I busted the flue bolts on my Jotul118 and thought maybe I could drill the bolts out and re-tap the cast iron. Anyone good at that sort of thing? I've never used one before. Any pointers?
Tapping Cast Iron
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I know about tap and dies and I know that cast iron is harder to tap than roilled steel in that it is much more brittle. But it is easy...Piece of cake, Walk in the park, Singing in the rain. Why do you have to drill and tap it in the first place is my first question?
What are flue bolts? Never heard of them....heard of flue screws, but not bolts
What are flue bolts? Never heard of them....heard of flue screws, but not bolts
The heads of the bolts snapped off. There's no way for me to re-attach the flue collar without the holes.
Get one of your buddies with a fair amount of experience fiddling around with engines to bring some tools over and a set of E-Z-Outs & see what he can do. Don't go messing with a hand drill trying to drill the holes out bigger with the busted steel fasteners still stuck in there, 'cause you'll just do more damage. Better shot to try to retreive the busted parts of the bolts and re-use the original threaded holes with new fasteners. Oh yeah...have an appropriate thank-you gift on hand for your buddy when the old busted bolts have been retreived. Rick
Yes... The flue collar has two bolts that hold metal strips with a hole in the center. The metal strips hold the flue collar flush to the outside from inside the stove. The heads of the bolts snapped off. One snapped off flush with the flue collar and the other protrudes about an eighth of an inch.
If it is an elderly piece of cast iron that frequently gets hot (sounds like it fits) it will typically be very hard by now since it is constantly getting carburized and started out pretty high in carbon to begin with. I spent an entire weekend trying to remove stripped and seized studs from my Toyota motorhomes exhaust manifold (same environment) and totally wasted my time. If you need 3 screws to hold the stove pipe in place, you would be better off trying to drill and tap 3 new holes in fresh locations. If you heat up the spots cherry red with a torch and hold them (hot) for a while to break down some of the carbon and let them cool very slowly (pack the part in insulation), you may get things to a state that will allow a tap to cut it.
In my case, even after I got the original studs out (sawed them off, then progressively drilled them out, then picked out what was left of the thread helix) I was unable to get the cast iron soft enough that a brand new tap would cut anything, even with tapping fluid. And I couldn't spring for a carbide tap, considering that the new manifold cost only $60 which is what I did after wasting all the time and knuckle skin....
In my case, even after I got the original studs out (sawed them off, then progressively drilled them out, then picked out what was left of the thread helix) I was unable to get the cast iron soft enough that a brand new tap would cut anything, even with tapping fluid. And I couldn't spring for a carbide tap, considering that the new manifold cost only $60 which is what I did after wasting all the time and knuckle skin....
they sell a little tap that might work you drill a small hole in the bolt,then this little tap screws in counter clockwise and as it tightens it grabs the bolt.if possible heat bolt with a torch,you can also put some liquid wrench on there.but chances are you will have to drill it out, its not uncommon it can be repaired.
bjkjoseph said:
That's an E-Z-Out. (They have other names, as well). A tapered, left-handed very long-pitch "tap" that you first drill a pilot hole for, then get it started counter-clockwise (they also make them the other way 'round for left-handed threaded fasteners) until it binds tight and (with any luck) unscrews the busted remains of the original fastener. They come in various sizes. Gotta be real darned careful how you drill that pilot hole to keep your bit in the fastener and not wander into the surrounding metal. I've had real good luck with them sometimes, and I've had bad luck with them other times. Rick
![[Hearth.com] Tapping Cast Iron](/talk/data/attachments/10/10753-5b756bf54e4e9f6fbf525f8958e5b2cc.jpg?hash=i98I93_QFd)
I would NOT recommend using an easy out, more often than not, if the screw is in frozen enough to twist off the head an easy out will just break off and make the job that much harder. If you have ever tried to remove a broken easy out you will know what I mean. The best bet would to drill out the old screw, (make sure to drill the hole in the center) and carefully re-tap the hole. Make sure you sue a good quality drill and tap or you may break them.
The problem with easy outs is that they tend to wedge the screw tighter, the more you turn the tighter it gets. There are some thread removers that have a shoulder to reduce the wedging action.
The problem with easy outs is that they tend to wedge the screw tighter, the more you turn the tighter it gets. There are some thread removers that have a shoulder to reduce the wedging action.
Depends on why the head broke off. If it was bottomed on the head, and the threads of the fastener hadn't yet begun to yield, and that's what caused the head to shear off, then the remaining part of the fastener down in the threads may not be in there all that tight. I doubt we're talking about a grade 8 fastener here. Sometimes they (EZ-Outs) work like a charm, sometimes not. Rick
I'm going to try the E-Z Out. (No pun intended)
Tap and die sets are expensive for one use. I probably would never need to use it again.
Tap and die sets are expensive for one use. I probably would never need to use it again.
Did the bolts break off when you were trying to remove them? What size are they. If you try the easy out, just know when to stop twisting as they are quite brittle. Maybe some penetrating oil and some heat would help. Good luck.
Had the same thing happen to me with stove bolts. don't mess w/ EZ outs - you'll probably snap them and they're nearly impossible to drill out. In my case, I drilled out the hole, then inserted a bolt through the cast and nut to hold on my flu collar.
WES999 said:
Yeah... one head snapped off right away when I was removing it. The other did after a few turns. I really don't have a clue what size they are exactly. They're pretty small, less than a 1/4 inch. I've got some SRC and a propane torch. I should have used these to begin with. Wasn't even thinking it was going to be a problem. When the first one snapped I knew I wouldn't be able to do anything with it unless the flue was completely off. Live and learn.
After all this gabbin' about it, I have to agree that, considering the new information you've brought to light, you don't want to be messing with E-Z-Outs on this thing. I like the drill through and install bolts w/nuts solution. Rick
Homesteader said:
Can't guarantee this yet - as I haven't fired my stove up for the year. I have a separate set of cast plates inside my firebox that I did not drill through. I wouldn't overtighten the nuts - and put the nuts on the outside of the stove so you can remove easily. A hardened steel bolt and nut would also be better.
If you have some shank to grip, spray day in and day out with PB Blast or Kroil (if you can get your hands on this it is GREAT). Do this for a good week and don't get anxious. If you can get some shank, put a good set of vice grips on it, not cheapies that will spread. See if that works. If no place to grip, do the same first, center punch (I use an automatic center punch as it takes hammer out of the equation) drill small and then a bit bigger and try the easy-outs. If you can get a left hand bit even better.
Hope some of this helps.
I would say use a small torch to heat the metals and then put a few drops of COLD water on the screw, but I don't know how the cast would handle this, so I will not recommend.
Chad
Hope some of this helps.
I would say use a small torch to heat the metals and then put a few drops of COLD water on the screw, but I don't know how the cast would handle this, so I will not recommend.
Chad
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