Yes they are taps, but they don't cut. Some of them have flutes.

Can you show me the specifications that a thread chaser meets? I would honestly love to read it.

Edit: https://www.ostermfg.com/resources/t...erating-theory
​​​(I forgot that the term "chaser" refers to the fully sized portion of a regular tapered tap. So a plug or bottoming tap would consist of mostly or only chaser threads. Hence my post above still is valid and so too would be even a regular cutting tap.)

There's ton's of summary talk about using a chaser. But I have yet to see a study or analysis or specification on chasing. To me it appears that chasing is a generic term used to describe a process. The technical information I have seen all mention chasers cut. Something that I would really not want to do in an existing aluminum threaded hole.

I saw a machinist say, and someone here as well, the best chaser is the fastener with flutes cut in it. And while I don't disagree in theory, you better make sure you didn't bugger up the threads in the process and you probably want to chamfer the leading edges of the flutes you just cut. Otherwise you just made a very poor tap.
​​And finally, a fastener won't fully clean the threads out because it won't be able to to reach all the way to the valley of the major diameter.

That's why I still prefer the solvent, brush (nylon or even a wood toothpick), vacuum technique of cleaning threads. If at that point a new clean bolt (sans threadlocker) still doesn't thread easily, I would use one of these chip less, non cutting forming taps. Because at that point you should have already removed any debris and now will only be dealing with actual deformed/damaged metal threads.

BTW, no shop is going to do that technique, but I would.

 

I think this sounds nice. But what is the pressure involved? A screw on cap would probably be plastic and have to be much larger. And you'd probably still have people over torque it. Then people would complain it was made out of cheap plastic.

An M5 bolt is similar in size to a #10. This is a beefy enough fastener. Usually we like to use this size as a min for strength. So it isn't like they put some tiny electronics screw on.

 

Taps are to create by forming or cutting threads. If they have flutes its so there is an area for the waste to collect. You are making some assumptions and acting like it's fact. I will admit that it's very possible for someone to call a thread chaser a tap but a tap is used to create threads. But all that said I agree that for us an old bolt with a dremmeled slot or just using a bristle brush is all we need.
"Threading taps are a tool used to create screw threads (tapping) into a pre-drilled hole, to create a clean fitting for bolts in metals and plastics. Used in engineering and manufacturing, threading taps work like a drill but due to the unique shape of a tap, when screwed into a piece of material, screw threads are created. Threading taps must be used in a predrilled hole and cannot be used for drilling entire holes.

The difference between taps and dies is that taps are used to create or repair threads in holes which is ideal for nuts. Dies are used to cut threads on materials such as steel rods to allow a fitting to be screwed on and attached (threading). The tap is designed for internal thread cutting, so this would be used on the fastener hole or a nut, whereas a die is used for the external thread, like on a bolt. In other words, tapping uses the tap part of the set and creates internal threads and threading is the process used by the die to cut external threads.

Threading Taps are available in HSS (high-speed steel) and carbide and can be used by hand or machine. Our range of threading taps offers the best tool for every machining method or process to meet all your requirements. Threading taps can be used with a tap wrench or power tool and are available in various sizes to accommodate a range of applications.

Taps can be used by machinists in different ways for different applications:

• Taper taps or starter taps, are used to initially start a new thread with the first 7-10 threads having a flatter profile than those further up the shaft.
• Plug taps are similar to taper taps but only have 3-5 starting rows ground down leaving more shaft to create a thread.
• Bottom taps are square in profile with no ground down threads and are used after a taper or plug tap has been used. Their full length cutting shape allow for threads to be cut at the very bottom of a hole for maximum thread length.
• Spiral flute taps – for blind hole applications
• Spiral point taps – push chips forward, ideal for through-hole applications
• Straight flute taps – most commonly, designed for short chipping materials
• Forming taps – compresses to produce a thread rather than cutting
• Taps come in both Metric and Imperial dimensions and can have different shank types. Threading taps are used in conjunction with a tap wrench so always consider the maximum side tap your wrench can hold when purchasing."

 

We always have to make assumptions, it's part of the job. I should clarify thses are presumptions it isn't based on nothing. But no these aren't facts. If they were I'd be charging $ for it.

But I had to revise my statement a bit:
https://www.ostermfg.com/resources/t...erating-theory
​​​I forgot that the term "chaser" refers to the fully sized portion of a regular tapered tap. So a bottoming tap would consist of mostly or only chaser threads.

The ideal is you want a tap that has only full size threads and no tapered (undersized threads) so for example if you took a tapered tap and cut off the tip and left the back portion. If you did this, you would also need to chamfer the leading edge, so the end result is essentially bottoming tap. (not technically, as a chaser might not have any tapered threads).

I would not use a cut bolt to chase, it won't clean the threads out well and fasteners are not made to the same tolerances as a tap. They are made to fit and be mass produced. I think one is more likely to damage the threads.

(disclaimer, this is a forum and I'm typing on a phone. I'm not going to write an entire technical white paper. Although it would be nice if someone did because I am still trying to find actual published info on this subject. It's important to understand that criticality of cleaning the threads. I think if you don't feel comfortable doing the job or having the dealer do the job then just don't buy the car. Do I wish GM put in a part number?,yeah. But it would have to be in a kit or have a GM part number. It sounds like they don't sell this chaser as a GM part number. So they can't list any part number and that number if replaced outside the control of GM would then cause people to freak because they can't find the correct part number, and then they can no longer maintain their vehicle.

So I presume that the engineer wants the mechanic to generally figure it out and not just clean the thread but also repair any damage. Thus mitigating the need to install an insert and ensure the lifespan of the original thread. But to say all of that in the manual is a bit much much and probably considered not as professional. )

 

Here's a thread, happens to even discuss the same size we are dealing with. Thought post #8 was a good answer.

https://bobistheoilguy.com/forums/th...r-taps.351572/

And here post #3

https://bobistheoilguy.com/forums/th...-block.273266/

So again, haven't seen any real hard evidence backing up legitimate chasers. I'm beginning to think that the use of a so call device is actually improper. Especially since I still have yet to find any well presented studies and even articles on it.

Especially knowing how weak aluminum is and can fatigue. I'm definitely still feeling the don't use a any tap unless you have to.

 

Just clean the threads however you want as long as you are using a method that won't damage the threads and then check with a bare (no thread locker) bolt. If it runs freely then you are done. If it doesn't run freely but doesn't feel like it is binding hard then work it in and out until it does run freely (use some lubricant). If if feels like it is binding hard (I don't think this will happen) then make a thread chaser or carefully use a tap, whichever you prefer.

I found some images of the filter housing online, the holes are through holes so you don't have to worry about a flute for debris. Again, I'm just going to run a bare bolt through the holes to clean out the threads. There won't be any more tolerance issues with a bare bolt than there will be for the fasteners that come with the kit with thread locker pre-installed.

 

Another option (and probably how it should have come from the factory):

If you don't want to screw up the threads or install inserts (which requires drilling) is to install studs and then use nuts to clamp the cover on. This will provide you with a much more durable and strong long-term solution without having to modify or wear out the existing threads.

 

cutting grooves in bolts is insanity- contacted both local dealer- they don’t know anything about a thread chaser- more insanity