Bandsaw woes

[markturner]

Hi Guys, I am having some real trouble with my bandsaw, a Scheppach Basato 4. Now, it seemed to be working fine, before and I have not changed anything, except swapped a blade. Now, I cant get it to cut straight, it drifts. I have Steve Maskery's excellent bandsaw DVD and have spent the last 4 hours swapping blades, checking table and fence alignments, position of the blade on the wheels, , all as per his recommendations. It will cut straight if I use a small piece, but anything over 2 inches high, it drifts and I cant think what else to try. The one thing I did see is the bottom wheel adjustment wont go as far as the top one, I cant adjust it any more, it is right up against the side of the housing. I am talking about where the blade sits on the wheel, forward and it will track left, and back it tracks right, correct? What is the important section of the blade to get centered, the teeth, or the middle of the blade? Obviously with a wide blade, if you put the center of the blade in the middle of the wheel, the teeth will be quite near the front. Well my problem is the with the fence to the left of the blade,the blade starts tracking left, IE narrowing the cut on the workpiece and forcing the blade over. This then makes it cut out of true vertically. So, despite max adjustment on the bottom wheel, it still tracks left, leaving the position of the blades different on the two wheels, what can I do?

Cheers, Mark

 

[Blister]

What make is the blade you fitted ?

All saw's rely on a good quality blade and the correct blade for the Job in hand

We recommend Tuff saw blades

http://www.tuffsaws.co.uk/

have a word with Ian re the job you want to do and he will recommend a blade

:wink:

 

[JakeS]

The one thing I did see is the bottom wheel adjustment wont go as far as the top one, I cant adjust it any more, it is right up against the side of the housing.
...
So, despite max adjustment on the bottom wheel, it still tracks left, leaving the position of the blades different on the two wheels, what can I do?

Do you mean to say that you can't get your two wheels co-planar? I'm no bandsaw expert, but I don't think I've ever had to adjust my bottom wheel at all... certainly not for fitting a new blade!



Alternate question: was it an old blade? Is there any chance that it had been used for cutting curves a lot, the teeth are more worn on one side (probably the right hand side/outside from your description) and it cuts itself towards the left rather than it having anything to do with tracking? (I have a dedicated cross-cutting and re-sawing blade for mine, it never gets used for cutting anything other than straight lines just in case.)

 

[markturner]

Hi Guys, yes, it would appear that I cant adjust the bottom wheel to match the top. I did not have to adjust the bottom wheel to change the blade, I changed the blade to see if it helped the drifting problem, which it did not. The blades are OK, as they were working OK before, I am not sure why the problem is manifesting now, I was resawing quite accurately pretty recently.....I am going to swap another blade in and see what that does..

Edit, Ok, I have just noticed that the top wheel has about 10mm of lateral play in it - if you grasp the spokes and rock it left to right, it moves.... presumably this is not right?

Rgds, Mark

 

[kirkpoore1]

Having your wheels coplaner is much less important than having a proper crown on the tires. If there's a groove worn in the tires it's time to recrown or replace them. Make sure the edge of each wheel has a nice smooth curve in it. (Sorry, so far I haven't been able to find a picture.) If not, you'll need to do some work. If they need recrowning, let us know. I can provide you a myriad of links to crowning methods (all shamelessly stoken from owwm.org).

Kirk

 

[markturner]

Hi, I don't have a groove in the tires, which is good. I have just put in a larger blade, 25mm, and set it all up again, I am managing to get pretty good re sawing. So I am wondering if the issues relate to smaller blades, which was what I had in before ( was approx 14mm blade) . I dont think the blade was worn, it was pretty new, but I had been doing some curves with it..

I am going to try some new blades and see what happens. meantime, does anyone know if there are any good engineers who will come out and "service" machines like this in the London area?

Cheers, Mark

 

[Newbie_Neil]

Hi mark,

I dont think the blade was worn, it was pretty new, but I had been doing some curves with it.

Once you've used a blade for curves, it won't ever cut straight again.

Thanks,
Neil

 

[kirkpoore1]

Mark:

Narrower blades are more sensitve to uncrowned or poorly crowned tires than wider blades. But I wouldn't call a 14mm blade narrow by any means. I finally found a decent tire crown picture:

This was taken after the bandsaw tire on the right had been crowned on the disk sander on the left. I would check your tires' profiles. If they're flat across, instead of being curved or having a peak like the above tire, you'll need to crown them. If not, well, at least you have the most common issue out of the way.

Kirk