How much loctite to use?

[LBD]

No, the only time KTM says to oil threads (and under the bolt head) is for cylinder head bolts. The rest of the time it's dry or with the specified Loctite (for the pedants; yes, the branded product as they OEM to KTM) or maybe some anti-seize compound. And I don't think it's just KTM (other manuals are out in the garage); I've never oiled threads and I'm an avid reader of instructions for getting the best results.

Yes, dry threads particularly into dissimilar metals are prone to galvanic(?) corrosion; a good way to stop this is to use threadlocker!

Yes well thread locker, is a lubricant when fluid....

But tell me... Does the manual specifically say "These threads must be assembled dry" or does it just omit to recomend you lubricate the threads?

But the whole idea of lubricating the threads is to reduce the friction especially when screwing bolts into aluminum housings...this prevents the threads from galling and increases the chances of acheiving the OEM's intended clamping force.

Certainly in no circumstances assemble with less (Or More) torque than the OEM recomends.

Galvanic Corrosion is only a problem with an electrolyte and dissimilar metals (Steel screws into aluminum housings)...Battery acid, sea water or some detergents...thread locker is a good solution as is a Cadmuim compound...Never Seize adds to the problem as it contains Copper and Nickel...both so much more noble than a steel bolt.

[Ocean1]

But tell me... Does the manual specifically say "These threads must be assembled dry" or does it just omit to recomend you lubricate the threads?

Most manuals have a disclaimer indicating a default procedure. I just checked a KTM 950 manual, (it was handy) and it doesn't specify. That's not good.

The point is in many cases that default is indeed "clean and dry". Perhaps because most engineering standards use that as a default procedure: http://www.engineershandbook.com/Tables/torque1.htm

A thread's just a wedge, the pitch angle on most is what's called self-locking, for most combinations of material once they're tightened they won't undo themselves. Unless you lubricate them. So sometimes it's a good idea to lubricate threads and sometimes it's not.

The torque values below indicate the amount of torque needed to produce the same stretch (clamping force) on a couple of sample bolt spec's.

5/16-18 threads per inch:
No Lube, steel threads - 29 ft lb (100%)
Plated and Cleaned - 19 ft lb (66%)
SAE 20 oil - 18 (38%)
SAE 40 oil - 17 (41%)
Plated and SAE 30 - 16 (45%)
White Grease - 16 (45%)
Dry Moly Film - 14 (52%)
Graphite & Oil - 13 (55%)

1/2-13 threads/inch:
No Lube, steel threads - 121 ft lb (100%)
Plated and Cleaned - 90 ft lb (26%)
SAE 20 oil - 87 (28%)
SAE 40 oil - 83 (31%)
Plated and SAE 30 - 79 (35%)
White Grease - 79 (35%)
Dry Moly Film - 66 (45%)
Graphite & Oil - 62 (49%)

As you can see there's quite a difference.

And there's a shitload more to consider when specifying a fastener's installation procedure. So it shouldn't come as a great shock that sometimes the manufacturers get it wrong. Sites like this are (supposed to be) good places to find out about those instances and what people have found to work better.

[warewolf]

Yes well thread locker, is a lubricant when fluid....

Not in this context. The K value on blue loctite is close enough to dry threads that you don't need to adjust the torque value, according to Dirty.

But tell me... Does the manual specifically say "These threads must be assembled dry" or does it just omit to recomend you lubricate the threads?

A Kawasaki manual I have here says "All of the values are for use with dry solvent-cleaned threads."

A Honda manual I have here says "Use a locking compound such as (blue Loctite) on all bolts and nuts" (see comment above).

A Hinckley Triumph manual I have here covers all carbed bikes up to 1997; "Lubricate threads with engine oil" is one of 10 listed deviations from the unspecified default, and it applies to only 2 of the several hundred torques listed in the table.


I'm quite comfortable with clean & dry being the default, thank you.

[Ocean1]

There's a product called Prolan which deals with the galvanic issue. It's basically lanolin, (sheepswool oil) and I don't know how it prevents galvanic corrosion, but it does.

I first came across it on stainless screws in an alloy mast, they'd been there for years and none of the usual white powdery deposit was evident. You can get it as a grease or as an aerosol and I've used it where appropriate ever since.

Of course it's a lubricant of sorts...

[LBD]

There's a product called Prolan which deals with the galvanic issue. It's basically lanolin, (sheepswool oil) and I don't know how it prevents galvanic corrosion, but it does.

I first came across it on stainless screws in an alloy mast, they'd been there for years and none of the usual white powdery deposit was evident. You can get it as a grease or as an aerosol and I've used it where appropriate ever since.

Of course it's a lubricant of sorts...

The Cadmium product I was thinking of is "Duralac" sets hard but fastenings come loose easy enough when wanted. Particularly good for aluminum with SS fastenings.

I think the prolan product is an insulator/sealer similar to the practice of using nylon bushing around SS fastenings in Aluminum...keeps the metals apart and keeps the joint free of moisture

I need to ponder your Torque argument...about 30 of us at lunch time were stunned that anyone would recomend torquing up dry fastening....and more to the point, use less than manufacturers recomended torque when they use a lubricant on the threads.... I notice your occupation...but equally I have a couple of mechanical years under my belt.

The other really good product was Res Q Steel from International Paint....the original brew was lanolin and red (Or white) lead...but that has changed...they still make it but to a different formula...works good if it does not get warm...it melts at low temp.