Filing corners round

[AndyT]

Inspired by AES's guide to filing, here's my one filing tip.
I was taught it by an experienced toolmaker when I had a Saturday job at a toolmakers/injection moulders.

Imagine you have a bit of flat mild steel, say four inches by two inches wide by an eighth of an inch thick. (Imagine it as 100 x 50x 3mm if you prefer - it's almost the same.) You want the corners neatly radiused so it can be handled comfortably or look neat when screwed down.
Many people would put the metal in the vice and file in line with the long side, tipping the file end to end to go round the corner. This is not the best way.
Instead, put the work in the vice the 'natural' way so a long edge is uppermost and parallel to the vice jaws. Stand facing the bench with the tip of your file resting flat on the right hand corner of the upper edge of the work. Push the file forwards, pressing down with your left hand at the tip in the usual way. As you do this, rotate your right wrist clockwise 90°. By the time you have completed one whole forward stroke, your file's width should be vertical. Repeat as required. This automatically produces a much tidier radius on the steel, as there is much better control of the file and the 90° twist is a natural movement for the wrist.

If you didn't know this, give it a try.
If you knew it already, give yourself a pat on the back!

 

[Robbo3]

Thanks AndyT.

I suspect that most amateurs like myself would have the metal stuck too far out of the vice, which would cause vibration. To counter that, we would file along the thin edge rather than across it instead of lowering the work. Then we think, job well done not knowing there is a better way.

That's why tips like this are invaluable.

 

[AES]

Thanks for that AndyT. That's one I didn't know, I must try it next time.

Was taught to make and use toolmakers buttons (or the correct size washers!) or cardboard/ply templates for outside radii, but never heard your method before.

As Robbo says, there's always something new to learn - keeps us old boys awake!

AES

 

[CHJ]

....Was taught to make and use toolmakers buttons (or the correct size washers!) or cardboard/ply templates for outside radii,

Yes it's my norm to provide the guide acting as additional support on thin stuff.

Filing radii can get interesting when yo need to do this.

Stepped Buttons was/is the norm when filing forms from solid stock such as this (case hardened helps)

As AES says washers are a good aid to material removal and support when tackling the quick sheet task as highlighted by Andy.

 

[sunnybob]

I was taught that way back in the mid sixties. have used it ever since. it also works just as well sanding wood.
use a long flat sanding block, and rotate the block like a see saw action as you sand. Does away with any flats across the curve.

 

[AES]

Thanks sunnybob. I'll try that for sanding curved corners on wood too. As above, that was a little trick I hadn't heard before.

AES

 

[bugbear]

Thanks for that AndyT. That's one I didn't know, I must try it next time.

Was taught to make and use toolmakers buttons (or the correct size washers!) or cardboard/ply templates for outside radii, but never heard your method before.

Could you expand on that? The only toolmakers' button I know about are precision ground small hardened steel cylinders, of identical sizes, with truly perpendicular end faces. They should NOT be (ab)used as filing guides!

BugBear

 

[CHJ]

Thanks for that AndyT. That's one I didn't know, I must try it next time.

Was taught to make and use toolmakers buttons (or the correct size washers!) or cardboard/ply templates for outside radii, but never heard your method before.

Could you expand on that? The only toolmakers' button I know about are precision ground small hardened steel cylinders, of identical sizes, with truly perpendicular end faces. They should NOT be (ab)used as filing guides!

BugBear

As a tool maker/instrument fitter making prototypes or specialist equipment it was the norm to regularly turn up buttons to suit a task in hand and case harden them if necessary as required for repetitive use. I think I may well still have some 55-60 years latter in the bits tin.
Different thing to metrology buttons but not unknown to make one offs for that purpose as well if necessary.

Two of them were used (case hardened) for the forming of the Boss for the G-Clamps above for instance.

 

[Eric The Viking]

If you didn't know this, give it a try.
If you knew it already, give yourself a pat on the back!

I've just poked myself in the spine with a half-round!

Seriously, no, I wouldn't have thought of doing that, and yes, it is a really good tip.

Thanks very much for posting it.

E.

(Who once had a summer job in a light engineering factory, but the toolmaker breathed fire when he was being nice to you, never mind when he was cross. It was a real shame: I'd have loved to learn but wasn't allowed anywhere near his benches, let alone to actually ask questions. And he was really good, too. :-( )

 

[AndyT]

I wish I'd paid more attention too - they did impressively accurate work making the moulds for little plastic parts, all on old manually controlled milling and shaping machines.

I was paid to make tea and sweep up and had to earn my 50p an hour but it was nice when the old guys just wanted to talk.

 

[Eric The Viking]

Our toolmaker made plastic moulds too, and like your chaps beautifully intricate.

It probably didn't help that I once almost blew up the plastic moulding machine I was operating (do you remember purging blocks?). The factory was officially on annual shutdown at the time, and so rather too quiet. The bang was "quite loud"

 

[CHJ]

Buttons went along with making your own Spot Face Cutters and other 'tools' to suit specific tasks, just a normal precursor to making a prototype or one off.
These came to light in the first tin I looked, suspect made 1958-9:-

If memory serves me that button was made to locate against a shallow shoulder that needed filing square, longer so file had a large register, it's case hardened.

 

[J-G]

I was paid to make tea and sweep up and had to earn my 50p an hour but it was nice when the old guys just wanted to talk.

50p per hour !!!

As an apprentice toolmaker I was earning less than 2p per hour !! (17/6 per 44 hour week) - - - - but that was some time ago (1956) and that was at the finest (and best paying) machine tool makers in the UK.

The concept of toolmakers buttons for use in prototype jigs brought back quite a few memories as well!

 

[AES]

50p per hour !!!
As an apprentice toolmaker I was earning less than 2p per hour !! (17/6 per 44 hour week)

" 'ole in't ground?" We considered o'selfs lucky wiv a shoebox!" "Shoebox? Height o' luxury!" "But will the youngsters o' t'day believe yer? Will they 'eck as like!"



(Happy memories - for us boring old f---s)

AES

 

[sunnybob]

ah, but for that 17/6 you were being fed and housed.
I started at £3 10s a week, of which my mother took more than £2.

Still managed to go the pictures each week and have a bag of chips on the way home. Couldnt afford the fish, mind.

 

[J-G]

ah, but for that 17/6 you were being fed and housed.
I started at £3 10s a week, of which my mother took more than £2.

Still managed to go the pictures each week and have a bag of chips on the way home. Couldn't afford the fish, mind.

Sorry to dis-abuse you Sunnybob, but I was still living at home and paid mother (I think) 5 bob.

The real inconvenience I had was that whilst waiting for my apprenticeship (about 3-4 months), I found a job at a local engineering works and had been used to earning as much as £3 a week with piecework bonuses.

Don't talk about a bag of chips !! -- now £1 (well last time I bought one) - back then I couldn't carry a pound's worth of chips
(it would have been 80 bags!)