Why?

[Jim Katen]

Around here, the most common system of drain piping in older homes was the "Durham" system, which included threaded galvanized steel pipes inserted into tapped cast iron fittings to serve the individual fixtures, and standard cast iron bell & spigot pipe for the larger pipes.

I frequently see peculiar patches in the steel sections of these systems. I looks like someone drilled a 1/4" or 3/8" hole in the side of the pipe and then patched the holes by driving in a tapered wooden dowel. Occasionally, someone will have tapped the hole and plugged it with a machine screw. The patches are remarkably effective.

These holes are not the result of corrosion. They were clearly drilled in the pipe.

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I see this so often, that I suspect it must have something to do with the installation of the system. I just can't imagine what.

Any explanations?

[Scottpat]

Could it be that a lever/rod/screwdriver was inserted in the hole to turn and tighten the section?

[kurt]

There was an era in Chicago when there was a lot of Durham fitting work. No holes, though.

[Bill Kibbel]

Around here, the most common system of drain piping in older homes was the "Durham" system, which included threaded galvanized steel pipes inserted into tapped cast iron fittings to serve the individual fixtures, and standard cast iron bell & spigot pipe for the larger pipes.

That description is not of a Durham system. Every joint would be threaded. It's usually only installed in large apartment or commercial buildings and very rare in single-family homes. The only one I've seen in a residence was a gilded-age mansion >25,000 sq. ft.

I frequently see peculiar patches in the steel sections of these systems. I looks like someone drilled a 1/4" or 3/8" hole in the side of the pipe and then patched the holes by driving in a tapered wooden dowel. Occasionally, someone will have tapped the hole and plugged it with a machine screw. The patches are remarkably effective.

Quality threaded pipe drain installations would include a threaded plug at every change of direction. Without, it's necessary to drill holes to find and clear blockages.

[Jim Katen]

Around here, the most common system of drain piping in older homes was the "Durham" system, which included threaded galvanized steel pipes inserted into tapped cast iron fittings to serve the individual fixtures, and standard cast iron bell & spigot pipe for the larger pipes.

That description is not of a Durham system. Every joint would be threaded. It's usually only installed in large apartment or commercial buildings and very rare in single-family homes. The only one I've seen in a residence was a gilded-age mansion >25,000 sq. ft.

OK, then, a hybrid system using threaded steel pipes and Durham fittings for everything 2" and under and cast iron for the 3" and 4" lines.

I frequently see peculiar patches in the steel sections of these systems. I looks like someone drilled a 1/4" or 3/8" hole in the side of the pipe and then patched the holes by driving in a tapered wooden dowel. Occasionally, someone will have tapped the hole and plugged it with a machine screw. The patches are remarkably effective.

Quality threaded pipe drain installations would include a threaded plug at every change of direction. Without, it's necessary to drill holes to find and clear blockages.

I suppose it's possible, but it seems unlikely. The photo I posted, for instance, is just below a bathroom sink. Could someone clear a wad of hair out of that pipe through a 3/8" opening? Seems like a lot of time and trouble would be necessary, especially when you could just pour some lye down the drain and wait a few minutes.

[Jim Katen]

Could it be that a lever/rod/screwdriver was inserted in the hole to turn and tighten the section?

It wouldn't afford much leverage and the hole would probably end up elongated. These holes are perfectly round.

Also, this was pretty much the exclusive method of plumbing drain systems from the late 1800s right up to the 1970s in our area. Plumbers knew how to install this stuff without drilling holes in it. I'm convinced that the holes appeared after the installation. I just find it unlikely that such small holes could be useful in clearing clogs.

[kurt]

Could someone clear a wad of hair out of that pipe through a 3/8" opening?

Sure. I use a 1/8" twist drill about 5" long, run it into my ancient tub drain, it twirls all the crap up perfectly, pull it out, reverse to clean, repeat until hair is gone. Getting it out through a 3/8" hole sounds a bit sketchy, but it'd be doable.

It works remarkably well. I kinda discovered it by accident when I was doing something else.

Note to self....determine why I do this sort of disgusting stuff.....

[Jim Katen]

That might be it. I'll have to start watching to see if the holes are always under bathroom drains.

[mlparham]

Around here, the most common system of drain piping in older homes was the "Durham" system, which included threaded galvanized steel pipes inserted into tapped cast iron fittings to serve the individual fixtures, and standard cast iron bell & spigot pipe for the larger pipes.

I frequently see peculiar patches in the steel sections of these systems. I looks like someone drilled a 1/4" or 3/8" hole in the side of the pipe and then patched the holes by driving in a tapered wooden dowel. Occasionally, someone will have tapped the hole and plugged it with a machine screw. The patches are remarkably effective.

These holes are not the result of corrosion. They were clearly drilled in the pipe.

Click to Enlarge

50.83 KB

I see this so often, that I suspect it must have something to do with the installation of the system. I just can't imagine what.

Any explanations?

I suspect that the holes were originally the result of corrosion, probably at a large inclusion in the pipe. The fix is to drill out the inclusion and plug the pipe.

[Jim Katen]

I suspect that the holes were originally the result of corrosion, probably at a large inclusion in the pipe. The fix is to drill out the inclusion and plug the pipe.

A good suspicion, but unlikely. When these things rust out, they always rust out along the bottom of horizontal runs and at the point where the threaded pipe meets the fittings. I've found hundreds of them where the bottom of the pipe is completely rotted - to the point where I can poke my finger through them - but the sides are fine.

These holes are (as far as I can remember) usually on the sides of the pipe.

[Rob Amaral]

I see that around here to guys... plugs in steel.. I always figured it was a guy clearing blockages out..

[Marc]

I've never seen such small plugs in drain pipes. Maybe there's a plumber around that likes to try using pressurized air to clear a clog.

Marc

[Jim Katen]

I've never seen such small plugs in drain pipes. Maybe there's a plumber around that likes to try using pressurized air to clear a clog.

Marc

He'd need a darn good way of sealing the inlet, though.

[David Meiland]

I assume these are not factory-drilled holes... they would be consistent if so.

[plummen]

My guess would be that somebody was running a small drain machin with a 1/4"-5/16" cable and needed an access point.

Around here youll see it done on cast iron pipes above a fixture without a cleanout plug,Then they will just use a no-hub fitting to cover it till next time they need access.