Was Draw Filing ever a chargeable offence in the RAF?

Hi all - I once heard it said that draw filing was a chargeable offence in the RAF but I have never had it confirmed that this was in fact the case. It may have been part of official policy adopted by the RAF training school at Halton, Bucks but when I mentioned it to an ex Halton RAF apprentice he was not aware of it. The mind set behind such a decision if true has always baffled me as it seems a perfectly proper and professional technique to me. Can anyone here through any light on the subject?

It might have been if the instructor had specifically forbidden it and was ignored.

I doubt it, when in the RAF where else would you put your filing other than in Drawers!

Silly humour time for which I apologise.

Robert Butler

I suspect Old Mart has it quite right. The other thing that occurs to me is that the military inevitably adopts different terminology to the rest of us mere mortals, so maybe some quite different operation was meant.

What would they have done instead?

"once heard", but has anyone here actually encountered it, and if so, for what known purpose?

I suppose it may have originated in instructions pertaining to finishing critical components; not necessarily a blanket ban.

As an apprentice electrician at the YEB in 1959, we were sent for 6 months training in the apprentice shop at ROF Barnbow, Leeds.
We were told then that draw filling was bad practice and not allowed, but never told why.

One of the things I did learn there was to use a machine to do the heavy work if possible.

It was years before the penny dropped for the YEB that it was cheaper for us to use electric drills for holes than hammer and chisel. Still keep a star drill for 1/2 inch bolts to remind me.

The only good reason that I can think of for draw-filing being considered bad practice is that it doesn’t make full use of the file.

See Figure 100 : **LINK**

http://armyordnance.tpub.com/Od16218/Od162180135.htm

MichaelG.

It's not bad practice, just not something you should do if striving for best dimensional accuracy etc.

As first year apprentices in the Chrysler training centre our first project was to file a 4" x 4" x 1" piece of black mild steel bar until it was "perfectly" flat and square and parallel on all six sides, as measured with a try square and micrometer. It only took a couple of months. But we got an hour off every afternoon to watch ancient black and white training films or lectures by the apprentice training officer. And a day a week to go to tech college, where we started out by -- filing a block of steel flat and square. Later in the year we got to file various G clamps and toolmakers clamps to perfection too.

We were told about draw filing and instructed in its use as a finishing operation to get a nice looking finish on a job, but it was not recommended practice for our filing block project because you don't have enough control over the file to make a "perfectly" flat or square surface. The file, as shown in MG's link above, can rock from side to side so you will end up with a slightly domed surface. Or the file may not be perfectly flat and impart irregularities to the job. Normal filing was the recommended practice, with the fingers of the front hand applying pressure on the side or end where most metal was wanted removed. I'm sure that we all tried draw filing but don't remember it as being any great help other than the final few licks to smooth down any file marks and make it look pretty.

So it was neither recommended nor particularly helpful. So was quite possible the RAF had some kind of censure against it. Like they say, there are three ways of doing every task: the right way, the wrong way and the military way.

By the time my youngest brother did his apprenticeship, things had become so lax he was able to sneak back at lunchtime when nobody was around and put his filing block on the surface grinder to knock it down flat. Probably draw filed the already flat surface to dress it up like he had filed it.

Edited By Hopper on 25/03/2021 00:53:49

We had to do the filing of a metal square which then would fit "perfectly" into another square filed in another piece of steel... I wish someone was teaching me these things now; I'd be far more grateful now I'm older!

I recall mine was one of the worst there.

Putting craftspersons on a charge for draw filing?

I can only imagine the alternatives must have been very onerous or tedious, for the authorities to make such a straightforward technique so unattractive.

As an aircraft apprentice, emery cloth was forbidden for use on Aluminium and its alloys, but wet and dry was allowed.

How odd ! Not an engineer, but at Brize, I used to 'haunt' the Station Workshops for cast-off materials and advice for modelling. One such offering was always to draw-file the edges of aluminium off-cuts at the area of bending, to avoid cracks at these stress points. Certainly worked for me !

rgds

Bill

As Bill says, it can help fatigue life by removing transverse scratches from the edge of sheet or plate material.

I was taught this by Desmond Norman when helping make the curved spray bar supports you can see under the the wing in this picture:

https://s3.eu-west-2.amazonaws.com/abpic-media-eu-production/pictures/full_size_0243/1365100-large.jpg

I'm avionics based but A. my traning included "fitting" and basic machining and B. We were in a rush to get the aircraft out for a customer demonstration. It was "all hands to the pumps" so I started filing as did Desmond. While the factory was "sheet metal in, aircraft out", we had no CNC machines etc. The supports were band sawed roughly to shape and then filed.
When doing filing exercises during training we were not allowed to draw file because it was to easy to get a nice finish. And yes those are the actual items in the 35 year old photo, we only ever made one set.

Robert G8RPI.

I can understand it. Draw filing was frowned upon when I was an apprentice but I wasn't with the RAF and it had absolutely nothing to do with surface finish because you can achieve a brilliant surface finish by using the file properly.

I even saw the explanation/ diagrams in a craft type text book that explained why draw filing was very bad practice if you wish to achieve a straight edge or flat surface.

Holding and using the file properly, lengthwise across the surface means that the length of the file 'helps' to keep the file flat on the surface and with care, it helps to remove the high spots. If you do it properly, you can easily achieve surfaces within 0.001" and you don't really need emery cloth to polish it either.

With draw filing, the width of the file, being much narrower, actually helps it to ride over the crests and hollows of a work piece and can actually exaggerate the lack of flatness. Yes it will be shiny but it is much harder to achieve a flat surface.

I wish I still had the text book. It was one of those old fashioned, good quality apprentice style books.

Anyway, we spent the first 12 months covered in engineers blue, using a file every day and it works. The text book and the apprentice instructors were definitely right.

Phil H

Your post brought back memories - I served my ESI 'indentured' apprenticeship with SEEB (Electricity Board in Kent, and spent the first year at their purpose built training school (boot camp) near Dover.

I made a complete set of hand tools, and a barn type tool box to keep them in, (I still have most of them) and spent many hours during the hard labour lessons draw filing huge lumps of black metal . . but, probably like you, I also learnt to use a lathe, drill press, gas/arc welding, heat treatment, cutting, and a host of other 'workshop' techniques.

Those were the days, apprenticeships seem to have fallen by the wayside. I stayed in the industry all my working life

All that I learned, coupled with my Grandfathers teachings (he was a R&D tool maker) laid the foundation for my own retirement 'hobby', I'm lucky to have a well kitted out workshop and a passion for 'anything' metal engineering, but mostly steam models

My better half thinks I would be a 'Fred Dibnah' with a full size engine given half a chance - hmm now there's a thought !!!!

Steve

When I first joined Post Office Telephones back in '79, draw filing was the official way to prepare the ends of aluminium bus bars for joints.
First draw file flat, then remove any file marks with emery paper.
Next step polish with emery paper and petroleum jelly, such that you leave behind a slurry of clean aluminium powder in the jelly.
Prepare a couple of fishplates the same way, butt join the two bus bars, with a fishplate either side and apply a clamp, (essentially a pair of square plates with a hole in each corner and 4x nuts and bolts)
The aluminium powder/jelly mix remained in the joint to prevent oxidation and to improve the contact area.
Next EL&P (Electric Lighting and Power) staff would attend with a large dropper box; think overgrown electric fire to provide a dummy load.

If you had got the joint correct, there would be less voltage drop across the new joint, than across a similar length of virgin bus bar, as the joint itself would be thicker due to the sandwiched fishplates.

Only -50V but all often done live out of necessity; small suites were fused @ 125A, larger runs fused @ 600A, and beyond that, faults were considered self clearing.

Bill

Hi Steve

Your post brought back memories - I served my ESI 'indentured' apprenticeship with SEEB (Electricity Board in Kent, and spent the first year at their purpose built training school (boot camp) near Dover.

I made a complete set of hand tools, and a barn type tool box to keep them in, (I still have most of them) and spent many hours during the hard labour lessons draw filing huge lumps of black metal . . but, probably like you, I also learnt to use a lathe, drill press, gas/arc welding, heat treatment, cutting, and a host of other 'workshop' techniques.

Those were the days, apprenticeships seem to have fallen by the wayside. I stayed in the industry all my working life

All that I learned, coupled with my Grandfathers teachings (he was a R&D tool maker) laid the foundation for my own retirement 'hobby', I'm lucky to have a well kitted out workshop and a passion for 'anything' metal engineering, but mostly steam models

My better half thinks I would be a 'Fred Dibnah' with a full size engine given half a chance - hmm now there's a thought !!!!

My tools made at the training workshop are still wrapped in the greased cloth I brought them home in, too much time and effort in getting them to the standard the instructors wanted to spoil them by actually using them.

We were not allowed to use machines apart from the drills, YEB did not wants us to use them. Rather a pity as the shop was full of mills, lathes and a large jig borer.

Funnyly enough my father was a toolmaker who learned his trade on cameras at Kershaws in Leeds, he worked on marking out Centurion tank turrets at Barnbow, then sowing machines special applications for Singers.

I guess the apprenticeships we both 'served' were pretty similar in format, I suppose all the 12 'Area Elec Boards' back in the 70's followed a very similar curriculum.

I had to nip out to the workshop and look at what I still have, I found a pair of mole grips, Junior and 12" hacksaw, a pipe wrench, a conduit diestock holder, a couple of wooden handled screwdrivers, a cold chisel, and a drill gauge, all in a sheet steel barn tool box stamped with my apprentice No '67' . . .but alas no cuddly toy !!

I also remember there was 215 hopefully spotty 16 year olds in my first year, by the start of my 2nd year that had dropped to just under 100, and when I 'passed out' there was just 71 left to be 'deployed' to the districts to then spend another year 'learning' how to make tea properly for the 'old hands' - haha !!

I find it quite sad that very few companies offer Engineering apprenticeships now, maybe with the exception of the likes of Rolls Royce and BAE . . but I imagine its all new fangled digital computer controlled, with hand tools being rarely used !!

There are plenty of jobs where appearance is the only parameter required so if draw filing provides this then why not use it? Appreciating its limitations is important but it certainly has its place.

Mike