Opening tapped vent in brand new radiator

Sethamin

So I just bought a brand new 4x19x8 slenderized cast iron floor from my local plumbing supply shop. I'm trying to install it, and I can't figure out how to get the plug out of the vent hole. The guy at the shop told me that you just put an allen key in there and screw it out, but every allen key in my set just spins in the hole (after some initial resistance). Have I stripped it? Or do I actually need to drill and tap the hole myself? I feel silly for not being able to figure this out. Has anyone had any experience installing these new radiators?

nicholas bonham-carter

No doubt it needs a metric sized key.--NBC

Sailah

That looks pretty wallered out, not sure an allen will do it at this point. But I would try metric as mentioned, auto parts stores carry them in large sizes for brakes and they are reasonably priced. You can try tapping in a Torx bit of appropriate size. Or a large EZ out. BUT, if you break either of those tools, you now have a major problem because they are hardened steel and require cobalt or carbide drills to excavate.

Assuming you don't want repaint that radiator, I would gently heat the area surrounding the plug with a heat gun and get it too hot to touch. Apply an ice cube to the plug to cool and shrink it and hopefully gain a differential enough to help extract the plug. Without seeing it in person and knowing how much depth you have, I personally would smack in the largest EZ out I could fit in there after the heat treatment and lean on a wrench to remove it.

If you promise to return in like condition I can send you some medium sized EZ outs to try as I know they are expensive to buy new.

BobC

That is a very generous offer

Bob

nicholas bonham-carter

Yes-extremely generous.
I would still drill it out, to avoid any chance of having the ez-out break off.--NBC

Sethamin

Thank you for the offer, Sailah, but I will decline for now. I'd rather try getting it out without risking someone else's tools.

How exactly would I drill it out? I'm sure I could put a hole in it, but that still wouldn't help me get any torque on it to extract it. Should I try an 11/32 bit and then use a chisel to extract the edges of the plug from the threads?

Or maybe I should just forget about this whole thing, and drill and tap the vent hole on the other side (which I'm pretty sure does not have a plug in it)?

Sailah

Sethamin said:

Thank you for the offer, Sailah, but I will decline for now. I'd rather try getting it out without risking someone else's tools.

How exactly would I drill it out? I'm sure I could put a hole in it, but that still wouldn't help me get any torque on it to extract it. Should I try an 11/32 bit and then use a chisel to extract the edges of the plug from the threads?

Or maybe I should just forget about this whole thing, and drill and tap the vent hole on the other side (which I'm pretty sure does not have a plug in it)?

Well, I wouldn't have offered if I wasn't willing to see a broken tool. I bought that whole bin (plus about 75# of REALLY big ones) for $10 at auction and I have multiple of each size. I brought them in because we needed to remove the pipe from some radiators that were snapped off. I was jumping on a 24" pipe wrench and they didn't break so I doubt you would run the risk of snapping one.

Regarding drilling, I always start with a center punch so the drill doesn't wander. Give it a light first tap and then look at the location of the dimple. You can massage the punch mark to center with increasingly harder taps. Once it's dead nuts center, rap it hard and there's your starter hole. Drill out in steps starting with something thin but stout maybe 1/4". Heavy pressure is needed to keep the bit cutting and not work hardening the material. On something that small I wouldn't bother with cutting fluid or if it's cast iron. You can tell from the chips. Cast iron is grey and dusty, the chips are fine. Steel with a sharp bit will get you nice curls.

Keep drilling until you can fit an EZ out in there. I'd go for the largest size because it's the strongest. Nothing makes your heart sink faster than a snapped EZ out they are harder than Chinese algebra. How much torque to apply is a feel thing. Keep torquing until it snaps, then back off slightly lol.

Heat is your friend for a job like this.

Seriously, my offer stands, it's not like I'm lending out my Starrett 15" super precision machinist level or something delicate. If you can manage to break one of these EZ outs I commend you. It's the tiny baby ones that you can risk breaking just like taps. I've broken a few 1/4"-20 taps but I've never broken a 1/2"-13 tap.

Sethamin

Sorry if this wasn't clear, but the problem is with the opening for the vent, not one of the supply or return holes. It should only be 1/8"-27. So it's really not that large, and an extractor of that size is not terribly expensive.

ChrisJ

Yeah, try to get the plug out and worse case if threads get damaged drill it out and tap it 1/4" and then use a plated 1/4" to 1/8" bushing.

I need to get some EZ outs and more taps and dies my self. I have 1/8" NPT and 1/4" NPT taps, but absolutely nothing else.

LarryK

Harbor Freight has a 1/4" 3/8" and 1/2" NPT tap and die set for ludicrously cheap. Not the best alloy probably but good enough to work a few times and save your butt. The are OK for cleaning threads, too.

ChrisJ

LarryK said:

Harbor Freight has a 1/4" 3/8" and 1/2" NPT tap and die set for ludicrously cheap. Not the best alloy probably but good enough to work a few times and save your butt. The are OK for cleaning threads, too.

And when the cheap tap breaks off you'll wish you were dead.

Pumpguy

The correct tapping size drill for a 1/8-27 NPT tapped hole is 11/32", so start out with a 1/8" drill or so, and work your way up. You may find that as you get close to full tapping size, you will be able to pick out what's left of the old plug with a needle point scriber or similar tool.

ChrisJ

Pumpguy said:

The correct tapping size drill for a 1/8-27 NPT tapped hole is 11/32", so start out with a 1/8" drill or so, and work your way up. You may find that as you get close to full tapping size, you will be able to pick out what's left of the old plug with a needle point scriber or similar tool.

Why do some 1/8" NPT taps call for 11/32 and others call for size Q?

Abracadabra

ChrisJ said:

Pumpguy said:

The correct tapping size drill for a 1/8-27 NPT tapped hole is 11/32", so start out with a 1/8" drill or so, and work your way up. You may find that as you get close to full tapping size, you will be able to pick out what's left of the old plug with a needle point scriber or similar tool.

Why do some 1/8" NPT taps call for 11/32 and others call for size Q?

An 11/32" drill is more readily available than trying to track down a Q. You are only talking about something like 1/100" difference

Matt_67

With something that small a left hand drill bit sometimes just spins it out while drilling

LarryK

The left hand drills are hard to find, you have to go to a machine tooling supplier like MSC. Hanson makes a set of easy-outs with LH drills that's pretty neat. They work wonderfully on motorcycle case screws but that's OT. I wonder if they would make much difference on a jammed taper plug. mcmaster.com/#2729a46/=10cuyab

Sethamin

Thanks for all your help everyone. I elected to just drill and tap the vent hole on the opposite of the radiator rather than try to extract this plug. I just foresaw that it could take a lot more time if things went wrong, versus drilling a tapping a new hole which was comparatively easy.

Abracadabra

Sethamin said:

Thanks for all your help everyone. I elected to just drill and tap the vent hole on the opposite of the radiator rather than try to extract this plug. I just foresaw that it could take a lot more time if things went wrong, versus drilling a tapping a new hole which was comparatively easy.

What do you mean "opposite"? The vent needs to be on the far side of the steam connection. Not the same side.

Sethamin

Yes, I'm aware of that. This is a brand new radiator, so it comes without any plugs in the supply or return holes (i.e. on each end of the radiator, there's a 1" hole on top and 1-1/4" hole on the bottom). Presumably they do this so that you can set up the radiator for different configurations (e.g. 1-pipe steam versus 2-pipe hot water). So putting the vent on the other side just means that I swap where the bushing and plug were going to go on the lower holes.

Sailah

Abracadabra said:

What do you mean "opposite"? The vent needs to be on the far side of the steam connection. Not the same side.

I'm wondering why this is true. all my experience with steam leads me to believe it would work fine as the steam will always go from high to low.

I would personally do exactly as you said, put the vent opposite the supply. Just wondering if there would really be any true loss in performance

nicholas bonham-carter

The thought is that with steam being lighter than air, it will rise up on the supply side, and close a vent located there before the rest of the radiator is full. This would certainly happen if the radiator were steam only, with no connections across the top.
The test would be to put a vent on each end, and see which closed first.--NBC

Abracadabra

Sailah said:

Abracadabra said:

What do you mean "opposite"? The vent needs to be on the far side of the steam connection. Not the same side.

I'm wondering why this is true. all my experience with steam leads me to believe it would work fine as the steam will always go from high to low.

I would personally do exactly as you said, put the vent opposite the supply. Just wondering if there would really be any true loss in performance

If the vent is on the same side as the supply you will only vent steam in the first section of the radiator. Steam won't reach the far side.

ChrisJ

Sailah said:

Abracadabra said:

What do you mean "opposite"? The vent needs to be on the far side of the steam connection. Not the same side.

I'm wondering why this is true. all my experience with steam leads me to believe it would work fine as the steam will always go from high to low.

I would personally do exactly as you said, put the vent opposite the supply. Just wondering if there would really be any true loss in performance

I have 10 single pipe radiators in my house and every one of them has the steam go to the top of the first section (pipe side) before anywhere else. If you had a vent in that section it would close after only a tiny portion of the first section heated.

I don't know why it's true, but it is true without a doubt. What I can also add is if I vent a radiator too fast, the steam will take a short cut across the bottom and hit the vent from that direction. Not sure if it matters but it always seemed like any radiator that bottom heated first didn't work as well so I avoid it.

Sailah

Interesting, did not know that. We only do 2 pipe steam here and run always 5 PSIG or higher. So it fills (and heats) anything instantly.

Dave in QCA

Yes, critical that the vent be on opposite side as the inlet. Also, NOT at the top. Should be located somewhere around 1/3. to 1/2 way up from the bottom. I don't think I would have spent more than a moment tryining to extract with a wrench. I'd get a 1/8" pipe tap and appropriate bit. You already have the Allen socket in the middle that will guide the bit. Drill the hole and use the tap to clean it Out. A 5 minute task.

Paul48

I think you were better off leaving that plug alone. I don't like the way it looks. It has what looks like fiberglass around it. Like they drilled a bad casting, then tried to hide where it blew out. Maybe I'm not seeing it correctly, though.