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Thread: Saw Restoration and Sharpening Pics

  1. #1
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    Saw Restoration and Sharpening Pics

    Here are some pics of a batch handsaw’s I am restoring and sharpening. There are lots of great tutorials on this subject, I highly recommend the one on vintage saws.com. These are just some pictures of how I do it, and certainly there are lots of different ways to skin a cat.

    I highly recommend learning how to sharpen your own saws. Yeah, it takes a little more practice than sharpening a plane blade with the jig, but the effort is definitely worth it! Lots of Neanders haven’t had the chance to use a sharp, well-tuned saw, and once you do you’ll understand how preindustrial woodworkers were able to build the buildings, ships, furniture etc. with well-tuned saws and muscle power. You don’t have to train at the knee of Henry Disston to learn how to sharpen a saw,anyone can do it.

    A good way to start is with a vintage rip saw you didn’t pay much for. The steel in the entry-level models made by all the Golden era manufacturers is typically a lots ofter than their top-of-the-line models and a good place to build your skills.Geometry of rip saw’s is simpler than cross cuts (no fleam angle), which also makes this a good place to start.

    IMHO saws sharpening/tuning is a matter of degree. Just like sharpening plane blades,some guys hone with the 4000 grit stone and go back to work, while others polish through multiple grit stones to get a highly polished edge. Neither way is right or wrong, just a matter of personal preference.

    The difference with saws vs. plane blades is that saws stay sharp a lot longer than plane blades and considering that the cutting surface of the saw is very small (the apex of the tooth), you can remove a relatively large amount of metal with one stroke of the file. The upside of this is that if you’re careful, with little practice you can get to the final sharpened tooth line you want with less effort, on the downside you can also foul things up fairly quickly.


    A couple general guidelines that work for me:

    1.If you think your files is dull, it is! Use a sharp file, when it stops cutting, get another one. In my experience, the biggest mistakes come when you’re using a dull file which means you have to take lots of strokes and is a lot easier to foul up the geometry this way.

    2.First things first, get the basic tooth geometry right before you start working on fleam angle, slope gullets or anything else. Work from one side of the saw and bias pressure on the file so that you get the spacing, rake angle, tooth line height consistent. Once that’s done, you can move onto the next steps. Trying to combine profiling with fleam/gullet angles is like juggling while riding a bike - easy to screw up both things.

    3.Error on the side of too few strokes, rather than too many before you check the results. For example, when profiling teeth after you’ve profiled the teeth from one side, jointed them one more time, flip the saw end for end and do it again from the other side.

    4.The test cut is what really matters. I’m not a machinist, I suck at math and my calipers are low-budget. It doesn’t matter if all the specs look right, if when you try the saw it binds, wanders or leaves a giant kerf – the proof is in the pudding.

    I start with tote restoration. I described how I do this in a previous post, here’s a picture of what I use. First step is to make any repairs. Here’s a picture of a repair that maximizes the original horn. It’s a lot easier to get a solid glue joint if you just saw the top of the horn off in one plane, plane smooth and glue on the repair block (rubber bands make a good clamp).
    2.5.jpg1.jpg

    I soak the plates in Evaporust, and try and scrape is much of the corrosion off with a razor blade as possible before sanding. This gives you the best chance of retaining any etch in the plate. I start with 2 inch squares of 300 grit wet dry paper and WD-40, which is more than enough to get you a clean, usable plate. Don’t worry about any discoloration or pinprick pits in the plates, that’s purely cosmetic, you just one remove the gross surface corrosion.


    I sand through 600 grit and then polish with buffing compound because I like slick, smooth shiny plates. Is that necessary – no. The functional benefit of the slick plate is that you can get by with less set in the teeth because the plate will slide smoothly through the kerf. Really I’m just a little OCD.

    2.jpg

    Having consistent tooth line with all teeth the same height is critically important because any teeth below the tooth line aren’t cutting. Check with the straight edge and it will give you a rough idea of how much jointing you’ll have to do with the mill file to get all the teeth a consistent height. Here’s a picture:


    3.5.jpg4.jpg


    A breasted toothline is one with a convex curve. Nice because in combination with the natural motion of your arm when sawing it keeps more teeth working. Straight is fine, but concave is not. Here’s a picture of a nice breasted tooth line:

    5.jpg

    Here’s my saws sharpening kit: I used to be able to do the coarser pitch saws without magnification, but now I pretty much use a magnifying visor for everything.Tolerances are small and especially when you’re starting it really helps to be able to see what you’re doing.

    7.jpg

    I use a shop made wooden saw vice with C clamps at the end in a twin screw face vice. I use the slope of the outside edge of the jaws as a visual guide for gullet angles and marker lines on the top as a guide for fleam angles. For me it’s easier to see these in your peripheral vision rather than a guide block set along the teethline. For me adjustable point lighting is essential.12.jpg

  2. #2
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    Unhappy

    9.jpg

    First step is to measure plate thickness and set see what you’re working with. These numbers illustrate the “double taper grinding” done on vintage saws. A lost technology that is part of the reason why these are still the best hand saws available.

    8.jpg
    The correct amount of set is one of most important factors that distinguishes a really well tuned saw from one that’s just been sharpened. Less set means you are removing less wood,which is faster and easier. The optimal amount of set also means the saw will track straight; on the downside minimal set means you have less margin to “steer” the saw once you get started. “Start straight, stay straight” is the Goldenrule.

    The amount of set varies based on: how much taper is ground into the plate, whether your sawing kiln dried domestic hardwoods, or damp construction grade softwoods, and frankly the idiosyncrasies of your calipers and your technique. With a little practice you’ll find what works best for you. A good rule of thumb is to add 15% of the thickest part of the plate (always at the heel, along the tooth line) for hardwoods and 20% for softwoods. The distinction is really kinda “saw esoterica”, it’s pretty easy to set a saw to work equally well in both hardwoods and softwoods, but then you have less rationale to keep a ton of saws hanging onyour wall!

    Use the longest mill file you have to joint the teeth. You can use a purpose built guide or just ablock of wood with a slot cut in it for the file to keep the file level on the tooth line.
    10.jpg

    The goal is to leave a flat spot on the tip of the teeth. This flat spot is the reference it tells you how much steel you have to remove from each tooth so it’s the same height as its neighbors. Keep the spacing even by biasing pressure on the file towards either the tooth in front, or the tooth behind, depending on which has the most steel that needs to be removed. This is where profiling the teeth in a couple passes, one from each side makes it easier to keep things consistent. I use a red felt marker to highlight the flatspot.

    12.jpg



    Saw files come indifferent lengths and tapers and there’s lots written about this and many guides about appropriate file size based on the pitch of the saw. In general smaller/slimmer taper files are little easier to maneuver, particularly when you’re getting fancy with sloped gullets or filing fleam angle in cross cutteeth.

    13.jpg14.jpg


    I’ve tried justabout every file under the sun and Bahco and Grobet are my "go to" files based onavailability, cost and performance. George and others here know lots more aboutmetallurgy and files than I do and can explain why some work better than others.Some of the vintage (I guess early 1900s?) Nicholson and others can either befantastic, or terrible if there rusted/corroded. I don’t know crap about platehardness, but I can tell you, you really learn about the quality of the steelin the saw plate once you start filing it. I usually go through 2 files per saw tosharpen the neglected tooth line and sometimes more for really hard plates.


    Shop made Guideblocks for rake angle just press on the tip of the file. I ALWAYS draw arrows pointing up and towards the heel on bothsides of the guide block – you can probably guess why- ugggh!

    16.jpg15.jpg

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    17.jpgI also put a little mark on the edge of the file on starting with. Saw files wear out along the apex of the triangle, and the marker helps me keep track of which edge is used up.

    This is a 5 PPI ripsaw. The guide block is for a 5° rake angle. You can tell this saws currently filed with more rake, probably 8°. 5° was Disston’s standard rip saw a rake angle pre-1928, 8° their standard post 1928 when their customers weren’t quite as familiar with hand saws. The amount of rake, fleam and gullet angles is a subject for another post. I’m filing this rip saw with 5 degrees of rake,5° of fleam and 25° sloped gullets.
    18.jpg

    I always start profiling from the heel and work towards the toe. Here you can see the first couple teeth are taller than the next two.

    19.jpg

    Here’s what they look like after profiling to 5° of rake.

    20.jpg21.jpg

    Here’s what you wanted to find a look like after profiling; nice consistent spacing, toothheight, rake angle etc.

    22.jpg

    After profiling, ideally your teeth will be a consistent height. The only way to know is to joint again. Hopefully tooth height is more consistent now so use less pressure and just a couple strokes, you just want the smallest possible flat spot on most of the teeth. The next sharpening pass of the file should get everything exactly the same height.

    23.jpg25.jpg


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    If your geometry is consistent, you should have shiny, filed surfaces on both the front and back of all the teeth.

    26.jpg

    If there are inconsistent shiny spots, make sure you start the stroke of the file with it the file firmly referenced against the bottom of the gullet and follow your rake angle guide block.


    Once the teeth are correctly profiled, you can move onto adding fleam angle if it’s a crosscut tooth (that will be the subject of another post), or sloped gullets for rip teeth.
    Sloped gullets are simply lowering the handle of the file below the tooth line so that you’re filing a “slope” in the gullet. You should do this, again working from the heel towards the toe, only on the teeth set away from you. In this picture the teeth marked in red are set away from the camera, while the others are set towards the camera. As you can see, the depth of the gullet in front of the teeth set away is deeper than the gullets on the teeth set towards the camera. If you flip the saw around and look at it from the other side you will see the same thing.
    27.jpg
    Here’s what the cutting edge of the teeth look like from the top; sort of like a skewed bladeplow plane.
    28.jpg

    These deeper “sloped”gullets carry more sawdust than if they were filed straight across. IMHO, “sloped gullets” are also a bit of saw esoterica. You absolutely don’t need them, particularly for finer pitch saws, but they do make a difference particularly with thicker stock – once the gullet fills up with sawdust in the kerf, the teeth stop cutting. I think these are most useful for coarse pitched ripping and particularly for re-sawing where you have a lot of teeth “buried” in the kerf. I would wait until you have a few saws under your belt before trying to add sloped gullets.

    Once the teeth havebeen profiled, jointed again and filed one more time from alternating sides toget nice smooth cutting edges, it’s time to check the set. Most saws have waytoo much set and really the only way you can get rid of it is to file it awaywhile jointing. This is why you measured the set in the very beginning, to seehow much to steel you had to remove to get to your target set. Sometimes you cantake some of the excess set out with a machinist vice, but you’ll always getsome spring back.


    29.jpg

    If you need to addset, use your adjustable saw set. IMHO the Stanley 42X is the easiest to use.For the small teeth of back saws SOMAX sets work well because they come withsmaller plungers, however you can’t really adjust them to add only the nominalamounts that you need in a back saw. FWIW, I just bite the bullet and buy two42X’s and file the plunger smaller for one of them.
    31.jpg

    After you set yourteeth, check with the calipers. Trying oriented them the same way you did whenyou took the original measurements. At least for me, measurements can varybased on whether the calipers are pointing towards the heel or towards the toe.
    32.jpg
    From here a rip saw’sbasically ready to go. For me, I like to lightly joint one more time to makesure that the cutting edges of the teeth are parallel with the work now thatthey have been “bent” by the set, and give a final pass from each side with asharp file to get nice, pristine cutting edges that are perfectly aligned. That’sjust me, I am more than a little OCD.

    Finally a light passwith a broken Waterstone (that you’ve been hoarding for no apparent reason)along the side the plate to remove any burs.
    33.jpg




















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  5. #5
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    Now as an opportunity to check one more time make sure the plate is straight. Ideally you already straightened it before polishing and sharpening, but it doesn’t hurt to check one more time and giving a final tweak if needed. It’s a lot easier to do this before you put the plate back in the tote.
    34.jpg


    Brasso, WD 40 and awire brush clean up the fasteners, and a punch will help you align everything to put it back together. Don’t forget the test cut! I have some rock-hard Eastern Maple that is a stern test for any saw.
    35.jpg36.jpg37.jpg


    And here’s the final result, a 28”, 5 PPI Disston #7 rip saw circa 1880, ready to go back to work.

    39.jpg40.jpg38.jpg

    If there’s anyinterest I’ll do another thread for sharpening cross cutters.


    Thanks for looking,Mike

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    Fascinating and educational. THANK YOU again Mike, Patrick

    P.S. Got a nice box today . . . . . yours should be there soon.

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    I like your fleam angle guide. I use something similar, but rather than having the lines on the vise, I have a variety of strips of plywood with different angles on them that I lay behind the vise. Each side or each piece of plywood has the lines angling in different directions.

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    Great write up Mike!! Thank you.
    Put me on the waiting list for the cross-cut tutorial.

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    This is an incredible post, thank you! I I would certainly appreciate an article on crosscut saws as well! How about a private class, I live in Temecula lol

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    Awesome thread Mike!
    Bumbling forward into the unknown.

  11. #11
    Very helpful thread; gorgeous work on the totes.

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    Saw Restoration and Sharpening Pics

    A big YES to the cross-cut tutorial!

  13. #13
    Well done Mike. This is very useful tutorial an commentary.
    Dave Anderson

    Chester, NH

  14. #14
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    Thanks for posting this Mike.

    It is always enjoyable to read others methods. It seems there is always useful knowledge to add to my own.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  15. #15
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    Thansk for posting Mike. For a variety of reasons, I'm planning a first attempt at saw sharpening in the next couple of weeks. I'm lucky enough to have a local mentor and this will help me not arrive feeling like a total rube

    Cheers,
    C
    "You can observe a lot just by watching."
    --Yogi Berra

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