Replies

1. 
   Rich14 | Jan 13, 2007 03:22am | #1

   bak, The myth that bandsaws have "drift" and one must set fences and make other accomodations for this "natural" tendancy of the saw is, well, myth. A bandsaw should have no drift if set up properly. None. Nada. Nicht. Zed. Zilch. At the proper tension and with the upper wheel's "tracking" adjustment set so that the band rides exactly on the top of the crest of the tire, the band should align perfectfly parallel with the miter slot. Check also to make sure the table has been trued to the vertical band and is exactly at 90 degrees to it. Rich

1. 
   Glaucon | Jan 13, 2007 03:43am | #2

   I agree- at least this has been my experience.Glaucon

   If you don't think too good, then don't think too much...

1. 
   wood_donkey | Jan 13, 2007 04:37am | #3

   I concur, I just tuned up a POS delta table top bandsaw, never had been set up properly by previous instructor.  Cuts like a dream now...no drift, just time to tune.

   Donkey

1. 
   eric314 | Jan 13, 2007 07:19am | #4

   Wood_donkey,Could you please give some details about the tune-up process?Thanks,
   Eric

1. 
   Napie | Jan 13, 2007 03:55pm | #6

   Contact these folks, their catalog has more bandsaw info than you know what to do with.

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2. 
   eric314 | Jan 13, 2007 09:27pm | #9

   Thanks for the tip Napie,
   Eric

3. 
   wood_donkey | Jan 13, 2007 07:05pm | #7

   As was stated in the post that followed, setting the blade to the position on the wheel to track properly, along with guides (at the mouth or opening at the table) are the key.  The saw I just tuned uses a knob on the back of the machine to adjust the camber (tilt of the wheel off horizontal) this forces the blade to track on the front, back or top of the wheel, or any spot in between.  The position of the blade in tracking will increase or decrease the amount of drift, in or out - based on my experience.  Tension should be set that the blade will not twist too much, but not so tight that the blade "streches".  So far as the guides at the mouth, they are to prevent the blade from moving in the direction that the guide is guiding.  Back guide and also side guides.  The machine that I tuned at work uses small round steel rods to prevent side to side movement.  You can look for aftermarket also (coolblocks?).  The back guide on the one that I use is a bearing, much like you would see on a router bit, this is adjusted so that the blade pushes on that, to prevent the blade from being forced out and off the wheels.  Check with your machines owners manual for "factory" settings.  The real "fix" is to tweak until you find the settings that work for you.  Drift is not necessarily a probelm, more of a special funky thing that makes the machine yours.  Much like the way my wife might eat oreos, not the way I would, but it makes her special to me.

   Donkey

4. 
   Glaucon | Jan 13, 2007 08:59pm | #8

   I agree, and I would emphasize the need for tracking correctly. If the blade is set to track on the very middle of the crowned tire, then the teeth of the blade will be perpendicular to the stock, and aligned spot on with the desired direction of cut. If the blade is too far forward, the teeth will toe in (towards the fence) and drift will result. If too far back, they will toe out.The guides and tension help to maintain the teeth in proper orientation when they come under tension as the stock advances into the cut. If not properly adjusted the blade will deflect or even twist, with negative effects on the cut.The blade itself is important- when resawing, having a hook or skip tooth pattern and a relatively low tpi allows for clearance of sawdust out of the work and prevents distortion of the bade in the kerf or over heating. Some try to use too fine a blade pattern in hopes of having a very smooth cut, but for resawing or heavy ripping, this is a mistake.In my experience, if you use a good blade, properly designed for the task, and set tracking up correctly, you will not have drift problems, even if your guides are not perfectly set. If you do set the guides correctly, you should not have problems, even if you are doing some heavy duty cutting.Glaucon

   If you don't think too good, then don't think too much...

5. 
   eric314 | Jan 13, 2007 09:36pm | #10

   Many thanks for the information...and for the comments at the end. This sheds a new light to my approach to machines.I like that.Cheers,
   Eric

2. 
   RMillard | Jan 13, 2007 03:30pm | #5

   Drift comes from two principal sources, the set of the blade and the crown on the wheels.

    

   The blade may have one side that is set slightly more than the other side, and this will cause that side to cut more aggressively, leading to drift.

    

   The wheel crown is in my opinion the chief cause of drift. I set my blade to run more to the front of the wheel. This causes the blade to be ever so slightly bent as it passes through the wood. Looking from the front of the table, the blade tracking in this manner would have its front edge skewed to the left ( of course the amount of bend can’t actually be seen). The opposite would be the case if the blade tracked on the back side of the wheel. This skewing, forces you to guide the cut, off the axis of the table.

   While it is possible to set up the saw to track perfectly and in theory eliminate machine induced drift, you’d still be left with blade induced drift ( which as I said is a secondary cause of drift). With this in mind I don’t worry about drift and having a perfectly set up machine, I just account for the drift. With my saw and the blades I typically use, I’ve gotten to the point where I don’t have to test for the drift, I can just set up the fence by eye. Also, in my experience the drift is not affected by the type of the material being cut, nor its thickness.

   Rob Millard

3. 
   colebearanimals | Jan 13, 2007 10:44pm | #11

   Hi Bak,              

    

           Your bandsaw fence might very well need to be skewed for different blades especially when resawing. If you don't already , this could give you a much better and truer cut.

            Start with a lenght of material that is ripped with parallel edges. Then draw a pencil line parallel with one of these edges. Now freehand feed this into your blade following your pencil line . Once you are cutting down this line, stop the bandsaw WITHOUT moving your stock . When your blade comes to a stop trace a line on your machine top using your unmoved stock as a straight edge. This is your drift line that you should set your fence parallel to.     

    

                                     Have fun working wood,  Paul

1. 
   Rich14 | Jan 14, 2007 12:19am | #12

   No!

1. 
   colebearanimals | Jan 14, 2007 12:43am | #13

   Hi Rich14,

          This is to componsate for slight variations in blade tooth manufacture or wear. If the teeth on one side of the blade are more worn or not manufactured correctly, it will be cutting more on one side than the other, causing it to go through at a slight angle. If you are cutting thin stock or doing curved work this isn't an issue, but for resawing it can help tons depending on your particular blade in use.  Check out Mark Duninski's " The Bandsaw Book".  Anyway, this works for me.

        Have fun working wood, Paul

1. 
   Rich14 | Jan 14, 2007 03:01am | #14

   Paul, I'm familiar with Duginske's book. The advice to skew the fence to compensate for a bandsaw's "inherent drift," like the advice that blades need to be tensioned to very high values seems to be something that gets repeated in "knowlegeable" sources over and over without any critical thinking or real investigation as to the need for the practice. Those bits of conventional wisdom are simply wrong, no matter how often they have been repeated or who has offered them. Any bandsaw can be set up to cut true and parallel to the miter slot (perpendicular to the plane of the upper wheel). This can be done, even if the "drift" is being caused by a blade that has an uneven set. But if the blade is at fault, it should be replaced as setting up the saw to overbalance for improper forces at the point of cutting is counterproductive to a quality cut. Read Michael Fortune's article in FWW No. 173, Dec 2004, "Five Tips for Better Bandsawing." It's a treasure house of vital information that is, unfortunately, missing in some of the "authoritative" books about this machine. Rich

1. 
   colebearanimals | Jan 14, 2007 04:56am | #15

   Hi Rich14,   I have to admit that I've seen less of this problem using high quality blades but have noticed it in the past. It's not the saw in question, it seems,  but the blade and how best it attacts the wood. Maybe blades have generally gotten better over the past 10 or so years. I'll definately check out the FWW article. Could be i'm missing out on some valuable info.

                             Thanks, Paul

2. 
   colebearanimals | Jan 18, 2007 01:14am | #16

   Hi Rich,  

         I read that article you recomended. Works very well. Looks like I'll have to get (   or should I say the tool will benifit from ) a more accurate fence. Even after working wood for the past 30 years an old dog can still learn new tricks.

       Learn something new every day and enjoy woodworking,

                                                  Thanks, Paul

3. 
   Rich14 | Jan 18, 2007 01:42am | #17

   Paul,

   Good deal.

   When that article came out, a lot of us old dogs praised it and admitted we had all learned quite a few new tricks. It changed a lot of habits!

   I wish it were posted here as something easy to get to and read.

   Rich

4. 
   DanG | Jan 19, 2007 07:07am | #18

   It's really not so difficult to get, if you can read a pdf:http://www.taunton.com/finewoodworking/ToolGuide/ToolGuidePDF.aspx?id=24093Dan

   Edited 1/18/2007 11:23 pm ET by DanG

5. 
   Rich14 | Jan 19, 2007 03:48pm | #19

   Dan, Everyone can read a PDF. But that link requires a membership. I wish we could post specific information which remained in a collection that was easily accessable without relying on the (less than useful) search function and weaving through a ton of old posts. Rich

6. 
   ptu | Jan 19, 2007 06:18pm | #20

   One thing that I found to be very imporant when setting up, and especialy important if you change blades, is to back off the guide blocks and bearing a little before you set for drift. Set you wheel, then reset the guide blocks, other wise, the guide blocks or bearing can stop the blade from moving to where you want it.

4. 
   drewcboggs | Jan 20, 2007 01:05am | #21

   I hate to differ with all the other "experts' who've responded to your question - but, I have Delta 14 BS with riser block and until two things happened in my woodworking life, I was not successful at resawing. Those two things were (1) the article in the Feb. 2007 issue on resawing; and (2) buying a 1/2" "wood slicer" blade from Highland Hardware. The article more-or-less acknowledges that blades do have a drift. If you want to spend hours fine tuning your BS, I guess one can get rid of the drift, but in my opinion, I'd rather not waste all that time; accept that the blade (though maybe not finely tuned) has drift, and deal with it !

1. 
   RMillard | Jan 20, 2007 02:49pm | #22

   Drewcbooggs,

   That is my position exactly, although I was not impressed with the Woodslicer.

   All my re-sawing problems ceased when I started using 3/8" bi-metal blades made by Starrett.

   Rob Millard

1. 
   JeffHeath | Jan 20, 2007 07:52pm | #23

   Rob

   I agree with the drift issue.  You can either spend hours, or even days, trying to tune the last 1/4" of drift out of a bandsaw setup, or you can just account for it.  I know you know this, but for the benefit of the discussion, it's valid to point out that every time you change blades, you'll be tuning out the drift all over again.  I'd rather not waste time with trying to overtune a tool, when it takes less than 3 minutes to mark a board, and account for the drift. 

   I'm surprised that you have had difficulty with the woodslicer.  I have been using their 1/2" 'resawing' blade, and have found it to be as good as some $200.00 blades. 

   Here's a picture of my shopmade resaw fence that took 15 minutes to make, and is extremely easy to set for drift.  Note the screws I use to help adjust the fence 90° to the blade.  1/4 turn either way registered to the stock fence rail, and it dials right in.

   Jeff

   
1. 
   mwenz | Jan 20, 2007 09:56pm | #24

   I know you know this, but for the benefit of the discussion, it's valid to point out that every time you change blades, you'll be tuning out the drift all over again.  I'd rather not waste time with trying to overtune a tool, when it takes less than 3 minutes to mark a board, and account for the drift. 

   One reason I often stay out of these discussions is one person's experience may not be another person's. As well, I suppose there are bandsaws out these which would refuse to be set up to account for drift.

   But I haven't personally met one yet.

   I go through a lot of blades. Often they are Woodslicers, but there are a few other brands. I have never spent 3 minutes adjusting off-cutting blades. But even if I had, it would be considered a wash for time.

   I was emminsely happy when the referenced article came out--it was also one of three times I ever wrote a magazine. Many years ago when I bought my first BS and set it up according to popular lore, I was amazed that such a tool had what seemed to me so poor blade control.

   The cure was simple. Decent blades and adjusting the off-cutting out of the saw using the facilities it had. While I gave the basic advice the article contained, I was dissmissed as all but an idiot. Since then a few bandsaws have passed my way and I have helped set up a dozen more for friends.

   I now use a Jet 18" saw as my larger saw and this past year bought the junky Jet 12" for tight curve cutting. But for fun, I placed a 3/8" cheap Olson blade on it, I was able to veneer at its capacity if feed slow--it doesn't have much power.

   Take care, Mike

1. 
   colebearanimals | Jan 21, 2007 12:23am | #25

   Hi all,

        Up until abaout 2 weeks ago I used to adjust the fence to compensate for blade mistracking. It does work to some degree. I then tried the tracking method used by the author of the FWW article Rich14 recommened ( see earlier posts in this thread )It works also, only better. I see an ease with which the saw makes heavy cuts. Allmost as if there was an increase in horsepower. This is just my observation on my perticular saw. These differences are small but real nontheless. This was all done on a delta 14" with a riser block.   Question......Would this type of adjustment be as effective on a bandsaw with a flat ( as apposed to a crowned ) tire? I wouldn't think so.     So....... use the system that works the wood for you. If you haven't tried this though, give it a go. you might just be surprised.

    

                          Enjoy your woodworking, Paul