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7x12 bandsaw problem, need help from another owner

Chris101

Plastic
Joined
May 5, 2024
Location
Ontario
I picked up a used 7x12 bandsaw and can not get it to cut square vertically, lowering the blade against a square I can see its out by probably a 1/4" over 6" distance.

It is a princessauto brand but same design comes with many brand labels(king, harborfreight, etc), no matter what adjustment I make it will not cut square.

Pulled the rear arm off and noticed that the pivot hole is not centered in the casting(see picture), I don't know if this is design intent or the problem.

If you have one of these similar saws could I trouble you to check if that hole is centered, it would be greatly appreciated, and thanks in advance...
 

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Blade and movement are seperate. Raise head, and lower head with square, if the gap doesn’t change it is just guide adjustments. Before adjusting guide arms set blade wheel riding to near perfect. Adjust lower then upper arm, then fine adjust guide bearings.

You are looking at paint masking on the hinge bore, that’s cosmedic.
 
Thanks for the reply, as I mentioned its the vertical movement that is out of square, it is not the blade guide squareness, that I have no problem adjusting.

It is not paint masking that I am referring to, there is a boss casted in the arm, and the pivot hole is not centered in that boss as you can see in the picture. What I am trying to determine is the hole supposed to be off center within the boss or not. thx
 
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the only place that effects motion vertically only is the bed frame pin holes. And reality is you can tweak saw bed level along x to compensate that, which I highly doubt is the issue. Even damaged pivot saws do not have that much out on those points. The bed frame would be cracked if they were. If the hinge pin is level to bed it is not that.

If your support arm was out you have a arc like error, now that it is off you will have to set and adjust it to get good motion.

Take the blade off. You can not be tempted by it when setting support arm. It is irrevelant until head swing is true and proper.

I am hesitant to say how you adjust guide arms, not the guide rolls. That part has no simple undo.

You have some work getting the saw back together and true, taking machines apart to that point is not a good idea unless you know that the problem is that far down the chain . Plumb bobs and blue tape on the floor after you level the bed near the vice.
 
Swap entire front and rear blade guide assemblies. I sold one of those saws to a friend, it was cutting straight. He took it apart to repaint and after reassembly it was way off, swapping the guide assemblies fixed it. Or if that is a new saw, maybe try returning it.
 
So you are saying even if that hole is not where it belongs that it will not affect head swing trueness to the bed? (this is head swing that is the issue not blade or blade guide related). This is a used saw, can't be returned, for all I know it could have always had this problem.

If I'm understanding this correctly, its the pivot pin holes in relationship to the bed that are not true. I will have to take another look, the saw is in fairly good condition and doesn't look like its been used much, this is maybe why.
 
In the situation I described above, I tried adjusting the guides first, it would still cut 1/4" or so off. I knew it had cut straight before, finally decided the only thing that could be different was the guides, so swapped positions on them and it cut straight again. It will take less than 5 minutes to swap them, easily worth a try. They look identical, I know it does not make sense, but at least on my old saw there was a slight difference, your mileage may vary.
 
The hinge is datum everything is based from after the fact. The part that looks off would be horizontal squaring mostly.
Wheels are next.
Guide arms after that.
Guide rollers next.
Vice pin last.

Vice can move up the tree, depends on how you approach the saw. The factory sets vice from the hinge point second.

Being multi point system there is a little back and forth- not much.

you use the blade as ruled edge only until the rollers part.
 
I have had my Taiwan saw for about 50 years and it still works fine. I can't recall ever needing to adjust anything. I think it cost me about $165 (new) and consider it a good buy. I expect the worm gear will wear out some day, maybe for the next owner, and am not worried.

I have noted that it does not cut straight if the blade is dull. I have a blade welder and weld a new blade when needed.

Larry
 

memphisjed you where right on the money, the main pivot pin was not parallel with the bed area, the whole back of the casting was slightly twisted. The twist was certainly caused by the forces of the downfeed cylinder, and not only that there are cracks where the upper casting attaches to the lower frame(see pic). I can see why many of the newer models have a horizontal mounted cylinder. I was able to remove most of the twist and looks much more square now, but I'm sure it will work its way back over time. Think I'll try making some brackets to remount the bottom of the cylinder more horizontal to the main bed casting, then the cracks wont be much of an issue. Thanks!!​

 

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