16 votes
Accepted

Stainless Steel Fasteners

Stainless and aluminum are pretty far apart in the galvanic series of metals with aluminum at the anodic (corroded) end. This means that in the presence of an electrolyte the stainless bolt will be ...
dlu's user avatar
  • 14.5k
13 votes
Accepted

What fasteners should not be loosened using an impact wrench, and why?

As the name suggests, impact wrenches have the ability to impart high amounts of momentum change. The delivery of this momentum change is hard to meter, so it is quite easy to damage: soft metals ...
Zaid's user avatar
  • 39.1k
12 votes
Accepted

What size hole should be drilled for an individual tap?

https://engineering.purdue.edu/ME463/Course%20Documents/Design%20Resources/starrett-inch-metric-tap-drill.pdf This is my favorite chart for tap drill sizes. The chart incorporates tap sizes and the ...
vini_i's user avatar
  • 16k
12 votes
Accepted

Torx vs. Star Fasteners

"Torx" is a trademark, i.e. a name for a company and can be renewed indefinitely. The Torx design used to have a patent that expired in 1990. After the Torx patent expired, ISO 10664 was created ...
Zach Mierzejewski's user avatar
9 votes
Accepted

"Always Replace" (torque-to-yield) Bolts

I cannot tell you directly if the bolts you are using are Torque to Yield (TTY or T2Y) bolts, but if Bently says to replace them, you bet I'd do it. What are three bolts in comparison to the well ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
7 votes

Stainless Steel Fasteners

The most immediate issue is galling. Stainless steel typically contains a lot of suspended carbides ie very hard particles in a soft matrix. This means that stainless threads are prone to galling and ...
Chris Johns's user avatar
  • 1,586
7 votes

What size hole should be drilled for an individual tap?

There is a formula for it.... take the nominal size (.250") and the reciprocal of the threads per inch (20TPI = .05). .250 - .05 = .205, the drill size. Here's another 3/8-16.... .375 - .0625 = ....
Wes Johnston's user avatar
7 votes
Accepted

Securing exhaust manifold studs?

According to their datasheets Resbond 970TS is capable of withstanding 2100°F Another method would be the use of locking wire on the studs
Martin's user avatar
  • 8,448
7 votes
Accepted

Removing rusted partially broken engine fasteners

Your best bet is to use heat. Take a torch (propane will work just fine) and heat the stud portion until it is cherry red. Then douse it in PB Blaster or WD40 or just about any other lubricant. Then ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
6 votes
Accepted

Torque specification thread lubricant best-practice as specified by manufacturers

In general, the assumption is that you are not using a lubricant. When a lubricant is specified, obviously then you use it. Using a lubricant will result in the same torque readings, but higher ...
dlu's user avatar
  • 14.5k
6 votes

Removing rusted partially broken engine fasteners

Not exactly what you're asking for, but maybe a different solution. I had similar problems with a couple of Chevys. More-or-less, I cut the studs flush, and used a pair of 'split flanges' to join ...
George's user avatar
  • 1,113
6 votes
Accepted

Circlip removal when pliers are too large

Snap-ring pliers can be obtained with various sizes and orientations for the plier pins: (photo from Motion Pro) You need pliers whose pins are close enough together (and small enough) to fit between ...
DavidRecallsMonica's user avatar
6 votes

Circlip removal when pliers are too large

While using pliers may be the best way to remove this circlip, another method would be to just use a flat tip screwdriver. Place one side into the notch and then twist to get the other side into the ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
5 votes

Removing rusted partially broken engine fasteners

These bolts can be very difficult to remove due to the rust and heat they are exposed to. The threads are rusted both externally and internally. I've had some success with the following: Soak with a ...
jwh20's user avatar
  • 12.1k
4 votes

Alternatives to left-handed thread without resorting to specialist tools

Left handed nuts are typically cut that way so the spinning of the motor/engine will not loosen the nut over time. A right handed nut will likely loosen over time from the torque of the motor starting....
rpmerf's user avatar
  • 8,403
4 votes

Alternatives to left-handed thread without resorting to specialist tools

The specific repair you describe; repairing a radiator fan without the correct fixings, can be done in a number of ways. One of the most creative ways I've ever encountered was on La Carrera ...
Steve Matthews's user avatar
4 votes
Accepted

Alternatives to left-handed thread without resorting to specialist tools

There is a tool known as a thread file. While it is a semi specialty tool, it is common for garages to own one. A thread file only depends on the thread pitch and independent of both the diameter of ...
vini_i's user avatar
  • 16k
4 votes
Accepted

Sources of Torque-To-Yield bolts?

The TTY bolts need to be specific to the application, but don't need to be sourced through the dealership. Fel-Pro makes a lot of bolts which replace the stock bolts in a TTY application. Usually ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
4 votes

"Always Replace" (torque-to-yield) Bolts

The other question I'd love an answer to is why are the bolts "always replace." Does the torquing process (20 Nm + 90º) weaken the bolt, or is it not reproducible? Or something else altogether? ...
alephzero's user avatar
  • 2,944
4 votes

Air trapped inside threaded "blind" hole vs. hole integrity

Air usually will not cause this issue. It will compress quite a bit without the worry of it causing issues. If thread locker is use, it would be trapped. Without it, it will escape past the threads ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
4 votes

Con rod fastener's washers: tabbed or spring washers?

I would use the tabbed washers : they don't affect the torque reading as once the nut is torqued, they bend easily and just lock the nut into place. Loctite - if available - may not always be ...
Solar Mike's user avatar
  • 34.6k
4 votes

Circlip removal when pliers are too large

That isn't a circlip, this is a grip ring. They are stronger than circlips, and normally reside on an smooth shaft, without notch. Therefor they have a larger clamping force. I found that they are ...
Martin's user avatar
  • 8,448
3 votes

Securing rods for threading: how to avoid vice bites?

Use a collet block These are designed to take a collet and tighten down on a rod. It works just like collets in a lathe or the spindle on a mill. You can hold the block in a vise, install the ...
Hari's user avatar
  • 781
3 votes

Head studs' threads larger length: problematic issue?

They will be fine - did something similar in the past. You say hardened, but did you get a sufficiently high grade steel? i.e. strong enough? It would be good practice to use a compound to prevent ...
Solar Mike's user avatar
  • 34.6k
3 votes

Washers under head bolts: Should I use them under stud nuts?

Yes, part of the function of a washer is to spread the load. If the manual or parts list lists them then they should be there - someone in the past may have made a mistake and left them out...
Solar Mike's user avatar
  • 34.6k
3 votes

Torque specification thread lubricant best-practice as specified by manufacturers

Best practice for all fasteners is clean and dry threads. There are three exceptions. If your using thread locker use the same torque. It is generally assumed that thread locker does not change ...
vini_i's user avatar
  • 16k
3 votes

"Always Replace" (torque-to-yield) Bolts

The actual reason to replace the bolts isn't specifically the bolts, it's the nuts. These are self locking (i.e. Nyloc) style nuts and after they've been removed and refitted, you can't be sure that ...
Steve Matthews's user avatar
3 votes

Spring vs worm gear clamps?

Spring style hose clamps are typically fabricated from steel alloy and plated with zinc for corrosion protection. Aluminum would not be a good choice for spring clamps due to low elastic limits and ...
Don Stante's user avatar
3 votes

Problem installing rivet nuts

Change the stainless screw for a hardened one of the same size. If that fails then you'll be splurging...
Solar Mike's user avatar
  • 34.6k
3 votes
Accepted

What is "non-hardening thread locker"?

Although I can't imagine it would be needed for your application, there is a truly non-hardening thread locking compound available. Vibra-Tite VC-3 is an acrylic polymer that dries to a resilient ...
David Matlock's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible