Lubricants for ratchet mechanisms

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Samuel D
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Lubricants for ratchet mechanisms

Postby Samuel D » 10 May 2019, 10:32am

I acquired an old Facom socket ratchet for next to nothing and opened the round head to find crud and dried grease inside. Rebuild kits are available for a few euros but I don’t think I need one. There isn’t much visible wear anywhere.

I cleaned the pawl and head teeth with a toothbrush using WD-40 for toothpaste. Looking at how this works, it seems that a thick grease might prevent the pawl teeth sinking in for full engagement. Maybe a light machine oil would be better, but would it last?

Getting the thing apart was a challenge because someone had used a lot of threadlock on the screw. Heating it over my kitchen gas stove until a wet finger barely sizzled on the head worked, hopefully without ruining the steel temper.

Clever mechanism! But I don’t like that it needs threadlock to stay together.

Any general rules for keeping ratchet mechanisms happy, wherever they’re found?

alexnharvey
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Joined: 10 Jan 2014, 8:39am

Re: Lubricants for ratchet mechanisms

Postby alexnharvey » 10 May 2019, 11:08am

I think any oil, light or heavy would be temporary and would leak out, especially from an old ratchet. A 'tacky' oil might stay put a bit better.

I'd use a semi fluid grease, I think that's the ideal lubricant for a poorly sealed ratcheting mechanism. If I didn't have a semi fluid grease on hand I'd fairly happily use a multi-purpose grease, expecting it might make engagement slightly slower and be more likely to be displaced from the points that we most want lubricated in the mechanism.

Before I had semi-fluid grease I used to mix gear oil and grease for this kind of thing. It's now a bit like like George's marvellous medicine with various various lithium greases and a dash of anti-seize mixed into the gear oil. The oil and the grease don't seem to separate noticeably when left to stand. It gets used on door hinges and old padlocks.

Samuel D
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Location: Paris

Re: Lubricants for ratchet mechanisms

Postby Samuel D » 10 May 2019, 11:22am

Thanks.

I don’t think slight leaking would be a problem here except that it would require periodic re-application.

I don’t have many choices available at home but I have synthetic 80W-90 and 75W-90 gear oils, TF2 bicycle chain lubricant, a viscous Finish Line lubricant for wet weather, and various greases including Shimano’s special “Freehub Grease”. I suppose the freehub pawls of a bicycle work similarly to a ratchet so maybe that’s a candidate.

I once ordered some Land Rover swivel-hub semi-fluid grease that got lost in the post and I never got around to re-ordering. There have been a few times since that I’ve wanted something like that. Perhaps I should order it again.

alexnharvey
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Re: Lubricants for ratchet mechanisms

Postby alexnharvey » 10 May 2019, 11:39am

I think thimano's special freehub grease would be very good for the reason you state, it's a light grease for lubricating a ratchet mechanism.

I doubt there's any benefit to using a more fortified grease like the Landrover stuff for this application, although it would probably be cheaper! Since the freehub grease is a sunk cost you might as well use it.

Brucey
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Re: Lubricants for ratchet mechanisms

Postby Brucey » 10 May 2019, 1:34pm

I would normally not use a grease of any kind in a 3/8" drive ratchet mechanism. A light oil (even though it will need fairly frequent reapplication) is most suitable. There are a few designed that use a sliding part and these may benefit from a very local smear of grease but the rest of them don't. What you are fighting for here are the following things:

1) that the pawls move freely
2) that the pawls engage fully
3) that the lube doesn't become contaminated with dirt etc
4) that the mechanism doesn't dry out in storage and go sticky
5) that the mechanism doesn't go rusty in storage
6) that the mechanism doesn't self-disassemble in use
7) that you can tell if the mechanism is in good shape before you use it


So threadlock is absolutely necessary in many cases if 6) applies; tools for professional use see lots and lots of knocks and even downright abuse. The pawls are characterised by a relatively large contact area so that the thing will withstand high torques, yet the backing force needs to be very low; this means that there is both much lube to be displaced (if the mechanism is flooded) and the spring to do it is relatively feeble. If the mechanism slips once, under load, there is usually catastrophic damage. All these things are very different from (say) a bicycle freewheel. The only thing that it has in common is that it either moves or sees load, not both at the same time; this means super lubrication per se isn't strictly required.

You can tell that there is no such thing as 'a perfect ratchet' because the guarantee usually specifically exclude these parts and they still bother to make breaker bars, often with longer handles. If ratchets were as strong as breaker bars the handles would be different lengths and there would be no need for breaker bars either. The designers (with varying degrees of success) do their best but the ratchet head needs to be small enough for good access but it should also be strong, reliable, wear resistant, and have a low backing force; this is always going to be a compromise.

So point 7) is arguably the most important; if the ratchet doesn't sound good it probably isn't good and it needs to be fettled; you can't tell if/how the pawls are moving if the lube is too heavy, and if it slips once it is often knackered. Cheap ratchets benefit from being stripped and fettled when new; they can be deburred and any small dimensional error can be corrected. Posh ratchets oughtn't need this. I'd recommend regular purging (without disassembly) using something containing a solvent (eg WD40) followed by some light oil. This should get rid of any crud inside and keep the mechanism sweet. Without disassembly, a good even clicking sound from the ratchet is as good a sign as you are likely to get that all is well inside.

BTW this may seem obvious but when purging with WD40 (or similar) if it runs out black and horrible, you know you have been doing some good.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Samuel D
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Location: Paris

Re: Lubricants for ratchet mechanisms

Postby Samuel D » 10 May 2019, 10:28pm

I found a video by Facom on this topic, which also shows the sort of round-head ratchet mechanism I’m talking about. At 1:30 a large blob of “grease with graphite” is applied where the mechanism slides. That’s more grease than I’d be comfortable putting so close to the teeth. However, nothing is applied directly to the pawl or teeth.

Dry metal sliding over metal doesn’t sound right to me, notwithstanding Brucey’s point about movement or high load but not both at the same time.

For now I’ve put a little lithium grease underneath the pawl (a tenth as much as in the video) and a single drop of TF2 chain lubricant (which is thin for what it is) on the teeth of the round head, smearing it around with a finger until it wasn’t visible but left everything slippery.

After reassembly the ratchet emits nice sharp clicks as it turns and the back-drag is low – certainly lower than the drag on cheap ratchets I’ve used in the past. I’m impressed.

I’ll get a light machine oil and redo it with that later.

On breaker bars versus ratchets, it seems there’s a trend toward using long-handled ratchets where previously a breaker bar would have been used. Snap-on makes very long ratchets, for example, even ones with flexible heads. There are also many socket sets on the market, especially from Facom and American companies, with only a ratchet and no other driver in the box. The other European companies still seem to favour including breaker bars, sliding T-handles, etc., in their socket sets. I’ve been looking into these things lately.

As usual, I could do with a good book to learn the theory and proper use of such tools, even though I’ve used them (badly?) for years. Maybe this one.

Brucey
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Re: Lubricants for ratchet mechanisms

Postby Brucey » 10 May 2019, 11:52pm

the dream condition is that you are working on nice clean stuff that was well made in the first place and that the tools you have are all in good condition and have known torque ratings so that you don't have any reason to abuse them or risk breakage.

The reality is often that the tools you have are not ideal for the task in hand and that the parts you are working on are in far from ideal condition.

Building stuff (like engines) is quite close to "the dream condition" and tool manufacturers sell a lot of tools to folk who build stuff, so unsurprisingly the tools they sell are quite well suited to that task. However in reality when you are repairing stuff there are such things as


- corroded fasteners
- damaged fastener heads
- rounded nuts
- weird styles/sizes of fastener that require special tools
- fasteners in weird locations
- fasteners where you need two identical tools, one on each end of the fastener, to loosen or tighten it
- other situations where the tools themselves are liable to break, or cause collateral damage

Needless to say learning how to work under 'dream conditions' is pretty easy and learning how to work "in reality" is a whole different ball of wax.

Particularly when working on car chassis the last thing I expect is that all the nuts and bolts will come undone easily using standard tools. Having multiple examples of certain tools (with minor variations) is often very useful. I probably own a dozen or more complete socket sets and in addition to that I have about fifty other ratchets, breaker bars, extensions and 'special' socket/bit sets. I guess I must have over a thousand pieces in 1/4" /3/8"/ 1/2" drive and in addition to that I have about a hundred 3/4" drive bits and pieces and even a few 1" drive odds and ends. [ I have a few pieces but I drew the line at buying vintage 9/32" drive Plomb stuff, even though it is much stronger than 1/4" drive and very well suited to certain tasks as a result.]

At one time I thought I'd eventually have everything I need to do most jobs but I no longer believe this; despite the amount of stuff I have, I regularly find I don't have the right tool for the job and I have therefore committed to memory roughly what local tool stores carry; I can nip off and buy what I need in less than half an hour, mid-job if necessary. Also (somewhat depressingly) I regularly find that there just isn't the right tool for a given job; having struggled/broken stuff I've had to make quite a few tools to do particular jobs.

FWIW good tool manufacturers used to make it clear what torque ratings their stuff was good to. However for whatever reason I could find precious little information of this kind when I looked more recently. Many manufacturers don't have warranties on ratchets, even if they do on everything else. This is OK provided the ratchets can be rebuilt easily/cheaply. Note that (even in quality kit) not all ratchets can be rebuilt and not all of them allow both the pawls and ratchet surfaces to be replaced, meaning that certain types of damage can't be tolerated.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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NATURAL ANKLING
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Re: Lubricants for ratchet mechanisms

Postby NATURAL ANKLING » 11 May 2019, 1:28am

Hi,
Crikey its only a ratchet :)
I must be missing something :?
If You Don't Try You Don't Do.....Don't Do You Don't Get...I'm Still Trying....Well Very..
You'll Find Me At The Top Of A Hill...............Somewhere...After Dark..

tim-b
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Joined: 10 Oct 2009, 8:20am

Re: Lubricants for ratchet mechanisms

Postby tim-b » 11 May 2019, 6:46am

Hi
I'd ask a calibration company because a part of their service (in the UK at least) is to adjust the torque wrench to correct errors, assuming that you're getting it checked of course :)
Regards
tim-b
~~~~¯\(ツ)/¯~~~~

Samuel D
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Location: Paris

Re: Lubricants for ratchet mechanisms

Postby Samuel D » 11 May 2019, 12:47pm

It’s not a torque wrench, tim-b. Do you mean ask them how they lubricate ratchets anyway? Torque wrenches often have ratchets of course (though they shouldn’t affect torque measurement).

The posts by Adam.C here pretty much agree with Brucey. Adam.C says elsewhere that he’s a mechanical engineer in aerospace on mechanisms similar to ratchets.

Brucey
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Re: Lubricants for ratchet mechanisms

Postby Brucey » 11 May 2019, 1:24pm

FWIW the first socket set I ever bought (when I was a kid, not even spotty yet) was a very cheap 3/8" drive set with everything made of rather soft steel including bi-hex sockets. I almost gave up trying to take things apart; it was so poor it was a real lesson in how not to do things. I learned lots about the difference between a good fit and a bad fit, whether a nut was already too damaged to try a bi-hex socket on it (which if the sockets are softer than the nuts you are trying to undo is a surefire recipe for a wrecked socket), and why not all tools are the same even if they look the same.

One of the things I did was I took the ratchet head apart and lubed it with grease. It was 'nice and smooth' when I'd done that, and it certainly wasn't ever going to go rusty, but I stripped the teeth off the ratchet soon afterwards. I beat myself up over that but in retrospect the pawl was the only hard piece of steel in the whole thing and the teeth it meshed with were just as soft as the rest of the kit, so I only hastened the inevitable failure I suppose. Nonetheless the conclusion at the time

"grease in a ratchet = bad"

wasn't wrong.

The only ratchets where you can safely grease them are (IME) ones with very few teeth and very strong springs. These are also the ones that gather dust in the toolbox, because the backing force is usually so high that you cannot use them easily. I have an old Britool ratchet with a pear head that is like this; modern versions of the same tool have 44T but older (squaddy-proof?) versions have 22T. I've even got some 22T rebuild kits for the thing too, which I shall never need, because I have other ratchets I much prefer to use; it takes a firm grip on an extension bar or socket to get the thing to ratchet and if you can't reach in to hold something the nut is never coming off....

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

tim-b
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Re: Lubricants for ratchet mechanisms

Postby tim-b » 11 May 2019, 6:23pm

Hi
It’s not a torque wrench

No, and no matter how many times I re-read I can't see why I thought that it was :oops:
Regards
tim-b
~~~~¯\(ツ)/¯~~~~

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Lubricants for ratchet mechanisms

Postby Brucey » 11 May 2019, 7:45pm

Image

IIRC it is necessary to use threadlock when assembling that particular ratchet design because without it, fully tightening the screw will simply cause the mechanism to bind. However this method does also allow you the opportunity to adjust the clearance in the parts so that wear can be allowed for. The rebuild kits usually come with a sachet of grease, which is OK provided it doesn't get into the teeth too much.

FWIW this ratchet design is slightly less likely to slip than many; the application of torque tends to drive the pawl harder into the teeth, with a sort of wedging action. However if the drive parts start to wobble in the head at all (e.g. because the screw is not correctly adjusted), the teeth may be presented skew to the mating parts, which will make for slippage.

Despite the fact that when a rebuild kit is fitted the ratchet teeth are not renewed, this is one of the better designs. I think the same design is sold under various different brand names. I have used this design a fair amount; I think it is also found in tools made by other manufacturers, e.g. I am sure I have an old Kamasa rathet that is made this way, as well as several facom ones.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Samuel D
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Joined: 8 Mar 2015, 11:05pm
Location: Paris

Re: Lubricants for ratchet mechanisms

Postby Samuel D » 11 May 2019, 11:10pm

Yes, that’s the one I have. I might try a few winds of thread-seal tape instead of thread-locking fluid when I reassemble it the next time.

In reading up on these tools recently I learned that there is a trend to higher tooth counts to reduce the swing of the handle needed to catch the next tooth in tight spaces. The trick seems to be to increase the tooth count, which requires pawls with more teeth to maintain strength with the finer teeth, without increasing the back-drag that if too high would defeat the object of the ratchet. But Facom appears to have solved this problem long ago with this high tooth-count, low back-drag, strong, round-head design. I like it.

And with the Paris area swimming in good deals on used (and barely used!) old Facom stuff, I think I’ll stick with this brand for a 1/4"-drive ratchet next. Look at the embarrassment of Facom riches on my doorstep:

  • 1/2" ratchet, extension bar, and 12-point sockets from 10 to 32 mm in a nice metal case – asking €60
  • KL.161 3/4" ratchet, new in bag (not that I have any conceivable use for this) – yours for at most €60
  • 1" ratchet with huge bar to drive it (for cathedral diesels or something?) – €50
  • 1/4" socket set with ratchet, universal joint, nut driver, couple of extension bars, and a bunch of bits – tempting at €45
  • 1/4" ratchet, “like new”, on its own – just €10
  • Brand new set of 8, 10, 11, 12, 13, and 14 mm 467S short ratcheting combination spanners – €45
  • Antique S.150 1/2" ratchet – €5
  • New S.151B 1/2" ratchet – €18
If there were as many 3/8" bargains on the used market (for some reason they’re much rarer), I’d be bankrupt already.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Lubricants for ratchet mechanisms

Postby Brucey » 11 May 2019, 11:34pm

years ago lots of mechanics didn't bother with 3/8" drive stuff unless they worked on motorbikes, aircraft, that kind of thing. Plenty would have 1/2" and 1/4" drive and that would do.

3/8" drive stuff is much better on motorbikes because everything is smaller and tucked into tight corners; these days car engines are like that too and you will struggle to get away without having a set of 3/8" drive stuff inside most engine bays. It is, if you like, still the coming thing. Add to that the fact that it is possible to break 3/8" drive stuff without undue difficulty, and it is perhaps no mystery that it doesn't crop up used in quite the same way as 1/2" drive stuff does.

One downside to the facom ratchet design is that it isn't compatible with a pushbutton socket release. Also, ratchets that use a small thumb lever (rather than a knob) to reverse direction are arguably easier to use too; you can get your thumb onto it more easily (one handed) and there is a visual indication whether you are set to go forwards or backwards. Another quibble is that the ratchet design doesn't incorporate a knurled 'spinner', which isn't essential by any means but is handy at times.

Fine toothed ratchets are great, provided they have a low backing force and they are strong enough. However there is no point in having ever finer teeth beyond a certain point, because there is always some lash between the socket and the bolt, and between the drive squares. One ratchet I have isn't a true ratchet; it contains a small roller clutch instead. In reality it doesn't seem much better backlash-wise than some of the fine-toothed designs.

I quite like facom stuff but I find it a bit weird/annoying that they appear to have discontinued 'Britool' products now, having bought the firm some years ago.

One of the oddball Facom tools I own is a 245.J2A wad punch set.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~