Page 1 of 2 12 LastLast
Results 1 to 15 of 16
  1. #1
    Join Date
    Mar 2004
    Location
    Brisbane (western suburbs)
    Age
    77
    Posts
    12,093

    Default Some more mucking about with tooth profiles

    Yeah, I know I said "no more saws for a long time" or something like that, but I'm always making foolish statements. Playing about with a Disston 77 got my creative juices flowing (my better half calls it procrastinating & dissembling), and I wanted to explore this extreme fleam angle thing a bit more.

    So I've made a couple of new saws. The first is a 12" 12 tpi that I showed on the other thread: 12tpi 45 fl.jpg This saw has no set and 45 deg of fleam. For anyone used to more conventional teeth, these look rather odd: teeth close.jpg and they certainly make the saw operate differently!

    The other is a 14" 10tpi: 10 tpi 40 deg fleam some set.jpg This saw has a teeny bit of set and 40 degrees of fleam. Both saws have 25 thou plate.

    On the longer saw, I put the minimum amount of set my pliers are capable of applying, then stoned most of that off before final sharpening (no slope). You can barely see the set, but to my surprise, it still cuts a kerf 30-31 thou wide, only a few thou less than a saw of the same thickness, with conventionally filed & set teeth does. And while the cut surface is pretty clean, there are visible scratches, the surface is not as clean as that off the zero-set saw. My working theory is that the little bit of set allows a teeny bit of wobble in the saw which enlarges the kerf & produces the scratches.

    The shorter saw, with 45 fleam & no set cuts a kerf that is barely wider than the plate (I can slide 26 thou of feeler gauge into the kerf comfortably, but no more). Provided I saw cleanly, & let the saw do its thing, it has slightly more resistance when it gets deep into a cut than the saw with the bit of set, but the amount of drag is still quite acceptable. Compared with an equivalent saw with 'standard' fleam & set, it does take a few more strokes to cut through a board, but not all that many. What intrigues me most is that the parallel blade seems to work just as well as the tapered blade on the Disston.

    Before I get too carried away, I should point out I have only made about a dozen test cuts with each saw, & the blades are brand new and highly polished, which does add to a saw's function. Nevertheless, it begs the question of which aspect is the more necessary, blade taper or those peculiar teeth??

    It's going to take me some time to figure out if 'extreme fleam' is a viable alternative to set on parallel-bladed joinery saws. I'll need to use them 'for real' on a wider variety of woods, and compare them with their siblings which have more conventional teeth to see how they perform overall, & how those fine-edged teeth stand up to tougher woods. I suspect there'll be trade-offs, there always are....

    PS - I've started making domed bolts and sleeved nuts as a change from the split -nut type. The split nuts are fine, but the domed ones add some variety... Saw bolts.jpg
    Cheers,
    Last edited by IanW; 19th January 2017 at 07:48 AM.
    IW

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Age
    2010
    Posts
    Many





     
  3. #2
    Join Date
    Dec 2013
    Location
    San Antonio, Texas, USA
    Posts
    3,070

    Default

    I have a feeling that these higher fleam angles work better with sloped gullets.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  4. #3
    Join Date
    Mar 2004
    Location
    Brisbane (western suburbs)
    Age
    77
    Posts
    12,093

    Default

    Quote Originally Posted by rob streeper View Post
    I have a feeling that these higher fleam angles work better with sloped gullets.
    Rob, I suspect the difference would be very hard to quantitate. Interestingly, Henry's instructions for the 77 say to hold the file level, i.e. don't use slope. By the time I'd proven to myself that doing it my way was not a clever idea, I figured I better follow the instructions to the letter on the next try, so straight across it was..

    There is a lot of space between those 45 deg teeth, even without slope but not sure if it translates to sawdust-carrying capacity. Eventually, I will get around to adding some slope, out of curiosity, but not 'til I've given the saw a good workout as it is. I was using the smaller saw for real today, and enjoying its smooth action. I could become quite a fan of this one, if it holds up in steady use....

    Cheers,
    IW

  5. #4
    Join Date
    Dec 2013
    Location
    San Antonio, Texas, USA
    Posts
    3,070

    Default

    Ian,

    I have some doubts about the 'sawdust' capacity notion but haven't formulated a good test yet, I think otherwise on the subject of PPI.

    I've caught Ol' Henry D. in lies twice recently and three times altogether so I'm skeptical*. It is interesting however that no claims as to the superiority of the 45o fleam angle were made.

    Like your new screw design.

    It's good to take a break, all work and no play...

    Cheers,
    Rob

    *
    1)
    Disston 240 metal cutting saws are 'harder' - NOT, the 240 I have is HRC 52.

    2) Disston saw blades are "Patent Ground' - NOT, Disston had no patents on the process of grinding saw blades, only on the machines to do the grinding.

    3) Disston Acme 120 saws are 'harder' and can't be set - NOT. Of the two I've tested only one is harder than average. I suspect this lie extends to the No. 77 saws too.

    The claims made for 'tensioning' and its purported benefits, particularly the 'springiness' assertion, are also a matter of concern. I think at this point that the primary benefit is reduction of oscillation or ringing of the blade while cutting but again I need to conceive an experiment to show that. The only quantified material benefit, if it is a benefit, is the strain hardening of the teeth - something that Henry was incapable of measuring because he died before the instruments became available.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  6. #5
    Join Date
    Nov 2011
    Location
    Melbourne
    Posts
    6,973

    Default

    All this tooth angle thingy.
    Gets me confused remember I'm a novice here gentleman.
    But Ian your domed bolts are looking mighty spiffy.

    Cheers Matt

  7. #6
    Join Date
    Mar 2004
    Location
    Brisbane (western suburbs)
    Age
    77
    Posts
    12,093

    Default

    Quote Originally Posted by rob streeper View Post
    .....I've caught Ol' Henry D. in lies twice recently and three times altogether so I'm skeptical*. It is interesting however that no claims as to the superiority of the 45o fleam angle were made.....
    Rob, it seems to be commonly accepted that Henry was a competent sawmaker, and a much better salesman! I wonder just how much he would've had to do with developing the 77, though? By the time that came along, would he not have had other clever people to do the tedious work?

    Anyways, so far, this is all just observation, and new to me. Whether someone figured out from first principles that 45o worked better for a no-set saw, or discovered it by accident, it sure seems to make a big difference. A saw with no set & standard fleam is unusable in my hands, but even my parallel-bladed saw cuts cleanly, with 45o of fleam. As I said on the other thread, I can only speculate what's happening at this juncture.

    Apart from the two possibilities I mentioned there (increased 'sharpness' of the leading edge of the tooth & slight outward deflection of the thinner tip as it moves through the wood), there is a third, even simpler possibility & that is that there is a slightly bigger burr on the tooth caused bu the lower file angle. If that's the case, I expect the effect to wear off pretty quickly, especially if I tuck into some hard woods, so the saw may need frequent touch-ups to keep on working. I guess I can test this pretty easily by stoning the sides of a freshly-sharpened saw, which I will try when I next sharpen it (if I remember )...

    Yep, you're right, these diversions are fun, and not having serious deadlines any more means I can fool about with ideas pretty much as I please.

    Cheers,
    IW

  8. #7
    Join Date
    Nov 2004
    Location
    Millmerran,QLD
    Age
    73
    Posts
    11,095

    Default

    Ian

    Firstly I do like the new saw nuts.

    Secondly, there are clearly such a huge number of combinations in terms of fleam, rake and, dare I say it, slope to be considered.

    I have to say that my first thought was with Rob's suggestion that it looked as if it would benefit from some slope, but that is my bias raising it's ugly head. In fact on further reflection I thought that less rake may be the first adjustment. It looks as though there is a high rake angle unless the camera is playing tricks again. I would consider going to about 15 deg rake with the 45 deg fleam. That may not make for a smooth sawing action however.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  9. #8
    Join Date
    Mar 2004
    Location
    Brisbane (western suburbs)
    Age
    77
    Posts
    12,093

    Default

    Quote Originally Posted by Bushmiller View Post
    .....Firstly I do like the new saw nuts......
    & how about the bolts, Paul?

    I've made quite a few of these now, & getting slicker at them. Took a while to figure out the right dimensions for the domes so they have enough curve without being too bulbous. I don't have any automated way of turning them, so I do them with a combination of files. By counting the strokes & applying my 'wood-turner's eye' I get them close enough to fool anyone without a micrometer...

    I liked the split nuts when I first started serious saw-making because there weren't so many around back then, & because they are relatively easy to make with limited gear, but they are fussier to fit well, unless you just bung 'em in & sand flush, which is a bit slack, imo. The Glover patent type bolts are fussier to make, but easier to fit neatly. It's six of one & half a dozen of the other, I suppose........

    Quote Originally Posted by Bushmiller View Post
    .......Secondly, there are clearly such a huge number of combinations in terms of fleam, rake and, dare I say it, slope to be considered.

    I have to say that my first thought was with Rob's suggestion that it looked as if it would benefit from some slope, but that is my bias raising it's ugly head. In fact on further reflection I thought that less rake may be the first adjustment. It looks as though there is a high rake angle unless the camera is playing tricks again. I would consider going to about 15 deg rake with the 45 deg fleam. That may not make for a smooth sawing action however....
    I have strong doubts that slope would add anything functionally but I will get around to trying some eventually, I promise! However, I need to get my hands familiar with this 'extreme' angle of the fleam, first! It's so easy to wreck one of these dainty teeth completely if the file catches or skips, and although I find filing with a bit of slope makes it easier on the 'standard' fleam angle teeth, it just seemed to add too much complication when forming the 45 deg. teeth.

    My first attempt went amazingly well, and I only botched a single tooth (near the back where it doesn't do anything, anyway). That was probably because I was doing it at the right time of day (I get the best lighting combination on my bench early afternoons) and I was concentrating like hell. The dogs must've sensed it, they didn't move or scratch 'til I finished! So a couple of days ago, I confidently sailed into a second saw , & made a right mess of it It was so far off I had to file off most of the teeth & start over! My problem is keeping the rake angle true on the 'return' side, i.e., when working left to right. For some reason that only my cerebellum understands, I have no trouble maintaining consistency when working right to left, but become a tangle of thumbs when I reverse positions for the opposite side, and have to work extremely hard to maintain rhythm and consistency. And it's exacerbated by the 'unfamiliar' angles.

    Incidentally, while the rake may look odd in the pic, it is actually around 15 degrees. At least it starts as 15 when the teeth are formed, which is then increased a bit when fleam is added, but it should be no more than 20, at the most. I think the very wide fleam bevel creates an illusion.

    From my various experiments with rake angles, I've found you have to vary them by a huge amount on crosscut teeth before you notice much difference in saw action. That's quite the opposite of rip teeth, where just a few degrees change in rake can make a big difference. Here, we're dealing with a bunch of little 'knives', and the more rake you have, the more 'slicing' the action, which should be good. However, you have to strike a compromise - too much rake produces stubby little triangles and little room for sawdust.

    I'm slowly evolving a 'feel' for what works best with small saws, but it takes a long time & I've changed my mind more times than I can count. You're right, there are so many combinations & permutations, and so many individual preferences, it makes my head hurt! I reckon I could make a saw that was near 'perfect', for a very narrow range of widths & depths of cut, and for specified woods only. Such a saw would be pretty useless in most folk's view...

    Cheers,
    IW

  10. #9
    Join Date
    Mar 2004
    Location
    Brisbane (western suburbs)
    Age
    77
    Posts
    12,093

    Default More on no-set saws

    An update, to report on my no-set saw: Been using it quite a lot over the last month or so, and starting to really like it. I can see where Henry was coming from, these saws are definitely not something you chuck in the toolbox "in case you need to cut something". They need to be used with care and full knowledge of their limitations. But they have their place, and that is wherever you need to make highly accurate, clean cuts. This is the saw I reach for now when cutting tenon shoulders. With this saw (and my new specs!) I can split the line almost every time:Sawing to line.jpg

    Some time ago, I made a saw based on the principle of a 'stair saw', for cutting the sides of dado & sliding dovetail trenches. I ended up making a second saw because I thought it might benefit from a longer blade (#1 was 225mm., or 9" for the Imperialists). I also lifted the hang angle of the grip a bit, which I thought would make it more comfortable to use. It didn't, really, which surprised me at first, but I've since figured out that these saws take a bit more effort to push with the entire blade engaged in the cut, so the slight 'discomfort' of the more vertical grip is balanced by the more direct thrust angle. Here are the two saws compared: Trenching saws.jpg

    So to get to the point, last week I had several sliding dovetail trenches to cut, and as I'd been using my no-set saw a lot on the same job, the grey cells got to chattering away up there, and decided it would be interesting to try no-set and 45* fleam angles on the trenching saw. I've not that long ago sharpened my newer model, so I dug out #1 and set to it with files & enthusiasm. Then I spent a happy hour or so cutting a half-dozen dovetail trenches using each saw alternately.

    One problem with an un-tapered, no-set saw is that there is absolutely no changing of direction once you get a few strokes into the cut, so you do have to be spot-on direction-wise as you commence your cut. However, that isn't a problem with the trenching saw because it's used against a guide or fence, which points it in the right direction (i.e. either perpendicular, or sloped for the D/T side). The other 'problem' with no-sets is that you really have to let the saw cut in its own time (which is plenty fast enough as long as it's sharp!). As long as you do that, it cuts quite freely and easily, but if you put more than a minimum of downward pressure on those teeth, it will start to bind. Because I was concentrating on holding it firmly against the fence, I found I was sometimes applying too much pressure on the tooth line, but by the time I'd sawn the last trench, I was getting better at it. Apart from the very clean cut, the advantages of not having any set are that a) the saw doesn't scuff up the edge of the fence as it starts the cut, and b) there is no wobble at all, so you get a very straight side-wall to your trench.

    So after 50 years or more of using saws, here is something entirely new to me. It wouldn't be everyone's cup of tea, but for experienced sawyers who have some sharpening skills and a suitable extra saw kicking around, I reckon it's worth fooling about with. I still don't understand how the 45* of fleam works its magic. It has to be 45 or darn close to it; I tried 35 and that doesn't do it at all, but 45 works, even without blade taper. Taper might allow just a teeny bit of wriggle-room and give me just a dash of steerage way & I'm hoping to have my hands on some tapered plate, sometime in the new year to test that theory. So I'll continue mucking about with this tooth profile business, & I'll report back at some point...

    Cheers,
    IW

  11. #10
    Join Date
    Apr 2012
    Location
    Sydney
    Posts
    1,501

    Default

    Thanks for sharing Ian. I'm keen to give this a try.
    What about your thoughts on setting just one side of the saw for cutting the sides of a dado?
    Of course you'd need left and right versions!

  12. #11
    Join Date
    Mar 2004
    Location
    Brisbane (western suburbs)
    Age
    77
    Posts
    12,093

    Default

    Quote Originally Posted by hiroller View Post
    .....What about your thoughts on setting just one side of the saw for cutting the sides of a dado?
    Of course you'd need left and right versions!
    Gavin, I suspect the tendency to cut towards the set side would be a problem. I have a "flush-cut" saw that is set on one side only and it cuts in an arc. Being light & narrow doesn't help, either and you have to work hard to cut anything resembling a straight line with it. Even with care, it invariably ends up wandering away from the intended line by the time it gets to the end of a cut. On a heavier saw, making shallow cuts (typical dado & sliding D/T trenches are less than 10mm deep), it might be a bit easier to keep straight. As you say, though, you'd also need left & right versions, which would soon have an old git like me thoroughly confused as to which saw to pick up next.

    I reckon the 'extreme fleam' approach is probably more practical, but you should try any and all ideas out for yourself - that's how we learn, and how great discoveries are made......

    Cheers,
    IW

  13. #12
    Join Date
    Nov 2004
    Location
    Millmerran,QLD
    Age
    73
    Posts
    11,095

    Default

    Quote Originally Posted by IanW View Post
    As you say, though, you'd also need left & right versions, which would soon have an old git like me thoroughly confused as to which saw to pick up next.



    Cheers,
    Ian/Gavin

    In something like a dado, you might just be able to turn the timber around and work from the other direction. Or would that be totally confusing?

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  14. #13
    Join Date
    Mar 2004
    Location
    Brisbane (western suburbs)
    Age
    77
    Posts
    12,093

    Default

    Quote Originally Posted by Bushmiller View Post
    Ian/Gavin

    In something like a dado, you might just be able to turn the timber around and work from the other direction. Or would that be totally confusing?

    Regards
    Paul
    Of course you could, Paul, though it seems to me turning a large board around is even more inconvenient than checking which saw you've got in your hand.....

    Cheers,
    IW

  15. #14
    Join Date
    Apr 2012
    Location
    Sydney
    Posts
    1,501

    Default

    I was actually trying to find Ian a good reason to justify extra saws in the rack ...

  16. #15
    Join Date
    Nov 2004
    Location
    Millmerran,QLD
    Age
    73
    Posts
    11,095

    Default

    "Justification." An obscure word allegedly attributed to a time when everything had to have a reason. In modern times when most things seem not to have any reason this word can now be regarded as antiquated and consequently superfluous.

    Have as many saws as you wish with a clear conscience in 2017.

    All the best to you all for the festive season and the New Year.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

Page 1 of 2 12 LastLast

Similar Threads

  1. Been mucking about with multi center turning.
    By tea lady in forum WOODTURNING - GENERAL
    Replies: 49
    Last Post: 29th November 2013, 10:26 PM
  2. Mucking about with chisels...
    By IanW in forum HAND TOOLS - UNPOWERED
    Replies: 8
    Last Post: 29th October 2010, 09:02 PM
  3. Mucking around . . .
    By Pat in forum WOODTURNING - GENERAL
    Replies: 16
    Last Post: 2nd February 2010, 04:18 PM
  4. Been mucking around on the Grizzley site
    By Phil Spencer in forum WOODWORK - GENERAL
    Replies: 2
    Last Post: 12th January 2008, 06:13 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •