Bandsaw

[user 19915]

Iv'e got a thin band saw blade on my band saw and it runs great for a while but if i leave it for a day or two before i use it again it wonders on start up and i have to tweak it up all over again can anyone explain what's happening or offer any suggestions please
Mock

 

[Alexam]

Hi Mock, difficult to say without knwing what size blade and how you do your 'set upo' Do you initially set e bblade with the guides top and bottom away from he blade and th thrust bearings also and with theteeth of the blade centred on the top wheel? THEN when running like that, move the guides and bearings into position?
Alex

PM also

 

[marcros]

it sounds like something is moving as a result of the tension. Thin blade under tension... my first consideration is whether it is stretching slightly.

 

[user 19915]

Regarding the size of the blade i think it's a 1/8"

 

[Alexam]

Regarding the size of the blade i think it's a 1/8"

If you want to call me, I have PM'd my number, but call soon as I'm going out to the workshoip in 5 mins.

Alex

 

[deema]

Hi Mock,

Can I ask, are you releasing the tension on the blade when your not using it? If not the tyres will be taking a set which will require you to re-adjust. It's always best to release the tension when ever not in use, even over night.

 

[marcros]

i dont think that the guides make any difference. On mine, certainly, it will track fine without the guides being set at all. my understanding is that the guide bearings typically/ideally are not touching the blade unless on a curved cut. If it is wandering after a period of rest, there are only a few things that can have changed, and all relate to blade tension- something stretching, or shrinking (spring relaxing?).

Does it happen with wider blades?

Do you have a de-tension lever on your saw, so you can relax it when not in use?

 

[woodpig]

it sounds like something is moving as a result of the tension. Thin blade under tension... my first consideration is whether it is stretching slightly.

That's what I thought. I always back off the tension after use on mine.

 

[Steve Maskery]

Just remember that the more steel there is in the blade, the more force is required to tension it. So a small, thin blade requires less force to tension it than a wide thick one. So if you apply a force to a thin blade, it will stretch much more easily than a bigger blade.

That would be my first point of investigation, too.

 

[user 19915]

Sorry i'm late getting back to you regarding the tension on the blade after use i haven't been releasing the tension '.Plus i can only go up the garage 3 or 4 times a month or there about's .So should i be releasing the tension all the time ???
mock

 

[woodpig]

I'm no expert but it's been suggested to release the tension if the machine is sitting idle, particularly if it's a small blade.

 

[deema]

Hi Mock

You definitely should always release the tension when the bandsaw is not in use, the tyres are a rubber / plastic compound with a slight crown on the wheels. If you keep them in tension the rubber / plastic will deform and you will have a 'flat' spot on both wheels at exactly the same place as the wheels rotate, as the wheels turn the tension on the blade will keep changing causing the blade to flex and cut off line. Equally the crown on the wheels is essential to keep the blade in the centre of the wheel and for it to not wander, a flat will cause the blade to wander and again you will not be able to cut straight. A wider bkade will not be affected as much as a narrow blade.

The good news is that normally, if you keep the tension of the wheels any flat spot will relax out again sufficient for the issue not to cause any problems. (Rotate one of the wheels by a quarter turn if they have been under tension to move the flat spots out of alignment, this will reduce the problem initially)

To check, a clock with a magnetic base can be used to see how far out of round the wheels are, if they have been left for a long time under tension they may need skimming to get them round and crowned again, not a real big issue and easy to do. There have been a few threads on here on how to do it.