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Introduction to Files and Rasps

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This is a basic introduction on proper use and care of files and rasps. Here we examine a number of different sizes and shapes of files and rasps.

When sawing and drilling, you create burrs and sharp edges on your workpiece that need to be removed; rasps and files take care of these. Using a rasp or a file is often the first step in finishing a project, or prepping a material for the next step.

 
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Step 1: Identifying Files and Rasps

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A short (non-comprehensive) list of files, as pictured below from left to right:

Flat rasp - has large, coarse teeth to quickly remove material
Flat file without a handle - allows you to remove burrs and rough edges
Multi-use rasp and file - has two files and two rasps on one tool
Fine flat file without handle - this tool is for finishing and scratch and gouge removal
Triangle file - allows you to get into corners and clean up edges that have notches
Small round file - cleans small round holes and inside curves
Medium round file - as above, but with coarser teeth
Large round file - as above, but coarser still

For more information:
Wikipedia Rasp Entry
Wikipedia File Entry

Briefly, a file is for detail work while a rasp removes larger quantities of material.

Step 2: Using a File or Rasp

Push the file in one direction only. Remember, it' s not a saw -- this file was meant to cut on the away stroke. Put pressure on the return stroke and you'll dull the file and mangle the cutting edges.

Here, Lynne is filing out the corner of a sign she cut on the plasma cutter. Since she's filing out both sides of the corner, she can butt the file up to both edges. In this situation, you could also use a triangle file to smooth the corner. (She's trying to smooth out a pit from the plasma cutter's piercing move... but that's a different instructable.)
dekonick1 year ago
pennies are no longer 100% copper - in fact they have zinc. http://en.wikipedia.org/wiki/Penny_%28United_States_coin%29

The link has a table that gives the % of zinc based on each year's production.

:)

Another trick is to use sidewalk chalk, just run the file over the chalk to load the teeth area with a fine coating of chalk.  After you are done filing, the wire file card (cleaning tool) with flick the metal filings out as the chalk layer separates easily. 
This works well with aluminum, and plastics.  For files used in metal only, a pre-coat of WD-40 is a handy way to aid cleaning, and to keep the file rust free.

Don't drag the file backwards, it ruins the cutting edge, and remember, don't press hard, the cutting edges do the work faster with a light pressure as the multiple edges each take a fine cut rather then trying to scrape off huge amounts with just a few teeth.
Sidewalk chalk is a great method, as is welder's soap stone, and I've heard of people using soap, though I wouldn't recommend it. As for WD-40, I wouldn't use that since it will cause fine metal dust to cling to the niches in the file.
The "oil" in WD-40 is a fish oil derivative that inhibits rust. The oil is very fine and will hold only the most minute of particles. The next time the file is used, the vibration will break the small particles free, The use of a small wire brush like a 'file card' (available at most hardware stores) will keep the file clean and clog free.
The file cards are minor tool miracles when it comes to prolonging the life of a file. I've just had issues with bits staying in the grooves/divots of files I've used oils on (including WD-40).
mtngrown1 year ago
My "trick" for old, rusty or dull files is to clean them in a bath of vinegar. I use an small mapp gas can (similar in size to the tall propane cans used for small torches) with the neck cut off. I stand the files up in the can and then fill with vinegar. After they've soaked over night, the rust has either flaked off or will easily rub off in bag/box of kitty litter or vermiculite.
Files that have been totally used up or with too many broken teeth, become awls, scribes, or specialty blades. With some tempering, they make very good knife blades.
Great instructable.
scempball2 years ago
A easy way to clean files at http://toolfools.blogspot.com/2011/11/how-to-clean-and-restore-file.html
tomblik4 years ago
Thank you for posting this.  In a former life, I taught a Sophomore Mechanical Engineering Design Lab at the University of North Carolina at Charlotte.  Teaching these students that a file only works in one direction and you ruin a file by using a sawing action was a tough sell.  However when they saw the results you get with so much less effort by using a file correctly, they were instant converts.  Its nice to see such advice "in the wild" as it were.
Jacaroo4 years ago
Jacaroo says:
Excellent presentation, take it from someone who has used files and made them unusable.
My dear departed Dad made me sit and clean each one of his files with a piece of Brass which was run along the grooves  and this dipensed of anything from lead to aluminium and other soft metals, it even removed rust if enough elbow grease was applied.
You see Dad was a Seargent Major and a Master Technician
juantam5 years ago
Hi! I heard from an old friend, an engineer, that the best way to effectively clean a files is to immerse it in hydrochloric acid. Thereby, the bits and pieces stuck in between the file teeth will either be eaten away by the acid or slowly be dislodged as the acid gradually eats away at the iron filings. Though, I really haven't tried this method because, I dislike the risk of burning myself with acid and finding a place where to dispose of it when I am done.
Yes, I have heard of using battery acid (if you have an old battery around).  But keeping it a little longer in muriatic acid (it is a moderately dilute hydrochloric acid used for cleaning concrete and 'shocking' swimming pools), or even in chlorine bleach (it again is even a weaker hydrochloric acid).  The weaker just takes longer. 

Once you get them out of the 'acid bath', rinse it off with water to get the acid off.  If it seems sharper, it is working.

If it doesn't seem sharp enough, then like the shampoo bottle says, 'rinse, repeat'.  I have heard of having to do this several time (3 to 6) depending on the initial shape of the rasp. 

If it is 'sharp enough', put a light coat of oil (like WD40 or similar) just to help keep the rust away.  If you don't protect from rust, rust will attack pretty quickly.

And noting will fix mechanically broken teeth on a rasp or file.  They are quality tools and should not be stored in coffee cans where they bang against other tools without protection (ok, soap box here, but you get the idea).
My grandfather believed one of the most useful things to have in the workshop was a load of candles. Rubbing a woodscrew on one would make it go in easier, on a saw would make it get caught less, and on a file it would make it easier to clean afterward.
Your grandfather sounds like he was a wise man. I still use this trick today. My grandfather told me keeping pennies in your toolbox helps prevent rust. Whether this was ever true (in the days they were made of copper) or not, I don't know, but I still keep a couple of pennies in each of my toolbox drawers as a sort of tribute to the old man's esoteric wisdom. ;-)
Well there might be some sort of galvanic/sacrificial-anode chemistry to back it up, like in boats, but would have thought it'd work best with nickel or zinc coins. So maybe he heard it from someone in the USA? The only other mote of wisdom that springs to mind was to place a small square of cloth between the drill bit and metal when drilling through a sheet to prevent it chattering and making a ragged hole. Seems to work, though I'm unsure if the cloth needs to be oiled or not for it to.
My mom kept a sacrificial galvanic plate in her silver ware box to keep the tarnish down. ... I don't see why the same principle would not work in a tool box.

I don't remember my chemistry, but if copper is more chemically active than iron, then keeping a couple of pennies (outside is still a good copper plating) in a drawer should work.

If the pennies get to oxidized, replacing them (or polishing the old ones - but no oil covering or anything to keep the oxidation off, the oxidation on the copper is what is helping, by keep the other metals from oxidizing.

Also the little bags of water absorbing material helps.  Those can be 'recharged' in a toaster oven by raising the temperature to a little above 100C or 212F for a while (an hour or so to just above the boiling point of water ).  It should drive off the moisture and let it absorb more.  Doing this regularly (very few months) can help too.  Let them cool and toss them back into the drawers!
Yeah this is a really good trick that I learned from my grandfather as well.  He kept wax on hand for saws, and bar soap for screws.
static4 years ago
A file card is a nonpower tool tool for cleaning metal files http://www.drillspot.com/pimages/356/35642_300.jpg A file in a tool box that's hauled around a lot gets dull quickly. I finally hit on a way to prevent that. Simply slide a length of clear vinyl tubing over the cutting part. So far this is the only video I nave found on youtube on the topic. The chalk trick along with a file card are shown. RATS! Using using boolean search operators I had the hit down to 169, but after changing it to reduce it further It returned over 38,000 hits. Enough of that for tonight.
scafool5 years ago
Nicolson File Company. (1956). File filosophy and how to get the most out of files (-being a brief account of the history, manufacture, variety and uses of files in general.) Twentieth Edition. Nicolson File Company, Providence, R.I. IS. The definitive guide to files and their use.
Awesome, you guys rule. I hope to see more stuff from you guys, maybe even a contest or something regarding you guys! +1 rating.
lordgerty6 years ago
nice instructable,having served an old school apprenticeship this one really comes home ,ha.you could add that using paraffin on a file when filing aluminium will stop it clogging and improve the surface finish especially with finer files.
Firebert0106 years ago
Good 'ible, however more information would not hurt. Like Offseid states below, information on how to properly use a rasp and more so about the files. Perhaps specific examples (with pictures) for each file type would be a good idea..
LostMachine6 years ago
Very Nice. I'd like to add one thing if I could. When cutting metal or wood you can use Oil or Chalk applied to the file to help keep the file from loading up with shavings. The chalk shouldn't stain the wood. I use a light cutting oil when I work on steel and aluminum.
offseid6 years ago
Nice. Would be good to see a bit of how to use a rasp on wood. Also, a bit about file sharpening? I heard once about some service out in California that sharpens files for like $3 a pop or something like that, and that they do such a good job that even new files sent to them come back better!
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