undergroundhunter":279428rk said:
I just need to sort the squareness to the back of the blade.
And I said...
I can't easily get the front back angle of the blade to stay at 90deg to the table, this is because it changes as the tracking is adjusted: the top wheel has to move! It's close enough and as long as the side-to-side thing is sorted, there's rarely an issue.
I didn't make myself very clear: the front-back angle of the blade to the table changes with blade tension and tracking. The effect is a lot less on bigger saws (but sadly mine is only 12").
You might shim the table; you might also improve it by altering the position/alignment of the bottom wheel (depending on how that is fitted - I understand some don't have adjustment). The trouble is that, with a steel-box-section frame, it is educated guesswork. You can only make the really fundamental adjustments without a blade in place, when the frame is not under tension.
If you think of the frame as a capital "C", the forces act in two ways: The obvious one is to pull the two arms of the C together so as to close it up. This moves the blade left-right across the table, it may also tilt it.
The not-so-obvious one is the twisting force exerted, because the wheels are hung off axles that stick out sideways from the frame.
Viewed from the front, as you increase the tension, the top guides move to the left and backwards. The table tilts so that the front moves upwards, and (left-right) very slightly anticlockwise. On my saw, with a 5/8" resawing blade fitted (the biggest that is sensible), the guide movement effect is really obvious.
None of the above is mentioned in Mr. Snodgrass's popular video. But he is using (selling?) bandsaws with cast frames, which are inherently far more rigid than 98% of the hobby saws available here. Setting up a box-section frame is far more complex than he would have you believe
if you do it thoroughly. It took me around 1 1/2 days to get mine set up the first time I did it (after a thorough strip-down, clean and fettlement). I really need to do it again now.
By the way, It does seem like your table is dished or something. If your square is correct and you are checking left-right
without the plastic throat plate in place,
and the two sides of the table are aligned (totally coplanar) at the front edge when the fence rail is in place, then that is the most likely reason you get different "squareness" when checking from either side. Even if your square was off, if your table was dead flat you would see a mirror image of any error from the square itself when checking either side.
E.
PS: Given it's cast steel, it's remarkable how easily I can bend the table on mine. I usually slide the butt end of the engineer's square across the join from both directions to check it, all along the slot. If it catches, the thing is twisted.
Once I'd discovered them I immediately removed the washers/shims I had in place till then.
