I ALMOST Gave Up On My Customer's CAT Exhaust Manifold!
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- čas přidán 4. 11. 2023
- What I thought was going to be an easy stud removal & thread repair turned into a nightmare! When the last guy does half the job, it makes it ten times more difficult! We didn't want to let this CAT manifold go to the scrap pile!
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One comment about the counter bore. It actually has a very important function. It increases the free length of the stud which clamps whatever part to that flange (I assume the turbo). More free length means the stud stretches more when torqued. More stretch means more preload remains after the gasket material inevitably settles some ten thousandths of an inch after a few heat cycles. And that makes the connection less likely to leak. The first repair and yours reduces the free length by however deep the counter bore is. I would strongly recommend the customer adds a spacer under the nut that is as thick as the counter bore depth to recoup the lost free length from the repair. If he does that it truly will be as good as new. I am a mechanical engineer for what it’s worth.
Thank you, I was wondering about that.
This is the cleaning guy. Thanks for the explanation. We didn't know the recess was there until after Nicolaus removed the first stud. The top of the recess with the existing stud gave us the illusion that there may be 2 more helicoils installed slightly below flush like the other 2 that protruded. After we found the recess, we discussed between ourselves why the stud was installed in that manner from the factory and assumed it had to do with the longevity of the stud itself. Since we did not have the means at the time to install a repair insert lower in the hole and considering we were fighting the remains of the old studs along with broken easy outs and drill bits in the bottom of the hole, we opted to install the inserts we had up higher eliminating the recess. I'm going to pass your explanation on to our customer. Thanks for the constructive input and advice!
@@JAMSIONLINE happy to help, I really enjoy your work and attention to quality!
Have you ever worked out how many degrees of rotation are needed to attain a specific amount of compression after attaining a snug tight condition in such a joint? It is a lot more accurate than torque, especially when working with gaskets. It let's you ignore variations in K factors, thread deformities, and gets tou the same load on all fasteners regardless of how hard it is or isn't to turn the threaded fastener.
@@gregorydiguido5078that makes complete sense now. Thanks for the explanation.
You know, I think you and your cleaner are the real machinist! So many shops will make fun of you guys because you don't have several million dollar CNC machines! But you guys try to fix stuff those guys would tell the customer to just junk that old stuff and put in a crate engine! I have a 1949 Studebaker Commander Sedan with its original 245 long stroke 6 with overdrive 3 speed and I would not trade that engine for a 500 hp SBC ever! If I wanted a drag racer I would just buy a Challenger RT Hellcat! I wish I could find a shop to rebuild the Crankshaft its rod bearings have been turned down as small as allowed! But the rest of that engine will out last me! Thank you for your excellent Service to keep old stuff running! You guys are awesome!
Since you have a ridged machine and setup, try using a 2 flute carbide center cutting end mill at lower RPM and light feed. It will cut taps, easy outs and other hard material out. Good luck.
I'm with you. A milling machine does a much better job of holding a bit side to side. Drill bit is not the best method here.
My father was a machinists and in my youth days he had milled out many of the taps , extractors, drill bits I broke off in various parts, a end mill would be best, I have to agree with you
I was almost yelling at my screen "Use a carbide end mill" ! I always mill a flat on the broken bolt before drilling. I've also had to go full depth with the end mill to hog out a drill or tap. Easy Outs are evil and should be banned. However they too can be milled out with a cobalt end mill.
I agree completely. Standard drill bits are a bad choice for removing broken bolts in this situation. Why? It's simply that they flex too much and the cast iron around the hole will easily be cut away by that wandering drill bit.
Im not a machinist but my dad is, i was thinking the same thing about the end mill (I didn’t know thats what it was called untill i googled it, lol)
Mold maker here. You should try a Machinist Centering Scope. It's basicly a microscope that mounts in a drill chuck. It has cross hairs in it that helps you line up on holes. You can line up directly in the center of a hole even if it's messed up.
I'm partial to indicators
Im not a machinist, and I didn't sleep at a holiday inn, but I really like this video!!
Thank YOU JAMI!!!
Helpful hint. Get some left handed drill bits. Sometimes they will grab and spin what’s left of a bolt out. Not saying it will work every time but it does sometimes.
You think these guys have never heard of or tried left handed bits?
My experience of exhaust manifold studs is that you just take your time and warm up the casting and surrounds to a nice red colour. Let it cool right down and repeat. Put a couple of nuts on the stud and give it a good braying on the top of the thread with a big hammer. After that try to get it to move. If it doesn't move repeat the heat and cool and hammer, while you get someone else to get the tooling ready to drill it out. But START with lots of heat.
Cussing at ‘em don’t work but it makes you feel better!
Like you already said, the last guy may have been doing it out in the field with hand tools....Sometimes you do stuff like that, and the customer says "It's just until we finish this job, then we'll have it fixed right...but that day never comes...
As much as you hated doing this work, we greatly appreciated the video!!! Excellent and detail oriented work.
You can also try left twist drill bits to drill out the bolt. Its a bonus if the left drill bit bites into the bolt causing it to loosen up. Happened to me more then once. Good job on this piece 👍
Second the left hand drill bits. If you're going to have to drill anyway they are worth a try. Always a great feeling when you get halfway through the stuck bolt/stud and it starts turning itself up the threads.
I've been machining for over 20 years, when I have to fix the last guys hidden mistakes it pisses me off. Good job!
I love taking on these so- called mistakes. But l rarely put it back the same failed design 🥴
heating the manifold jet hot, then immediately turn out the stud has always worked best for me.
💯
I used to work with an old timer and he would use the torch to liquify the stud while leaving the threads in the manifold in good shape. It was cool to see.
agree. And try pressure clockwise first before turning counter clockwise to remove.
Master mechanic at CAT dealership here. Manifolds, like oil pumps and cylinder liners, are an art form. Advice: bronze studs (NOT stainless) with the unthreaded portion turned down to the root diameter of the threads. They rarely break, and if they do, they can be drilled easily... unlike stainless.
Yea, I would have used stepped studs if possible because those inserts will unscrew themselves next time the turbo gets removed.
Stainless seems to be the worst exhaust fastner. I find them nay times galled and seized in the threads and impossible to get out without damage. Meanwhile plain high carbon bolts usually come right out with some heat and cooling to seperate the rust weld. Where does one find bronze studs and what kind of torque loads can they handle?
@@bcbloc02Bronze studs can be purchased at McMaster Carr. Torque to same values as steel. Bronze does not have the tensile strength of steel, but it's close, and plenty strong for exhaust studs.
@@martin-vv9lf They mentioned they were Big-Serts (oversized Time-Sert) earlier in the video. Unlike Helicoils those inserts have features to lock themselves into the hole. Depending on the style, they have a combination of incomplete internal threads near the bottom to expand the insert , serrations, and a pin that is pushed out to lock threads. The install tool has lobular threads to expand the insert to the proper size without binding up.. too badly.
Helical inserts are almost always good enough when installed properly. They are also much more flexible when you don't have time/space/tools for a proper repair, which is where they get a bad reputation. Time-Serts are when you want belts, suspends and pasties.
The factory studs on those manifolds are a taper lock. One end of them have an X stamped into them to dictate that end goes out. The other side has a taper at the very end. Many times I've seen them installed backwards and the side with the X will mushroom out when it hits the taper in the bottom of the manifold. The next time they get pulled out, they chew up the other threads on the way out. The studs actually call out for a torque spec on install (21' lbs i think). The manifolds are also available separately in 3 pieces. Just heat the slip joint and it'll either fall apart or need just a little persuasion.
I noted the recessed threads. Does the assembly rely on the length of the stud to maintain clamping force? The stud now has a reduced effective length from putting the Big Serts where they are, with threads going to the mating surface.
@@1djbecker i don't believe so. My only basis for that is that I've never seen one pulled out, but always broken close to flush with the head. It was always such a lousy job to do on international 8600's or Freightliner m2's. No room to work.
Fun side-note, I've come to learn with a bit of trial and error, that the best way for me to make bolts that see high temps removable later, is to hit it with some copper anti-seize before install. The stuff turns into powder if it gets hot enough. I do have to re-apply after every reinstall though, or I've found out it can still be prone to seizing.
don't use the copper on exhaust fasteners use the nickel anti seize it's rated for higher temperature and is better on stainless
Yup the Nikal / Nickel-ease is the stuff to use on exhaust components it works way better than any of the Copper anti seize products in that application..
But CZcams mechanics say anti seize is evil.... For me it's like Franks Red Hot, I put that sh*t on everything. I'd rather be covered in anti seize glitter than rust dust from trying to get stuck fasteners un stuck.
@@truracer20 The stuff is amazing, the only downside is that it does make some bolts a little bit too easy to remove. The only ones so far though I think, that have given me issues, are the hardware securing the exhaust manifold to the engine.
I really love watching you guys, as I learn an awful lot from every single episode! Even though I got nothing to do with machine shops, for me it's mainly the right approach to problems and the attitude that brings me forward. Thank's a lot for teaching us viewers! Greets from Germany!
Kroil then wait then more Kroil, homemade Kerosene and Tranny fluid is an excellent rust buster but you have to allow time for any of these products, good luck 👍
Nice repair guys.
Always difficult to repair something that someone else messed up in the first place.
You did great.
Have a good day.
Honest self reflection on CZcams? Love it! Thanks for being so genuine
Have you ever tried plunging with a center cutting carbide end mill? This would also be a good job for a disintegrator.
A spark eroder is great for removing broken drill bits etc.
We used to have one @ an engineering company I ran. Basically a copper tube through which you pumped coolant, attached to a power supply and mounted in drill press (or in our case a radial arm drill)
Agree, no risk of further damage.
Just wanted to pop by and say I got my mousepad today! Took a while getting it shipped all the way to Norway, got it just after I got my mechanics degree/certification! Love the design! Love the YT channel! Thanks for the entertainment and education, guys! Keep it up!
As a tip , Induction heaters are also a cleaner and easier way of removing broken bolts . Can't believe I was the first like as well . Love from Australia ...
What does an induction heater set up look like on a broken bolt or stud like the video showed for example just curious thank you.
Yes. I would have put an induction heater on the two studs still in the casting. I realize they get bigger when hot, but still breaks the rust loose.
Valve guides make great drill guides/bushings. Really helpful when trying to keep a drill bit from wandering on an uneven surface.
I really enjoy these videos….the knowledge that the cleaning guy has is huge…you are so lucky to have him….I think the new guy could stand on his own but with the golden encyclopedia--why would ya….
Left-hand twist drills work pretty well.
the best penetrating oil i have ever used was a 50/50 mixture of acetone and ATF. they don't mix, and have a tendency to separate like salad dressing, so you have to shake it up before each use. i hit it with that, then wait 20 minutes. most of the time it will come right out, if not, then i heat it and reapply the acetone/ATF mixture and try again. not sure why it work, but it work better than anything else i have ever used. i was shone that trick by an old cleaning guy and i have used it ever since.
Does it work better than Kroil (formerly named Aerokroil) that stuff is the best penetrating oil I've ever used.
I actually work in a foundry (probably the one that made that exact casting) and we make manifolds almost exactly like that. It's insane the amount of physical abuse those ductile castings can take. We literally toss them fifteen feet into a metal bin and it does absolutely nothing to them. It honestly amazes me sometimes what they can take.
I'm sure the aircraft industry loves to hear that😮
@@tcmits3699 XD. Never seen an aircraft company in the computer. Ford is the closest thing to an aircraft that we make parts for. Ford Racing M-4033-F975 in case your interested.) but aside from that, it's mostly heavy duty equipment like CAT, John Deere, Eaton. And the occasional engineering company that needs something that will likely outlive you. Literally.
It's for a truck, there, Bunkey.
Great fix for a previous bad fix! You guys rock!
I've been there behind the last person many times. At least you have lots of awesome equipment to help you repair those type of things! Thanks!
This channel provides amazing and entertaining instruction and the folks watching the videos leave some great comments. Looking forward to the next video.
Yes I agree with you that the comments are priceless & I recommend this channel to many mechanics that are working on my stuff.
Another approach is to drill much deeper, even breaking through the back, tap threads through and use longer studs.
Also I’ve had success using a inside out drill bit, the edges are lowest and the centre is 120 degrees inwards, (effectively making a cone shape at the bottom of a hole) this cuts away the bolt that the broken tap or drill is in, just gives you clearance to break it off then go a bit deeper.
I love the little video clips you throw in there, hilarious 😂
Great job saving the manifold and yes if the if the rust busting creeping oil doesn't work good old wax will penetrate with no problem....great content.
You did something similar to what I did on an Edelbrock 4.0l Jeep L6 head. I had one of the 3/8" factory helicoils pull out. I made a solid thread insert from a 1/2" bolt. I tapped the hole for the 1/2" and red locktited it in. It's so much better than the factory inserts.
Awesome video! Shows people what it's really like to deal with stuck and broken studs. I often find I have to drill a broken fastener as close to full size as possible and break or peel out the remnants with a tap. Glad to see a pro using the same methods.
Peal out- Never do what he did and just try to get a tap to pick p in the right place- He even said it did not feel right.- Because it was crossed.
@@mathewmolk2089 Meh I've had solid success. When there's not much left of a corroded fastener it tends to crumble and/or finally rotate and come out.
get the stud cherry red and let it cool, ive found when the stud get really hot and expandes then cools it makes clearance for the threads
Yes I used to take stuff like this and use a fine thread bolt and use that as a oversized type of plug, then I would just throw it out and for the right size stud or bolt. That was before they came out with all this fancy stuff. Works great with green sleeve compound.
Thanks for sharing I hate working on exhaust all the heat cycles and rusting always makes it so hard
Another trick for your tool box. Take a can of air. Key board duster. Turn it upside down and you’ll get some very cold almost liquid air to come out and you can rapidly cool the stud while the housing is smoking hot. Just like everything it doesn’t work every time but sometimes it’s awesome.
Just water in a spray bottle is a millwright favorite, but I see the extra cold of the air can working even better
When dealing with broke exhaust studs I skip the drill bit and go straight to the carbide end mill. Great salvage job Fellas!
If you get a masonry drill bit with a tungsten tip & re-sharpen its tip to a high speed steel drill bit profile they will drill through just about anything including drill bits & taps.
yes I worked on something (don’t recall what it was) where the previous guy had work hardened the broken stud. A regular HSS bit couldn’t scratch it. So I bought a small mason army bit and cut through the stud like it was butter!
What you need is a small sensor camera that has a deep depth of field for your kind of recordings. Like a Sony triple chip camera that is 5 to 8 years old. They are fantastic. Excellent auto focus, auto or manual, everything
Thanks for keeping it real and not editing out the real life moments
One tip that has helped me is to get a slide handle breaker bar to use on it. Put it in the middle so that you are pushing and pulling on both sides. This way you are not pushing sideways on the stud or bolt. Similar to a tap wrench.
Keep an eye out for an old die sinker EDM. The mold shop I worked in would remove drill bits, easy outs, end mills, carbide tooling, and taps from bolt holes. All you had to do was make a brass, tungsten, or graphite electrode of the tap drill size. Didn't know the difference between carbide and HSS. Most times you could pull the remaining threads out like the Heli-coil coming out.
Nicely saved! Thanks, it was interesting and informative.
I had a nitrided crank checked out by a shop, for balancing, journal polishing, and to tap for threaded oil gallery plugs instead of factory aluminum peened plugs.
The crank came back to me with the threaded plugs already installed and loctited in place, when I certainly didn't ask for that. Took them out, and, of course, they left a broken-off tap in one of the holes....
thank you guys for taking the time and effort to document a dying talent and profession
Over the years of taking out cat exhaust studs the ends are tapered and when the drill bit removes the stud, the very end seams to stay in the bottom of the hole, and people tend to not take it out. Had to take and dig out that little end peace to be able to tap to the bottom of the hole. Cat also had a great tool kit for broken stud removal.
I have a tiny item in the shop I show to people. Doing the weld trick on a yamaha head. So many bolts and threads messed up. I fought and fought. Had to try several times. When a few threads finally came there was an ez-out extractor tip sticking out of the threads! Had 4 in a set of parts Thursday night. 3 came easy-ish with welding. #4 after only about 3 threads came out I ended up drilling it.
I have found on automotive exhaust manifolds with hard to remove studs is to heat up the manifold around stud cherry red then blast with room temperature water . Stud will then spin out easily . Have used this method many times with 99% success rate.
Love the videos. Thanks!
Lovely work, solved it very well.
Pleasure as always to watch your videos 👍thanks for the upload
I was surprised to see the surfacer used on those hard timeserts (at the end). Brave man!
I thought is would be nice to surface grind them but of course that requires a grinder and set up and more time spent.
I have repaired a manifold on my Bridgeport using carbide drills and four flute center cutting end mills. Find the center of the hole drill down through with an under size carbide drill then using a 7 /16 carbide end mill and proper clearance drill clean up the hole. Re tap for 5/8 inch bolt. Screw 5/8 inch bolt in cut off flush then drill and tap for a 3/8 inch stud. In essence you are making an insert. Takes a little more time but the old machine is still running and that was several years ago. Your results will vary but it worked for me...
Been there, done this laying on my back under a tractor. Previous guy had begun drilling off-center, and then broke off the bit. After ruining a half a dozen bits, I finally got the remainder of the bolt out.
When you hear that creaky squeaking sound that is the telltale for "im cooling off heat me up more " hahah
Greetings from Finland and thanks again for the great video!
Nice repair, I'm a solid insert kind of guy, I have installed many helicoils in chainsaws but prefer the solid inserts if there is room.
That was absolutely a great proper job.
Man, I am learning so much, and I really appreciate the knowledge you and your viewers have. 3 questions: what was the contraption that you used at the beginning of the video that looked like a socket that was able to grab a hold of the stud bolt? What are the best drill bits for drilling out material like broken off drill bits / easy outs (I'm assuming drill bits that are made of even harder material)? What are the best taps for trying to clean out threads that have bolt material still left in them after the majority of the bolt has been drilled out? If anyone can point me to specific makes / models I would be super thankful. Keep the videos coming!
Many moons ago I was working as an equipment mechanic at a shipyard and one of the tool and die makers made me a set of hollow drill bits (think mini hole saws). They would take the old bolt out like a plug with the broken drill or E-Z out still in the middle. He would also make custom thread inserts if we needed them cuz sometimes we just did not have the luxury of waiting for store bought parts.
Buy a induction heater. Works great when you have other heat sensitive parts on the vehicle. Heat cycle a few times. Red hot, then cold water, lubricant of choice. I believe your repairs will last the life of that engine. Love your channel.
I love the logic and knowledge thrown down by Dad
Another option to get the studs out is to heat the stud only to cherry red then let it cool and try to move it. The stud heats down into the treads and expands. The manifold is still much cooler so it acts to confine the expansion of the heated stud. Then as the stud cools, it shrinks inside the threads. It may take several tries but it will work.
Welding a nut on a broken stud that broke off at the bore does the same thing.
The rigors of farm equipment to moisture, mud, chemicals, and manure can freeze a broken stud beyond normal means. That is the method I use to salvage parts that are obsolete. Good luck!
Did one of these a few months ago. Big-sert saved the day
use a carbide masonry bit. I just did it to drill through a broken rethreader. worked like a charm
The heat of manifolds and turbochargers (especially if waste oil or ATF has been added to the fuel) tends to harden carbon steel studs, but primarily, the heat promotes corrosion, which removes iron (in the form of rust - Fe2O3, I think...) and leaves carbon - very brittle - which is one reason they break, and almost un-drillable. I think that's a word...
I always use antisieze in case , next guy is me . I just keep candles around and don’t cut em just touch candle to hot bolt or stud . What ever works , is the best . U kept your cool , I’d of blown up . Great job
Have you ever used Kroil with graphite? It is made for high temp lubrication and is perfect for these type of removals where heating is necessary!
Geezz what a nightmare! Glad you saved the day.
We use carbide ball end mills or radius mills to take out broken taps, and other hardened items. Even then you have to lose a lot of oil and go slow. I’ve put in tons of helicoils over the years and even though they work I’m not really a fan. They have Issues built into them that, if you’re not careful during installation causes issues. The main ones I’ve seen are tangs that do not break off, but bend down in the way, and if they do break off sometime the very last thread that was connected to the tang pops out of the groove, that it was supposed to be in and moves down to the next groove. When either of these things happen, the bolt that is screwed into the hole, begins to interfere with the helicoil at the bottom of the hole which chews the bolt up. when you go to remove the bold, it sucks the heli coil insert out with it. I’ve used them in aluminum Mazda, heads to hold the camshaft bearing blocks into place without issue in the past. But if at all possible, I prefer keenserts. they use standard tap sizes so that you don’t have to have special helicoil taps, and they install with regular bolts. Even if you don’t have the installation tool to drive the tangs down it can still be done if you’re careful.
You are fine.
I sometimes have to this but not with a nice drill press at hand .
A vice and work bench & shop light. Lol
Good job
I think the recessed threads are to prevent the machined surface from distorting around each stud after the nuts are torqued to spec. Better flange seal and longevity.
I was wincing this whole video lol nice work!
that was cool, nice repair!
finished result is a thing of beauty
Only suggestions I would make: 1) buy yourselves a set of left hand drill bits. A half dozen sizes to about half an inch should suffice. Once you've drilled your pilot, use the next size LH drill, turning the other way, and drill into what's left of the stud. In all probability it'll unthread from the hole.
2) buy yourselves a tub of "Anchorlube" to use when drilling and taping. I know it's not "necessary" in cast iron, but neither is a broken tap.
3)When trying to extract studs and bolts from exhaust flanges I've found heating the area and the stud to just under red heat, let it cool a little, then apply your WD 40, makes lots of smoke, but the rapid contraction of the metals will usually beak the rust bond free.
4)When installing new studs coat with anti size. Good luck.
My first thought on the loose HeliCoil inserts was that they're basically springs after all, and maybe the exhaust temperatures made them loose their springiness
In the bush I used a spring dowel as a guide(no drill press available). Knock it in to get centered. Choose the right size drill bit for the rest of the way. Great channel guys.
Thats a hellava good idea! After doing this shit for 50 + years, learned something new from you!
Learning from you too. Old school get the job done. You guys are great.
Best I've found On the cat taper lock studs is heat stud cherry red weld a nut let cool use my weak 3/8 impact once it moves spray with penetrant. If you get real tuff one after stud has shrunk then heat manifold or head....
I've have luck a couple times drilling a small hole from the side to get oil to the threads a long with heating, I had to do that to get an AC compressor free from a plow truck where the shank of the bolt was seized to the hole through the compressor body. In that case the hole I drilled wasn't small as the compressor was bad and didn't have a core charge.
i made my own "shake and break" (search "shake and break tool" if you're not familiar) style tool , but with 1/2 square on end for driving sockets . i'm thinking that after nut is welded to stud , the downward impacts of air hammer/shake and break attachment , combined with being able feel how much torque you're applying with other hand would work a little better . haven't tried it on studs yet , but judging by how well these work on screws (amazing) , i believe it'll work pretty well . for using on bolts , you'd need to make spacers for inside of sockets , or grind down sockets , so that impacts are striking top of head of bolt .
Albright chucks are great chucks. I have two of them but I never use them for tapping. Reversing is pretty much an automatic release of the tap.
Hey guys, great work. Im a machinist for a very large CAT dealer here on the east coast and I've worked on... more than a couple of these manifolds. Those studs are absolute nightmares and break 95 times out of a hundred when removing. Honestly, i don't even waste time on removing them anymore. I just run a nut down them and weld the nut to the stud. Either the heat breaks it free or the stud breaks off and saves some time. Then plunge it with a 3/8 carbide end mill to clean out anything hard that may be inside and then over size for heli-coil or keensert. Our labor rate is high enough where it just makes more financial sense to accept that it's going to get an insert and not waste time to try to remove the stud without damage.
Been there done that. I've done hundreds of them. Now I can sit back and watch you guys do them. Isn't retirement great? NO!!! My doctor said that I am not allowed in my shop anymore. Grrrr!!!
Get yourself one of those handheld induction heaters. They allow you to heat cycle the stud very quickly. Heat, penetrant, heat, penetrant... do that a few times; then grab the stud with vise grips, heat the manifold and twist out the stud.
My ritual: use induction heater to get the stud red hot, let it cool down for 15min. whack it with a hammer, weld a nut on, use impact driver back and forth until it starts to move
Lots better to use cold water instead of oil
Lots better to use cold water instead of oil
In our workshop we had a spark eroder, used for removing many a broken tap
Removing broken studs is one of my pet hates. Easy outs are really hard outs, the like to break off and make the job 10 times harder.
I find left hand drill bits useful (usually hand butchered from a normal bit. With heat, penetrating oil and the dodgy bit the threads usually come out. Sometimes I can save the original thread.
I just ran into the same thing on a dozer with a broken drill bit that was at an angle in the hole also a broken tap that was also at an angle. I also had to do the same thing you did and repair all 4 holes. What a mess.
One thing you might consider are drill bushings. We use them all the time in aviation. You can center your drill bit quite well. Just another tool in your tool box.
Of course broken drill bits and easy outs are another thing . Good luck....
When you use penetrating oil, you tap it with a brass hammer after applying the oil to drive the oil into the threads. The hammer impact vibration makes the oil wick into the threads or crack such as getting a bearing race off a spindle.
Get the cast glowing cherry red, then crank the stud out. It helps if you have someone else work the torch while you work on getting the stud out.
I have pulled hundreds of locked studs out of manifolds while still installed on the vehicle. There has been times that the stud/bolt is broken off, so you take a nut, hold it there centered and take the mig welder and fill the hole in the nut including into the broken stud/bolt with the weld and then real fast while the heat is still there take the impact to it and zip it out. Do it fast but not while there is any red glowing otherwise the welded nut will just break off.
@16:13 That Loctite won't work unless it's super high temp.
Whenever I run into this situation, I begin by heating the whole thing until the EZ Out and drill bit are glowing orange and letting them cool for an hour or so to take the temper out of the broken bits, then use your end mill to get a flat spot to start the drilling process.
So.. When you hit the side of that hot casting with the air hammer it doesn't serve to peen in and tighten the hole around the bolt and stick in in harder after it cools? I would have thought that to be a potential pitfall rather than just using heat.
17:35 I had to repair a French horn rotor valve in the mill. Someone had broken w retaining screw off inside, and then just drilled the hole larger making it useless and then soldered the screw in.
When I went to drill out the old damage for an insert, I got about .075" in and the spindle I was drilling suddenly exploded, shattering out the side.
The previous guy had left a roughly #53 drill bit inside, and when my #47 drill bit made contact it caught and just blew out the side.
At that point, I called my supplier and luckily they had the VERY LAST rotor available for sale ever. Now the part is obsolete, and the French horn has a new rotor.
I always had great luck heating the manifold up red hot and blasting it with cold water. Most often that does the trick of breaking it free. I never try try to move a heat-softened bolt.
That is what I learned in a shipyard. Steam is a beast!
I'm a former Turbo Technician - For broken studs, bolts & whatever, here's my 2c worth.
Get a carbide masonry drill, sharpen it up like a 135' twist drill and use that to drill out the remaining material.
If it's a broken drill bit, use a centre cutting carbide end mill to work your way through.
If you manage to break the carbide, find your local toolmaker and ask about spark eroding or EDM to remove the material.
Here is a trick for broken bolts and screws: Start drilling and keep drilling the bolts remnants out only using LEFT HANDED DRILL BITS. I have had lots of bolts and screws catch on the bit's flutes and back out that way. If you are a fraction of a smidge off center the remnants of the bolt collapse and the it catches on the bit and it comes out, and you can use the original threads. One of the local shops had a little old Vietnamese guy who burned out broken bolts with a tungsten rod. He had a very special gift for doing that.