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  1. #31
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    Jul 2019
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    Yes thanks Neil. I did cobble up a straight edge system which lets me look at the alignment of the two wheels. Top is around 6mm further back than the bottom. Can't really move the top wheel forward much as there is very little tolerance in the sliding blade guard and the blade will contact it. I'm going to look into the possibility of moving the bottom wheel back. I will check other blades first as you suggest.
    The set up for the bottom wheel mount on the outside of the body can be seen in the attached picture. It appears it can be moved in and out and in different planes. I'm going to try and find some info on how to adjust this type of wheel mount.
    Bottom Wheel Mount.jpg

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  3. #32
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    Apr 2007
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    Adelaide Hills, South Australia
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    Quote Originally Posted by doragus View Post
    Yes thanks Neil. I did cobble up a straight edge system which lets me look at the alignment of the two wheels. Top is around 6mm further back than the bottom. Can't really move the top wheel forward much as there is very little tolerance in the sliding blade guard and the blade will contact it. I'm going to look into the possibility of moving the bottom wheel back. I will check other blades first as you suggest.
    The set up for the bottom wheel mount on the outside of the body can be seen in the attached picture. It appears it can be moved in and out and in different planes. I'm going to try and find some info on how to adjust this type of wheel mount.
    Bottom Wheel Mount.jpg
    Chris - that bottom shaft bracket looks promising if you need to realign the top and bottom wheels to make them coplanar in the horizontal direction. This is sometimes also referred to as lateral coplanar alignment.

    See the following video at the point where I have copied it to start at 3mins 58sec. You will see four diagrams side by side. Each of the four diagrams has two views of the condition it describes; viewed from the top (plan view) at the top and viewed from the side (end elevation) at the bottom. The misalignment that causes the twist problem is shown in the third diagram.

    How To: Bandsaw Tracking & Coplanar Adjustment - YouTube

    I wouldn't bother at this stage if you have only 6mm of offset in the condition shown in the second diagram, especially with a large blade. That is not going to cause your saw cut drift problem. There could be extra washers behind your bottom wheel that can be removed to sort that out when you get around to it later.

    In my experience, misalignment as shown in diagram three can cause your saw cut drift problem by creating a twist in the blade between the top and bottom wheels that can't be counteracted by the guides.

    The above video shows how this is corrected on top wheel adjustable models (see at 6min 13sec). I have achieved lateral realignment with a similar setup to what you have on your bottom shaft; loosen one side and tighten the other in small incremental step until both wheels are horizontally coplanar
    Stay sharp and stay safe!

    Neil



  4. #33
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    Jul 2019
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    Lke Macquarie NSW
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    Eureka I have it!

    I have at last managed to get my saw to cut something resembling a straight line – relatively straight freehand, with rip fence, with mitre guide and cross-cut sled. I did this with another complete tear down, rebuild, blade change and saw set up. I have the guides set according to Snodgrass and the blade centred somewhere between the kerf and the blade centre. I have the table, fences and guides set according to Snodgrass and some others I found on Youtube. Blade is square to table both vertical and horizontal. As Neil suggested I made a slight horizontal planar adjustment to the top wheel yesterday and, although it didn’t help, I have left it like that even though the blade runs close to the back of the wheel when turned in reverse.

    It seems to be that the problem was crap blades as Malb suggested. I have four Carbon blades all bought online and none have done enough work or have tooth damage that affect their sharpness – AYAO 13mm X 4 TPI, Starrett 16mm X 6 TPI, Toolstorm 16mm X 4 TPI and Starrett 10mm X 6 TPI. Only the 10mm Starrett will cut straight after all my mucking around. I’m now in touch with a saw doctor about new blades.
    Somewhere along the line I suggested that effectively operating band saws was a “Dark Art” and I’m now convinced that’s true. For example:

    • I learned on Yoytube that you must centre the blade on the bottom line of the kerf and I also learned you must have blade centre on wheel centre. Either someone is wrong or tracking is OK anywhere near wheel centre.
    • Some Youtube experts tells me that coplanar wheels aren’t necessary while others tell me they are. Again, someone has got it wrong or coplanar doesn’t really matter much as long as the blade isn’t going to run off the wheels.
    • Some Youtube experts tell me the guides should be set as close to the blade as possible without touching while others tell me the guides should be 2mm from the blade. Once again maybe it doesn’t matter as long as the lateral guides aren’t so far from the blade that they don’t make contact when the blade runs completely off line and the thrust guides aren’t so far back that they fail to stop the blade being pushed off the back of the wheel. I’ve set the lateral guides so they line up just behind the blade kerf.


    For what it’s worth, I now think the two key issues in blade tracking are:

    • Good quality sharp blades with tooth set which is even on both sides of the blade. Uneven set will obviously force the blade to one side. Looking closely at the three larger blades I have I can see that the tooth set seems to dominate on one side of the blade. If I have the patience I’m going to try and reset one of these blades with my hand saw set and see if it makes a difference.
    • Blade tension is definitely an issue. I now have the blade tensioned according to Snodgrass #2 where he uses the bit of blade on the left of the top wheel housing so it deflects around 5mm with the pressure of one finger not pushing hard enough so the finger goes white where it touches the blade. (Fair dinkum - talk about Dark Art! Maybe we could test it with a blood pressure monitor.) Anyway, the tension is about as high as I can get it with my primitive thumb screw tensioning arrangement and it's a bit more than I'm really comfortable with...but is semms to be working. Blade tension is complicated on saws that only have screw-type tension adjustment – particularly as you need to take the tension of at the end of the day and reset for neat use. I’m not sure I can retrofit one of the more modern tension-adjustment devices to this saw but I’m going to look into it.


    Thanks to all for the advice and help on this one. I’ll post again if I learn more.

    Chris

  5. #34
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    Oct 2008
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    Leopold, Victoria
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    Be careful which saw doctor you get blades from as some may not do a good job at welding bandsaw blades. I have a local saw guy who does a great job at sharpening circular saw blades but seems to have trouble making reliable bandsaw blades, especially smaller ones. Henry Bros seems to get a good name in your area.
    Dallas

  6. #35
    Join Date
    May 2011
    Location
    Albury
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    Quote Originally Posted by doragus View Post
    Blade tension is complicated on saws that only have screw-type tension adjustment – particularly as you need to take the tension of at the end of the day and reset for neat use.
    Congrats. It's always nice to have a win before you run out of hair.

    I have an older 18" Carbatec bandsaw and had this problem as well. A person of my height and strength has virtually no hope of tensioning a 1" blade on my machine. I made up a 'drive spanner' with 3 dogs to engage with the indentations on the outside of the metal screw handle, which is less than 65mm in diameter, and haven't had a problem since. The other thing that I've found difficult on my saw is adjusting the tracking with tension on wider blades, the screw mechanism isn't made to take the stresses imposed on it and tended to bind up the threads. Changed it to high tensile nut and screw and now always release the blade tension a bit before making adjustments, then check tracking once tension is re-engaged. Works much better.

    I suspect the Chinese were still trying to get these saws right when mine was made.

    +1 for Henry Bros. The premises might be a bit Dickensian but they sure know their stuff.

  7. #36
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    Henry Bros. At Vineyard, been going there for decades.

    dont watch YouTube cowboys, most of them wouldn’t know scheeit from a shovel.

  8. #37
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    Apr 2007
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    Adelaide Hills, South Australia
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    Quote Originally Posted by aldav View Post

    +1 for Henry Bros.
    Me too.

    They will post to anywhere in Australia.
    Stay sharp and stay safe!

    Neil



  9. #38
    Join Date
    Apr 2011
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    McBride BC Canada
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    I have the same issue.
    I stand on the tooth side of the blade and feed the wood forward.
    The blade always, always, always wanders off to the left. It has done so for years.
    New blades, set tolerances with a feeler gauge according to the book ( 9" Ryobi).
    Messing with the table can't possibly make any difference, as the wheels are disconnected.

    I'm going into the shop in the next few days, I'll crank up the blade tension until it either sings or breaks.
    I have a sneaking suspicion blade tension is the significant issue.
    But as much as I ask, nobody explains how to set blade tension. Everything else is explained 10 times.
    Blade tension.

  10. #39
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    Apr 2017
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    Éire
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    39
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    297

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    Quote Originally Posted by Robson Valley View Post
    I have the same issue.
    I stand on the tooth side of the blade and feed the wood forward.
    The blade always, always, always wanders off to the left. It has done so for years.
    New blades, set tolerances with a feeler gauge according to the book ( 9" Ryobi).
    Messing with the table can't possibly make any difference, as the wheels are disconnected.

    I'm going into the shop in the next few days, I'll crank up the blade tension until it either sings or breaks.
    I have a sneaking suspicion blade tension is the significant issue.
    But as much as I ask, nobody explains how to set blade tension. Everything else is explained 10 times.
    Blade tension.
    Not sayin that a bandsaw that size is up to using anything but a point fence, regarding ripping,
    but for some operations it might make sense to try squaring the table up.
    That's the idea of these bandsaw buddy/ Carter f.a.s.t thingamajigs
    I'm gonna make a nice one if I ever get some rare earth magnet, so it can be much longer.


    SAM_2805.JPG

  11. #40
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    Apr 2011
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    McBride BC Canada
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    I don't speak "Bandsaw" so I have no idea what a point fence is. That's OK, you couldn't have known.
    I was really tempted to throw the fence away. The damn thing cuts so crooked the fence is a theoretical joke.
    I need to cut shapes, rough shapes, for adze handles and wood carving body parts.
    As it is, I have to rotate the wood 45 degrees in the feed to get a cut anywhere near any line.

  12. #41
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    Tension fixes everything

  13. #42
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    Oct 2009
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    South Africa
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    Quote Originally Posted by riverbuilder View Post
    Tension fixes everything
    As long as the blade is OK.

  14. #43
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    Jun 2005
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    Helensburgh
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    Manufacturers can get very optimistic on the largest blade size most saws can tension. My saw is a Minimax SN45 and there is no way on God's earth it would tension the 25mm blade that they say it will. In fact it is battling to tension a .75 blade properly even with the uprated spring I fitted in the tensioning screw. I tighten it up to just short of spring bind and call it done. Highly scientific but it works to the extent that it always cuts straight against the fence or using a sled. I think the sled is one of the handiest things on a BS.
    CHRIS

  15. #44
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    Apr 2007
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    Adelaide Hills, South Australia
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    Quote Originally Posted by Chris Parks View Post

    I think the sled is one of the handiest things on a BS.
    +1 on that, Chris.
    Stay sharp and stay safe!

    Neil



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