files and sandpaper..

[elk killer]

after reading the post on lock polishing,,
and after last night of thumbing through the gunsmith of grenville county,,
its states that you should never use a file to back sandpaper with..
as it dulls the file,,after doing it for over 30 years,,i have never found it to dull the file..
maybe im wrong,,,,

[Jim Filipski]

only if you use the smooth side out

[Acer Saccharum]

I use that technique a lot. Guess I should read the book.

only if you use the smooth side out

Jim, that is brilliant. No wonder my files shine so.

[Acer Saccharum]

Not in defense, but when trying to keep a fresh piece of sandpaper in use, you have to roll the strip around the file, or stick, or piece of plastic to keep exposing new grit. If you glue the paper to the stick, well, in a few strokes you have to peel off the paper and glue new paper on. A pain.

A stick without glue is miserable, because the paper, having grit, bites into the workpiece metal and the stick just slides back and forth on the backside of the paper. very frustrating.

The file teeth bite into the paper backing, giving traction to overcome the paper's tendency to grab on the workpiece.

Plus, files come in many ready made shapes to get into nooks and crannies, gullies and corners.

A coarse stone might work as well as a file. The grit of the stone might grab the slick paper backing to help push it around.

Acer

[Dphariss]

Not in defense, but when trying to keep a fresh piece of sandpaper in use, you have to roll the strip around the file, or stick, or piece of plastic to keep exposing new grit. If you glue the paper to the stick, well, in a few strokes you have to peel off the paper and glue new paper on. A pain.

A stick without glue is miserable, because the paper, having grit, bites into the workpiece metal and the stick just slides back and forth on the backside of the paper. very frustrating.

The file teeth bite into the paper backing, giving traction to overcome the paper's tendency to grab on the workpiece.

Plus, files come in many ready made shapes to get into nooks and crannies, gullies and corners.

A coarse stone might work as well as a file. The grit of the stone might grab the slick paper backing to help push it around.

Acer

I use the old file wrap thing at times, use it on needle and chainsaw round files for small inside radius parts.
But if you want to keep things flat the paper has to he stuck to a flat surface. On a file is wads up and causes problems then a file tooth cut though, just did that polishing a TG last week. Etc etc. On dowels or tubes it does not seem to wad much at all since it wraps tighter. On anything else its a PITA and while I do it for some things I tend to use the stickum when I set out for serious polishing. Like after I gouged the TG because I was too lazy to take the time to do it properly. Plexi-glass is infinitely shapable too.
I KNOW the double stick tape is a PITA. But it sure works good. When doing barrel flats and a 2" wide piece of plexiglass you can do several flats with the grit before its shot even on harder barrels. Besides by that time I am ready for a break anyway
Also with some searching you may find some stuff that is made to be easier to remove on one side. I liked this but unless I think to look in Billings or Bozeman I use what the local stores have. Last I bought is kinda sticky but leaves residue that will stick paper to aluminum. Its also too thick and this can cause trouble too it allows the paper to move slightly since the tape is slightly compressible and then it can wrinkle or tear. The really thin plasitc stuff in better from the pure polishing stand point but its harder to remove in many cases.
This allows the paper to be used just like a super fine file.

But as I have pointed out here before we all have our "pet" shop practices and what one person really likes is just an irritant to another.

Dan

[jerrywh]

 I never back sandpaper with a file for the same reason Dpharris stated. sometimes the file will break thru and score the part.  A few times like that will cure you. Usually the harder the backing the better. I use rubber hoses, cardboard tubes, wooden dowels, and sticks the most. sometimes rolled up newspaper.

[Waksupi]

For all you guys with piles of dull files around, try these guys.

http://www.boggstool.com/

I have sent them over a hundred files and rasps over the years, from needle files, to horseshoeing rasps. All came back sharper than new, and at a very reasonable price.

[George F.]

Thanks for re-posting this site. I haven't used it for I'm terrible at mailing stuff, but for the life of me, I can not figure out how you can sharpen a miss used file. I can see where replacing the cabinetmakers rasps #59 & 60, they are kind of expensive, but  the $10-$20 files, can that be cost effective as well?  ...Geo.

[Acer Saccharum]

I wrap sandpaper around a stick, pinching the paper between thumb and forefinger. This is for miniature and detail work, so the sticks are small, 1/4" wide or narrower. Make a chisel point or rounded, depending on what you're polishing.

Ordinarily the paper would slide off the stick, but, here is a trick: rub the stick on a piece of violin rosin, and that gives just enough tack to keep the paper in place. When the paper loads up, roll it to a new surface.

Use hardwood for fine shapes, chisel points, miniature flats, getting into corners. Use pine for conforming to contours and smoothing gullies etc.

You can also put grit directly on a pine stick with great results.

Acer

[G-Man]

The "Tadpole" countour sanders available from Woodcraft are great for backing sandpaper or emery cloth and they come in sets of different sizes of general shapes - everything from flat, round, sharp edge, square edge, concave, convex etc.  They are stiff but flexible rubber, so the sandpaper stays put fairly well - you just wrap it around the piece and hold the ends in place with your thumb and fingers - so you can create and infinite range of shapes and cuts by using the different shapes, edges - almost like having an infinite range of file shapes and cuts.  They are nice for getting into tight corners around moldings, or working in the tight areas on lock parts.  Since they are flexible they don't exert as much leverage onto the surface as a file so you have to press harder, but I have found them to work well for getting into tight places on wood or metal.

Guy

[Stophel]

I don't use sandpaper that much to worry too much about it!   

[rick landes]

One of my favorite backings for sandpaper is a "Pink Pearl" style eraser.

[Stophel]

I have never had a file cut through sandpaper.  The grit wears off long before that happens.  Plus, on metal, I use the abrasive cloth made for metal anyway.

[Roger Fisher]

Thanks for re-posting this site. I haven't used it for I'm terrible at mailing stuff, but for the life of me, I can not figure out how you can sharpen a miss used file. I can see where replacing the cabinetmakers rasps #59 & 60, they are kind of expensive, but  the $10-$20 files, can that be cost effective as well?  ...Geo.

Seems I read somewhere sometime that a good soak in apple cider vineager does a good job on bringing them back....Never tried it.    Anybody?

[PIKELAKE]

Mr. Fisher, I have had good luck in renewing old files by soaking in muratic acid for a bit. I really don't think it sharpens them, but it cleans them up real good then etches the teeth. They are almost..... like new afterwards. Old files, cheap muratic acid, give her a try.

[George F.]

I have also soaked my #49 &50 rasps in muratic acid. It seems to clean them up alittle, but not great. Some have glue embedded in them, one has white paint, but are dull. I adopted other tools, like those micro planes, and other types of rasps. I just might try shipping them out and see what they can do.  ...Geo.

[davec2]

File sharpening is done mostly by acid etching (usually with dilute hydrochloric or dilute nitric) and sometimes by electro stripping.  Either way, the file must be really clean first or the process doesn't work as well.  With the teeth clean, the etching / metal removal occurs evenly on both exposed surfaces of each tooth and leaves the new tooth edge as sharp or sharper than it was when originally made.  However, if you do this too many times, the file will load up much more rapidly because each sharpening makes the gullet under the tooth shallower.  (You can do it more often on a coarse rasp than you can on a fine cut needle file).  On a fine file, the process works really well once or twice, then it's time to use the file steel for something else.

[Benedict]

File sharpening is done mostly by acid etching (usually with dilute hydrochloric or dilute nitric) and sometimes by electro stripping.  Either way, the file must be really clean first or the process doesn't work as well.  With the teeth clean, the etching / metal removal occurs evenly on both exposed surfaces of each tooth and leaves the new tooth edge as sharp or sharper than it was when originally made.  However, if you do this too many times, the file will load up much more rapidly because each sharpening makes the gullet under the tooth shallower.  (You can do it more often on a coarse rasp than you can on a fine cut needle file).  On a fine file, the process works really well once or twice, then it's time to use the file steel for something else.

I have had some success with soaking files in vinegar.  It was not great but it was sharper.  I did not particularly clean the file before soaking.  Would I have had better luck by cleaning the file or was the problem that I was using vinegar?

Bruce

[jerrywh]

I have cleaned and sharpened my files with 10% nitric acid for more then 40 years. I wash them in detergent, bead blast them and soak them in the acid for about 5 to 10 minutes. They come out sharp as new. afterwards they can be dried off in lime. If not super dry they will rust.

[davec2]

Benedict,

Like Jerry says. 

I don't bead blast, but clean my files with detergent and a fine wire brush and then etch them.  I there is glue or paint in the teeth, it is best to pick it all out clean.  If any part of the file is covered with debris, it won't etch there and will leave dull teeth or a high spot.  I usually soak them briefly in a solution of baking soda and water to neutralize the acid, rinse, dry, and then give them a shot of WD-40.  Vinegar is too week an acid to do you much good.