When using my Jet bandsaw to cut veneers, doing re-saw or other deep cuts I keep getting the blade drifting off at the lower end of my cut. I have checked the blade tension, I am using the right width of blade – what else should I try to solve this problem?
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There's a great video of Alex Snodgrass (I think that's his name) tuning a bandsaw that worked for me.
But, the first thing I think of is the lower guides. Are the two side guides aligned correctly? And, if so, is the rear guide properly aligned and not pushing on the back of the blade?
Fivebirds - I'll check that. AFAIK the lower guides are within the recommended paper thickness distance off the blade. Not sure about the rear guide - I'll definitely check that. Thanks for the tip about Alex Snodgrass - I have watched his video and he mentions the guides but not what it is they achieve, so I have not done any fine tuning or measurement on them. Is my assumption of a thickness of paper 'twixt blade and guide correct? The guides are roller bearings, not inserts like his.
This video from Ethan at Stockroom supply should help. He talks about drift in depth. Good luck.
https://www.bing.com/videos/search?q=ethanswers+youtube&docid=608022821886033961&mid=72E5F020EE32F91F513272E5F020EE32F91F5132&view=detail&FORM=VIRE
I went back and adjusted everything like Alex said in his video. I had the side guides in the wrong place, relative to the teeth, and the rear guide too close. I did not change tension but I did change the band alignment relative to the tire. Ethan's advice seems not to care about any of those elements. So, I just made a trial cut in a piece of Angelique and, within 3-inches of the start of the cut, drift was happening, using a fence. I get what Ethan is saying, about tension in the wood, and I think I understand that. So - here's my next question: if the blade tension is not important, the guide height above the wood (other than the obvious potential for cutting off a finger or two) is not significant, the guide lateral and horizontal position and the blade position on the tire is not important - why should I use a fence at all? Is it the use of the fence that is causing drift? One last question: I also get vertical drift (the bottom of the cut is not vertical under the top of the cut) - is that a separate problem? Thank you all for you responses!
I get a kick out of the Stockroom Supply video that "explains" why fences don't work on bandsaws. They state that the way I have been cutting veneer for years won't work. We're all entitled to our opinion but, to state something as empirical that can be disproved doesn't really help a lot of folks.
That said, I agree with the video in the link that drift can be dialed out during initial machine setup / alignment. I change blades anytime I want and only change the guides and tension as required by different blade dimensions. I can't remember the last time I touched the upper wheel alignment controls.
The point is that we should be sharing our experiences, talking about how we do things and offering assistance. Stating that something is "so" or "not so" when so many variables are involved gets a little risky.
To the OP, I will assume this is a cast iron Delta 14" clone with crowned wheels. If not, stop reading now and give us some more info ;-)
The following diagram shows how blade position can affect the direction of cut. I think Alex is great and love watching him but, when I setup my wheels co-planer on my 17" saw is when I stopped having to adjust for drift.
I took the time to do so on my 14" and 10" machines and can change blades any time I want with no fuss. Due to my experience I tend to think co-planer wheels are important. If it would have had no effect, I wouldn't offer it up.
The last pics are me using a bandsaw fence that apparently won't work, cutting veneer against the fence which is apparently impossible ;-) This is just a small cut that I took pics of for a discussion elsewhere. I use a push block for smaller blanks. I do the same thing at 7" with double-stacked feather boards . . . or 11" for that matter ;-)
Getting the wheels coplaner solved many of my problems also. When the wheels are aligned I find no need to adjust for drift.
Sharp blades are the second solution for me.
Thanks, GeeDubBee,
I have no idea if this is a Delta clone. As I originally posted, this is a Jet but I did not mention that it is a 14" Jet. My apologies. What is a Delta clone and should I be concerned about the upper and lower wheels being co-planar?
Hi LambrechtFurniture,
Thanks for your response. Sharp blades are not a problem here, because they are brand new. I tried a piece of 1.5" wide by 7/8" thick angelique and tried to cut it down the middle. Drift was almost immediately evident when using the fence. Should I not use the fence? If not, what is the purpose of it?
This is a good thread for bandsaw newbies, and I’d like to piggyback (sorry OP). Can the experienced folks say a bit about technique? Amount of pressure to apply against fence, feed rate, where the pressure should be applied (how close to blade), pressure to apply on the “outfeed” side of the blade, etc.
To put it another way, if I was to visit GeeDubBee’s workshop and use his bandsaw and I was getting drift, what would I be doing wrong?
I might be overthinking things (a chronic problem) and making too much of technique, but when I’ve had poor results on bandsaw, I think sometimes it’s because I’m not paying enough attention to the subtleties of technique and/or getting sloppy or nonchalant about it. I also see a lot “out there” on bandsaw drift, but all the attention is on setup with no mention of technique. Is there no impact of technique on drift?
Thanks to the experienced folks for offering their experience and expertise :)
A properly setup bandsaw will not drift. Drift is a term invented by someone that needed to explain a way to compensate for something they could not figure out how to eliminate.. or maybe was selling a fix for it.
Laguna has videos stating that drift is a myth, but will also sell you a Driftmaster fence for $400.
GDB's diagrams are at the heart of it. Undo every adjustment and rebuild around a blade tracking properly... you should not have to compensate every time you change blades.
Drift is real and fortunately it has a cure. Drift is definitely not an inherent part of using a bandsaw. Unfortunately, drift is really a generic term that describes multiple problems that have different solutions.
Drift is caused by either misalignment of the saw itself or from unbalanced forces on the blade when it is cutting through the wood. Realignment will not correct unbalanced forces and balancing forces will not compensate for misalignment.
Your bandsaw needs to be set up appropriately and there are many videos on the internet on how to do this. I personally used the Michael Fortune approach and it works for me. A well tuned saw lets us change blades and not make any adjustments to the wheels, table, or fence. The only adjustment needed is to the guide wheels/blocks.
Setting the wheels to be coplaner is the most important part. If the wheels are not coplaner the blade actually twisted inside the cut and you will never fix your drift. After that, the table needs to be perpendicular to the blade and the fence has to be square/parallel to the blade (actually normal to the plane of the wheels). Saw misalignment can create any type of "drift" from curved or angled surface from the top to the bottom of a cut to the cut that is not parallel to the fence.
Nobody really talks about unbalanced force on the blade during a cut, but this is a really issue. A dull blade is the most common problem. Because a blade wears unevenly, there will be a sharper side and a duller side. The duller side requires more force to cut the wood, this mean the wood pushed with more force on one side of the blade, slowly bending the blade during the cut. What I start to see when my blade gets dull is a cut that starts straight and will slowly transition into a tapered cut as I saw off veneer. I end up with a nice even cut at one end and a tapered piece at the other. More tension on the blade cannot fix this. The laws of physics can prove that blade tension cannot fix this. I have also determined through extensive testing that board needs to be flat and square. Any twisting of the wood in the cut will generate these unbalanced forces in the cut. The rate of saw dust/chip clearance can also cause problems. Thicker stock requires a low tooth count with large spaces to hold chips and a slow feed rate.
Once your saw is set up, you can cut whatever you want. I can cut veneers with the veneer against the fence, I can veneer with the main board against the fence. I can rip stock and it results in a cut nearly as clean as my table saw cuts. I can resaw up to the full 12" capacity of my saw without issues. This is all being done on a 14" Grizzly bandsaw, so nothing special.
When I have to fight to get a straight cut on my bandsaw using the guide, I get a piece of plywood with a straight edge and make a partial cut, stoping the blade after it has made a couple inches in the plywood. I then use feeler gauges to check that the rear of the blade is dead center in the kerf and if not, I adjust the table/guide assembly to make it so. It happened two times since I have my latest bandsaw (5 years). Once when I first set-it up and 6 months ago when I got my freshly sharpened carbide rip blade back from Laguna. The blade never could be managed and drifted badly irrespective of any adjustment I made. Laguna promptly sent me a new blade and all problems disappeared.
Feed rate seems to be a key, from what has been said here. Harder woods or those woods with curly grain, especially if the blade is not sharp and even both sides. My thanks to all those who have contributed so far - you have all been very helpful!
Sorry some of these posts get rather long-winded but, I'm sure we are all just trying to be helpful . . .
"What is a Delta clone and should I be concerned about the upper and lower wheels being co-planar?"
Many 14" cast iron "C" frame bandsaws are commonly called Delta Clones due to so many versions of this format of saw based on that ubiquitous machine. It is by no means a disparaging remark so I hope it was not taken that way ;-) I was just trying to refer to a 'typical' cast iron 14" machine.
Arguments about the necessity of co-planer wheels run on as long as Saw Stop, Festool, sharpening and cap iron position threads. I will try to avoid taking a "right" or "wrong" position as these discussions are endless.
For myself, LambrecthFurniture and others, going though the small amount of time it generally takes to get your wheels co-planer has met with good result. The ability to take a 3/8" x 6 TPI blade used for curved work off the saw, put a 3/4" x 2-3 TPI skip blade on for re-sawing, set the tension, set the guides and confidently go back to work is a real effort saver over time.
It may be that your wheels are already fine. I looked at a Jet 14" manual and under blade tracking they state:
“Tracking” refers to how the blade is situated upon the wheels while in motion. The blade should track in the center of both wheels."
There is no instruction for aligning the wheels so it is assumed they are already co-planer. This is easy enough to confirm. Adjust the blade position on the top wheel and see if it is in the same approximate position on the lower wheel. If so, you're done.
The preferred actual position on a crowned tire saw is another endlessly debated subject. My diagrams in the previous post show you what happens based on blade position.
If your wheels are not co-planer and you want to get them that way, either the upper or lower wheel will have to be moved in or out. On all of the saws I have done this on there has always been adequate room on the axle. Therefor I am no help as what to do if the correction requires more than adding a washer behind the upper or lower wheel/bearing.
*** Note *** The appropriate washer may be waiting in a coffee can in the corner. Cutouts of shim stock or an old aluminum can can be added if you can't find a washer that is close enough to work. Put the shim stock against the non-moving part of the assembly or it will get spun to death ;-)
There is a decent discussion of this adjustment in the manual for the Grizzly G0513 / G0514 manual, page 68:
https://cdn0.grizzly.com/manuals/g0513x2_m.pdf
The plywood "gauge" (dimension will have to be altered for your saw) can be very helpful. It is important to remember that the lower wheel's plane is fixed while the upper wheel tilts for blade position adjustment with different tensions / blades. With the blade off, set the upper wheel's plane to be that of the lower (perpendicular to the floor). You can now check for forward and backward co-planer positioning with a shop made gauge or even a plumb bob.
This has gotten quite long before I was able to address technique questions so I'll stop here and continue if you have other questions.
Hello GeeDubBee, Many thanks for your response. I recognize now that "drift" is one of those issues that either does not appear for some or, fo others like me, is ongoing, with all kinds of adjustments being necessary or not, depending on results. I have had the opportunity to work on other bandsaws (at Cerritos College in California) so I have learned that drift can and does exist but is most likely caused by either technique (how fast to push, where to use a fence) or how sharp the blade is. I am going to resolve my issue by checking and re-checking blade sharpness before each use (I don't use my bandsaw every day) and watching my technique, because I saw several different types of wood, from hardwoods that are very dry to recently cut street lumber (felled trees, from which I am lucky to get a branch or trunk section). Again, my thanks to you and all others for the very helpful advice.
I had a drift problem on my 14" Rikon that was cured by readjusting the upper and lower wheels to be aligned and that did most of the trick.
One thing I didn't see any other mention of is the blade itself. If you've been using a high tooth count blade in the hopes of getting a fine finish on the cut, you may be packing too much sawdust between the teeth and that pushes blade hither and yon. A 3 or 4 pitch blade is what you want, big gullets can carry away more sawdust.
I changed out my 3/8 blade for my 3/4 blade, which also has fewer teeth per inch (4 tpi on the 3/4 and6 tpi on the 3/8 blade) and tried to cut a veneer with the 3/4" blade out of a 6-inch sq. piece of 3/4" cherry offcut. Success! I was able to cut a 3/32 veneer/thin-piece off the cherry section! I cannot let it go to my head, but it feels pretty darn good to know that it may yet be possible. BTW, I drew a line on the cherry and used the curved fence/re-saw guide. This allowed me to follow the pencil line to one side with a reasonable amount of success - thickness of the cut piece varied from 3/32 to 5/64 so I think it was good. Thanks again!
I see you have fixed the issue - drift is often caused by the blade gullets choking up if they are too small. You want a 3TPI blade and if you can get it, a skip-tooth variety for deeper resaws.
Also, to quote the wood whisperer "Sharp fixes everything" - if your blade is dull it will not cut straight.
Snodgrass, coplanar wheels, drift is a myth — hogwash, I say! I say embrace the drift! LOL.
Seriously, try adjusting the table instead of the fence. Michael Fortune has a video on this. I’ve tried it and to me, it’s the only way to go. I’ve tried Snodgrass on both my saw and it didn’t work.
He’s a slick presenter, but after looking at manuals for both my saw, it has sections for drift. And, I found out some saws are designed noncoplanar & I tech support advised me not to change factory setting. Also, if it doesn’t have crowned wheels it won’t work.
To the question, if I’m understanding correctly, the cut is “drifting off at the lower end of the cut”.
If this means as you get to the end of the board, then a featherboard will keep it firmly against the fence especially if you’re pulling through the last few inches. Outfeed support is important for long boards.
OTOH, if this means the off cut is narrower at the bottom than top, the same applies, but be sure to check the blade for 90° to table, be sure a jointed side against fence, and 90° edge on table.
Lastly, tension the heck out of the blade, way more than the gauge on the saw. I typically tension a 1/2” blade past 1”.
Hope this helps. I meant no offense, Snodgrassites. :-D
What rob said re: 3tpi.
There are specific blades for re-sawing such as Woodslicer.
The reason behind adjusting the table to the blade is that the miter slots become non operational if they are not parallel to the blade. Of course the fence has to be also adjusted parallel to the miter slots in the first place.
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