Band saw Blade drift

[Lonsdale73]

Myth or fact?

I can't find it now but I watched a demo on youtube, American guy who'd spent most of his life operating band saws and he said it only occurs if the machine isn't set up right. Which sounds reasonable except that he appears to work for one of the 'name' band saw manufacturers, Stateside at least. Is he right or telling porkies?

 

[Rorschach]

Only occurs for me when the blade is buggered. A sharp blade and things set up right and I have no trouble. And before anyone says it, doesn't have to be a tuffsaws blade either.

 

[marcros]

i would say that he isnt far off the mark.

A blunt blade is one of the parts of machine set up, and probably the biggest cause of blade drift- most other issues, in my experience, tend to throw the blade off rather than cause drift. People adjust the fence to compensate for drift, so there must be alternative ways that it can occur. Proper set up should alleviate the need to do this.

 

[Alexam]

Rubbish. If the bandsaw is set up correctly, with a good blade, you should not get any drift.

Having repeated that many times, the tuning of a bandsaw can take time and all sections link with each other, so if you do just one, then it wont be enough.
You may have already seen the following information,

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.
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 brough 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

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.

.......................... but provided you have taken time to 'tune' your machine well and are still getting drift, please explain more and tell us which machine you have problems with. I'm sure that a number of members should be able to help you with your problem

Malcolm

 

[ColeyS1]

Doing loads of curvy cuts, then expecting the blade to cut straight can be asking a bit much. When curvy cutting, one side of the teeth will dull quicker than the other, making straight cuts much more difficult

Sent from my SM-G900F using Tapatalk

 

[Lonsdale73]

GET THE BEST TUNING FROM A BANDSAW 'Alex Snodgrass of Carter Industries has an excellent video https://www.youtube.com/watch?v=wGbZqWac0jU o

Malcolm

That was the one; think it was from a link you posted in reply to someone else that I found it in the first place so thanks for that, twice over.

 

[Rorschach]

Gullet near the centre of the wheel seems to work fine for me, but also watch the blade, some blades seem to track better a little forward or back of that point especially those with a higher TPI

 

[dp341]

Like most, I have wider blades for straight cuts and narrower blades for curves. When the wide blades are sharp, right no. of teeth for the stock width, proper feed rate, I get no drift.

Try and cut a straight line with a blade I've used for curves and there's no chance.


Sent from my iPad using Tapatalk Pro

 

[transatlantic]

Gullet near the centre of the wheel seems to work fine for me, but also watch the blade, some blades seem to track better a little forward or back of that point especially those with a higher TPI

So how do you get the gullet at the center? For me, it doesn't matter where I position the blade by hand, after a few rotations it's moved to where it wants to be. I assume I can mess with the tilt to move it more to the center, but that video also says not to mess with the tilt and leave it how the factory left it?

 

[Alexam]

I think you have not understood correctly. Adjusting the tilt of the top wheel is what positins the blade. It was designed that way, as the factory setting, just for that purpose. You may have been confued by some people saying you shold change the bottom wheel to obtain co-planar with the top wheel, which is not necessary. The bottom wheel should never be changed from the way it was set up.

Position the blade on the wheels and 'back off' all the guides and rear thrust bearings so they do not touch the blade at any time it rotates. MOve them back at least 1/4". With the eletric disconnected, turn the top wheel by hand sevral revolutions and if the blade moves forward or back, adjust the tilt lever very slightly ( clock wise, 5-10 minutes) and repeat the revoloutons again. Once the blade has its teeth in the centre of the top wheel, close up and connect the electric to power up. Start up very quickly on and off and then wait for the blade to stop rotating and open up and see if it has moved at all from centre. If it has moved under power, you need a little more adjustmant of the top wheel. Once it stay in place under power for a few seconds, then is the time to bring in the guides and thrust bearings until almost touching. You should then be set up correctly.

Try it and let us know how you get on.
Malcolm

 

[transatlantic]

I think you have not understood correctly. Adjusting the tilt of the top wheel is what positins the blade. It was designed that way, as the factory setting, just for that purpose. You may have been confued by some people saying you shold change the bottom wheel to obtain co-planar with the top wheel, which is not necessary. The bottom wheel should never be changed from the way it was set up.

Position the blade on the wheels and 'back off' all the guides and rear thrust bearings so they do not touch the blade at any time it rotates. MOve them back at least 1/4". With the eletric disconnected, turn the top wheel by hand sevral revolutions and if the blade moves forward or back, adjust the tilt lever very slightly ( clock wise, 5-10 minutes) and repeat the revoloutons again. Once the blade has its teeth in the centre of the top wheel, close up and connect the electric to power up. Start up very quickly on and off and then wait for the blade to stop rotating and open up and see if it has moved at all from centre. If it has moved under power, you need a little more adjustmant of the top wheel. Once it stay in place under power for a few seconds, then is the time to bring in the guides and thrust bearings until almost touching. You should then be set up correctly.

Try it and let us know how you get on.
Malcolm

I guess I did missunderstand - will watch again!

 

[woodbrains]

Helllo,

Don't bother, there is no benefit in getting the blade to track with the gullets on the centre of the wheel. It will not prevent drift. Snodgrass is a buffoon, and obviously easily impresses the amateur. He is a salesman selling his guides. There is nothing in his video that is of any use, unless you think limiting the width of the handsaw blades to half, because you are only using half the width of the wheel is a neat idea, just to save adjusting the thrust bearing when you change out a blade. Nonsense!!

Mike.

 

[sunnybob]

Like malcolm says, top wheel HAS to be adjusted. Bottom wheel NEVER adjust.

I spent a lot of time adjusting top wheel inclination and blade tension to get a good cut with a blade. Then I marked the side guide in line with the gullet. Then when I change the blade i turn the top wheel and inclination by hand till the new blade gullets are very close to that mark.

Close it up run the motor, and adjust tension and inclination again untill the blade appears stationary from the front and (roughly) in line with the mark from the side.

But from my own experience, blade drift happens after you screw up the bearing adjustment and squash all the teeth flat by having the rear bearing too far back.

 

[Alexam]

You are right Bob, but we need to remember that some people do take a little longer to understand how improvements can be made.

Bandsaw Drift can be eliminated and it takes time to understand the machine you have and how best to make it work well. Alex Snodgrass has shown a very good way to correct problems and those who have managed to follow his advice have improved. There are various methods that were adapted many years ago by others and were good in their day, but new ideas keep coming up and we all need to adapt. If you have a problem don't try them out you simply have to put up with what you have and live with your drift, not just say it cannot be eliminated when it can in most cases.
Malcolm

 

[dynax]

I don't know if i was lucky or just have the knack, but having never used a bandsaw before, my scheppach came today, and i have just finished setting it up, i watched a couple of yt videos before starting on it, and i stripped it down before actually putting it together, took it all apart and basically set it up from scratch, refit and tension the blade i worked on the same method as i use on the scroll saw and ping the back of the blade for a nice tone, got the blade running true, although the gullets were not central on the tyre it did track evenly, then set up the bushes, on this model it uses piston type bushes but so far seem ok, fitted the table and fence rail, i then squared the table to the blade using the fence and a light behind, set the table for flatness 90 deg to the blade, then did a test cut on some stock and cut a cross in the end to check for square, and then cut a slither off the edge, and all is perfectly square and runs like a dream, it took me about 1 1/2 hours to do, as i said never even used one before now, let alone owning one, some new blades will be on their way next week for it from tuffsaws, but atleast now that when i come to change blades i know what to do and should only take a few minutes to set it up,

 

[galleywood]

From scratch, I would:-

Adjust tension and tilt to get gullet in centre of top wheel.

Set the fence parallel to mitre slot - if necessary loosen table bolts and turn table to compensate - I have had to enlarge bolt holes in trunnion to achieve this.

Make a test cut and re-adjust table.

When the cut is as close to parallel as possible , I finalise it by very fine adjustment of the tilt screw.

It worked for me.

 

[sunnybob]

Oh no, you have " the knack"

https://www.youtube.com/watch?v=Dx6HojL ... =sgispider

 

[dynax]

Oh no, you have " the knack"

https://www.youtube.com/watch?v=Dx6HojL ... =sgispider

Noooooooooo!!!!!, anybody got any tablets (hammer) (hammer)

 

[sunnybob]

I've had that clip on my puter for at least 6 years, I still laugh every single time i watch it (thats because I'm socialy inept)

 

[CHJ]

I'm with Rorschach, the only time I experience drift is when Blade is wearing and loosing its sharpness or damaged by hitting something.

I've only got a basic 14" SIP

I never even look at blade location on Top wheel other than the occasional check that the tyre is Ok when checking for any excessive dust accumulation.
Just fit new blade,
Adjust Top wheel inclination for Blade running at 90 deg. to the Fore and Aft plane of the table.
Set support guides.

I find no difference in behaviour regarding cutting straight cuts after curves as long as blade is sharp regardless of width.
Tooth wear affecting the set on one side of the blade does not appear to occur as long as there is adequate width of kerf to accommodate the blade width in a given radius and is not trying to twist it.

Sorry if folks are fed up with seeing this image but it is what I would expect from a sharp blade,