Is it Better to Leave Thread Repairs to the Professionals?
Yes. Well, at least when it gets to the extreme.
A common motivator to start handling repairs yourself is to save money. However, the reality is that you're not going to start saving right away. Buying the tools you need to start working washes out any savings of the initial few jobs and many more depending on what tools you buy and of what tier. The good news is that you rarely need to add to the list of commonly used tools for basic jobs. It's when you start getting into specialized work that you'll start to strain your resources. You do need to buy tools and learn to perform specialty work in some circumstances, though.
Thread repair, for example, is something you'll likely need to learn if you're working with used goods that have had cruel and unusual lives. The only problem is that not every thread repair job benefits from the same practices, and you can quickly find yourself on a slippery slope if you're not careful. That's a slippery slope I recently found myself going down. Since I'm part of The Drive's ace team of overly confident DIYers, I figured why not give you a look at what I ran into so that you can explore the idea of determining your own limits and when it's better to just call a pro.
Let's get after it.
The Drive and its partners may earn a commission if you purchase a product through one of our links. Read more.
Are Bad Threads a Death Sentence?
Stripped threads have a way of catching you off-guard and jamming things up, but they aren't always something to lose your mind over. A lot of times, even if there are plenty of reasons to dislike them, threaded inserts are a great way to get yourself out of a sticky situation. All you're doing is enlarging the existing hole, threading that, and running down an insert that returns the hole to the original thread size. You even have options to work with to handle a litany of different situations. For example, Heli-Coil inserts are great for minor jobs, whereas EZ-Lok's inserts are a great help in more dire situations.
What if you run into the worst-case scenario, though? What if a large threaded insert was in place, and both that and the threads to hold it were botched? You've got serious problems.
I ran into that exact situation in my Charger project. It wasn't a death sentence, but it meant to get the job done was simply out of my capacity, even if it all seemed relatively simple on paper.
Where Does Room for DIY Run Out?
There are a few ways to handle this type of thread repair. The approach I opted to take involved boring the hole out to an even larger diameter, plugging that hole with a larger bolt, cutting it flush, and starting from scratch. That sounds pretty simple, right? Let's break down where I went wrong.
I didn't consider what this job would cost to handle myself versus what a professional would charge for it. Between a good set of drill bits and threading tools that are actually worth anything, I had already put myself in the hole. The cost of replacing broken bits and taps along the way made matters worse and then factoring in the amount of time I spent to get it done only added insult to injury. For the record, I spent about $140 by the time all was said and done. That doesn't sound too horrible in the grand scheme of DIY repairs. That is unless you hear that I was quoted about $100 to have it professionally repaired. Even with the $20 head gasket, letting a pro handle it would put me ahead.
Keep in mind that drilling through hard metal is done rather slowly with a good amount of pressure, moving through much smaller increments in bit sizes than you would with softer materials. It’s a lot more work than it appears to be when doing it by hand, even when tapping 3/8-inch threads.
The silver lining is that I did walk away with an acceptable final product. Though not perfect, I'm comfortable putting it into service. I also know that if things were to go totally sideways someday in the future, I could fall back on this skill to get me out of a bind. However, the price of a replacement head gasket and a trip to the machine shop would have saved me money and time while yielding much better results. And realistically speaking, I can't exactly justify the loss as this isn't a situation I commonly encounter.
The point that I'm getting around to is that there's a limit to the work we should be willing to perform based on our personal situation and the scenarios we commonly encounter. For me, this is my limit, and the most logical solution to this problem is simply to take this level of thread repair to the pros because that's far more beneficial than the results I can produce by taking it on myself. I'm confident in saying that the same is true for most gearheads of my skill level, with room for some exceptions.
Consider It All Before You Begin
It’s also worth mentioning that you can really jam yourself up by taking on bigger challenges like this on the fly.
While the top end of the engine inside of my 1969 Dodge Charger needed to come off for some other work I had opted to take on anyway, I put myself in a position where I added a significant amount to my existing workload. I had to come up with ways to keep my engine clean, as I decided to leave the head in place. The hood had to come off to start, but the work I originally signed up for took a back seat in the meantime. Had I let someone else handle it, not only would I have saved money and time, but I'd be further along with the original project.
If I were to isolate just this thread repair issue in an area that was easier to access and less demanding of a clean environment, it might be something I'd feel comfortable approaching again. But that comes back to the point that personal limits are situational, and you must think about all the moving parts before you decide to jump on something as in-depth as thread repair can be.
Knowing how to handle thread repair will save your wall from some wrenches, though. That’s why I’ve attached a video that runs through a few of your options for dealing with stripped female threads. It’s a good watch, and a great excuse to hang out with Adam Savage's Tested crew.