Delta bandsaw Tension

Larry Fredric

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8
I purchased a Delta 28-475X bandsaw about a year ago. Other work situations did not allow time to use it much. A friend saw that I had it and asked to use it. BIG mistake, He said that he had moved the tension nut around several times and never replaced it back to the original setting (Why?). I recently have had time after the Holidays to do some resawing.I have a Starret and a Woodslicer,1/2 inch, 4 tpi. With both blades they cut very well, two finger push and all goes easy and reasonably fast in 4 and 8 inch Oak.I am getting 1/8" slices and without barreling/drift. My concern is I can hear/observe "fluttering" of the blades to the left in the blade guard. This situation starts to occur as I am cutting. To me this indicates lack of proper tension. I've read, reread the supplied manual. I am not asking how to set the tension. Question 1, How do you set/reset
CORRECT tension to what was set from the factory, which according to Michael Fortune, is usually close to spec? The numbers really mean nothing without an "indicator"
Am I not seeing this correctly or did they not include an arrow of some sort? QUESTION 2, the nut shown in the pic (I hope it shows) how do you set this to indicate that 1/2 or 3/4 is what they intended? I really want all the proper tension available but do not want to over tension and bend/break:huh: the upper axle. Don't want to under tension and barrell cut expensive veneer,
Thanks, hope someone can enlighten me.
Larry
 

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My bandsaw is homemade, so I have no tension meter, this is how I set up my blades.

Back off all the guides, have them well out of the way.

Remove the throat plate, you want to give the blade lot of room. Tighten up the blade so it is so so tight, and turn the top wheel by hand, to make sure the blade is tracking on the center of the wheel, once that is done, then close the top cover.

Turn on the saw and watch the blade, usually you will be on the low tension side of things, the blade will flutter, (usually) slowly tighten the blade tension knob, and the blade should stop fluttering, when it stops, I turn mine an extra quarter turn. I then put the guides back in place, don't make them too tight.

Done.

If you want, mark the scale on the saw, but I find that often each blade varies somewhat.
 
Oh, I see, it has a quick release tension thing.

Look >> HERE << and you can see a video on how to adjust the tension, or maybe I'm misunderstanding your question.......... :huh:
 
re-reading the question

Thanks for the reply Stuart. How do I say this without offending. I do know how to set the Initial tension of the blade.I may have went on a :rant: to explain my problem. Let's say I ordered every thing in the picture that did not come with the 475X. how would I set it up to reflect that the black dial with the blade size would match the spring numbers cast into the side of spring window?:dunno:
the other..., Larry:)
 
Larry, forget there is an tension indicator on your saw. Most of them are merely a very rough guess, and different brands of blades tend to have their own "best" tension setting anyway. The coarse marks on that tension gauge are almost meaningless. And I wouldn't worry about bending or breaking an axle on the saw from over-tensioning the blade. I have yet to hear of someone bending the axle from having too much tension on a 14" saw. You've got a good saw, so it's even less of a concern in my book.

The steps Stu mentioned are indeed for setting the blade tension. Google around a bit for "flutter method". It is a fairly common technique for setting bandsaw blade tension, regardless of the brand of saw or blade.

Another concept I'd like to clear up: In respectful disagreement with Michael Fortune, if your saw came from the factory "at the proper tension", it was a fluke accident and would change anyway the first time you changed blades. (And unless your bandsaw is strictly for decoration, you WILL be changing blades on it. Band saw blades are shop expendables much like sandpaper...they just last longer.) There's nothing magical or sacred about the tension setting from the factory. Second only to the guide bearings, the blade tension is likely to be your most-adjusted parameter on that saw. As you get comfortable with it, it'll become second nature. ;)
 
Vaughn states my feelings as well. The tension indicator on my saw is a set of numbers 1 through 7 IIRC. They are simply for reference for some folks who prefer some sort of indication. I also use the flutter method that Stu describes and is shown below as stated by Suffolk Machinery:

FOR TURN SCREW AND SPRING TENSIONING MACHINES


  1. Remove guides--you CANNOT run this test if the band saw blade is restricted in any lateral movement.
  2. Make sure tire surfaces are in good condition--they cannot be hard, flattened out, cracked or brittle. On mills with loose fitting V-belts, replace them with the next size down so they are tight fitting. This will eliminate over 80% of the vibration in your mill and the blade.
  3. Mount the blade on the machine and apply the tension to the band that the manufacturer recommends for other steels.
  4. Close all covers for safety purposes.
  5. Start the machine, engage the clutch into the high speed cutting mode. NOTE: You will not be cutting any wood.
  6. Stand at the head of the machine, with your hand on the turn screw tensioner and your eyes on the band saw blade. Very slowly start detensioning by half turns at a time, keeping your eyes on the band saw blade. The object is to bring the tension of the blade down to a point that the blade starts to flutter. TAKE YOUR TIME.
  7. When you see the band start to flutter, you have hit ground "ZERO". Now start ADDING quarter turns of tension, SLOWLY, until the band stops fluttering and is running stable again. At this point ADD one-eight to one-quarter turn of tension.
  8. You have now tensioned our blade correctly. Shut off the machine and put your guides back in place. You are now ready to start sawing.
  9. ALWAYS DETENSION YOUR BAND SAW BLADES. Since you do not know exactly where the proper tension is, it will be easier to remember if you take off 8, 9, or 10 full turns of tension until the band is completely relaxed. The next time you use our bands, add the same amount of turns of tension that were taken off. At this point, you will only have to run the flutter test one time.
Been working great for me on 1/4" through 3/4" blades for years. Once you do it once or twice, the whole process takes just a few minutes. I used to jot down the "number" for a given blade but eventually found I could go through the flutter setup quicker than I could find the paper I wrote the number down on ;-)
 
I agree with Glenn that's the proper way to do it. The flutter in the guard don't worry about it. It happens when the blade rolls off the bottom tire there is a ripple effect. if you could see what a car tire looks like on the backside at 60 MPH you probably wouldn't drive. It totally distorts and looks like a wave in the ocean. it all straightens out just before it recontacts the road and you don't feel a thing. My drag race car (40 Willy's coup) the tire grew so tall during the run they looked like motorcycle tires when you let off the gas you thought you had two flat tires as they resumed there original shape and at over 160mph you had to fight the urge to counter steer. You need to fight that same urge when you heard that flutter in the return band guard. Sometimes there is an adjustment you can move the guard a little so you don't hear it or as much. :D

Bill
 
Bill McQueen Answers..

at least part of my inquiry and as long as that does not indicate lack of proper tension. Bill, here's a challenge for you.:D I am aware of how to set the tension to cut 4 and 8 inch with 1/8 inch thickness accuracy, don't need that lesson today:thumb: Take a look at the picture and my question again. Why would they set this up the way they do? It must be at least a way to tell if you'er close or way off! I still am thinking, I have pulled the tension all the way to 3/4 setting and is not enough when cutting an increase of 1 more inch on 9 inch board. On this 9 inch oak the blade will have have a slight barrelling effect. This is the reason I posted the pic with the nut and the question What would you reference as a "pointer" or "indicator" to establish a base.
PS. I can relate to the tire analogy, I live 21 miles from the Gatornational's. Coming in March.
Larry
 
at least part of my inquiry and as long as that does not indicate lack of proper tension. Bill, here's a challenge for you.:D I am aware of how to set the tension to cut 4 and 8 inch with 1/8 inch thickness accuracy, don't need that lesson today:thumb: ...I have pulled the tension all the way to 3/4 setting and is not enough when cutting an increase of 1 more inch on 9 inch board...

Larry, if the tension (and the rest of the saw) is set properly, it won't matter if you're cutting 1 inch boards or 10 inch boards, the cuts should come out straight and true. I've never seen it recommended to set different blade tensions for different wood thicknesses. Yes, problems are going to be more apparent and noticeable on thicker wood, but the problems are still there on the thinner stuff, too. (You just can't see them as easily.) And cranking the tension all the way to the 3/4 setting is not necessarily gonna fix the problem.

Feel free to discard the suggestions others and I have made, but it sounds like you're using a different approach and methodology to setting the blade tension than most of us. ;)
 
Larry I'll be honest with you I didn't even notice the attachment picture.
Sorry i mislead you, I hate you for being so near a racing establishment. :D:
 
I know on mine, I use that little red line (washer) to match up to the indicators in the window. As others have said, it's only a guide, and you should probably follow their directions for setting the tension.

On mine, I've just got the little knob on top for setting tension. Not sure how you would do it with that fancy quick release. I replaced my knob with a homemade crank to make setting the tension quicker and easier, and usually just set it so that it stops fluttering...
 
And I wouldn't worry about bending or breaking an axle on the saw from over-tensioning the blade. I have yet to hear of someone bending the axle from having too much tension on a 14" saw.

Believe it or not... I actually know a guy who broke the axle on his bandsaw from overtensioning the blade. Yeah, I was surprised, too. I can only think that the axle had stress cracks in it already.
 
How can a tension be set at the factory when each and every blade is different. :huh: As the blades are made by welding the eds of a long lenth of blade and no matter what brand, there are small differences in length. So the tension will change. Factory sets to approximately what it might be or close so if you are not accustomed to set up, you get a good start.

Stu had the best suggestion for adjusting tension. almost as good as mine. I have always used a musical tone to determine if I am satisfied with the tension. but I look for the flutter to stop and then pluck the blade to listen for a musical tone If it sounds like it is in tune then there is where I leave it.
I look at the indicator on the tension spring and usually it is right on my setting. But these are approximate indicators not rules.

Again, all adjustments are made with Upper and lower guides and thrust bearings out of play. only after tracking and tension is obtained do you bring in the thrust bearing to (thickness of a dollar) and each guide to (thickness of a dollar) they do not touch as the guuides do not control the blade, the tension and tracking control. the bearings and guides are there to keep YOU the operator from pushing the blade off track.

some fellow think and preach that you need to release the tension when not in use (most likely th reason your friend did so) IMHO this is a waste of time and effort. However If I am gone for long periods, I sometimes let it off. But by long times I mean Months or longer. Daily use and weekly use does not require changing tension.
 
Larry,
Thanks for posting this question... I read each and every response with interest... I have a 14" Delta without a riser that I have always felt I didn't have it set quite right... I don't do any resawing since I don't have much depth under the throat, but still have a little trouble with drift...
Stu/Vaughn
I'm going to try the flutter method and see if I can get my tension set more to my liking... I was always afraid to go beyond the markings on the back side of the tension housing for fear of damage to the saw... since Vaughn said there's little danger, have to give it a try.
Bill,
I can't use your tone method... kinda like plucking the strings of a guitar... I am too near tone deaf to know if I hear the same tone each time or not.... but, believe it or not, I wound up a radio operator in the Navy because when we were given our basic battery test at the beginning of boot camp, I took the sonar and the radioman test... qualified for both schools, just qualified higher for radioman. I guessed at 2/3 of the tones... (Then wound up a teletype operator instead of a CW circuit)
 
Larry,
Bill,
I can't use your tone method... kinda like plucking the strings of a guitar... I am too near tone deaf to know if I hear the same tone each time or not.... but, believe it or not, I wound up a radio operator in the Navy because when we were given our basic battery test at the beginning of boot camp, I took the sonar and the radioman test... qualified for both schools, just qualified higher for radioman. I guessed at 2/3 of the tones... (Then wound up a teletype operator instead of a CW circuit)

The tone I am looking for is a nice resonating sound , not a rattling "plunk" "clink" "clunk" So a tone deaf ear can tell the difference. :thumb:
 
...I was always afraid to go beyond the markings on the back side of the tension housing for fear of damage to the saw... since Vaughn said there's little danger, have to give it a try...

Not likely to break the saw (although as Tim pointed out there can be exceptions), but it is possible to break the blade. ;)

I've found when I use the flutter method that if you go too tight, you actually get the flutter back. Somewhere between low-tension flutter and high-tension flutter is the sweet spot for cutting wood.
 
Not likely to break the saw (although as Tim pointed out there can be exceptions), but it is possible to break the blade. ;)

I've found when I use the flutter method that if you go too tight, you actually get the flutter back. Somewhere between low-tension flutter and high-tension flutter is the sweet spot for cutting wood.

That would be a third octive "C" :thumb:
 
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