4 by 6 horizontal band saw not cutting straight vertically

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dansawyer

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The saw is an older 4 by 6 horizontal saw. The issue is on a three inch vertical cut of 1/8 mild steel the cuts starts square for the first 2 inches and then slowly arcs out. The final deflection in the last inch is about 20 thousands.
I have tried adjusting the band tension and the cutting pressure.
The bearing guides are turned to twist the the blade to cut inward as far as they will go. The guides are ground and have very little range of adjustment.
What affects the vertical cut? Blade tension? Feed tension?
Is the only way to change the cutting angle to grind the guide ways to allow additional adjustment angle?
Dan
 
How is the feed rate controlled? Kinda sounds like its being pushed through the cut as the saw goes from vertical to horizontal position which may be due to a weak spring or air shock,if that makes sense!
 
Worn or damaged teeth can also cause a wandering cut. The blade could still cut fine but all it takes is a few bad teeth to cause crooked cuts. Check your blade to see if any teeth look out of the ordinary.

Drove me crazy once, had a 10-14 blade on my old 4x6 with a small section of worn out teeth & no matter how I adjusted the guides it would never cut straight. When I finally noticed it I replaced the blade & problem solved.

But oddly on my current bandsaw, I damaged a 5-8 blade being lazy, it had like 3 teeth broken but it still cut straight, just a lump as the blade came around to that section.
 
Thank you Mikey & MontanaLon for the link to the Pitken procedure.
I would add have a very close look at the guides themselves. My bandsaw used shielded bearing and eventually they started semi-seizing and I had tracking problems. Replaced with sealed bearings and no problems. On inspection the outers of the originals had worn to be tapered.
 
NortonDommi said:
My bandsaw used shielded bearing and eventually they started semi-seizing and I had tracking problems. Replaced with sealed bearings and no problems. On inspection the outers of the originals had worn to be tapered.
Click to expand...

Couldn't agree more. I switched to sealed bearings almost from day one, too. Must be close to 15 years on those bearings and they run fine, no problems - very cheap insurance.
 
When you check your blade for uneven wear, check the side of the teeth make sure they are the same,sometimes a blade will wear more on one side that the other, causing it to wander when cutting. nothing much can be done with a blade worn on one side

Also try slowing down on the feed, often a blade will cut crooked when to much feed is used. Excess
tension should help it cut straight, but will also lead to early breakages. Too little tension can induce a crooked cut, by allowing the blade to wander.
 
Dan: What type of saw? Foreign or domestic?
20 thou in 3" isn't all that bad actually, I doubt if mine is much better
 
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