrating too deeply, but the main issue is using any bit that cannot be used to drill both sides of the pipe to the correct dimension will require boring one set of holes to depth, turning the pipe over, and drilling the other side, effectively requiring me to drill more than 4000 holes. Using a regular 9/16", 135 degree S&D bit will probably not yield good results, even if I drill a smaller pilot hole, plus then I am back to drilling 4000 holes, again.

I suppose I could partially sacrifice a step bit by hand grinding off all the lands larger than 9/16" by hand. In fact, I guess that is what I will do, unless someone here has a better idea.
Click to expand...

I had to install 100s of top hat grommets into a pvc supply line, I used regular twist drill with a stop collar and held the pipe in the vise. I only drilled one side of the pipe but I could have increased the depth and drilled right thru.

I used a straight edge and small vise grips clamped to the end of the pipe as an anti-rotation devise. As I moved the pipe 6" to drill another hole the vise grips rode along the straight edge so all holes remained vertically aligned.

I second the thought of custom grinding the tip of the drill bit to ease the start of the holes
 
Okay, I'll ask... What is the purpose of all these holes?
 
If you decide to go with a a step drill, you grind off the diameter above 9/16" That way you have the 9/16" as the largest hole and can then go through the other side. I made a jig for my wife's work that way. They also drilled ABS and got several years out of it. Went to Harbor Freight, got another $10 drill and did the same.
 
Have you considered a 9/16" pilot point drill bit. Sometimes referred to as a brad point bit. They are commonly used by aircraft manufacturers. I don't have the 9/16" size, but I do have several smaller sizes. my 1/4" size has a pilot point, then a small section that's 1/8" in diameter, the the remaining is 1/4"
 
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