Drilling Lots of Holes in PVC Pipe

[Bi11Hudson]

A few years (20+, ~1998) back, I had the hots for "Geodesic Dome" construction. Fascinated by the geometry of the triangles, I was using PVC water pipe for struts and 2 inch black sewer pipe for hubs. Schedule 40, Home Depot stuff, nothing exotic. I wanted to drill many 6 point hubs that were not symetrical at 60 degrees, so couldn't be drilled through.

I started with a step drill but that was too slow. I took a piece of rigid conduit, 1/2 inch, and cut it down to a snug fit. With cutting spurs on the end. It was only a couple inches long, I didn't intend to go completely through. With a bell reducer on the threaded end and a stub of 1/8 inch pipe to fit a drill chuck. The "drill" didn't come from HD, I acquired (stole?) a cutoff from the mill. The cutting teeth weren't evenly spaced, cut with a coarse file.

The contraption wasn't hardened, hell it wasn't even a tool grade steel. Just a piece of scrap from a conduit job. But for cutting plastic there wasn't much hardening required. I only made a hundred or so hubs, with 5 or 6 holes per hub, mostly 6. The custom drill held up through to completion of my project as well as a couple for friends. Cheap greenhouses. . . I did have to stop and punch out the slugs on occasion, that was a PITA mostly because I had to stop what I was doing and it broke my rythym.

For thinwall PVC, the pipe will tend to collapse under the pressure from a press. But with a thin wall tubing should hold up pretty well. The up side is that you don't need tool steel, even a copper tube will should hold up for a thousand or better. If the cutting edges were properly machined, it would be sharper, cutting better.

.

 

[whitmore]

Turning the entire hole into chips just makes messy waste; I'd consider a 9/16" hole saw, with appropriate
workholding ( block of wood clamped to the drill press table, bored to guide the pipe) and
maybe a shop vac to suck the swarf.

As long as the hole saw stays cool, the holes will be neat. Yeah, a step bit has
good finish, but it's SLOW going. 2000 holes; slow; unhappiness.

 

[lesrhorer]

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

I could, of course, but 9/16 drill bits are rather expensive, and I only have one. I would rather grind a cheap step bit. I have a few of those.

 

[lesrhorer]

annular cutter?

I thought of that. I'm not sure how well it would work. I wonder if the plastic will deform under the cutting pressure?

 

[lesrhorer]

Okay, I'll ask... What is the purpose of all these holes?

See the big tree on the right hand side of this video? I am replacing it.

 

[lesrhorer]

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.

How big were they? If the holes were less than 1/2", I have some Plasdrill bits. Trying to drill 9/16" holes in thin wall PVC is a little different, I think.

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.

These fit into flag holders, which have a 6mm screw perpendicular to the holes I will be drilling. I am going to drill the 6mm hole, first, and create a clamping jig out of Aluminum to hold the pipes while drilling.

I second the thought of custom grinding the tip of the drill bit to ease the start of the holes

See above.

 

[lesrhorer]

Turning the entire hole into chips just makes messy waste; I'd consider a 9/16" hole saw,

I am not sure that would work very well. First of all, I don't have a 9/16 hole saw, and drilling a round surface that deep? Those saw teeth are pretty aggressive. This is thin wall stuff, and I think it might grab.

with appropriate
workholding ( block of wood clamped to the drill press table, bored to guide the pipe)

I am making a jig out of Aluminum.

and
maybe a shop vac to suck the swarf.

Definitely.

As long as the hole saw stays cool, the holes will be neat. Yeah, a step bit has
good finish, but it's SLOW going. 2000 holes; slow; unhappiness.

In order to keep a hole saw from grabbing, I suspect I would have to feed very slowly. I don't know...

 

[lesrhorer]

I started with a step drill but that was too slow. I took a piece of rigid conduit, 1/2 inch, and cut it down to a snug fit. With cutting spurs on the end. It was only a couple inches long,

That's a thought.

I didn't intend to go completely through.

I do.

 

[projectnut]

I could, of course, but 9/16 drill bits are rather expensive, and I only have one. I would rather grind a cheap step bit. I have a few of those.

There are currently at least half a dozen 9/16" drill bits listed on eBay in the $12.00 to $20.00 price range. They include names like Cle-Line, Dewalt, Vermont American, Drill America, Milwaukee, and Bosch, among others. They may not be the top-of-the-line bits, but they should be more than sufficient for PVC.

There are even some Chicago Latrobes available for $9.99 plus $3.95 shipping:

Chicago Latrobe TRW 9/16" Drill Bit HSS | eBay

Find many great new & used options and get the best deals for Chicago Latrobe TRW 9/16" Drill Bit HSS at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Here's a lot of 4 Chicago Latrobes for $12.00 plus $10.00 shipping. That comes down to less than $5.50 a unit.

Lot of 4 Chicago-Latrobe 44036 Style: 150 9/16 HSS Jobber Length Drill | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0;">Chicago-Latrobe 44036 Style: 150 9/16 HSS Jobber Length Drill Black Oxide. 4 bits total.</p>

www.ebay.com

 

[mattthemuppet2]

I thought of that. I'm not sure how well it would work. I wonder if the plastic will deform under the cutting pressure?

annular cutters are very free cutting, if anything I would expect them to do better than regular drills in that regard. They make beautiful holes too.