bandsaw woes

[Richard S]

Hi All

A couple of years ago I bought a SIP 12" bandsaw and I has sat quietly in the corner of the workshop hardly being used ever since, mainly because I have never really been happy with its performance and partly because I never seemed to have the time to investigate and tune up its workings.
However I thought the time had come this weekend to have a look and see what can be done, so I bought some decent quality blades and set about replacing said blade and making sure all the adjustments where spot on.

Upon opening the doors it became apparent that the original blade had moved forward on the wheels to such an extent that it has sawn almost halfway through the door catch, now having replaced the blade with a new one I can't get the blade to stay centred on the wheels, no matter how I adjust the upper wheel the blade always moves to the front of the wheel and at some adjustments even comes right off the wheels, it also seems to get worse as you apply more tension to the blade, that is to say if you start off with the tension just enough to grip the blade and turn it it moves forward on the wheel by a few mm but as you crank up the tension towards the mark for the size of blade it gradually moves further forward on the wheel.

I have a book that says to check the wheels are in alignment with each other using a straight edge but because the frame is in the way on my model I can't see a way to do this.

Help!! Any ideas?

Thanks in advance

Richard

 

[paulm]

Richard,

The top wheel should have a tracking adjustment, usually a knob on the rear of the upper cabinet, that tilts the top wheel in the vertical plane. This is what you would usually use to get the blade to run centred on both top and bottom wheels, having first of all backed off the guides and rear blade supports both above and below the table.

Let us know if you have backed off the guides and supports and adjusted the tracking first then we can try to figure next steps.

Cheers Paul.

 

[Richard S]

Hi Paul

Thanks for your quick reply but I have tried this and it makes no difference, if I start with the tracking adjustment in the centre of its travel it makes no difference whether I adjust it in or out, the blade still moves to the front of the wheel. I also slackened off the guide bearings in case they where forcing the blade forward, there is no contact at all now on the guides.

I'm stumped

Richard

 

[orangetlh]

Have you got the tracking knob maxed out in the oppositre direction for when the blade comes off the front? Sometimes the tracking knob has a locking nut on it as a referance and may need moving to allow the top wheel to track further back than it is now.

 

[paulm]

Hmmm, I think I'm stumped too !!!

Sounds like it's something more fundamental with the machine. Might need Scrit's help with this one !

Just a thought though, and apologies if it's grannies and eggs, but on my two bandsaws the tracking adjustment knob has a second locking wheel in front of it which you use to tighten and lock the tracking knob once adjusted.

You're not by any chance just turning the locking wheel rather than the actual tracking wheel ? Only there should be some visible effect from adjusting the tracking knob....... Apologies again if you're more experienced than I may be assuming !!!

Have to go and make some dinner for SWMBO so will be back a bit later !

Cheers, Paul.

 

[Paul.J]

The adjustment might only be very slight too,to make a difference.
Paul.J.

 

[MIGNAL]

I don't know this particular machine but usually there is an adjustment for the bottom wheel. If you want to run it co-planar you need to make a straightedge out of thin MDF that has a cutout to straddle the frame but still allows the straightedge to touch at 4 points of upper and lower wheels. You will have to remove the table and be prepared to put some time in whilst doing this, it can be very frustrating.

 

[Richard S]

Thanks all, I'll try Mignals idea for the cut outs in the straight edge and see if the wheels are in alignment.

Richard

 

[MIGNAL]

The straightedge should touch at 2 'O' clock and 4 'O' clock on both top and bottom wheels, 8 'O' clock and 10 'O' clock on both wheels. Hope that's fairly clear.

 

[Sawdust]

On my bandsaw I found the most important thing was to get the wheels co-planar, without doing that, nothing would persuade it to cut straight.

As mentioned above, make a straight edge with a cut out to straddle the frame and move the wheels until they are in line.

The Bandsaw Book is pretty good and explains pretty much everything. He states that adjusting the tension affects the tracking as the fram moves slightly as the tension is increased so be prepared to adjust both of these to keep it running true.

Also, make all the adjustments with the blade guides (top and bottom) out of the way. Get the blade running true on both wheels, get the tension right and then adjust the blade guides. In my experience, once the bandsaw is set up properly, it is an excellent machine however if it's wrong, it's an absolute pain to use. Also, getting it set up properly takes a fair bit of time and can be a bit frustrating. Persevere and you will get there.

Good luck!
Mike

 

[jasonB]

Also check the wheel bearings, if there is play /wear then no amount of tracking abjustment will stop them running out.

Jason

 

[devonwoody]

What condition is the wheel surface in?
They usually have a rubber/plastic coating, was that damaged also in addition to the other problems you spoke of?

I could imagine a damaged surface on the wheels would cause havoc in trying a tune up.

 

[Richard S]

Hi Guys

Bearings are fine as are the tyres, in all I would say that this machine has run no more than ten minutes since new. I'm sure it is just a set up problem and my lack of experience with this type of machine. I have to take number one son back to University in York so I don't think I shall have time to do any further investigation today, I'll post the results of my wheel alignment check tomorrow.

In the meantime thank you all very much for your time and assistance so far it is greatly appreciated.

Richard

 

[OPJ]

Just out of interest, what size is the blade you're trying to run on this machine?

I have the 12" SIP saw and have found running the largest 'compatible' blade (in my case, 5/8") to be a real pain - basically, these saws aren't built to properly tension a large blade, despite what is claimed.

 

[OPJ]

What about the thrust and side bearings above and below the table? I don't suppose they've been 'knocked' forwards in the time since you last used the saw, which would stop the blade from tracking towards the rear of the wheels?

 

[Richard S]

Success, I checked the wheels for alignment using a straight edge with notches cut out for the frame and it showed the bottom wheel to be leaning backwards, fortunately the axle is adjustable, so a little tweak here, reset the guide bearings and its cutting like a champion.

Thank you very much to everyone who took the time and effort to offer help and advice it is sincerely appreciated.

Regards

Richard

 

[Woodmagnet]

Hi Guys

Bearings are fine as are the tyres, in all I would say that this machine has run no more than ten minutes since new. I'm sure it is just a set up problem and my lack of experience with this type of machine. I have to take number one son back to University in York so I don't think I shall have time to do any further investigation today, I'll post the results of my wheel alignment check tomorrow.

In the meantime thank you all very much for your time and assistance so far it is greatly appreciated.

Richard

My son's at York Uni as well,small world.

 

[paulm]

Glad you got it sorted Richard.

Cheers, Paul.

 

[Richard S]

Kevin

Whats your son studying, mine has just started his second year in Film and Television Production. He is having the time of his life and makes me feel I missed a real trick not going to university myself, particularly as it was all paid for in my day!!!

Richard