How many times can you reuse lock washers.

[Sarikatime]

I have some nice but very rusted lock washers, but are they still good to reuse or should I buy new ones every time I retighten a nut? Do they lose their tension or usefulness after being used for some time and are they just as safe to use as the first time?
Silly question but I am using lock washers now more than catter pins. Frank

[Rich Eagle]

They lose a little. Unless they stay flat after use they have some tension in them. I would consider how vital a spot they are in.
Rich

[Rich P. Bingham]

My opinion, but if you compare a "vintage era" lock washer with one newly minted, you'll find the old ones have a sharp, square profile twice as thick as a new one. I have never seen one "go flat", and wouldn't hesitate to reuse them. In my experience, when they fail, they break.

[Don D]

While I am not a metallurgist and do not play one on TV, a commonsense approach is wise. Heat and water are the chief enemies of metal. I would attempt to clean up slightly rusted bolts, nuts and washers. Heavily rusted fasteners may need replacement.

In the past I have cleaned up lock washer, they are then slightly bend, heated and quenched. I hope this is of some help.

Dom

[Jerry VanOoteghem]

Split lock washers have been known to break in two. I would not use them anywhere where safety is an issue... which is pretty much anywhere on a T.

Here's what NASA says, (see page 9)...
https://ntrs.nasa.gov/api/citations/199 ... 009424.pdf

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[pron022020]

Most of the times while working on my all original 27 recently, the lockwashers split into two upon being taken apart. Sometimes they come out in one piece, but some are flat. It is getting rare for them to be reusuable.

[Mark Gregush]

When buying lock washers or just washers, take a sample bolt with you and try for size. Many are oversized so next size down may work better or check the metric sized ones.

[Craig Leach]

Hi Frank,
Things may have changed since I was in shop class 50 some years ago but here goes. The purpose of a split lock washer is to put pressure on the nut/screw that it is installed on to prevent it from coming loose. It is wound CCW so it will not inhibit the rotation of the nut/screw from turning when tightening.
It is not intended to cut into or bite into anything to prevent it from coming loose. Washers designed to do that are of the star or toothed variety.
NASA put a man on the moon with the lowest bidder doing the job! So that does not surprise me. If a split ring lock washer has retained it's shape it will probably be OK for most applications. For brake, steering & other safety applications I spend the extra pennies on new ones. As I understand Ford did not use lock washers until the improved car. Is that correct?
Craig.

[TRDxB2]

Split, waffle or spring lock washers are intended to put tension between the surface and nut when the bolt is fully torqued.
"Bolt Science" did comparison test between a flat washer and spring washer to prove that split washers don't work. Take a look at the two video's and see if you can tell why the comparison test is invalid and what it actually did prove. https://www.boltscience.com/pages/helic ... ashers.htm

[Scott_Conger]

From Minuteman guidance systems; Shuttle nose wheel steering, Shuttle Hand Controllers; ISSA JEM Robotic Arm Controllers; B-52 ESG gyros; M119A Howitzer Navigation and Aiming Computers...in 33 years of assembling and then overseeing production and finally designing devices, not once on those 33 years did I ever touch a split washer. There are lots of ways to lock things used in NASA, Air Force, and Army applications , but in my experience, split washers were not among them. The caveat to that, is this: there are in fact MIL-SPEC split washers, and the military does use them...with respect to the parts I put on the M119A Howitzer, my parts were originally designed to more stringent space applications.

The NASA paper declaring that split washers do not lock is a declaration of a fact which lacks complete context. It is a true fact within the world that NASA exists. The fasteners used are of a completely different quality and hardness...the cost of which would ruin you financially if you were to assemble an automobile with them. As such, split washers are simply springs which will skate along the bolt or nut's face and in that context and tested through environmental testing through SINE Sweep and G shock testing, they will not hold fasteners like you typically expect. The Design Paper is absolutely correct. It is remarkable what can happen to an assembly if subjected to high enough G forces at it's natural frequency, either SINE or Random vibration.

That's not the world that laymen live and work in, though.

Compare the NASA environment (special fasteners, etc) to say, a brass carburetor with a part held on with a mild steel screw. The split washer will dig, resist, and practically unwind while fighting you and your best screwdriver tooth and tong. It will lock as intended or expected.

While the man that walked on the moon got there on a craft built by the lowest bidder, the lowest bidder met or exceeded every specification set forth by both the design, and the contractual requirement. Not only that, but every assembly was tested to to near destruction (and sometimes beyond), analysed, and the design and specifications modified and adapted as necessary, such that the device would survive many times it's expected environment.

The lowest bidder shipping a poorly designed or assembled device to NASA or the military mostly happens in the movies and typically has Charleton Heston saving the day.

As for how many times you can re-use a split washer, I personally think you can re-use them every place where it wouldn't matter if they fell out.

[Craig Leach]

Hi Frank,
Looks like I stand corrected again. "Lock washers never worked in the first place" so through them away.
Craig.

[Allan]

Interesting comment that they were housed on T's until the improved cars. That is actually when they were dropped from the front end of the rear radius rods. Another cost cutting measure, with the back nut also being deleted.
Allan from down under

[DanTreace]

Lock washers were originally used many places on the T.

Among those are under the Bendix cover screws, under hex nuts around the crankcase to block bolts after late 1924 when cotters were omitted there, at the radius rods, under the bar mounted headlamp buckets late ‘26 and a few more places am sure!

[Scott_Conger]

Craig

you really do need new split washers installed where they originally were installed on your car. The shorter version of my earlier longer reply is this: The NASA paper was valid for fasteners certified and qualified for use within NASA design requirements. Automotive fasteners are NOT the same as what NASA uses, and under the designed loads and vibration frequencies encountered, do, in fact, work.

[TXGOAT2]

Lock washers of good quality will perform as intended on common hardware. In such applications, the torque applied to the fastener provides the locking force. A good lockwasher correctly installed will prevent the fastener from unscrewing if it loosens slightly. In applications where significant vibration or reversing loads are applied, the lock washer can delay unscrewing. Once the fastener has loosened a turn or so, any resistance to unscrewing from the lockwasher is lost. I believe that safety wire ought to be used on Model Ts where specified, and lock washers used where and if specified. There is a lot of variety among the split type lock washers, and probably a lot of variation in quality and effectiveness. On any critical application, I believe that new lockwashers of good quality and the correct type ought to be used, where specified. I would not replace safety wire or "star" type lockwashers, or any other fastener locking device, such as tabs, pins, etc, with common lockwashers. I would not re-use any lockwasher on a critical joint.

[George Mills]

Hmmm...I haven't been game for a technical discourse since the vast majority of those who would usually egg on my advice have joined the dearly departed club. But this one should be simple and quick.

Caveat #1

With the fact that someone says the OEM split lock washers of the time were twice as thick, there comes a built in caveat...since lock washers are simply square shaped spring coils...that means that originals will have twice the holding power as their later SAE equivalents. (Twice the cross section equals twice the spring load for the same deflection for the same basic material-true science).

Also, as long as they are 'open' and the coil doesn't overlap in a plane...they should still be good to go as they still have their 'spring'. The choice however is yours but also keep in mind that a more modern low grade steel lock washer, at reportedly half the height will also have half of the restraining power...a little bit of lock-tite or find a modern lock washer that SAE calls 'high alloy'. The material change has a near equal and opposite effect. So, half the thickness of original design, a grade of material probably closer to twice the rating than that of originals = all good

Caveat # 2

Unless proven otherwise by drawing or change card, you pretty much have to go with the times and such devices would have been a Grade # 2 or Grade #3 steel material that was dunked into a hot arsenic or other salt bath to provide surface hardness and in theory some strength. Since Material Science was not an agreed science until the 30's, no one realized the heat affected zone transition to the core and this kind of stuff undoubtedly came out more brittle than ductile but still worked most of the time.

All of this....for what its worth. Good luck

[jiminbartow]

Until they become flat washers. You can revive an original lock washer by putting in a vice, heating and slightly rebending to increase the tension, then quenching in oil. Jim Patrick

[Original Smith]

I have noted the old lock washers are thinner than what is available today.

[John Codman]

Split, waffle or spring lock washers are intended to put tension between the surface and nut when the bolt is fully torqued.
"Bolt Science" did comparison test between a flat washer and spring washer to prove that split washers don't work. Take a look at the two video's and see if you can tell why the comparison test is invalid and what it actually did prove. https://www.boltscience.com/pages/helic ... ashers.htm

I purposely have not read the posts after the video of the split washer loosening. It appears to me that the bolt has too small a diameter for the hole. A correct-sized bolt should not be able to move sideways as much as the pictured bolt does. Another tiny little issue is that the lockwasher goes under the nut, not the bolt head.

[TRDxB2]

Split, waffle or spring lock washers are intended to put tension between the surface and nut when the bolt is fully torqued.
"Bolt Science" did comparison test between a flat washer and spring washer to prove that split washers don't work. Take a look at the two video's and see if you can tell why the comparison test is invalid and what it actually did prove. https://www.boltscience.com/pages/helic ... ashers.htm

I purposely have not read the posts after the video of the split washer loosening. It appears to me that the bolt has too small a diameter for the hole. A correct-sized bolt should not be able to move sideways as much as the pictured bolt does. Another tiny little issue is that the lockwasher goes under the nut, not the bolt head.

EXACTLY! There are all kinds of lock washers ( split, wave, wedge etc) designed for specific applications and when properly used and installed they will perform. A generalized statement is always ambiguous and leads to false conclusions. like "any color as long as its black"

[Jerry VanOoteghem]

Until they become flat washers. You can revive an original lock washer by putting in a vice, heating and slightly rebending to increase the tension, then quenching in oil. Jim Patrick

???

How much can a new lock washer cost?
Besides, you've only just made it brittle.

[Jim Sims]

If you look at a good lock washer you will see the split is cut at a angle. This forms a barb that digs into the nut and keeps it from turning. Look at a nut you have removed and usually can see where it has dug into it.

[jiminbartow]

Jerry. Some purists would prefer original hundred year old split washers which, earlier, was pointed out were thicker than new ones. Original split washers would be worth saving. They would not be brittle if quenched in oil. They would be brittle if quenched in water. Oil slows the cooling time, which merely tempers the steel. Jim Patrick

[Scott_Conger]

I think this thread is like a bad car accident: you know you shouldn't look or linger, much less go back to, but human nature is such that sometimes you just can't NOT look...

anyway, if you're inclined to rework them (which to me makes as much sense and safety-consciousness as replacing plate glass with more plate glass...or babbitt thrust washers with more babbitt thrust washers...), do you know what type of steel it is? What the metallurgical make up is? If you soften them to reform them and they don't break, to harden them again, do you heat them to red, orange, cherry red? Do you quench them in water, or oil? If oil, should it be heated? If so, to what temperature? Once it's hard, how hard is it? To temper it, do you heat it to blue, straw, or some other color?

After you've answered all of these questions (which few if any can) and have "new" lock washers, which one can you stand to have break in half and fall out while in service?

I like original vehicles, or vehicles which are brought back as close to what was original as possible, but at some point, there is a threshold of safety which I would not cross and am amazed by those who would.

[Allan]

Scott, your comment re fitting replacement babbit thrust washers in place of originals brought a thought to mind about doing same. I believe the original material used in these washers was different to that used in babbit bearings. In my stuff I have a thrust washer made without the grooves characteristic of original Ford parts. It is likely a replacement, but interestingly, it has the same appearance and finish as newly re-babbited bearings. If I had a pair of them I would be tempted to use them in a rebuild. I guess this would be like replacing plate glass with laminated glass.

I would be interested in the opinions of others re bearing babbit material being serviceable in this application.

Allan from down under.

[TXGOAT2]

I have some very old items made of babbit such as was commonly used in bearings a hundred years ago and more. Some of these are large shaft bearings and some are smaller, factory-cast and finished bearings. Some are simply blobs of babbit metal left over from bearing pours. Some are brass-backed with babbit overlay. They have laid around for decades out in the weather and show no deterioration. I have seen a number of old radio parts, phonograph parts, and some magneto parts made of a babbit-like metal that have become cracked and distorted or even fallen to pieces sitting on a shelf. I'm guessing these decayed items had too much zinc, or some other component, that oxidized.

[Dropacent]

This thread should win an award………..

[TXGOAT2]

Pot Metal, Base Metal.... similar to, but not the same as babbit metal.

[TXGOAT2]

Babbitt Metal - McMaster-Carr
[Search domain mcmaster.com] https://www.mcmaster.com › babbitt-metal
Casting Metals Melt and pour these alloys into molds to create metal parts and prototypes. Lead-base babbitt is a soft alloy. Use it to cast light-load bearings. It has superior antifriction properties. Lead-base coppered babbitt is able to withstand shock and vibration and requires less lubrication than other types of babbitt......

[Jerry VanOoteghem]

This thread should win an award………..

Yes, the honored "Babbitt Lock Washer Award"...

[Dropacent]

I’ll offer the “Tizzy Award” for the worst idea of the year. Also known as the “ WHAT COULD POSSIBLY GO WRONG ? “ award. Now, if you’ll excuse me, I have a big pile of cotter keys to rebuild.

[Nv Bob]

Can't tell yeah as T guys supposed to use cotter pins