I Filed Backwards 2500 times, and this happened.

today in this video i'm going to be testing if backdragging dulls your file i've gotten a lot of comments recently saying that i file wrong i like to file like this cut on the forward stroke then do a light lift drag on the backstroke but proper textbook filing looks something like this as you're pushing forward the teeth do all the cutting then lift the file up off the material and reset for the next cut with the drag technique the file never leaves the work the file gets reset by a lightweight drag motion but the textbooks say this dragging motion dulls the teeth of the file so i'd like to see how much doling really does happen on the backstroke this is the machine that i built to test the files i built this test machine in an earlier video and it's going to take the place of a human and be able to do thousands of strokes at a time i'll be able to recreate the lift technique and the drag technique all with this same setup so let's talk files for a second here i want to use the best file that i can think of and that i have experience with and that's these third machinist files you get your whole assortment around your half round your triangle flat square but for this test we're going to be using the flat file this is a 10 inch long file these are extremely good so what are we actually going to be filing to do all this testing i'm going to use these coupons it's a piece of hot rolled steel three quarters by three quarters or 19 millimeter by 19 millimeter and i would like to see how soft this is in comparison to the file so i'm going to be using the hardness tester and we're gonna find out so let's test out the file on the rockwell c scale 67 rockwell c and then i know if we put the mild steel in here yep it doesn't even register it registers zero these numbers are so far off from each other they're not even measurable on the same scale obviously our coupon's way softer so we are going to see this thing get hogged away i chose the 1018 mild steel because that was the material that the commenter said was dulling my file so that's what we're using for this test it has a threaded hole into the back this is going to attach to a cylinder that's going to push this coupon hopefully right through the file as it tears it apart as it's filing away i need to regulate the air and this is what's going to control the pressure that the cylinder has so the specs say on the cylinder at like 60 psi we're going to get about 40 to 45 pounds of force and i want to test this to the extreme as if you're really filing hard and really possibly dulling the file so i want a lot of pressure on this to see what would happen so that's where we're going to set it at 60 psi i have a little tang holder on this side and it just gets flipped in like that and this little tab holds it into place and now on the cutting stroke it gets pushed back into the wedge of the tang so when this thing pushes it can't go anywhere but overall that's pretty simple i'm going to be testing coarse medium and fine files we're going to be doing the test twice each file is going to have a lift on one side technique and then we're going to flip it over and do the drag then we're going to average the results from this coupon giving us our number what we'll do is we'll measure the length before and then we'll measure the length after and we'll take the difference that way we have something to gauge from because who knows maybe this myth is more about how coarse the teeth are and less about a file itself for this first test i'm going to be using this course file and it is going to be the control i need to put it in the machine and dull it i don't know how many strokes it's going to take but no matter what we get to it's going to be the number we're going to use on every single file i think we're ready to rock and roll everything's set up dialed in our counter is set to zero hopefully we see some file doling that's what we're looking for three two one for the first test i'm going to try to see how many strokes actually takes to get the file dual and i'm using strokes instead of time because it's a much more reputable measurement i'm stopping the test right here at 100 strokes because i've noticed that the file is completely plugged up and it is no longer cutting imagine that but i don't want to stop the whole experiment i would like to flip the file over and then do a drag test because there is a myth floating around out there that back dragging clears the chips so let's test that to see if it's true okay switch is out of the way that won't be causing us any problems push this over that's just going to stay on the whole time putting constant pressure on the forward and the backstroke all right let the test begin three two one [Music] we're a few strokes in and i'm already noticing some chips starting to stick to the teeth i'm also noticing that the chips are getting smaller there's absolutely no way that this file is dull yet so that only leaves one thing that the chips are actually blocking the teeth from cutting alright stop the test this isn't working anymore after 100 strokes the back drag still is not clearing the file so right there that myth is completely busted this experiment is about file doling not about file chip removal but in order to fix this problem i'm going to add a wiper to clear those chips off so that we can continue testing the toothbrush is going to remain constant in every experiment removing the chip buildup as a variable with the toothbrush installed let's see how many strokes it actually takes to dull the file and then off we go it's almost like this brush was designed to clean teeth i no longer see any file clogging this is going to give us much more consistent results the rig seems to be working perfect has this really nice cadence to it it's almost musical tried to set up the machine to replicate a human filing and i've timed myself and i ended up around 35 strokes per minute so i've set up the machine to match my filing speed [Music] okay i'm stopping the test here the chips are really fine which i'm going to consider dull and what i can notice is when i drag my glove across the surface i can drag it pretty easily and then on the side that's still sharp it grips and almost wants to pull my glove right off my finger we're sitting at 2500 strokes which i'm going to use for every experiment after this and sheesh that took an hour and a half to perform one file test i have 11 more tests to do a lot of filing so video montage in three two one go [Music] so [Music] [Music] [Music] standing [Music] all right now that we've done all the tests let's gather all the coupons up and measure them and see where we ended up i tested every file twice and will be taking the average of the two results this will help out with any file discrepancies so i have all the files that we've been testing but before i look at the results i want to sit down under the microscope and look at the individual teeth to actually see we can really identify if any of these are really truly dull let's do some shop analyzation here which is going to be quite fun i'm going to be comparing the used dual files to a brand new one this is going to give me the best chance to see any visual damage that was done to the dull file the first file tested is the coarse file that was lifted on the backstroke it removed 782 thousandths of an inch and 2500 strokes the first thing that i'm noticing is that the teeth have a flat spot in them it's pretty hard to detect the flat spot with your naked eye but if you get the light just right you can see a reflection off the top of the teeth at the end of the 2500 strokes the file was definitely underperforming and you can see this when we review the high speed footage now let's take a look at the backdrag on the course file it averaged 803 thousandths of an inch in 2500 strokes the dullness of the file almost looks exactly the same as the lift the teeth have been flattened across the top and it's really unnoticeable by the naked eye i also can't find any chipped or missing teeth if we look at the slow motion footage i can see a very little difference between the two as far as chip size with that being said the drag technique did outperform the lift just by a little bit if i showed you both files back to back the one that was lifted and the one that was dragged you'd have a hard time telling which one was which let's take a look at the medium file with its much smaller tooth this is my go-to file for most general filing applications so i'm really curious to see the results here with the proper textbook lift stroke it removed 526 thousandths of an inch i can definitely see some signs of dulling with that tooth being flattened off the top but overall i think the file looks pretty good this is what i'd expect to see after about 2500 strokes let's take a look at the slow motion footage this is at the end of the test and the file is still cutting just not as well as it used to but i can't see any damage missing teeth the metal isn't sticking to the file so the toothbrush is doing a good job let's move on to the drag on the medium file it averaged 735 thousandths of an inch that's crazy that's right up there with the course file and once again i'll perform the lift technique so i want to see if this extra metal removal comes at a price or damage to the file i can see no evidence that the file has any more damage than the lift technique the tooth is still flattened on the top i see no chipped damaged teeth and overall it's pretty hard to distinguish both of them apart the slow motion footage reveals something interesting there's a myth that says back dragging the file clears the chip but what i'm looking at here shows no evidence of such you can see that the chips are still clogged inside the file even with the brush wiping it the chips are still there it took a heavy duty file card to get all the chips out but even the chips clogging the file it still outperformed the lift technique let's move on to the fine file the material removed by the lift technique was 462 thousands of an inch this file has a tiny tooth and is generally only used for finishing or to try to achieve that perfect surface finish my first observations are the tooth does have a little bit of a flat spot on the top and randomly there's a chipped tooth here and there but overall the file actually looks pretty good we can see just how dull the file is in the slow motion footage those chips are just tiny i would still call this file dull though when i rub my finger or my fingernail across it it just doesn't have the bite like the brand new file does [Music] let's take a look at the drag method on the find file the average coupon measured 558 thousandths of an inch this again removes more material than the lift technique so let's see how much dulling happened to the file this time first observation is this file looks straight up trashed i see chipped teeth flattened teeth and a whole bunch of steel that looks like it's stuck in there on the file's behalf i do have a lot of back pressure on the back drag i would never back drag with this much back pressure but i do want to simulate what would happen at the extreme limits it is interesting though to see that even with the damage it still outperformed the normal lift when looking at the high speed footage the file is definitely doing filing things chips are coming off but man the file just looks horrible it's hard to argue with the numbers though compared to the lift versus the drag technique the drag still outperforms the lift pretty amazing so where does all this extra material come from i want to run one more experiment to find out so i would like to confirm that it's the backstroke removing material so i'm going to throw one more coupon one more file in the shaper and we're going to test it with backstroke only so in order to back drag only i could flip the file over and go the opposite direction or the easier method is to flip the switch by flipping the switch backwards we're going to drag on the backstroke and lift on the forward this is totally tool crime to put a file in backwards i almost can't believe i'm doing this but on a positive note this rig has almost gone 50 000 strokes without a hiccup that's truly amazing even that little air switch is going like crazy all righty that's 2500 strokes first impressions i see a lot of chips there's a lot of filing action going on i did not notice anything that looked suspicious first observation of the file is that you know it looks used it still feels sharp even though it kind of looks like it's been drug across material for 2500 strokes but the proof is in the pudding let's get the coupon out get it over to the microscope we'll measure it and see how it looks so the medium file drag only removed 164 thousandths of an inch of material that's pretty crazy i see a couple teeth chipped here and there but nothing too crazy when i watch the playback of the file cutting i can actually see chips come off the back so it is cutting can you believe that this thing cut 164 thousandths of an inch going backwards i think ferd needs to change their motto our files are so good that it cuts backwards but i'm not going to stop there at 2500 strokes going backwards we're going to actually try this thing cutting forwards to see what happens this is going to be the an interesting experiment my first observations of this pulling my finger across the surface is that it actually feels sharper than the brand new side which is completely contradictive of what everybody says but we're gonna find out here in a second wow look at those chips so after 5 000 strokes 2500 of them backwards we removed 515 thousands of an inch and that number falls right in line with the average lift test so i really don't see a big difference with back dragging well guys i had a lot of fun with this experiment but it's left me more curious than ever i know in the future i would like to test some different materials maybe even different file brands and see how they compare but until then i will see you guys on the next one

Channel: Fireball Tool

Views: 3,625,207

Keywords: fireball, tool, Fireball tool, Welding, File testing, Pferd files, cincinnati shaper, back drag file, dull file, sharp file, coarse file, medium file, fine file, bimba piston, 1018 steel, backdrag, clear chips, rockwell hardness, rockwell c, file vs steel, slow motion, slo mo file

Id: xbykic--SKA

Length: 16min 41sec (1001 seconds)

Published: Sat Nov 20 2021

Reddit Comments

[u/Eisernteufel]

I just do less pressure on the non cutting stroke

[u/we11ington]

I just do what feels right. Sometimes that's lifting (e.g. if I'm deburring an edge), sometimes that's dragging (e.g. if I'm trying to keep the file at a consistent angle).

[u/yeet-ism]

You can make anything on a shaper except money.

[u/Qutlicopatlixhotutti]

As a mechatronician? Mechatronic? ( what the heck is it called?) we had to file parts for like 3 months (the first thing most mechanic apprentices do in Germany) and I never heard that I had to lift the file at the back stroke... And after filing millimeters over millimeters off Steele no file ever got dull. Also Noone would ever would lift their hacksaw on the back stroke alltho the teeth on that thing are a lot thinner and the tips receive a lot more preassure that on a file where the area of all teeth in contact is a lot greater in most cases.

[u/Reakion]

This is exactly what This Old Tony said in one of his videos.

This one.

[u/chobbes]

Pretty great content and methodology as usual for Fireball and Jason, I’m just curious about all the permutations. What about other materials? What about suboptimal (or just other) stroke angles?

Great to have at least some seemingly conclusive data, anyway.

[u/sodak748]

The other reason you don't drag a file backwards is because you want to roll a bur. It amazes me how many operators and machinists I see that don't understand the concept of rolling a bur..... whether they're using a file or die grinder.

[u/An_Alex_103]

I was always taught to avoid it, just because it makes your cuts harder to square up.

[u/caaaaaaaaaaaaaaaarl]

One thing I noticed was that there were still chips stuck in the file while it was cut on the back stroke. I wonder what the effect on surface finish from the stuck chips is. While it does remove more material, it might be cutting with a more irregular profile than if he had installed toothbrushes on the front and back. Those pieces of steel in the teeth could be work hardened from the process.

Edited to not sound so assertive with the work hardening suggestion