Thread: Bandsaw blade twists while cutting

Just watched the Woodwhisperer on setting up a bandsaw. He invited Alex Snodgrass to demonstrate. Interesting enough, besides recommending the bottom of the gullets on the blade be on the crown of the wheel, in this video ALEX ALSO SETS THE FENCE PARALLEL TO THE BLADE !!

I don't recall him doing this in his earlier demonstrations

Have a look here:
https://fpdl.vimeocdn.com/vimeo-prod...w+Setup-HD.mp4

Did this drift issue/blade twisting occur before the blade sharpening and with all blades? I ask this because you initially made the point it was only the RSK after resharpening that was the problem and now a second blade appears to have the same issue. Reading post #8 again it appears as though this problem has developed over a period of time so my suggestion would be to get the table off it for a start, check the mechanical condition of the machine such as bearings, condition of the wheels, tracking mechanism not hanging up etc. Snodgrass in his video makes a big thing of removing the table and it does make things far easier in the trouble shooting department. Did you ever get it cutting correctly after this thread Cannot remove drift on blade

As you say doing the same thing over and over is madness. It might be that the machine has a manufacturing defect in it from new. Bandsaws are so simple until they won't cut correctly in my experience.

Was a bit worried doing the process of Peter Youngs where initially the bandsaw is used to cut the test piece without the guides in position. Then I found this video which shows that guides are not really necessary, they are a nice accessory.
You can check it out here: https://youtu.be/7SHG3R2mEMM

Except for the back guide, which is a necessity, unless you like the blade coming off the back of the wheel whilst cutting.

I have used ALEXs blade set up from day one except for his guide set up as Ceramic are different than bearing guides, and I mostly follow the guy who designed the Laguna BS and his reasoning and videos on setting the ceramic guides.

FYI my blades are parallel to the mitre slot. You can adjust the wheels for that but you need to know what you are doing - there was a Laguna set up video that suggested that.

Chris Parks thanks for your comments, and taking an interest in this. Firstly, my memory is a bit hazy on the exact sequence of events, as I was recovering from serious illness and working in the shed very intermittently for short periods of time each session while in recovery.

The historical time line, to the best of my memory is this:
1.The bimetal blade was burning the RH side of the cut timber. I was playing around with the tracking, and during these tests the blade snapped, rather spectacularly. I did not have any trouble with burning prior to this blade.
2. I then put my resharpened LRK on , for the first time since sharpening, and noticed it too was burning on the RHS, but to a lesser extent.
3. After reading the AWR #93 article by Peter Young, I followed his process of disconnecting the guides, and using the tracking knob, varied the position of the blade on the wheel to see if there was any change to the blade angle ( compared to the mitre slot).
4. I could not find a position on the wheel where the blade was parallel to the mitre slot, unlike the AWR article.

I am going to try a new blade tomorrow to see if I can get a zero blade angle, but not very hopeful.

With regards to my previous long forgotten thread posted just after purchasing the Laguna bandsaw, post #78 indicates that when I installed a new blade the problem of blade angle disappeared.

Originally Posted by Dengue

Chris Parks thanks for your comments, and taking an interest in this. Firstly, my memory is a bit hazy on the exact sequence of events, as I was recovering from serious illness and working in the shed very intermittently for short periods of time each session while in recovery.

The historical time line, to the best of my memory is this:
1.The bimetal blade was burning the RH side of the cut timber. I was playing around with the tracking, and during these tests the blade snapped, rather spectacularly. I did not have any trouble with burning prior to this blade.
2. I then put my resharpened LRK on , for the first time since sharpening, and noticed it too was burning on the RHS, but to a lesser extent.
3. After reading the AWR #93 article by Peter Young, I followed his process of disconnecting the guides, and using the tracking knob, varied the position of the blade on the wheel to see if there was any change to the blade angle ( compared to the mitre slot).
4. I could not find a position on the wheel where the blade was parallel to the mitre slot, unlike the AWR article.

I am going to try a new blade tomorrow to see if I can get a zero blade angle, but not very hopeful.

With regards to my previous long forgotten thread posted just after purchasing the Laguna bandsaw, post #78 indicates that when I installed a new blade the problem of blade angle disappeared.

As a really way out there idea swap the tyres on the wheels and see what happens to the tracking. I have given some thought to designing a jig to measure the angle of a bandsaw blade while the machine is running and the idea surfaces every now and then but trying to do it on blades under 12mm might be a mission too far. If that was possible you would be able to watch the angle change and it would be far easier to track the blade correctly.

So many things can affect the blade of a bandsaw. The most important one is getting the blade set up correctly in the first place which does take time, but worth the effort. The following may be of help to you

GET THE BEST TUNING FROM A BANDSAW 'Alex Snodgrass of Carter Industries has an excellent video https://www.youtube.com/watch?v=wGbZqWac0jU on a tune up method that works well. His updated version also here - https://www.youtube.com/watch?v=bxVyKsbuwZQ
The following video may help some owners with a Record BS400, but it is similar to most machines blade changes - https://www.youtube.com/watch?v=c-aHHxEKw6g

Blades can run and cut without any guides whatsoever (https://www.youtube.com/watch?v=7SHG3R2mEMM) as long as the machine is tuned correctly. This is how the blade should be running BEFORE the guides are brought into play on your machine, so that they can 'bump back' the blade should it wander, so please don't get guides near the blade before you know it is running clear and staying in the same place.

CHECKING BLADE TENSION - Flutter test Video's -
https://www.youtube.com/watch?v=chyo9chuwJs and https://www.youtube.com/watch?v=z8zZuDosSy0
Tuning a bandsaw is only that and nothing else. If you really want to get the very best use of your bandsaw on an ongoing basis, then the Steve Maskery DVD's will show you far more and they are a real investment that you should own. http://www.workshopessentials.com/shop/ '.

BUY BEST BLADES FROM ..... http://www.tuffsaws.co.uk/

Whenever you have put a blade on a bandsaw, ask yourself the following questions
....... are you managing to get the blade running freely and central on the top wheel ( without guides or rear bearing near the blade ) with the gullet of the teeth in the centre of the top wheel ? The exception would be with wider blades, as 1/2" and wider may not sit 'centred' on the top wheel).
That's the first priority before closing in guides and thrust bearings. The blade will not be in the centre of the lower wheel as the manufacturer allows the top wheel to be adjusted and tilt to allow tuning.
Is the blade running vertical 90° to the table alignment, front and back as well as side to side?
Once the guides and bearings have been brought to the correct position, (not touching when the blade runs freely) is the blade remaining where it should be when run under power and switched on and off checking several times ?

Are you sure that the tension is correct, or as near as it can be. Each blade could be different, even if it is the same depth, so needs to be checked whenever changing blades.

If all these things are correct, then you should get a true cut unless you are trying to cut the wood too fast and it's filling the teeth with sawdust and pushing the blade out of line and see if teeth are damaged in any way.
Finally, if you have used the blade before, make sure the teeth are clean, as sawdust will stick in the teeth gullet. Cleaning with a wire brush will result in a far better cut before starting a new job, but certainly on a regular basis.

Hope some of this will help you. Best wishes for the New Year
Malcolm
UK

One point I did not mention to my earlier reply. If you have a wider blade 1/"2 plus, then the teeth of the blade will not run in the centre of the wheel.
Malcolm

This was the earlier post which seems to have moved?

GET THE BEST TUNING FROM A BANDSAW 'Alex Snodgrass of Carter Industries has an excellent video https://www.youtube.com/watch?v=wGbZqWac0jU on a tune up method that works well. His updated version also here - https://www.youtube.com/watch?v=bxVyKsbuwZQ
The following video may help some owners with a Record BS400, but it is similar to most machines blade changes - https://www.youtube.com/watch?v=c-aHHxEKw6g
Blades can run and cut without any guides whatsoever (https://www.youtube.com/watch?v=7SHG3R2mEMM) as long as the machine is tuned correctly. This is how the blade should be running BEFORE the guides are brought into play on your machine, so that they can 'bump back' the blade should it wander, so please dont get guides near the blade before you know it is running clear and staying in the same place.
CHECKING BLADE TENSION - Flutter test Video's -
https://www.youtube.com/watch?v=chyo9chuwJs and https://www.youtube.com/watch?v=z8zZuDosSy0
Tuning a bandsaw is only that and nothing else. If you really want to get the very best use of your bandsaw on an ongoing basis, then the Steve Maskery DVD's will show you far more and they are a real investment that you should own. http://www.workshopessentials.com/shop/ '.
BUY BEST BLADES FROM ..... http://www.tuffsaws.co.uk/
TUNE WITH SOUND ? http://www.youtube.com/watch?v=JPyc2iDQnOA&vl ( UNPROVEN )
Whenever you have put a blade on a bandsaw, ask yourself the following questions
....... are you managing to get the blade running freely and central on the top wheel ( without guides or rear bearing near the blade ) with the gullet of the teeth in the centre of the top wheel ? The exception would be with wider blades, as 1/2" and wider may not sit 'centred' on the top wheel).
That's the first priority before closing in guides and thrust bearings. The blade will not be in the centre of the lower wheel as the manufacturer allows the top wheel to be adjusted and tilt to allow tuning.
Is the blade running vertical 90° to the table alignment, front and back as well as side to side?
Once the guides and bearings have been brought to the correct position, (not touching when the blade runs freely) is the blade remaining where it should be when run under power and switched on and off checking several times ?

Are you sure that the tension is correct, or as near as it can be. Each blade could be different, even if it is the same depth, so needs to be checked whenever changing blades.

If all these things are correct, then you should get a true cut unless you are trying to cut the wood too fast and it's filling the teeth with sawdust and pushing the blade out of line and see if teeth are damaged in any way.
Finally, if you have used the blade before, make sure the teeth are clean, as sawdust will stick in the teeth gullet. Cleaning with a wire brush will result in a far better cut before starting a new job, but certainly on a regular basis.


Hope something here helps. Have a great New Year.
Malcolm
UK

It appears all the tweaking did not produce the desired results. In my opinion - and I am no expert - the same principles that apply to a table saw also apply to a bandsaw. The mitre slot has to be parallel to the line of cut or the blade (to get accurate cross cuts) and the fence has to be parallel to the mitre slot. If lining up the blade on the top wheel does not achieve the desired result then I think the whole table has to be aligned to the line of cut or the blade. There is probably enough play to adjust the 1 - 2 degrees you require, that way the blade will also be evenly spaced in the kerf and will not rub with back edge.

Why does the mitre need to be aligned to the blade?

It is not a tablesaw. Nobody uses a mitre gauge with any accuracy on a bandsaw an even if you did it is trivial to set it for the offset with a setsquare on the blade and tightening the gauges knob once the angle is set.

The big issue is getting the fence aligned to the blade, with is simple using the MDF-and-centre-the-rear-kerf trick.

It appears all the tweaking did not produce any results. In my opinion - and I am no expert - the same principles that apply to the table saw also apply to a band saw. The blade or line of cut has to be parallel to the mitre slot and the fence has to be parallel the mitre slot. This is also important for accurate cross cuts apart from rip cuts. If lining up the blade on the wheel does not produce the desired results then I think the table has to be adjusted to the blade/line of cut. This will also ensure that the blade is spaced evenly in the kerf without the back rubbing. There is probably enough play in the table mounting to adjust the 1-2 degrees required.

And the last posts show there is more than one way to solve the problem. I have never used the mitre slot on a band saw so it would not worry me and getting the blade aligned to the fence on mine can be done with tracking. I do like the sliding table in the above link though.

Actually, I USE THE MITRE SLOT TO ALIGN FENCES ALL THE TIME. I have several custom made melamine fences of varying height for resawing, which are ribbed and therefore stiff over the full height of the fence, and better than the fence suplied with the bandsaw. And these need to be set parallel to the mitre slot.

I have actually removed the long chrome bar the Laguna fence runs along, because I was sick of walking into it all the time, the way it projected well past the rear end of the bandsaw table was a constant safety hazard, as my ribs will testify.

For my normal rip fence, I use a length of dressed 70x 35mm radiata pine with two strong magnets fitted on the flat side to help keep it in position on the table while I clamp this fence in position.

Fitted a brand new Henry Bros 3/4" carbon steel blade today, ran it for several minutes at the correct tension, with the guides removed, only to find that with the blade was 0.75 degrees out of parallel with the mitre slot. This best result was a achieved with the blade sitting centrally on the upper wheel tyre. Moving the blade either forward or backwards increases this angle.

When I used it to cut along a line on a test piece against the fence set parallel to the mitre slot, the blade sat along the RH side of the kerf, leaving quite a gap to the left of the blade.

I don't know what is wrong with my setup to make this angle, resulting in burning on the RH side of the kerf when the fence is set parallel to the mitre slot.

I am also concerned that the upper ceramic guides on the bandsaw are not parallel with the blade, and there is no swivel arrangemet to allow this to happen on the Laguna 14-12. The lower guide assembly will swivel.