Filing

[Nathan MussonParticipant @nathanmusson56573]

Hi again,

Just thought I would share another tip with you about precision filing. As a die sinker/toolmaker I have to file things really flat,Hence the term "as straight as a die" AND YES, FILES STILL HAVE A PURPOSE IN TODAYS WORKSHOPS AND MANUFACTURING. One thing you should never do when filing is touch the work with your hands and I mean don't touch it no matter how clean your hands are. As an experiment go to the workshop and get a piece of metal about 2" square and file one face in the vice. When you have cleaned the surface rub your finger on it then file again and you will notice it will feel like filing glass. This is because you have placed a film of finger grease/oil on to the surface you are filing. The file will now slide over this and files the parts that haven't been touched leading to uneven filing. It does have its purposes. If you can't get things flat then you need a straight edge and a lamp. Put the straight edge on your work and place the lamp behind it and you will see where the high and low spots are. On the low spots rub your finger. When you start filing you will hit the high spots and glide over the low spots where your fingers have been. Check again with the straight edge and repeat if necessary. There is no easy way with filing. You have to practice, practice,practice

[Nathan MussonParticipant @nathanmusson56573]

Dont touch your work for precision filing

[JonParticipant @jon]

It also can be far quicker to remove metal than to mill.

Pretty good filer myself, used to work to a few microns finished product, one of two people left in the world who used to do what i did.

Top tip, work clean. If using a vice, set top of jaws at elbow height.

Good tip looking for light in between a straight edge and job for flatness, its the only way i could do it. Daylights better than artificial, so take job outdoors or agianst a window.

Practise, well theres an element but you either have it or you dont. You know you arent far away when you can draw smooth with a 12" three square bastard for the roughing stage that will look like a second cut had been used.

We had our own specific files for finishing when using oil on the job, same with cloth backed abrasive roll. No problem filing stuff direct off the mill with slurry on the parts, just got to get under it assuming theres metal left but better to dry off. Most of the problem is the oil transfered in to the file teeth which never seems to come out. I dont suffer with oily hands, good job since intricate parts needed man handling continuously. We used to have one chap, anything he touched turned to rust within hours.

[julian atkinsParticipant @julianatkins58923]

i am sorry nathan but i dont agree at all! what error can possibly be caused by rubbing a finger over the work?! i regularly do exactly that as the finger dulls the work and allows me to see how accurate my next few strokes of the file are!

bunkam!!

cheers,

julian

[Ian S CParticipant @iansc]

When I learned to file in my basic training in the RNZAF, we were taught not to handle the work surface that we were filing, as the file would skid over that area, also the file would pick up the gease patch and clog up. Ian S C

[Phil H 1Participant @philh1]

I reckon that I did my fair share of precision filing. I remember noticing the oily dull marks left by some of the other apprentices on fine surfaces but for whatever reason – I never ever had an issue. My hands were always and are still very 'dry'. I'm sure that I do leave some sort of residue but I definitely do not leave any kind of a patch that stops a file from cutting.

PhilH

[BazyleParticipant @bazyle]

A file? Isn't that where the computer stores the CNC instructions?

Similar 'hands' problem in electronics. Some people create electrostatic damage and some don't.

[Boiler BriParticipant @boilerbri]

There is a very good article running in ME at the moment by Stan Bray. Like all the old salts (of which there are getting fewer in numbers) i trust what they say. I remember being given round bar at tech and told to make a rectangle block by filing. What a task that was, but you never forget it. What really got to me, was when we had finished the tutors binned them in front of us! Rotten beggers, or words to that effect come to mind.

I think as Stan Bray points out, some of us who have milling machines have forgotton the usefullness of such items. Mind you, i still use a riffler to clean up the edges!!

No one ever said anything about oily fingers, but we had a few choice wordsd for the blisters we got

Bri

[The Merry MillerParticipant @themerrymiller]

I remember the first exercise given to us new intake of apprentices in September, 1953 at Bankside Power Station.

"Here we are lads", said one of our instructors,"we are now each going to make a pair of firm joint outside calipers"

With that he gave us all a piece of 1" x 1/8" black mild steel.

" I want both arms to be 0.625" thick to within .001" he said"

We had to form the curves first of all in the forge and then proceded to file and file and file but we got there in the end with rather sore hands.

It was like being punished for being good boys but it was an exercise worth learning for the worse ones to come later on in life.

We had a student apprentice in our intake who was 18 years old. He could do almost everything blindfolded and his work was always spot on, how we envied him.

Len. P.

[NobbyParticipant @nobby]

Hi Guys
Nobody's mentioned filing out dies on peirce & blank tools etc. and backing them off using A M&W
Diemakers square. also strippers & punch plates.
Nobby

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