Drilling out stuck air vent plug on steam radiator

branimal

I've got a one way steam system and the prior owner of my building was using the top air vent hole to vent. I want to use the lower steam air vent but the plug in there isn't coming out.

I tried using a impact driver (not an impact wrench) to remove the plug. It's just stripping the screw head. Even if I could borrow an impact wrench I dont think it will work b/c the slotted plug is recessed I won't be able to get a flat head bit in there.

I think I've read that I need to drill it out. And rethread it.

Should I start with a small bit and make a starter hole, and then come back with an 11/32" bit (I think that's the correct size)?

I have a 1/8" 27 NPT HSS tap one hand.

HVACNUT

Are you trying use the plug with the scrape on it? I'm not sure but that might be too low. Better wait for a steam pro. 
If it is ok, you'll need a tap and die tool.
Always start with a small drill bit and gradually increase in size until it's the size needed to tap.
I use a little Zoom Spout oiler so I don't burn up the bits.
An EZ Out bit might work as well. 

EBEBRATT-Ed

That's going to be difficult. You need to center punch the exact center and that will be difficult with the slotted plug.

If you don't get it centered exactly you may end up with an oblong hole.

If it was me I would use the vent hole you already have.

If you drill that one out be prepared to drill it out to 1/4" npt to be able to drill out the oblong and put a 1/4 x 1/8 bushing in the radiator

Steamhead

That hole location is right for a steam air vent in that particular radiator.

Start with a small bit, drilling gently in the middle of the plug. Work your way up. Go slowly and pay particular attention to centering the hole. When you get most of the way to the edge of the plug, try an EZ-Out- you may be able to unscrew the remainder.

branimal

I think the difficult part of drilling out the plug is centering the first hole I drill. I could center punch it as Ed mentioned.

I have tried removing a broken off vent nipple with a nipple extractor before and cracked the radiator. I imagine getting a center drilled plug out is going to be way tougher.

The only success I've had removing a plug was using an impact wrench with ground down slotted bit. The plug was the type that protrudes from the radiator about 1/4". I used a cutting disc on the plug and cut a slot for it. She came right out.

Because the plug pictured above is flush with the radiator body, I'd need to get a good fitting slotted impact bit. Maybe a small diameter dremel cutoff wheel could help deepen the slot. The slot is just a hair under 3/8". So a 5/16" slot impact bit might work.

https://www.homedepot.com/p/TEKTON-1-2-in-Drive-x-5-16-in-Slotted-Bit-Socket-SHB20202/310621564?MERCH=REC-_-pipsem-_-310621568-_-310621564-_-N&

Grallert

Get yourself some left hand twist drills run your drill in reverse. that plug might just come out while drilling. go slowly and be careful. If drilling doesn't spin it out carefully pick the remaining bits out.

mattmia2

one you are almost up to the threads you might be able to cut a wedge out of it with a tiny reciprocating saw blade by hand and a tiny cold chisel.

real cutting oil will work a lot better than general purpose oil, it has extreme pressure components that regular mineral oil does not.

branimal

Grallert said:

Get yourself some left hand twist drills run your drill in reverse. that plug might just come out while drilling. go slowly and be careful. If drilling doesn't spin it out carefully pick the remaining bits out.

Grallert you've told me to use these left hand twist drills a few months ago and of course I didn't listen and cracked a radiator using a nipple extractor. I'm going to buy 'em this time around.

Is there a product you like? This seems to get good reviews.

https://www.amazon.com/Neiko-10037A-Titanium-Nitride-Coating/dp/B000HS0UJQ/ref=sr_1_2?dchild=1&keywords=LEFT+hand+twist+drill&qid=1614010790&sr=8-2&th=1#

Grallert

Those should work. I use high speed steel, just what I have. Go slow and be patient. There are few things worse than breaking off a drill bit in the material. Get a good center punch that will guide your drilling. Don't be afraid to use a bit of heat and penetratingly oil with an easy out once you get most of the plug out if you need. In fact it wouldn't hurt to use a bit of heat and oil in the threads while you drill. It would be nice if this were an exact science but it's not LOL. good luck.

branimal

I going to order a better set from HD.  A lot of crap reviews on the set I posted earlier. My rad plug is effectively welded in there.

 I can see many uses for left hand twist drills.  

So I’m kind of in a rush to heat up my workspace in brooklyn nyc.  I’m getting a hardwood flooring delivery in a few days.  And I want to get the space to 70 degrees.

If I temporarily install the incorrectly vented rad, will it give me some heat?

Thanks.

mattmia2

It will definitely work with the vent in the upper tap, it just may not all get hot because the steam may hit the vent ant close it before most of the air is vented out of the radiator, so it might be more like half or 3/4 heats. you could also drill and tap another hole somewhere near the plugged hole.

branimal

3/4 heat works.  Thanks

HomerJSmith

Why not try PB Blaster. Tap the plug with a hammer apply Blaster and tap more, apply more, tap more etc, then try an impact hammer, but don't go crazy with the power of the taping. Lite tapping over a period of time is better. You can always drill it out later.

kflory

I'd think that a broken bolt extractor kit would work well on that... https://www.amazon.com/gp/product/B000H6PM32/

colinbarry

Another option... I've pulled a 1/8" plug out of a radiator like that by welding a nut to it and using a socket wrench to get it out.

HomerJSmith

I should add to my previous post how to use the impact hammer. After spraying the plug with PB Blaster or CTC Knockem Loose take the impact hammer and put it on tighten so as to tighten the plug and tap lightly then put the impact hammer on loosen and tap the plug lightly. Repeat this a number of times. Don't rush it. Light taping is best. It takes time to loosen the plug. Don't rush it.

You might want to heat the outside of the boss and go thru the procedure again. Everyone wants to just unscrew it which strips the plug or cracks the boss. Once it is out, chase the threads with a pipe tap.

If you have no luck, the reverse drill with a screw extractor is the next step.

SteamingatMohawk

I have had to destructively remove remnants like plugs and parts of a male pipe end from a fitting. My process is to carefully drill a hole as close to the center as possible, then use slightly larger bits to enlarge the hole until I can use a saw blade (usually by hand) or a file (triangular or jewelers/needle no more than about 6 inches long) to cut to the threads in the base metal of the fitting or radiator. Once I have as small a remaining connection I try to tap on each side of the filed slot to break the metal. Once it is broken, the remnant may be able to be worked by tapping and using a punch to try to rotate/loosen it. If necessary, I make a second groove so a small piece can be removed, if cutting just one groove doesn’t work. It’s a tedious process, but if you are sufficiently lucky and careful, you can split the remnant and it will come out. Hopefully, there will be little to no damage to the base metal fitting or radiator. Use heat or PB Blaster too, carefully…you don’t want a fire.

EBEBRATT-Ed

@SteamingatMohawk

I agree with your method most of us have had to do that. 1/8" plug is pretty small not very easy

retiredguy

If all else fails you may have to drill the hole bigger and increase the thread size to 1/4" and bush it down to 1/8"

SteamingatMohawk

One problem with the Easy-Out design is that the bit is tapered and as you turn it in the unthread direction, the bit may have a tendency to go further into the material you are trying to remove, increasing the holding power (friction) as you try to remove it. Unless I am pretty sure I can get the material out, I prefer to not use one or just try as a first choice without putting too much load on the bit.

branimal

Thread update... (removing old plug)

1. I tried using heat, PB blaster and an impact wrench with slotted bit. The slotted bit head twisted its own head.
2. I center punched the plug, the best I could. Then I used a set of left hand twist drill bits Starting with 1/8" and worked my way up to 1/4". The Left hand twist bits never caught and twisted the plug out.
3. I tried an easy-out bit in reverse, and it catches the plug, but I'm afraid it will crack the boss with any more force.

The hole may be a touch off center, so I'm hesitant to drill it out with an 11/32" bit.


I think the next step is to use set of small metal files as some here have mentioned. And file from the inner diameter toward the outer diameter in one spot. I see a set at my local big box store.

Then use a small flathead screwdriver and a hammer to pry the plug out.

Any other ideas?

mattmia2

you can also get very thin hacksaw blades for a reciprocating saw that may be better than the needle files. There are very tiny cold chisels available. A good impact rated bit won't twist with the impact driver.

branimal

mattmia2 said:

you can also get very thin hacksaw blades for a reciprocating saw that may be better than the needle files. There are very tiny cold chisels available. A good impact rated bit won't twist with the impact driver.

do you have a link for the thin hacksaw blades? It’s got to have a width of less than 1/4”. Can’t seem to find one. Thanks

JUGHNE

Perhaps the blade that goes into a jig/saber/scroll type saw. Then use a vise grips for a handle.
If that is still too big you could grind off the back side of the blade...very carefully....wear goggles.

mattmia2

There is this:
https://www.zoro.com/milwaukee-3-58-14-tpi-super-sawzall-blade-5-pk-48-00-5162/i/G2525397/#specifications

there may be a finer version but Milwaukee's web site is abysmally bad so I couldn't even find this on there.

branimal

Thanks.  I’ll try grinding down a steel cutting blade.  If that doesn’t work I’ll pick these up.

how do I keep the metal pieces from falling inside the rad? 

ethicalpaul

They won't hurt it. They'll lie there for the next 100 years doing nothing except maybe rusting a bit.

branimal

Got 3 slots cut in the remaining portion of the plug.  Now I’ve got to wait for Amazon to deliver a 1/4” cold chisel.  Will this one do the job?

Grallert

Looks like you'll have to pick away at it. Should break away now. A small center punch on the outside of the remaining threads could very well fold and break the "pie" pieces out.

ethicalpaul

Yes, that chisel should work nicely, or a punch like Grallert said.

branimal

The plug started to crumble with a center punch and then I pulled her right out with screw extractor. First time that bit ever worked for me.

I did cut the radiators threads ever so lightly with the hacksaw. I refreshed the threads with a tap. And wrapped a lot of white thread tape on the vent and installed it. Hopefully she holds.

That was a fun little project. Looks like I got a few more improperly vented radiators so now I know how to approach it.

Thanks for everyone's help!!!!

ethicalpaul

Nice. It's nearly impossible not to at least nick the threads. It should hold fine, it's only going to ever see 1.5 PSI max, right?

But does that vent require to be vertically oriented?

Grallert

ethicalpaul said:

Nice. It's nearly impossible not to at least nick the threads. It should hold fine, it's only going to ever see 1.5 PSI max, right?

But does that vent require to be vertically oriented?

Nice work!! You'll want a vertical vent there of course.

Hap_Hazzard

ethicalpaul said:

But does that vent require to be vertically oriented?

It will drop off when it sees a vacuum, but the trouble is it will gradually fill up with water and start spitting. It can be mounted on an elbow, but I'd use a different vent anyway.

branimal

Yes this is a temporary vent I bought when I was using the top vent hole.  An elbow vent wouldn’t fit in the top slot because of the top bolt.  

I’m going to crack open Dan H’s book to figure out the best vent for that radiator.

 If the vent does spit, I have some blue compound (forgot the name), that will seal up the gap.  I’ve used that before on a nicked steam pipe.  

Hap_Hazzard

The best vent depends on the size of the radiator and the pipe leading to it. Generally, the farther it is from the boiler, the faster the vent needs to be. @ethicalpaul and I like to use the Maid-o-Mist vents because the outlets are interchangeable. If you get a few different sizes, you can leave the vent in the radiator and swap outlets until you end up with the right size, and keep any extra vent bodies for spares.

Steamhead

Unless that radiator is near the thermostat, I'd use a Vent-Rite #1, which you can fine-tune very easily.