Radical Changes for Saw Sharpening (video)

For more information on saws, see our beginner site Common Woodworking.

Save your files and makes the saw filing experience more pleasant

I thought this up some time back about the time I used a hacksaw to line out a recut on saw teeth using a guide made from wood and a hacksaw. This followed the act of filing off all teeth and then recutting new ones from scratch. This additional fix champions my effort there for a couple of reasons not the least of which is it will save wear to your saw file faces and even enable you to use those saw files that already have fractured narrow edges.

If you have followed my blogs at all you’ll know that saw files have six facets not three, three broad faces and three thin ones. The thin facets, because they are so narrow, fracture intermittently long before the wide faces and this reality leaves the saw file unusable for continuing use in filing saw teeth because the fractured edges stop cutting and prevent the other wide faces of the file from deepening the cut. This simple trick changes all of that. Watch the video below to see how it works. You’ll just love this radical alternative!


  1. Brilliant. Makes sense and I can’t imagine it not helping the sharpening process. Thanks Paul.

  2. Paul –

    How many TPI does your hacksaw blade have?

    Thanks for the tip.

    Hope you all have a MErry Christmas & Happy New Year.



  3. Wow,

    It seems so obvious yet it’s a “fresh” idea. You’ve relieved the small edge of the file from having to do the heavy “plow” work.

    It’s also becoming obvious that you are a natural “Tool Maker”, you’d fit right in on the AirBuss projects.

    Brilliant stuff here!

    Tony in Michigan

  4. Dear Paul,
    Simply brilliant.
    Thank you.
    No excuses now about bad files for not trying to sharpen our saws.
    Best wishes for 2017.


  5. That was quite an enlightening demonstration. Should make saw sharpening a quieter and more mellow experience. Thanks much.

  6. Brilliant as usual, Paul. And very timely for me, as I am restoring several old saws and was just getting ready to sharpen them. I will try this out right away.

  7. I wonder if the hacksaw will have to be used prior to each sharpening, or if it will be more like using a saw-set to set the saw, and only required after every 2 or 3 sharpenings? I suppose it will largely depend on how deep the previous sharpening sent the file down.
    Thanks for the great technique. It will come in handy to prolong the life of your files, as well as making it much more pleasant and relaxing during the actual filing process.

    1. It depends on how deep you go, obviously, but two strokes as I did is good for three or more sharpenings.

  8. !!Genius!!

    I also think the ‘Tags’ links are long awaited — Tag everything — there is so much knowledge/content in your blogs it needs a proper index (In my humble opinion 😉 )

    Terry Hennessy — The Saw used is a “Junior Hacksaw” still sold by Eclipse but also Very many copies in Diy sheds and Fleebay — Number of teeth — LOTS!!
    (The blades come in a packet and I’ve never seen them described in TPI)
    Hope that helps.

  9. Few woodworkers, present or past, are as innovative as you. Despite you belonging to the older generation of woodworkers, you are open to new methods of doing things and trying out new solutions. Not only do you share the knowledge of traditional woodworking, but you also expand the body of practice. Thank you.

    Wishing you all a Merry Xmas and a Happy NY,


  10. That is one of those things that seems so obvious once you pointed it out! Funny it took a couple of hundred years for someone to think of that. Well done once again! Thanks Paul! Merry Christmas to you and your family!

  11. Any limit on small teeth Paul? Before the saw is hacking at the sides of the gullet?
    Very neat idea

  12. Works brilliantly! Many thanks for this and all the other advice that you have so freely given out over the years. Hope you spend a happy time with your family over the festive season!

  13. Paul,
    I’ve already commented that this is fantastic, but on thinking about it, this leaves a rectangular gullet. As cracks propagate from sharp changes in section, have you experienced cracking in your saws? Perhaps the rectangular slot left by the saw teeth should be completely removed by the narrow face of the file by the last stroke, to eliminate the stress concentration that would result in cracking. Clearly a rounded gullet bottom does not result in cracking, so we should replace it.
    At the end of WW11 The Liberty ships sunk due to cracks propagating from sharp cornered hatches, then brittle failure finished the job.

    1. Liberty Ships used rather new mass-production techniques, they had to deal with ferocious forces of Ocean Weather.

      Hand Saws require about 200 Watts of human power ( about 1/4 horsepower ). If hand saws had 2 to 3 horsepower behind them ( as in the Red Freud circular saws which are deep cut ) then careful stress relief would be of benefit.

      Still, the triangular file has a square face just like the hack saw blade ( which is a quick wear-out point ), worn out it acts as a limit to file effectiveness.

      Being able to keep hand saws “Sharp” would probably shorten the Saw’s Life as it would be used more often. I suspect these old saws are still around because people stopped using them from being dull and very difficult to keep sharp.

      2,700 Liberty Ships were built, average build time was 42 days, 2,400 Survived the War. Early ships had failures attributed to unskilled workers and corner cutting, low temperature embrittlement of ductile steel and severe overloading.

      Tony in MIchigan

      1. Thanks for the reply Tony, pretty comprehensive about liberty ships, but do you think saws will be immune to cracking from a sharp corner? I don’t agree with your comment about the file having a square face as, if the narrow face is flat, then the angle will be 120 deg not 90. however, I’m not getting into e-mail ping pong about it. I just asked if cracking had been observed as sharp corners cause high stresses from which cracks can propagate. I’m happy to go with Paul’s method and see what happens as I respect his judgement and experience.

  14. Any new way of doing things will carry a risk and until we try it enough, we will never know if it works or not. That’s how we improve and advance.

    Here we are talking about sawing wood, not sawing steel pipes and from a risk mgmt point of view, the risk is low. Start with an economical used saw and the risk of failure is well managed.

    Of course, those who are worried should stay away from this experiment.

  15. Thanks once again Paul. It does go to show that although rediscovering the skills of our forefathers is high on our list of priorities, it is also essential to keep focusing on uncovering new techniques as well. Thank you. On the subject of saw files, two questions please; how would you recommend cleaning then during/after use (I use a wire wheel rather than a wire brush) and should you do anything to prepare them when you buy them new and take them out of the box? Secondly, a blog or two ago you mentioned buying Bahco files instead of the Nicholson ones – to what do those lists of numerals and hyphens attached to each file refer to? Are they grooves per inch or some other system you know of? Cheers and keep up the excellent work.

  16. To make things easier would there be any benefit to add a piece of wood to the tooth line so that the gullets are all the same depth? Also would using a guide that Paul used to cut the teeth help with preventing cows and calves where shaping may be necessary due to differing tooth size?

    1. Personally this seems to change what is truly simple and quite intuitive into something more complex and possibly time consuming.

  17. John Heinsz, in Canada ( if that makes a difference ) is sharpening teeth ( including Carbide teeth ) with his Eze-Lap diamond paddles!
    I seem to be sharpening everything ( or just touching-up everything ) with my set of 4 Eze-Lap paddles, I rarely use the coarse one but I hadn’t considered using them on the two or three hand saws I own. I will now!
    Relieving the area between the saw teeth is “Genius” which isn’t all that much “extra” work once the commitment to sharpen has been made. The tiny v between the teeth could be relieved with a small round file or a dremmel tool or any number of things commonly owned by us workmen.
    I’m even considering buying one of the Edge-Pro fixtures for sharpening my stuff because at my very old age I’m having trouble holding my cutting edges at a consistent angle. The Edge-Pro can and does use 3M 261x diamond grit papers from 1000 to 6000 grit. It’ll even do scissors and Stanley Blades ( for gods sake ) . That 261x stuff ranges from 1000 grit to 25000 grit with a cost for an 8×11 inch about $4.00 from Woodcraft.
    Since I discovered Paul Sellers ( about 1 month ago ) I’ve been sharpening my tools each time I work with them, I’m on a learning curve and trying to get some practice time in. Maybe after a hundred hours of practice sharpening I’ll begin to gain a bit of confidence. ( stiff fingers crossed ).

    Tony in Michigan

  18. I wonder, old saws with somewhat brittle teeth — would this lead to teeth breaking off when set?

    1. It does happen. I own a couple of saws with very hard teeth so I set them a minor amount of set. Sometimes older saws have unequal tempering so parts in the plate are overtly hard next to areas that are fine. 95 percent of old saws have no such issues though and I haven’t had any problem with newly made saws in the last two decades that I can recall.

  19. great quality videos, and they’re getting better all the time, but the audio needs some improvement.

  20. Hi Paul, Thanks for all the amazing content you make available to us. I watch your videos on repeat and wish you had a workshop or some courses offered in South Africa.

    We have a limited supply of guys supplying hand tools in this country with the majority of them bringing in only the high end brands like Veritas and the like. I’m struggling to find saw files and saw sets. Are there alternatives to this?
    We do perhaps have files but not specifically named “saw files” – with this in mind, can one use any 3 square file to sharpen? or is it better to get a needle file set to accomplish sharpening.

    PS. would you consider doing a video on making that sharpening stone board you use for your stones?

    Greetings from Cape Town 🙂
    Thanks again for your fantastic contribution to this art form.

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