Question About Bandsaw Setup

[Ken Krawford]

I've had a Delta 14" bandsaw with riser for about 10 years. I usually have a 1/4" blade in the saw but needed to do some resawing so I changed to the blade shown. I immediately noticed that the blade was not centered in the throat plate. For the purpose of the picture, I backed the cool blocks off the upper and lower guides to show the natural resting place of the blade. The riser is still bolted firmly to the saw. I suspect the smaller blade was centered the same way but I just never noticed it. Any ideas on why the blade is so far off center? Any fixes??
Thanks.

Ken


http://img854.imageshack.us/img854/8092/img0370jj.jpg

[Neil Brooks]

As a basic "policy" matter, whenever you change the blade out, you should expect/be prepared to re-tune the saw.

It is ... what it is. Unless you're far off of centered on your wheels, I doubt there's a major problem, other than ... re-tuning. Check the position of the blade on the wheels, first, though ... just in case.

[Kent A Bathurst]

I'd urge you to get some plastic throat plate inserts, and toss that aluminum one as far as you can. :D

Notice how the side of the opening has been hit by a blade.....can't avoid that happening in my experience. Lesson learned.

[Jim Matthews]

I wonder if the blade has excess "slack" leaving curvature along the span?

If the blade cannot be fully tensioned, it will try to assume a coiled, round shape.
If I were to guess from the picture, I would say that your upper wheel tension spring isn't strong enough to manage this new blade.

[Van Huskey]

Based on where the throat plate has been chewed my guess it the table needs alignment and has for some time. Adjust the table and you should be fine. As noted you need to tune the saw whenever a new blade is put on. I would also get a plastic insert, but when you get the blade table centered on the blade you shouldn't have any issues.

[Charlton Wang]

My guess is that your resaw blade is wider and imparts more distortion on your frame which is causing the "arm" that holds the upper wheel to be more horizontal than usual and, thus, the wheel is shifted to the right. Just my guess, though.

[Van Huskey]

My guess is that your resaw blade is wider and imparts more distortion on your frame which is causing the "arm" that holds the upper wheel to be more horizontal than usual and, thus, the wheel is shifted to the right. Just my guess, though.

A quick check for that would be to check that the blade and table are near perpendicular. He may indeed be over taxing the frame but I don't think it would move the blade that far out in the horizontal. It also "appears" his blade is parallel with the guides which would tend to disprove that. If the guides and blade are in alignment and the blade my guess is still the table was never centered left to right on the blade line.

[Charlton Wang]

You're absolutely right. But I actually don't think it's perpendicular. If you look at the blade and the vertical part of the guide assembly, it looks as though blade to edge distance at the bottom is shorter than it is at the top which suggests that the guide post might actually be out of vertical.

[Van Huskey]

You're absolutely right. But I actually don't think it's perpendicular. If you look at the blade and the vertical part of the guide assembly, it looks as though blade to edge distance at the bottom is shorter than it is at the top which suggests that the guide post might actually be out of vertical.

Too hard to tell from the picture, one time I look and I convince myself it is in line, next time it seems out of line. Time for a square!

[Bruce Wrenn]

Your tires have a crown in them. Bring the blade forward on the upper wheel and see if problem goes away.

[Van Huskey]

Your tires have a crown in them. Bring the blade forward on the upper wheel and see if problem goes away.

Curious about your theory, it seems if the blade were not fully on the crown it would if anything be closer to the spine, the crown being the high point of the wheel would push it away from the spine. Is there something I am missing?

[Ken Krawford]

Thanks all for your input. I'm embarrassed to say that a quick table adjustment took care of the problem. I didn't realize that you could make slight lateral adjustments to the table. There are 3 bolts holding each trunion. All it took was loosening them and sliding the table a bit to center it.
In regards to the other concerns:
The blade was perfectly perpendicular to the table. A straight edge showed no bow in the blade so I think I had it tensioned properly.
Thanks again.

[Jim Matthews]

Awesome. Doncha love this forum?
I had know idea the table could move laterally.

[Myk Rian]

Based on where the throat plate has been chewed my guess it the table needs alignment and has for some time. Adjust the table and you should be fine.
BINGO!!
Loosen the trunions under the table, and adjust it.

[larry cronkite]

I am having this same problem except the blade is riding so far to the right that it barely touches the upper thrust bearing and completely misses the lower thrust bearing.
This seems to have happened suddenly as I had been cutting some dogwood burl.
I have replaced the tires, blade and thrust bearings and no improvement.
It is not the table because the thrust bearings are completely independent of the table.
Louis of Iturra Design (the bandsaw experts) has no ideas for me.
Anybody on the forum have any ideas?

[Jim Matthews]

Get a deadblow hammer and 'persuade' the table
back into alignment.

There's few parts that can woggle much
on any bandsaw. My guess is that the table has been
loosened and slid 'downward' under gravity.

If you give it a rap, and it moves - see above.

[larry cronkite]

Get a deadblow hammer and 'persuade' the table
back into alignment.

There's few parts that can woggle much
on any bandsaw. My guess is that the table has been
loosened and slid 'downward' under gravity.

If you give it a rap, and it moves - see above.

Do you read my post?
It is not the table. The thrust bearings are independent of the table. The blade is too far to the right with the table removed.

[Myk Rian]

That blade is not off center. The guide block is made to be adjusted for inaccuracies in manufacture.
You will notice that the shaft that bearing on is hex. You can adjust where the blade touches the bearing by pulling that shaft out, turning it, and putting it back in.

[Myk Rian]

Get a deadblow hammer and 'persuade' the table
back into alignment.
And if you break a trunion, or both, too bad?
You do not take a hammer, or and sort, to the table. Loosen the trunions and move it by hand.

The problem with this thread is we have issues on 2 separate saws, instead of having 2 threads on 2 saws.

[John Donhowe]

You don't say what make/model your band saw is (I assume Delta, since the OP had a Delta). Anyway, from my limited experience, for most if not all Delta clone types, the shaft that the thrust bearing rides on is eccentric on the end of the shaft that mounts in the bracket (both upper and lower). That larger shaft can be either round or hexagonal in cross section, and can be rotated to adjust the location of the thrust bearing shaft.

Could the mounting shaft have rotated out of position in its bracket hole, such that the thrust bearing has moved laterally out of position relative to the blade? Just a thought.

[John Coloccia]

I am having this same problem except the blade is riding so far to the right that it barely touches the upper thrust bearing and completely misses the lower thrust bearing.
This seems to have happened suddenly as I had been cutting some dogwood burl.
I have replaced the tires, blade and thrust bearings and no improvement.
It is not the table because the thrust bearings are completely independent of the table.
Louis of Iturra Design (the bandsaw experts) has no ideas for me.
Anybody on the forum have any ideas?

I've never heard of or seen anything like this, but given that it's further off on the bottom than it is on top, it suggests that something's gone wrong with the bottom wheel. What type of saw do you have? Are there co-planar adjustments on the bottom wheel? Can you post some pictures?

[larry cronkite]

I've never heard of or seen anything like this, but given that it's further off on the bottom than it is on top, it suggests that something's gone wrong with the bottom wheel. What type of saw do you have? Are there co-planar adjustments on the bottom wheel? Can you post some pictures?

The wheels are coplaner.
Attached are some photos with the table removed.
The blade is tensioned.
The saw is a Delta 28-276

309679
Lower thrust bearing ass'y

309678
Upper thrust bearing ass'y

309681
View of trunnion ass'y

309680
Another trunnion ass'y view

[John Coloccia]

I was actually hoping for some better pictures of that bottom wheel. IMHO, from what you're describing, something's gone wrong in the area of the bottom wheel. Even just looking at the 4th picture, it almost looks like the blade is wrapped around something it shouldn't be wrapped around. Maybe it's the funny camera angle, but if I draw a straight line down, it doesn't appear to come anywhere near the actual wheel. I'll bet you money if you just take your hand, and follow the band up from the bottom wheel to the trunnion, you're going to find your problem.

[Myk Rian]

It's riding on the door clip.
3/4" blade? 1/2" is really the max for these saws.