Draw filing

Had to make some geometric modifications to my wall-oven hinge receivers. Basically, I extended one of the surfaces by a little over 1/8" by acetylen
e welding. Had to file the project smooth after the weld. Metal is about 1/8" thick mile steel.
Anyway, while receiver is firmly held in the vise, I noticed that using a d raw stroke (brand new 12" Nicholson bastard file) I could remove a lot more metal with absolutely no chatter. Using a push stroke I get nothing but c hatter. Somebody please educate me.
Also, is it true that 50+ years ago machining education started out by hand ing an apprentice a hacksaw and a file? Is this another urban myth?
Thanks, Ivan Vegvary
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Basically, I extended one of the surfaces by a little over 1/8" by acetylene welding. Had to file the project smooth after the weld. Metal is about 1/8" thick mile steel.

stroke (brand new 12" Nicholson bastard file) I could remove a lot more metal with absolutely no chatter. Using a push stroke I get nothing but chatter. Somebody please educate me.
well, the angles of the teeth are pretty different in those two situations.

In Japan machinists start with a piece of metal and a file. They work on that for a very long time before doing anything else.
There really isn't anything more hands on than a file. You really get a feel for how materials behave.
It may be taken for granted here, but there are people who have never worked with their hands and have no idea how different materials behave. One example of this is how 99% of all superglue attempts are completely bungled from the start.
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Generally, one can attain about 5 different finishes with almost any metalworking file. It depends on the angle of direction it passes over the workpiece.. filing right handed, vs. left handed, for example. Also depends on which direction the file is controlled to drift as it cuts.. drifting left differs from the cut of drifting right as the file cuts.
Draw filing doesn't mean just pulling the file.. it's when the file is laid across/perpendicular to the workpiece and pulled toward the user to cut, then the file is lifted and restarted again at the far end of the workpiece.
There are files that are intended to be pulled during use, used in die filing machines.. the file cuts on the downward/retract stroke (the way a sawzall does). These files are extremely useful for general hand filing and deburring. I have some of these marked Disston USA - Oliver of Adrian.
Pulling a file is nearly always chatter-free and the cut is easier to control.. kinda like pushing a pencil to make a straight line, or pushing a chain instead of pulling it.. the movement of the forearm and shoulder are reliably straight when pulling, moreso than when pushing. These files are also very handy for one hand filing, where a hole in a large panel precludes two-handed filing, for example.
For deburring files I break off the bare handle end and secure the opposite/start end into a handle.. 3-cornered files are great for this use. For round holes, typical rotary deburring tools are used, but for sharp straight lines/corners, the backwards files work very well when pulled, not pushed.
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WB
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- -Also, is it true that 50+ years ago machining education -started out by handing an apprentice a hacksaw and -a file? Is this another urban myth? -Ivan Vegvary
~50 years ago I learned woodworking with handsaws and planes that we had been taught how to sharpen. The first exercise was to straighten and square hand-sawn edges, which quickly made us more careful when sawing them. jsw
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On Wed, 29 May 2013 23:13:50 -0700 (PDT), Ivan Vegvary
Basically, I extended one of the surfaces by a little over 1/8" by acetylene welding. Had to file the project smooth after the weld. Metal is about 1/8" thick mile steel.

stroke (brand new 12" Nicholson bastard file) I could remove a lot more metal with absolutely no chatter. Using a push stroke I get nothing but chatter. Somebody please educate me.

I think you have to go back more than 50 years, but it was true in some, if not most, plants and shops.
One well-known example was Rolls Royce in the early days. A job applicant was given a piece of brass plate with a round hole in it, a round brass bar, and a file(s). He had to file the hole square and file the end of the bar square to fit. The bar in its square hole was held up to the light; if light could be seen, he didn't get the job.
It's hard for many of us to believe how much work was done with files and chisels in the early days of metalworking. I wrote a story about an industrial archaeology dig in Paterson, NJ, at the old Rogers Locomotive Works. When they dug up the floor is was littered with layers of worn-out files. They had no milling machines. Imagine what it was like to build a steam locomotive with lathes, chisels, drill presses, and files. That's all they had.
--
Ed Huntress

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On Thu, 30 May 2013 06:54:31 -0400, Ed Huntress

Basically, I extended one of the surfaces by a little over 1/8" by acetylene welding. Had to file the project smooth after the weld. Metal is about 1/8" thick mile steel.

stroke (brand new 12" Nicholson bastard file) I could remove a lot more metal with absolutely no chatter. Using a push stroke I get nothing but chatter. Somebody please educate me.

When I started, in 1946, the "apprentice master" was in his 60's. He used to tell war stories about what it was like, "in the old days". He said that the first year in his 6 year apprenticeship he learned to use a broom. The second year he learned to use a file. His journeyman test was to make a surface plate.
Early on I had a job where I had to file the end of a round bar flat and when I took it to be checked the old guy whipped out his try square and held it up to the light and says "I can see a little light". Being a teenage wise ass, I said, "I'd like to see someone do better". The old boy popped that bar in a vice and, I swear, hit it about three strokes with the file and says, "See of any light shows now".
I spent the next month with a pile of castings and a 24" file learning a skill they called "Snagging castings" :-(
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John B.
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wrote:

Basically, I extended one of the surfaces by a little over 1/8" by acetylene welding. Had to file the project smooth after the weld. Metal is about 1/8" thick mile steel.

draw stroke (brand new 12" Nicholson bastard file) I could remove a lot more metal with absolutely no chatter. Using a push stroke I get nothing but chatter. Somebody please educate me.

Ugh, a nasty job. I've watched snagging being done with very coarse grinding wheels, but I didn't realize they were done with files.
My uncle was one of those guys trained initially with files and chisels, in the 1930s. He encouraged me to use them more, and to go to use my friend's milling machine less. I'm glad I did.
--
Ed Huntress

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On Wed, 29 May 2013 23:13:50 -0700 (PDT), Ivan Vegvary
Ivan,

I remember seeing apprentices in Singer's factory at Clydebank working on making an exact size cube of steel using only files and scrapers. this was in the late 1950s. They may have had to start by rough cutting a cube using a hacksaw, but I didn't see that. Singers was reckoned to be one of the top apprentice training companoes on Clydeside.
jim.
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On Thu, 30 May 2013 11:54:34 +0100, Jim Guthrie wrote:

BACK IN THE 60'S I had a German guy work for me that had a little jewelry box in the top of his tool box. I asked him one day what it was in the box and he showed me. A cube, about an inch in size. He said it was his journeyman's test and after it was accepted he had it gold plated and kept it in his tool box. He said it was a pretty good answer when someone asked you what you could do.
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On Thu, 30 May 2013 11:54:34 +0100, Jim Guthrie wrote:

Old Danish friend of my family who started out on sailing ships and then went back to school and became Vickers head designer told me they gave him a block of steel and a bunch of files and told him to turn it into a sphere. When he had sucessfully done that..they handed it back to him and told him to turn it back into a cube. That was one of the tests for his apprenticship program.
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"You guess the truth hurts?

Really?
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My father-in-law started his career as a machinist and tool-and-die maker after graduating high school in about 1940. He said that's how it was done then....
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Basically, I extended one of the surfaces by a little over 1/8" by acet ylene welding. Had to file the project smooth after the weld. Metal i s about 1/8" thick mile steel.

draw stroke (brand new 12" Nicholson bastard file) I could remove a lot mo re metal with absolutely no chatter. Using a push stroke I get nothing b ut chatter. Somebody please educate me.

nding an apprentice a hacksaw and a file? Is this another urban myth?

Apprentices in the British Royal Engineers used to be handed a chunk of steel and a file, had to file a perfect cube out of it, then make a sphere out of the cube with nothing more than a file. If your time is worth nothing and you don't have a machine shop, you can do a LOT with files. Guy Lautard in one of his Machinist's Bedside Readers wrote about a a guy that he knew of that spent his spare time making guns with nothing but files, some ground and modified for certain operations.
I used to draw file military barrels back in my starving student days, used up a lot of chalk and most of a file card doing it. Never noticed the chatter on push or pull, but you DO have to have the file facing the right way for either. Don't get a lot of metal movement pulling OR pushing on the backside of the teeth! Brownell's has special files just for draw filing, have a circular tooth pattern kind of like the body files used on Bondo, much finer pitch, though.
They used to do a lot of stuff as apprentices that don't get a lot of play these days. Like chipping cast iron surfaces flat with chisels and a hammer. Of use when power tools were scarce, cutting tools were carbon steel and most castings were soft gray iron, not so much use these days with alloy steels, carbide tooling and CNC.
Stan
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