Tool Maintenance: Corrosion Prevention

A Rusted Plane Blade by Hatsukuni. What did it do to deserve such horrible neglect?

“How dull it is to pause, to make an end,
To rust unburnish’d, not to shine in use!
As tho’ to breathe were life!”

Alfred Lord Tennyson, Ulysses

Between damaged tools and guns, corrosion prevention has been a high priority for your humble servant over the years motivating me to purchase many corrosion-prevention products and test them in various climates. After climbing mountains of hype and swimming floods of BS I think at last I have something of value, perhaps even the genuine article, to share with Gentle Readers.

There are three aspects of corrosion prevention for steel tools we will address in this article: Corrosion due to sharpening, corrosion due to handling, and corrosion due to storage.

But first, to help Gentle Reader understand the basis for the measures I will recommend below, allow me to explain my sharpening philosophy.

Tool Philosophy

The word “philosophy” is of Greek origin and means the “love of wisdom.” I won’t flatter myself that I developed any original wisdom about maintaining tools, because the truth is I stole most of what I know from better men and the rest came ipso facto from my own screw-ups. Embarrassment is a fine teacher.

Professional craftsmen have no choice but to constantly maintain and repair the tools of their trade, but necessary or no, clients and employers often resent the time craftsmen they hire spend maintaining tools during the work day. After all, they are paying them to make a product, not to fiddle with tools. The perceptive craftsman will strive to understand his Client’s perspective if he wants to be trusted with profitable repeat work.

Therefore, I don’t sharpen, fettle, or repair my tools at the jobsite anymore than is absolutely necessary, and never in front of the Client or employer. This is not some feel-good yuppy-zen BS, but a serious, concrete work philosophy with physical and financial consequences. It was taught to me by experienced craftsmen in America and Japan, all since retired to the big lumberyard in the sky, who knew what they were about. It has served me well.

So how do I keep working when blades dull, planes stop shaving, power tools stop spinning and bits stop biting? Whenever possible I have multiple saws, planes and chisels in the types/sizes critical for that day’s work, and even extra bits and power tools on-hand, so that if a particular chisel or plane becomes too dull to get the job done, or a bit breaks, or a circular saw, for instance, goes tits-up, I need only pause work long enough to retrieve a sharp, ready to rock-n-roll replacement from my toolbox or tool bag.

This means I must purchase, sharpen, fettle and carry around more tools than I am likely to use during that workday. But since my tools are partners that earn their keep, it is not wasted money or effort. In fact, this philosophy has resulted in tool-maintenance habits that I believe ultimately save me time and money while improving my work efficiency all while reinforcing my Client’s or employer’s confidence in me, just as the old boys said they would.

Of course, after a few days of continuous work I will have accumulated multiple blades that need sharpening, so if I am to keep making sawdust I must sharpen them in batches of 5~10 at a time. And because I sharpen in batches, as do professional sharpeners, I have given great thought over the years to maximizing positive results such as speed, sharpness achieved, and economical use of stones while minimizing negative results such as rusted steel. I humbly encourage Gentle Readers to give these matters just a few seconds of consideration. What have you got to lose besides steel?

Corrosion Prevention: Wet Sharpening

The bevel of the Hatsukuni blade shown above. Lovely colors.

The corrosion risk to tools when sharpening is corrosion caused by residual water in the scratches, cracks and crevices of the blade, as well as accumulated chlorine from tap water, promoting rust, especially at the very thin cutting edge. Yes, that’s right, I’m more worried about corrosion dulling the cutting edge than of it creating red spots elsewhere on the blade.

When sharpening a batch of blades in my workshop, after a blade is done on the final finish stone, I dry it with a clean paper towel, apply a few drops of Corrosion Block, smear it around on the blade to ensure a complete coating, and set it aside to draw water out of the pores and seal the steel. It works.

Corrosion-X is another good, but stinkier, product. Neither is good enough long-term, however.

After the blades have sat for a while, usually at the conclusion of the batch, I wipe off the CB and apply CRC 3-36. This is a paraffin-based corrosion preventative that floats out water. Paraffin won’t evaporate or wick-off and is the best product I have found to prevent rust developing on a clean, moisture-free surface.

CRC 3-36 sprays on easily and soaks into everything, and if allowed to dry, will give good long-term protection, as in years. It’s especially good for saw blades because it gets deep into the teeth. But you don’t want to apply it to anything even a little wet with water because paraffin will seal it in promoting rust. Ergo, Corrosion Block first.

There are many rust-prevention products on the market, so I am not suggesting CRC3-36 is the best, only the one I prefer, partly because O Mistress of the Blue Horizons doesn’t object to the smell too strongly if it wafts into her holy chambers from the workshop. If I use Corrosion-X, however, she bars the door with a broom, bayonet fixed, and makes me strip before she’ll let me back into the house. A gentle flower, indeed. But I digress.

This system works fine for short-term, and even for long-term storage if I wrap the tool in newspaper or plastic to protect the coating.

When sharpening in the field, or if I will be using the tool right away, I don’t bother with spray products, but just strop the blade on a clean cloth or the palm of my hand to generate friction heat, apply some oil from my oilpot, and call it good.

If you don’t own and use an oilpot already I won’t call you an idiot, but I still remember the time long ago when that word was directed at me by someone I respected for not making and using one. He was right.

A useful trick I learned from sword sharpeners is to use chlorine-free, slightly alkaline water for sharpening. I mix Borax powder with distilled water in a plastic lab bottle to use to keep stones wet and to wash blades when sharpening. Washing soda works too. A little lye added to sharpening water will also increase its pH. Using such water will not entirely prevent corrosion, but it certainly slows it way down. Test it for yourself.

Corrosion Prevention: Handling

We sometimes pull out a chisel, saw, or plane blade to gaze upon it. They are lovely creatures, after all. There are two things to be aware of when doing this, however.

Recall that the adult human body is comprised of approximately 60% water, some of which is constantly leaking out of our skins mixed with oils and salts. When you touch bare steel with your hands, skin oils, sweat, and the salt contained in sweat stick to the steel and will cause rust. It’s only a matter of how quickly and deeply.

The solution is to avoid touching bare steel you will later store away with bare fingers, and if you do touch the blade, wipe it clean and apply some oil from your oilpot or spray can right away before returning it to storage.

Gentle Reader may be unaware, but there can be no doubt that harsh words not only hurt the tender feelings of quality tools, but can directly damage them. How do I know that rude language offends steel tools, you say? Well, I have ears don’t I? In addition, over the years I learned a thing or two from professional Japanese sword sharpeners and evaluators, who are even more obsessed with rust than your paranoid humble servant, no doubt because of the high financial and historical costs of corrosion in rare and expensive antique weapons.

With the gift to the entire world of the Wuhan Virus from the Chinese Communist Party, we have all become more aware of the human tendency to constantly spew droplets of bodily fluids, often containing nasty bugs, into the air around us sometimes with unpleasant consequences. A handsaw can’t catch the Commie Flu, but fine droplets may find their way to the steel surface when we talk to them or around them. Corrosion ensues.

In Japan it is considered rude to speak when holding a bare sword. Indeed, it is SOP to require viewers who will get close to a bare blade to place a piece of clean paper between their teeth to confirm the mouth is indeed closed and not spewing droplets of spit onto the blade.

I am not exaggerating the cumulative long-term damage fingerprints and moisture droplets expelled from human mouths and noses cause to steel objects. Any museum curator can confirm.

How does this all apply to woodworking tools? If Gentle Reader takes a tool out of storage and either talks to it, or to humans around it, please wipe it clean, apply oil, and rewrap it unless you will be using it immediately.

Tools deserve respect. Perhaps I’m superstitious, but I’m convinced that if we avoid rudely smearing salty sweat or spraying globs of spittle that would cause our tools to turn red and go away, they in turn will be less inclined to cause us to leak red sticky stuff. Some tools are vindictive if offended, donchano.

Corrosion Prevention: Storage

The air on earth contains dust and moisture. Dust often contains abrasive particles harder than steel as well as salts and other corrosive chemicals. We must keep these particles and chemicals away from our tools.

Air also contains moisture that, given access and a temperature differential, can condense on steel tool blades causing condensation rust.

Your humble servant discussed these matters in length in earlier articles about toolchests, but a critical criteria of proper storage is to prevent dust from landing on tools, and to prevent the tools from exposure to airborne moisture and temperature differentials. A closed, tightly sealed, clean container, cabinet, toolchest or toolbox is better for tool storage than pegboards or shelves.

If Gentle Reader does not already have such a tool container of some sort, I urge you to procure or make one.

Tool Rolls

Your humble servant owns and uses tool rolls. They are handy for transporting tools such as chisels, files rasps and saws, but they have limitations Gentle Readers need to be aware of.

The first problem with tool rolls is that they appear to protect the cutting edges of chisels and saws, but that is only wishful thinking because the delicate and dangerous cutting edges are only hidden behind a thin layer of cotton or leather. Guess what happens if you drop a cloth tool roll of sharp chisels onto a concrete slab.

If you bump a tool roll of chisels against another tool, then brush your hand against the now exposed but hidden cutting edges while digging in your toolbox, sticky red stuff may get everywhere. Will the bloodshed never end!?

Do tool rolls protect tools against corrosion? No, in fact they can make it much worse because fibers in contact with steel, especially organic fibers such as cotton, can wick moisture to the steel producing corrosion. Please see the photos above.

Leather tool rolls can be especially bad in some cases because of residual tanning chemicals.

I’m not saying don’t use tool rolls, only to be aware of their limitations and use them wisely.

As mentioned above, I do use tool rolls in the field. The trick to preventing rusted blades is to insulate them from the fabric, so I make little plastic liners from the hard but flexible plastic used for theft-proof retail product packaging that fit into the pockets. Just a strip of plastic cut wide enough to fit into the pocket tightly and folded in half. Besides preventing rusty blades (the crowns will still rust) these little liners make it much faster and easier to insert blades into the pockets without cutting the tool roll. They also help prevent blades from cutting through the cloth or leather. The price is right too.

If you need to use tool rolls for long-term storage, I recommend you clean the tools, coat them with a paraffin-based rust-prevention product, and wrap them full-length in plastic wrap before inserting them into the tool roll’s plastic-lined pockets.

If tools are faithful and profitable servants, indeed extensions of our hands and minds, don’t they deserve more from us while they are in our custody than a rusty, pitted, neglected ruin like the plane blade pictured above?

YMHOS

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Our erstwhile apprentice from the clothing-optional workshop has dropped a chisel into the water while sharpening, and laments the inevitable corrosion. Being bald as a bowling ball, I’m desperately jealous of her long hair, but it must get in the way when working the stones.

The Essential Oilpot

The Matsui Precision Notched Straightedge

Matsui Precision Bevel-edged Straightedge with notch

You cannot teach a crab to walk straight.

Aristophanes

This post is about a tool that looks quite ordinary but is in fact extraordinary in subtle ways.

Why Do Woodworkers Need a Good Straightedge?

When woodworking we need to be able to mark and measure straight lines and examine the precision of edges and surfaces. There are several ways and tools available to accomplish these tasks, but the steel straightedge is efficient for shorter distances, assuming one’s straightedge is up to the job.

For most woodworking tasks we don’t need a precision straightedge. But for those few activities where it is necessary, nothing can take its place. So what are some of those activities? I can suggest a few from my experience:

  1. I use a precision straightedge as a “Standard” to check that my working straightedges and squares (the ones that are used and abused daily) are truly straight and square. This is necessary because, during use, Murphy governs all operations, while pernicious Iron Pixies dance among the piles of dandruff on his shoulders. Due to their malicious ministrations, measuring and marking tools are easily damaged, wear-out, and lose tolerance so I need a reliable “Standard” to check them against regularly. Of course, you can’t check for straight or square unless you have a truly straight line/surface to index from. It would be silly to imagine that the edge of one’s tablesaw top or jointer table are perfectly straight without first checking it against a reliable standard;
  2. I use a precision straightedge to examine the soles of my handplanes to help me keep them straight, flat and free of wind because it’s very difficult to plane a flat surface with a screwy plane. No matter how much time I invest in truing my planes, I’ve found the results are never better than the straightedge used.
  3. Check that lapping plates and the float-glass plate I use for truing stones and plane soles remain within tolerances. Yes, they wear out too.
  4. Check that the tables of stationary equipment such as tablesaws, bandsaws, jointers, and planers are true, and that infeed/outfeed soles of handheld electrical planers are properly aligned;
  5. Check that surfaces of wooden components of special projects requiring extra precision are true.

Do you ever need to accomplish any of these tasks?

Tasks for Which the Matsui Precision Straightedge is Not Ideally Suited

The Matsui Precision Straightedge is not an expensive tool, but since it is one I rely on, it is most cost-effective to protect it from premature wear and damage, so the following are tasks for which I use a less-expensive and less-protected “working straightedge” instead of my Matsui precision straightedge:

  1. I don’t use it for checking sharpening stones. The Matsui straightedge can do this job with style, but after a few years of being pressed against (and dragged over) abrasive stones, the tool’s precision would be degraded. Better to use a less-expensive straightedge for this job, and check it occasionally against the Matsui Precision Straightedge to confirm it’s still straight. If it isn’t, fix or replace it.
  2. I don’t use it for daily general woodworking tasks. Once again, the Matsui straightedge can do general jobs with style, but after a few years of being pressed against (and dragged over) wooden surfaces, the tool’s precision would become degraded prematurely. Instead I use a “working straightedge” that has been checked against my “Standard” Matsui Precision straightedge;

How To Use a Precision Straightedge for Checking Tools and Surfaces

Neither the human hand nor eye can measure a straight line or a true plane with any precision unaided, but there is one technique older than the pyramids all woodworkers must be proficient at, namely to place a truly straight, simple straightedge on-edge on a surface to be checked, be it a board, a jointer outfeed table, or the sole of a plane, and shine a light source at the gap between the straightedge and the surface being examined. If gaps exist, light will pass between the edge of the straightedge and the surface being checked confirming the surface is not straight and/or flat. The human eye can detect even a small amount of light this way and both quickly and effectively judge how flat the surface being checked is with a surprising degree of accuracy.

Feeler Gauge

Another technique that yields more precise values without relying on Mark1 Eyeball is to place the straightedge’s beveled edge against the surface to be checked, and insert feeler gauges into gaps between the straightedge and the surface. If the feeler gauge selected won’t fit, then one replaces it with thinner gauges until one that just fits is found.

Once you know the value of the gap between your straightedge and the area of the board you need to true, for instance, you can divide the measured thickness of the shaving your planes takes in a single pass (easily checked with a vernier caliper) to calculate how many passes it will take to true the high-spots on a board. eliminating a lot of the guesswork that makes precise woodworking difficult at times.

To reliably perform these checks, we need a truly straight straightedge. Straight is a relative thing, but straightedges sold for woodworking are seldom straight because purveyors rely on purchasers to not bother, or even know how, to check the quality and precision of the straightedges they sell.

Another reason honest, precision straightedges are relatively rare among woodworking tools is that making a high-tolerance piece of hardened steel that is straight, and will stay that way, is hard work that most woodworkers are neither inclined to appreciate nor bother to check, much less pay for. Is ignorance bliss? I believe it is in the natures of our Gentle Readers to always strive to improve the quality and efficiency of their work. A high-quality precision straightedge is an essential tool in that blissful quest.

Challenges & Solutions

The dilemma of the straightedge is that it must be thick and rigid enough to prevent warping and flopping around in-use, but reasonably lightweight and not too bulky or it will be clumsy. At the same time, it must not be too thick, or it will block out most of the light passing between its edge and work-piece making it useless.

Another challenge the straightedge faces is the constant threat of damage. If the delicate edge is too soft, it will become dinged and deformed instantly becoming inaccurate. And if the straightedge rusts (the bane of steel since ancient times), precision will suffer.

What are the viable solutions? They are obvious and proven, but seldom implemented well. Here is how Matsui Precision does it.

Stainless Steel Construction

First, they use high-quality stainless steel to prevent corrosion. If you work in humid conditions or if you will admit to perspiring salt-laden moisture at times, then this is important, but not rare.

Properly-sized, Precision-ground & Polished

This straightedge is not an insignificant piece of stainless steel. It is available in various lengths, but in the case of the Matsui’s 400mm straightedge (a handy, reasonably-priced length), the blade is 34mm wide and 3mm thick, enough to keep the blade rigid in use and prevent warping, but not so wide or thick as to feel heavy or clumsy. It weighs 320gm, a nice balance of rigidity and weight.

Compact, lightweight tools made using quality materials efficiently have a deep genetic attraction to the Japanese people.

What is more rare is the fact that Matsui then precision-grinds and precision polishes the stainless steel (not the same thing) so the tool is as straight and flat as machinists require, because this is a tool designed to the higher standards of machinists, not just woodworkers.

Hardened & Trued

Matsui also hardens the stainless steel to ensure the tool is rigid and will resist wear and damage over its long useful lifespan.

During heat treating and grinding the metal warps slightly. After stress-relieving the tool, Matsui inspects each tool one-by-one and corrects irregularities or rejects those that cannot be sufficiently corrected. It’s called quality control, something that never happens in China or India in the case of tools intended for woodworkers.

Beveled Edge

To make it easy to see light passing between the straightedge and surface being checked, one edge is beveled. The importance of this detail cannot be overstated.

The Notch

The Matsui Precision Straightedge being used to check the sole of a 70mm finish handplane with a blade by Sekikawa-san. The notch fits over the cutting edge so one can check the sole with the blade protruding as it will be in-use. In this photo the blade has been extended waaay too far out of the mouth to make it easy to see the cutting edge. Please notice the light showing between the straightedge and the sole indicating that something is not right. The wedging pressure of forcing the blade to project this ridiculous amount has warped the block so that the most important part of the sole, the area directly in front of the mouth, is not touching. The point is that the notch makes it possible to check the sole with the blade projecting the intended distance, a job simply not possible with an ordinary straightedge.

In the case of the tool we are introducing here, Matsui cuts a small semi-circular notch in the beveled edge of the blade to provide clearance for irregularities in the surface being checked, such as welds, or in the case of woodworking tools the cutting edges of the blades of handplanes, electrical planers and electrical jointers. This is an important and unique feature.

Why is this notch so useful? The problem with using a metal straightedge to check/true the sole of a handplane has always been that, in order to correctly check for flatness/wind, the blade must be set to project from the plane’s mouth the same amount it should be when the plane is being used, because in the case of Japanese planes the wedge-shaped blade applies slightly different pressures on the wooden block at different depths in the block, producing variable degrees of deflection.

But if the blade is projecting from the mouth from the same amount as it will be in use, then the straightedge will ride on top of the blade preventing a proper examination, and at the same time, possibly dulling the blade and gouging the straightedge. The solution has always been to adjust the blade to not actually project, but to be just in-line with the sole, a fiddly process that has resulted in many dulled blades, scratched straightedges, and inaccurate examinations.

With the elegant Matsui Precision straightedge, however, the notch fits directly over the projecting blade avoiding the irritating and time-wasting fiddling normally required to get the blade in the exact position, one that ultimately yields an imperfect reading.

If you need to maintain handplanes, electrical woodworking tools, or do precision woodworking and need an accurate, reliable, lightweight, durable, reasonably-priced straightedge to help take the guesswork out of these jobs, this product is just what you need. I have been using one for years and couldn’t get by without it.

If you are interested, send us a message using the form below.

YMHOS