Grease/Loctite bolts on assembly

sandman768 wrote:

After working on numerous vintage bikes where no one used grease on anything, I use a small dab on all bolt threads unless it’s a bolt...

After working on numerous vintage bikes where no one used grease on anything, I use a small dab on all bolt threads unless it’s a bolt that is common to come loose, then I use blue loctite. I don’t know if it’s right or wrong, but my bikes come apart nice & easy.

Brett Campbell wrote:

I use the same setting.

FWYT wrote:

Thank you!

Luxon MX wrote:

The torque values listed in manuals are typically specified for non-lubricated fasteners. If you add a lubricant or anti-seize (typically a specialty lubricant), you need to...

The torque values listed in manuals are typically specified for non-lubricated fasteners. If you add a lubricant or anti-seize (typically a specialty lubricant), you need to account for the reduced friction. It varies based on what lubricant or anti-seize you're using, but a 40% torque reduction is a reasonable starting point if you don't know the properties of the lubricant.

We use Loctite C5-A anti-seize for our titanium bolts, and we supply some with our parts to ensure everyone is using the correct stuff. The data-sheet is available here:

http://tds.henkel.com/tds5/Studio/ShowPDF/C5-ACBAS-EN?pid=C5-ACBAS&form…

It references a k value (essentially friction value) of 0.27 for an unlubricated bolt and 0.16 for a bolt with anti-seize applied. That's a 40% reduction, hence the 40% reduction in applied torque for the same bolt tension.

The Permatex data sheet (https://441py33rout1ptjxn2lupv31-wpengine.netdna-ssl.com/wp-content/upl…) does indeed say "Reassemble parts using normal torque values.", but it also says that the anti-seize is a lubricant, so I wouldn't trust their instructions for using normal torque values. And in general, I stay away from Permatex as I've had bad luck with their threadlockers in the past. Henkel (Loctite) is my preferred brand by far.

cdncombatmedic wrote:

Just curious on your issues with Permatex. I have been using it for quite a while with no issues. It's more readily available to me than...

Just curious on your issues with Permatex. I have been using it for quite a while with no issues. It's more readily available to me than the Henkel brand.

debun wrote:

I'm an engineer and have designed several bolted joints and done plenty of laboratory testing. I would not deviate from anything in the manual. Not only...

I'm an engineer and have designed several bolted joints and done plenty of laboratory testing. I would not deviate from anything in the manual. Not only will you see variation in the clamp load but also with lubricants (grease a vs grease b could be 40% difference right there) but you will also see variation with repeat tightening. The last company I worked for, we specified a wax top coat on 100% of our hardware. That is if you used a bolt from the hardware store you likely be off by about -50% in clamp load. Pretty scary when you think about all the aftermarket bolt kits from companies that likely have no clue how the OE fasteners perform. I'm not sure what the OEM's do but I try to design for a >4X factor of safety since you see huge variations in user serviceable joints. On some vehicles they will even have single use bolts that stretch when torqued correctly. Unless you know what the thread modifier is doing to the joint I would stick with what ever the manual says.

debun wrote:

I'm an engineer and have designed several bolted joints and done plenty of laboratory testing. I would not deviate from anything in the manual. Not only...

I'm an engineer and have designed several bolted joints and done plenty of laboratory testing. I would not deviate from anything in the manual. Not only will you see variation in the clamp load but also with lubricants (grease a vs grease b could be 40% difference right there) but you will also see variation with repeat tightening. The last company I worked for, we specified a wax top coat on 100% of our hardware. That is if you used a bolt from the hardware store you likely be off by about -50% in clamp load. Pretty scary when you think about all the aftermarket bolt kits from companies that likely have no clue how the OE fasteners perform. I'm not sure what the OEM's do but I try to design for a >4X factor of safety since you see huge variations in user serviceable joints. On some vehicles they will even have single use bolts that stretch when torqued correctly. Unless you know what the thread modifier is doing to the joint I would stick with what ever the manual says.

cdncombatmedic wrote:

Honestly I just use a very light coat of anti seize or thread lock and torque to what the manual states. Knock on wood have not...

Honestly I just use a very light coat of anti seize or thread lock and torque to what the manual states. Knock on wood have not had a problem yet. At the end of the day, some of the information posted is just too complicated. Maybe if you are working on the space shuttle.

kb228 wrote:

Just want to throw this out for discussion. Putting steel bolts into aluminum uncoated will facilitate corrosion and possibly seize the bolts. When you do finally...

Just want to throw this out for discussion. Putting steel bolts into aluminum uncoated will facilitate corrosion and possibly seize the bolts. When you do finally get the bolts out theres still going to be residual corrosion in the threads that will not be cut out with a tap or thread chaser. That will cause rougher thread surfaces and more friction. Because of this, whos to say that additional friction gives you the correct torque reading on your wrench but doesnt provide the clamping force as a proper clean fastener at the correct torque reading.

From what has been mentioned above, it sounds like theres an inverse relationship between the clamping force and the amount of friction on the threads. More friction = less clamping & less friction = more clamping.

kb228 wrote:

Just want to throw this out for discussion. Putting steel bolts into aluminum uncoated will facilitate corrosion and possibly seize the bolts. When you do finally...

Just want to throw this out for discussion. Putting steel bolts into aluminum uncoated will facilitate corrosion and possibly seize the bolts. When you do finally get the bolts out theres still going to be residual corrosion in the threads that will not be cut out with a tap or thread chaser. That will cause rougher thread surfaces and more friction. Because of this, whos to say that additional friction gives you the correct torque reading on your wrench but doesnt provide the clamping force as a proper clean fastener at the correct torque reading.

From what has been mentioned above, it sounds like theres an inverse relationship between the clamping force and the amount of friction on the threads. More friction = less clamping & less friction = more clamping.

debun wrote:

That's a common miss conception and easy one to make. Steel bolts come in many kinds. Stainless, black oxide, zinc, nickel etc. In addition to plating...

That's a common miss conception and easy one to make. Steel bolts come in many kinds. Stainless, black oxide, zinc, nickel etc. In addition to plating your OE may put a top coat which is invisible to the user. What you described will happen if the incorrect fastener is specified. Not only could you have corrosion issues but galling which will occur during tightening. Trust me, if you are aware of this the engineer designing that joint is too. The very last joint I designed was in aluminum and there is zero grease or anti seize applied. All the magic was is in the top coat on the fastener which is invisible to you the user. This is why I recommend you follow whats in the manual and use OE hardware. If you use some bolt kit of ebay all bets are off. Just google "fastener top coat" and you will find more info. You can safely install steel hardware into aluminum when done right which describes most modern day vehicles.
Remember you need the right about of clamp load. It's like tire pressure, more is not always better and too low is always bad.

debun wrote:

I'm an engineer and have designed several bolted joints and done plenty of laboratory testing. I would not deviate from anything in the manual. Not only...

I'm an engineer and have designed several bolted joints and done plenty of laboratory testing. I would not deviate from anything in the manual. Not only will you see variation in the clamp load but also with lubricants (grease a vs grease b could be 40% difference right there) but you will also see variation with repeat tightening. The last company I worked for, we specified a wax top coat on 100% of our hardware. That is if you used a bolt from the hardware store you likely be off by about -50% in clamp load. Pretty scary when you think about all the aftermarket bolt kits from companies that likely have no clue how the OE fasteners perform. I'm not sure what the OEM's do but I try to design for a >4X factor of safety since you see huge variations in user serviceable joints. On some vehicles they will even have single use bolts that stretch when torqued correctly. Unless you know what the thread modifier is doing to the joint I would stick with what ever the manual says.

cdncombatmedic wrote:

Honestly I just use a very light coat of anti seize or thread lock and torque to what the manual states. Knock on wood have not...

Honestly I just use a very light coat of anti seize or thread lock and torque to what the manual states. Knock on wood have not had a problem yet. At the end of the day, some of the information posted is just too complicated. Maybe if you are working on the space shuttle.

debun wrote:

Mostly consumer products but most recently vehicle accessories. All Ford and GM hardware has a friction modifiers, That's not the space shuttle. My point is if...

Mostly consumer products but most recently vehicle accessories. All Ford and GM hardware has a friction modifiers, That's not the space shuttle. My point is if you have no clue whats going on, don't think you know more than the engineer and start applying lube where there wasn't. Just follow whats in the manual. I for example would not lube my fork clamp bolts.

kb228 wrote:

Just want to throw this out for discussion. Putting steel bolts into aluminum uncoated will facilitate corrosion and possibly seize the bolts. When you do finally...

Just want to throw this out for discussion. Putting steel bolts into aluminum uncoated will facilitate corrosion and possibly seize the bolts. When you do finally get the bolts out theres still going to be residual corrosion in the threads that will not be cut out with a tap or thread chaser. That will cause rougher thread surfaces and more friction. Because of this, whos to say that additional friction gives you the correct torque reading on your wrench but doesnt provide the clamping force as a proper clean fastener at the correct torque reading.

From what has been mentioned above, it sounds like theres an inverse relationship between the clamping force and the amount of friction on the threads. More friction = less clamping & less friction = more clamping.

debun wrote:

That's a common miss conception and easy one to make. Steel bolts come in many kinds. Stainless, black oxide, zinc, nickel etc. In addition to plating...

That's a common miss conception and easy one to make. Steel bolts come in many kinds. Stainless, black oxide, zinc, nickel etc. In addition to plating your OE may put a top coat which is invisible to the user. What you described will happen if the incorrect fastener is specified. Not only could you have corrosion issues but galling which will occur during tightening. Trust me, if you are aware of this the engineer designing that joint is too. The very last joint I designed was in aluminum and there is zero grease or anti seize applied. All the magic was is in the top coat on the fastener which is invisible to you the user. This is why I recommend you follow whats in the manual and use OE hardware. If you use some bolt kit of ebay all bets are off. Just google "fastener top coat" and you will find more info. You can safely install steel hardware into aluminum when done right which describes most modern day vehicles.
Remember you need the right about of clamp load. It's like tire pressure, more is not always better and too low is always bad.

kb228 wrote:

That makes sense. Leads me to another question, what about bolts that have been reused over and over? That coating wears off. You either need to...

That makes sense. Leads me to another question, what about bolts that have been reused over and over? That coating wears off. You either need to buy an entire new set of hardware for your bike or put a coating on. Manual doesnt say replace every bolt. Axles and swingarm pivot bolts are good examples of high reuse, high levels of dirt, and high corrosion items. its more cost effective to put something on the threads than to replace them. Especially if you have a resource like one luxonmx provides where it tells you how much to reduce the torque to achieve the correct clamping force.