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Thread: To float or to rasp,
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18th November 2013, 10:57 AM #16.
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It was really good to see that someone organised to do this test on new files because it clearly demonstrates that it does not recreate file teeth and in fact it makes good quality new files worse. However. if the test is done on old files every file would have shown some improvement and depending how dirty and dull files are is it is not an improvement that usually lasts for very long.
Here is a quote from the PM forum where like here this has been discussed ad nauseum but they have done some interesting tests.
Many years ago when I worked for GE, there was a story going around about an engineer that had developed a means of sharpening files using acid. The theory as presented was that the would eat back the surfaces equally and gradually the rounded cutting edge would disappear. The fly in the ointment is that the acid does not attack the surfaces uniformly. Those [surfaces] that stick out, ala the cutting edge, are attacked quicker. The reason is field intensity which I won't go into (unless you want to). The acid will dull the file not sharpen it. This is the same reason that electro-polishing works. This is the same for rusting.
Dull files have rounded and clogged teeth so they cannot grab metal so they skate across the surface of the metal. The teeth will also have bits knocked out of them on a fine and coarse scale (I'll call these notches) - the notchesl quickly become galled and are very difficult to clean. As FF says acid etching cannot reform or replace the lost metal from the rounded teeth - all acid can do is remove metal. Acid cleaning should clean off the galled metal as it will be full of cracks and will etch small rough pits and jagged edged into the rounded surface and notches and this is what enables the teeth to grab some metal. The pits and edges and established notches in effect act like a sand paper but the pits being relatively shallow will clog more easily and wear away and round over again quicker than a new file. This is also why a rusty old file will work better than a non rusty old file.
The teeth on a acid cleaned file will definitely look and feel sharper - here is a macro photo from some one on PM that tested acid sharpening. Sharpening files - Anybody done it? - Page 3
The dull grey area on the left has been acid sharpened while the shiny area on the right is the original used file surface.
I don't believe all of the edge shine on the undipped file is dull edge - some it is galled metal - what is interesting is that the acid (HCl) did not dissolve the bit of brass on the left
So there is a really good reason for acid dipping a used file and that is to give it a good clean.
What I'd like to see is this photo done with a new file.
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18th November 2013, 09:43 PM #17GOLD MEMBER
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18th November 2013, 09:58 PM #18
From memory I think it was 10, I could be wrong though
(as one of Bretts testers) I think the old files would would look cleaner, feel sharper but I can't see how the massive tooth loss
would be any different. Unless the old files were a better quality steel (which they very well could be) The ones we tested were absolute
train wrecks as far as tooth loss went and while they kind of felt sharper, they were also rougher to use and felt like there was gravel under the file. It wasn't gravel, they were teeth rolling through under the file
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18th November 2013, 10:01 PM #19
People regularly talk about the Nicholsons, where do the Wiltshires fit in??
…..Live a Quiet Life & Work with your Hands
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18th November 2013, 10:07 PM #20
Like the old Nics the old Wiltshire files were good to but I think the new ones are crap too. Brett can confirm this I think.
Since the test the only files I have bought are Bahcos. I am waiting to see if Brett gets his new design off the ground, then
I'll buy those. Common Brett shake a leg
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18th November 2013, 10:38 PM #21
I have a bunch of old Wiltshire rasps and files, many of which are past there serviceable life. But I noted that what I have inherited are lots of Wiltshires & a few much older with interesting makers stamps. Not a Nicholson to be seen. Hence my question were the oldies as good, better or cheaper.
Trying to see what I can find that is still useable until I can afford some new ones. Pity the acid dip sharpening theory seems to be a bust.…..Live a Quiet Life & Work with your Hands
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18th November 2013, 10:43 PM #22
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18th November 2013, 10:43 PM #23
The old Wiltshires were Australian made so I guess more available or cheaper than imported going back to the 50's, 60's, 70's and probably 80's.
You could try a vinegar clean. I did a couple of oldies with vinegar just to check out the teeth, shape and markings when we did the test but I
didn't actually ever try and use them. Might be worth a test.
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18th November 2013, 10:45 PM #24
It sure does Brett. So when is your next toolie challenge ? what can we test next? I learnt a lot and had a lot of fun in the file tests
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18th November 2013, 10:47 PM #25
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18th November 2013, 10:49 PM #26
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19th November 2013, 07:44 AM #27
Iwasaki files
Getting back to those Japanese wood files - I bought one a few years ago, and it's certainly capable of removing wood in a hurry, but I found it too "bitey" and harder to control than my rasps. It also has a bit too tight a radius to the back for what I wanted it for. I tend to work with a lot of harder woods, substantially harder than Pear and Ebony, for e.g., so that may have a bearing on my assessment. It is certainly a sharp implement, and as long as you can control it, you can remove wood in a hurry, leaving a fairly smooth surface, as Klaus demonstrates; no argument with that. I use mine for jobs where I can get two hands on it, but for one-handed use, I prefer the easier control of rasps, so my Iwasaki file spends a lot of time just sitting in the toolbox. Perhaps I need to persevere, and practice that sliding motion Klaus talks about....
Cheers,IW
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19th November 2013, 08:21 AM #28
What cut is yours?? They come in Bastard, Medium, Fine & Extra Fine. For hogging out Klaus uses a medium. In regards to the radii there is also 4 different sizes. My partner is in East Timor at present and I have her searching for some Diospyros Celebacia (Makassar Ebony) also known as Indonesian bony. Unfortunately she isn't having much luck, it appears during the Indonesian occupation the general's cousin or brother some close relative logged all the ebony, sandalwood, and mined all the marble and took it out of Timor without regard to sustainability May have to send her back to visit her mother's family in Africa and see if she can find a source there.
…..Live a Quiet Life & Work with your Hands
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19th November 2013, 09:39 AM #29SENIOR MEMBER
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Citric Acid works well for sharpening old files and rasps (don't bother with modern alloy steels) for use on wood. I have not tried any on metal, but do not expect they would work for long. Obviously if the teeth have been removed/damaged, there is nothing to sharpen, eg the corners of saw files*. Worn, but cared for old rasps sharpen particularly well. I find wood rasps too coarse, but the revived ones are much smoother and work well. There are heaps of old files out there, some are in worn, but cared for condition - give them another life. Remember to take the files/rasps out of the solution when they are sharp to your taste, leaving them in for long periods will only eat away the steel and leave a tough to remove deposit on the file.
I tend to work in the following sequence these days - Nicholson #50 NOS and Liogier #9 10" (seem to remove wood at around the same rate to me, but different round profile is handy), Liogier #11 8" (cabinet and round), Grammercy Fine 5" rasp, NOS Wiltshire 10" 1/2 Round 2nd Cut and Smooth, NOS Wiltshire 8" 1/2 Round Smooth. After this I wonder if sandpaper is necessary. So my revived files/rasps are "in reserve".
Cheers
Peter
* old saw files (especially larger ones) make useful dovetail chisels, I made skew chisels out of a few to avoid butchering bench chisels. BUT BEFORE you touch the file/chisel after grinding, PLEASE run the grinder lightly along each corner, the edges are deadly sharp... as I am sure you will discover for yourself... once only. I have an ex-large saw file 10" burnisher that is mirror finished and works very well; and an expertly ground 3/4" (originally a thick flat file) bevel edge chisel with welded socket that is my favourite, beautifully balanced. Lots of other tools made from files... so do not discard your worn out files. If you peruse an old English file catalogue you will find a wide array of files/rasps to look for and work on, and rummaging in flea market boxes turns up some great finds.
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19th November 2013, 09:42 AM #30
Dunno, Dale - I didn't even know they came in different cuts! I bought mine off the rack at Carbatec, and all I noticed at the time was that there were two sizes - I bought the smaller size because it was a bit finer. They definitely need further investigation....
Good luck with the Ebony. Quite a few years back, I was at a workshop/conference in Sri Lanka (nothing to do with wood) but I thought I would take the opportunity to get my hands on some Ebony. It's a long story, but I did manage to get a chunk of reasonable quality Ebony, at a price similar to an equivalent weight of gold bullion. Then I damn-near lost it at Quarantine on the way in. The piece was very rough at one end, and had some dirt in it, so I washed it out at the hotel the night before leaving. I left it out on the (ground-floor) balcony to dry overnight, and a stupid green looper caterpillar decided the split end was a good place to curl up for a nap. It decided to wake up & investigate its new surroundings just as I handed it to the AQIS man for inspection. He nearly had a fit when he saw a little green face staring up at him, & I had a very hard time convincing him that it was not some evil wood-munching monster about to destroy our forests, and simply squashing it between his fingers would solve all problems. He eventually let me keep it. I've got one small piece of it left, and still trying to decide on the perfect use for it!
Cheers,IW
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