Filing Technique

[DiogenesIIParticipant @diogenesii]

It's funny how things stay in the memory – one of the best pieces of hacksawing advice "keep your bl**dy feet still" was drummed into me at the age of 11 or 12 by Jack Hovell, I still hear him perfectly to this day..

+1 for the 'Tome..' files from ARC..

[Tim StevensParticipant @timstevens64731]

I wonder if Mr Dobson (see Mark rand's post above) ever thought hard about his advice. To affect the temper of steel you need to get it hot enough to change its temper colour or 'blueing' – starting (as every metalsmith knows) with the palest yellow and ending with purple. His advice – if based on good science – would mean that filing quickly produces blued swarf. Not in my (60 years) of experience it doesn't.

Regards, Tim

[Mark RandParticipant @markrand96270]

Actually, O1 steel, which files were made from, loses hardnes fairly linearly from 100°C to 700°C. 100-200° temperatures are easily produced at the teeth with hand filing and sawing.

Edited By Mark Rand on 30/11/2021 10:46:42

[Neil WyattModerator @neilwyatt]

Posted by Mark Rand on 30/11/2021 10:45:57:

Actually, O1 steel, which files were made from, loses hardnes fairly linearly from 100°C to 700°C. 100-200° temperatures are easily produced at the teeth with hand filing and sawing.

Edited By Mark Rand on 30/11/2021 10:46:42

But files aren't normally glass hard or they would shatter easily in normal use, the tempering they receive is probably in that range, and the tang can be very soft some times too soft!

[Tony Pratt 1Participant @tonypratt1]

Posted by Mark Rand on 30/11/2021 10:45:57:

Actually, O1 steel, which files were made from, loses hardness fairly linearly from 100°C to 700°C. 100-200° temperatures are easily produced at the teeth with hand filing and sawing.

Edited By Mark Rand on 30/11/2021 10:46:42

Even IF hand files got to 200°C in use the hardness will hardly be affected maybe 62 RC? I have seen needle files snap a few times so they are very hard / brittle anyway, they will be tempered but I believe not too much.

Tony

[Harry WilkesParticipant @harrywilkes58467]

My problem is can't file for toffee even before the Arthritis and Carpal Tunnel I was not that great I can however cut straight with hacksaw

H

[Bo’sunParticipant @bosun58570]

Posted by Andy Stopford on 27/11/2021 20:04:26:

Of course, once you know, it seems reasonable that dragging the file back increases wear on it's teeth – but is it true?

This guy decided to find out:

Aside from attempting to answer the question, its a nice demonstration that you can use a shaper to do all sorts of things it's manufacturers never intended (when I had one, it occasionally did duty as a tool and cutter grinder for horizontal milling cutters).

An interesting video Andy, although it did go on a bit and was perhaps a little over the top. But some surprising results none the less.

[old martParticipant @oldmart]

I keep a few good quality files at the museum, including a number of NOS Stubbs, they no not get lent out to be abused.

[Andy StopfordParticipant @andystopford50521]

Well, today I was doing some filing, and guess what, I do lift the file on the return stroke! Admittedly I was shaping a bit of aluminium to fit into the moulded plastic case of a Dremel-type tool I was repairing so I needed to keep eyeballing the developing shape, but even so…

So do I always do it? I don't know, I'll have to catch myself next time I'm filing without thinking about it first.

[Author]

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