Model Engine Maker

Help! => Machines, Tools and Fixtures => Topic started by: Kim on December 08, 2021, 11:37:13 PM

Title: Interesting File Facts...
Post by: Kim on December 08, 2021, 11:37:13 PM
I ran across this video today; it's a guy doing a series of tests on a file to see if dragging the file backward over the work on your return stroke does, in fact, dull a file.  I found the video pretty interesting to watch (granted, I watched it at 1.5x speed  ;D) and thought he did a nice job of designing the study. Certainly more work than I'd have gone through for this.

His conclusion is that dragging the file on the backstroke does not damage or dull the file any more than lifting the file on the backstroke.  There are a few other interesting conclusions he draws too, but I don't want to spoil the whole video for you :)

Title: Re: Interesting File Facts...
Post by: propforward on December 09, 2021, 01:23:09 AM
I like Fireball Tools. He has a good approach to a lot of his investigations. This test was very interesting.
Title: Re: Interesting File Facts...
Post by: 10KPete on December 09, 2021, 01:38:23 AM
Chris comes up with some outstanding stuff. His big vise.... 'nuf said!
Title: Re: Interesting File Facts...
Post by: ptross on December 21, 2021, 03:57:15 PM
a very interesting video and test, to be sure. I have enjoyed many of his videos, his skills, and thinking, and have great admiration for his abilities.

  As one who has spent many hours each day filing steel and iron, this was very informative. I think the test illustrated exactly what it was designed to test- whether heavy pressure on the backstroke dulls a file. I was not expecting the result, as I've heard all my life that this was poor practice.

I've thought about the test and how the results can be applied to actual shop practice. One condition not covered in the test is what I observe in real use- people applying only light pressure during the stroke. This can be either forwards or backwards. I find this is the most likely way to dull a file- apply insufficient pressure so that the teeth don't really bite, but just glide over the surface. With an older file this pressure can be considerable, but the file will still cut well given enough pressure. I have also witnessed a new file quickly dulled by "rubbing" it over the work and not cutting. The work becomes an abrasive in effect, and wears the file teeth.

How does this apply to the video? I have seen very few people who can apply enough pressure on both forward and back strokes to make the file cut. It is triring enough to apply correct pressure on just the forward, and that is when you are using your more powerful muscles. So, I think the risk here is dulling the file due to less pressure on the backstroke, not because of the direction of the stroke.

many people think of a file as an abrasive, not as a cutting edge, and treat it that way. This will scrape the surface but not produce the controlled, consistent finish that proper filing can offer. There was no measurement of the filed surfaces on the video test pieces comparing forward and backward results. While I agree the video proves certain points, I am not completely convinced that workshop practice should be changed.

Hope to hear observations and reactions from others.


Title: Re: Interesting File Facts...
Post by: simplyloco on December 21, 2021, 04:24:53 PM
To drag or not to drag?
Us apprenticed folk who spent a lot of time with hand tools usually develop a personal style which suits them and gets consistent results. My view of files is that the quickest way to blunt files is to lump them together in a drawer. That's way all my files are in Terry clips on the wall!
Title: Re: Interesting File Facts...
Post by: mcostello on December 21, 2021, 04:34:46 PM
Some powered hacksaws have a mechanism to lift the blade on the back stroke. Someone must have thought it important.
Title: Re: Interesting File Facts...
Post by: simplyloco on December 21, 2021, 04:42:08 PM
Some powered hacksaws have a mechanism to lift the blade on the back stroke. Someone must have thought it important.

Most powered hacksaws rely on the (heavy) weight of the moving arm to provide the downforce. The teeth would soon be blunted if there was no relief on the return stroke.
Title: Re: Interesting File Facts...
Post by: ShopShoe on December 22, 2021, 01:50:55 PM
I agree that maybe traditional practice may still apply. One also learns and practices a skill that works for the individual.

However (Number One), I think there may be something different about how files have been made more recently rather than anciently historically and that may change what works and what doesn't work (Just like my Dad kept insisting that cars had to be washed only with a chamois and never with anything else as the paint was so fragile: Paint technology is so much better now such that it is no longer true, besides modern "car wash chamois cloth" is not what my Dad used in the 1930s and 1940s.)

However (Number Two), I have had to relearn how to apply pressure to file metal: What they taught in K-12 shop classes years ago for woodwork is not the same. I had a tendency to put on enough pressure to bend the file and file the edges of the piece more than the middle: I had to give myself a mental rap on the knuckles to change my behavior on that.

Title: Re: Interesting File Facts...
Post by: Edward on December 22, 2021, 05:08:00 PM
Perhaps its a mindset thing. I'm with Tom from Oxtools, I view files as cutting tools that are essentially disposable like a hacksaw blade. I don't mean you should abuse files for no reason, but you should view them as something that is 'used up' rather than an heirloom to be passed on. Most hobbyists like me won't use them up all that quickly, although filing a load of hard bronze braised joints smooth did for one of my files pretty quickly.

Remember dull files can be turned into all sorts of useful scrapers and trimmers so don't necessarily ditch them. One of my go-to deburr tools is a ground down triangular file :-)
Title: Re: Interesting File Facts...
Post by: steam guy willy on December 23, 2021, 01:42:37 AM
I have done quite a lot of filing in my life and when I do rough filing to remove lots of metal quickly a hacksaw is used first. Also when I want to produce a flat surface I always raise the file between strokes to see what is happening ..I also file obliquely with a well placed lamp to show where the file is cutting as the file marks will show up after each pass.  I allways use the best old stock files ...namely Stubbs or Nicholson... Using a brand new file is a pleasure to use especially a 14" bastard  and it is a good idea to use a file card if possible and also tap the file on the cast iron part of the vice to remove swarf...