Cheaper bandsaws tend to drift in the cut more, but any bandsaw can suffer from it. You can watch the line it is cutting along, and adjust to it, or you can try to resolve the problem. There are a few issues.
If you need to push the material through the cut too hard, then it tends to twist the blade. This will cause the cut to go at a angle. Why might you be pushing?
- A dull blade
- Thicker material than normal to cut
- Impatience
Another factor is the blade tension. A bandsaw has a spring that you tighten to keep the blade under tension. Your saw will probably have instructions for how tight to make the blade. This spring can loose its ability to properly tension the blade after some time, allowing the blade to twist in the cut. Replacing the spring can thus help you to bring your saw back to optimum cutting performance. A sign that it is time to do this is if your saw tends to drift when it did not do so in the past on a similar cut, with a good blade installed.
Next, check the blade guides. If your blade guides are damaged, then they may be allowing the blade to drift off line. Most saws have a set of lower and upper guides. Some are small rolling bearings (on more expensive saws) but on a tabletop saw these are probably metal, held in place with a set screw.
The blade can actually wear the guides away from friction. The metal guides can often be reversed before they need to be replaced, but they are inexpensive to replace. You can usually find a non-metallic (slippery) replacement for those guides, which runs a bit cooler. This is good because less heat means your blade will run more cooly, so live longer before it dulls.
Finally, check the tires. Your saw has rubber (or plastic/polyurethane) tires that the blade runs on. There will be either two or three such tires. After a few years time, these tires dry out. The saw will then start to behave poorly. Those tires can be pulled from the wheels and replaced.
The users manual for the saw should have all the information you need to get the saw setup. This is important because each model of saw will have different guidelines. If it is new saw such manual should have been in the box with the unit.
For a used saw that you purchased at some auction, sale or craig's listing there was not likely a users manual delivered with the unit. :^(
There is help available on line though. Do a search on "Delta Bandsaw Users Manual" will turn up a good bit of information.
One link I found was here.
Key items that they list that would be applicable to band saws:
- Ensure the blade is the correct length
- Make sure the teeth are pointing in the right direction (up/down) when blade is installed.
- Set the tension levers to apply tension to the blade
- Hand rotate the tires that the blade rotates on to see if the blade tracks and centers.
- If there problem then check the blade tension and adjust if necessary
- Finally if the blade seems to want to come off the wheels it will be necessary adjust the coplanarity of the wheels to make sure that they are correct.
Best Answer
Check your lower blade guide. Blade guides are either blocks or small roller bearings. To be out that much, I suspect that someone didn't reset the guide after the last blade change, or perhaps the block has fallen out.