Replies

1. 
   juglans | Nov 17, 2005 03:40pm | #1

   John,

   Do you have experience with band saw blade tension meters, e.g. Starrett, Iturra Design? Are these worth having in a professional shop?  I have two band saws and I am never really certain if they are tensioned properly. The pluck and push methods are OK, but would correct tension enhance performance in a measurable way?

   Dan Santos

1. 
   JohnWW | Nov 18, 2005 08:09pm | #5

   Dan,

   Very low tension can lead to poor cuts when resawing, and very high tension can lead to excess wear and tear on the saw's  bearings and tires, and frequent blade breakage.  If you aren't having either of these problems you shouldn't need to invest in a tensioning gauge. 

   If your saw has a built in tension gauge, you can check its calibration with a simple gauge I designed and wrote an article about a few years ago.  You can find it here:   http://www.taunton.com/FWN/Workshop/WorkshopPDF.aspx?id=2702 

   You can also use my gauge to get a sense of what various tensions feel like, which is usually more than adequate for tensioning the saw for day to day work, and much faster than fussing with an accessory gauge.

   As long as a blade is tensioned somewhere in the broad area between much to high or much too low, it will cut reasonably well.  In almost all cases where there are cutting problems, the cause is due to a dull or inappropriate blade, or badly set guides or tracking, and I would check these areas first, especially blade sharpness, before worrying too much about incorrect tension.

   John White 

    

   Edited 11/18/2005 12:13 pm ET by JohnWW

1. 
   DougF | Nov 21, 2005 06:04pm | #6

   John,

   I use your tension gauge for regular band saw blades but what about the "low tension" blades such as Timberwolf.  I have never been comfortable with the "flutter" test. 

   Doug

1. 
   JohnWW | Nov 23, 2005 01:51am | #7

   Doug,

   In the magazine about a year ago we did a test of band saw blades for resawing.  With the exception of the Highland Hardware blades, all of the other blades, including the Timberwolf blades, cut better as the tension was increased.  Because we were using a Delta 14 inch band saw we stopped increasing the tension at 15,000 psi, so I would just tension a Timberwolf blade to that level and skip the flutter test. 

   You can save a little wear and tear on the machine, and possibly extend blade life a bit, by using a lower tension, so if you are getting an acceptable cut at lower tensions, it can't hurt to stay with those, but you will probably find that you will get a better cut at higher tensions.

   I discovered something in the course of the testing that makes me suspicious of the flutter test.  As you change the tension on a band saw blade, the tracking of the blade also changes.  As you increase the tension, the blade will drift towards the front of the wheel, if you decrease the tension, the blade will move a bit towards the back edge of the wheel. 

   I discovered that if you tensioned the blade so that it would flutter and then corrected the tracking to get the blade recentered on the upper tire, the flutter would disappear.  Following up on this observation, I found, through experimenting, that fluttering seemed to be mostly controlled by the position of the blade on the upper tire.  In other words, I could make the blade flutter, or not, just by changing the tracking with no change at all in the blade's tension.  So the flutter test may in fact determine some "sweet spot" for the blade to cut at its best, but the spot seems to have more to do with tracking than tension. 

   As I mentioned in an earlier post, dull blades and improperly adjusted guides are almost always the cause of cutting problems on a band saw, tensioning, unless it is very far off, is rarely the primary cause of a bad cut.

   Hope this helps,

   John White  

1. 
   DougF | Nov 23, 2005 03:21am | #8

   John,

   Thanks for the response.  I will try the higher tension settings. 

   Doug

2. 
   vssmith | Dec 19, 2005 04:45pm | #9

   I recently re-read an article in FWW #173 about bandsaws by Mike Fortune. He advocates among other things a lower tension than is the conventional wisdom. I am interested in your thoughts on this or any other of his ideas in the article.

3. 
   JohnWW | Jan 13, 2006 01:29am | #10

   Vssmith,

   I'm finally beginning to get caught up with the back log of work that piled up while I was out.  Again, I apologize for not responding sooner, or at least acknowledging your question.

   I'll give my take on Mr. Fortunes opinions in the order he laid them out in the text.  With one notable exception, concerning the need for tracking, I agree with almost all of his comments. 

   I second his opinion in the introduction that a band saw is the best choice for ripping, primarily on the grounds that it is safer.  Unfortunately, in many shops, the saw is stuck in a corner where long rips can't be handled.  Properly set up, with infeed and outfeed tables or at least roller stands, a band saw usually quickly becomes everyone's favorite tool for ripping.

   Using a 1/2 inch wide, 3 TPI, skip tooth blade would be my recommendation also, for all but fine scroll type cutting.   The newest carbide tipped blades may finally be worth investing in, especially if you cut abrasive woods or sheet goods with high glue content.  At least until recently carbide blades weren't worth their additional expense because they would crack long before they wore out.  Supposedly the newest carbide blades have better fatigue resistance when used on 14 inch diameter wheel machines, but I haven't tested them to see if this is true.

   Using a sharp blade: Absolutely!  Nine times out of ten, if the saw doesn't seem to be working well, putting a fresh blade on will solve the problem.  In my experience a dull blade usually doesn't look or feel like its dull, so when in doubt replace it.  Buying blades in bulk to keep their price down, and getting proficient at blade changes, encourages keeping a good sharp blade on the machine.

   From my own experience, I can back up Mr. Fortune's opinion about not needing a lot of horsepower for a 14 inch wheel saw.  My personal saw is a Ridgid with a riser block, and it cuts just fine with its original 3/4 HP motor.  I certainly don't see a need to go up to the 1 or 1 1/2 Hp that a lot of the newer saws are being sold with.

   Several years ago I wrote an article on tensioning saw blades "by the book", at 15,000 PSI and designed a small shop made gauge that would give an accurate reading of blade tension.  Since then I have pretty much come to share the author's opinion that having a high tension on the blade is not necessary for most operations, although a higher tension will usually give a slightly better cut when resawing. 

   I would, however, recommend replacing the original spring that is used on most 14" Delta style saws with the aftermarket spring sold by Ittura Design.  The original springs on many of the 14" saws are of such poor quality that they aren't even capable of achieving the moderate tension needed for trouble free cutting.   Regardless of blade tension, it is worth checking the condition of a saw's tires on occasion.  If the tires are stiff and have permanent grooves worn into them they need to be replaced.  A quick test of a tire's condition is to press the tip of your thumbnail into the tire, it should compress easily and spring back immediately.

   Drift: I still believe that it exists and that the saw will cut better if the fence is adjusted to correct for it.  When the magazine did a test of resaw blades a few years ago, I tested dozens of blades under identical conditions.  All blades were tracked right in the middle of the saw's tires and each blade seemed to have its preferred tracking and would cut a least somewhat better if the fence was adjusted to take this into account.  For ordinary ripping of thinner stock it may be a waste of time to worry about tracking, but for cutting thin, wide veneers I still think it is worth adjusting the fence for the best cut.  I haven't had a chance to run a rigorous test of Mr. Fortune's assertion, so I reserve the right to change my mind, someday, on this subject.

   I concur that the standard steel side blocks, as long as they are flat faced and square, are perfectly adequate for any band saw.  I see no point to installing the ball bearing guides that several manufacturers are promoting with such fervor. 

   My personal preference for the past few years is to use ceramic side blocks which seem impervious to wear, but otherwise perform just like the standard steel blocks.  I have, but haven't yet installed, the ceramic thrust blocks that are now also being made to replace the thrust ball bearings that come standard on most 14" saws.  We have had a ceramic thrust bearing on our larger shop band saw for a couple of years and it works so well that I'm fairly sure that putting one on our smaller saw will be an improvement, eliminating the noise and occasional need for replacement of the stock ball bearing.

   Like Mr. Fortune, I like to set my side blocks tight to the blade, but I prefer to set the thrust bearing so that it also lightly touches the back of the blade even when the saw is idling, thus preventing even a minor shift in the blade's alignment when actually sawing.  The thrust bearing touching the blade may create some annoying noise as it spins while the saw idles, but this doesn't have any effect on the life of the bearing.

   I also have found that a brush on the saw's lower tire keeps the tire clean and prevents the build up of a hard layer of pitch and chips that can affect performance.  Occasionally scrubbing both of the saw's tires with a dry Scotchbrite pad also helps to keep them at their best.

   The author's final point, that you shouldn't have to use more than mild pressure to get a steady smooth cut, is one that I also share.  If you and the saw seem to be struggling to get a good cut, something is almost certainly wrong, starting with the possibility that the blade has probably gotten dull.

   A long winded answer to your question, sorry you had to wait so long to get it.

   John White                                                                                                                    Shop Manager, Fine Woodworking Magazine

   Edited 1/12/2006 6:24 pm ET by JohnWW

4. 
   vssmith | Jan 13, 2006 03:03pm | #11

   Thank you for your "long winded" reply. It was worth the wait
   vssmith

2. 
   BossCrunk | Nov 17, 2005 06:02pm | #2

   Where are the article archives?

1. 
   MBerger | Nov 17, 2005 06:20pm | #3

   Hi Boss,

   The archives are integrated throughout FineWoodworkingNetwork.com, sorted by topic.

   Click on the "Network Home" link above and it will take you to the home page of FineWoodworkingNetwork.com. From there, use the navigation to find a category that interests you.

   Once you're in one of the six channels listed in the navigation (Tool Guide, Skills & Techniques, etc...) you will see a second level of navigation that will take you to a more specific topic, such as Turning, or Furniture Construction, or Bandsaws (there are 150 of these categories). From there you will see lists of all the articles and videos on a particular subject. You can also find tool reviews on these category pages (in the Tool Guide) or browse the Gallery.

   Let me know if you're looking for something in particular and I can point you in the right direction.

   - Matt

1. 
   BossCrunk | Nov 17, 2005 08:44pm | #4

   Thanks... I got it.... I like it.