Good question. I'd rather use a power tool than do it by hand, but fettling often involves removing small amounts of metal with careful control so that parts fit accurately together. A slip of the hand with a power tool might remove too much, whilst files in different shapes and sizes with different teeth provide a lot of slow but sure control.

Another common fettling job is removing burrs from edges: often quicker to do with a few strokes of a file rather than plug in a power tool.

Skilled filing is a joy to behold. I wish I could do it. Experts seem to remove metal almost effortlessly, producing accurate neat flat surfaces and matching curves with a good finish. What I do with files is much cruder, but I couldn't do without.

I see a milling machine as my best replacement for filing. Grinding is the commonest way of removing metal in industry but the technique isn't as useful in a small workshop, where most jobs are done by sawing, turning, boring, drilling, milling and filing. Nonetheless most of us have a bench grinder for sharpening tools, an angle grinder for cutting, plus a Dremel for fine work.

Just as well I don't need a surface grinder – my workshop is already full!

Dave

Edited By SillyOldDuffer on 12/06/2022 15:06:04

Castings are fairly soft and soon clean up, try doing 10 driving wheels on a 9f.

Many a good casting has been ruined by over enthusiastic use of a grinder.

I use a bit of everything depending on the casting and what shape I'm fettling picking what tool suits the job in hand.

Files are next to useless if you have hard castings and the thin flash around joint lines tends to cool quickly and therefore is at risk of being chilled. But I mostly use files (hand powered) for fettling as you have more control and can blend in steps and flaws better.

Dremel gets used where it's hard to get in with a file and I also tend to run a slow Dremel over the surface with a tear drop shaped stone to get a uniform texture.

Angle grinder is Ok on larger castings or to remove large lumps left by the gates and runners but you could not easily clean up the split lines on say a flywheel with one as you simply can't get in to the areas needed.

Or I just fabricate and cut from solid which negates the need to fettle

Horses for courses. Dremels and die grinders work well on small intricate complex curves. But unless used with great care and skill they will leave a scalloped surface due to the small diameter of the grinding surface. Files on the other hand come in an endless range of sizes and shapes and can be selected to match the job in hand. Using larger files will give nice flat surfaces or gently flowing curves without the series of divots that a Dremel will often give.

For instance, if you want to put a uniform radius along the edge of a block of steel say 4" long and 1" thick, a 10" flat file will do the job easily with little effort. A grinder will leave all sorts of scallops and flats and rough surfaces. But if you want to clean up the complex casting of a small model engine, then a Dremel will suit better.

Filing is a slower process — as you say, grinders will remove more metal faster. But slow is good if you are trying to achieve a precision finish. You slowly approach the desired shape and can get it just right file stroke by file stroke. Grinders make it too easy to remove too much metal, and you can't put it back on once you have removed it.

And in precision grinding work, such as tool and die making of complex shapes for press tools or plastic moulds, grinding is a roughing process and the final finish is done with rubbing stones and abrasives for final smoothing and polishing, so no quicker or easier than filing really if you want a true precision finish.

The other tool that is very handy for such work is a belt linisher. Removes a lot of metal in a very controlled way without the small divots of a Dremel etc. And a cheap hobby horizontal/vertical bandsaw has pretty much made manual hacksawing obsolete in my workshop.

The other thing is that files are a gentle, peaceful way of shaping metal. Their quiet steady repetitive motion soothes the soul. Grinders irritate it more than just about anything. And start workshop fires.

An anger grinder is a good way of quickly removing tge majority of the metal from raw material, but being hand held, it will not be a precision result.

One slip and the job is scrap!

Use a file and emery for finishing. A few strokes will remove a small amount of metal.

In the old days, a good fitter could work to within 0.005" with a hammer and cold chisel, before finishing off with a file and then emery.

The men who built the pumping engines for Cornish tin mines did not have the luxury of electricity and angle grinders, but produced some pretty accurate results by hand.

Howard