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Bandsaw blade drift - it's pretty bad

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Forum topic by abehil posted 12-05-2015 08:09 AM 1283 views 0 times favorited 29 replies Add to Favorites Watch
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abehil

104 posts in 801 days


12-05-2015 08:09 AM

I’ve got an old 14 BS I got recently on CL. I’m going over it to get it tuned up.

I have a big drift problem. There are several different symptoms that I don’t know how to interpret and not sure which should be adjusted and which can be ignored and/or which to adjust first, second …

Blade is centered on top wheel but rides forward on the bottom wheel. In order to get rid of blade tilt (forward/backward) so the blade would be 90 degrees against the table I adjusted the tilt of the top wheel. Performed a test cut and the drift is so bad I had to adjust the Kreg fence as far as it would go.

The wheels are obviously not coplaner but also I don’t think the shafts are vertically aligned. I think they are off by about 1/4” off making the blade tilt sideways. Again, it’s an old saw and I have no idea whether bandsaw wheels must/should be aligned or not so I would appreciate guidance. I mean, there is a 1” bolt that attaches the top wheel assembly to the lower part of the BS and I suppose I could loosen that and move the entire upper wheel assembly forward or the right or whatever. But I don’t want to do that unless someone thinks that is the right thing to do to fix really bad drift.

Also I’m using a 1/2” blade that came with the saw and I’m not sure it’s tensioned correctly. I set the tension to the 1/2” mark but without the cool blocks literally almost touching each side of the blade it twists a lot when cutting. I don’t want to accidentally break the blade but it seems to me like it needs more tension. How can I be sure how much is correct. The former owner had to replace the tension bracket about 6 months ago if that makes any difference.
I put on cool blocks and set the guides and thrust bearing to the right location so I don’t think they aren’t part of the problem.


29 replies so far

View daddywoofdawg's profile

daddywoofdawg

1010 posts in 1037 days


#1 posted 12-05-2015 08:40 AM

98% of the time you need to tension the blade to at least the next size up from the blade size you have on.1/2” blade, tension should be for 5/8” or 3/4”.the tension guide is just a guide.
How do the tires look? may need to replace them
Have you checked if the table is square to the blade,
Have you looked at the youtube bandsaw tune up videos?
Have you checked to see if all the bolts have been replaced and tighten after the tension replace the former owner did?

View mmax's profile

mmax

177 posts in 2918 days


#2 posted 12-05-2015 08:57 AM

This was recently posted, but I think after watching this you can solve much of your issues.

https://www.youtube.com/watch?v=wGbZqWac0jU

-- Always remember you're unique, just like everyone else

View abehil's profile

abehil

104 posts in 801 days


#3 posted 12-05-2015 09:10 AM



1. 98% of the time you need to tension the blade to at least the next size up from the blade size you have on.1/2” blade, tension should be for 5/8” or 3/4”.the tension guide is just a guide.
2. How do the tires look? may need to replace them
3. Have you checked if the table is square to the blade,
4. Have you looked at the youtube bandsaw tune up videos?
5. Have you checked to see if all the bolts have been replaced and tighten after the tension replace the former owner did?
- daddywoofdawg

1. Thanks, I’ll increase to the 3/4” mark and try again.
2. The tires are not bad I think. They are ureathane.
3. The table is slightly off. There is a bolt that is supposed to stop it at zero and I’m going to adjust it ever so slightly.
4. I have watched the tuning videos. They allude to drift don’t go into detail about how to eliminate drift.
5. I think they were tight. I’ll check again.

Should the wheel shafts be vertically aligned or is that usually fixed by just tilting the table?

Is there a point where adjusting drift by angling the fence becomes too much and something else has to be done to eliminate some of the drift?

View Blackberry's profile

Blackberry

17 posts in 616 days


#4 posted 12-05-2015 11:11 AM

As mentioned before often times it’s a lack of proper tension. Additionally is it a new or used blade? If the blade has been used the set may be out of it and it’d drift.

View webwood's profile

webwood

626 posts in 2713 days


#5 posted 12-05-2015 11:57 AM

coplanar is critical with drift , sounds like the bottom wheel needs to be shimmed outward

-- -erik & christy-

View Jim Finn's profile

Jim Finn

2409 posts in 2384 days


#6 posted 12-05-2015 11:59 AM

In my experience drift encountered while re-sawing is caused by a dull re-saw blade 100% of the time. I re-saw a lot and now use “Supercut” 1/2” carbide re-saw blade.

-- "You may have your PHD but I have my GED and my DD 214"

View HarveyM's profile

HarveyM

92 posts in 1485 days


#7 posted 12-05-2015 12:22 PM

Here’s a good article on how to rehab an old bandsaw:
http://vintagemachinery.org/files/PDF/FAQ/1993-FWW78-79.pdf

As the author says, don’t think of it as buying a bandsaw on CL, but buying a CL bandsaw kit.

-- Just a Duffer

View johnstoneb's profile

johnstoneb

2143 posts in 1635 days


#8 posted 12-05-2015 12:47 PM

Co planar is not that critical to anything. You can adjust wheels so they are coplanar and as soon as you adjust the tracking the wheels are no longer coplanar.
Jim Finn is right on. You have a dull blade or uneven set.

You can’t tune a bandsaw with a dull blade. First replace the blade then go thru the tuneup procedures.

-- Bruce, Boise, ID

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Glastron

14 posts in 468 days


#9 posted 12-05-2015 12:48 PM

I’m a plus one for mmax suggestion and video, by watching Alex’s videos it has removed all issues that I’ve had in the past.

View JAAune's profile

JAAune

1640 posts in 1779 days


#10 posted 12-05-2015 10:41 PM

As others have said, it’s almost sure to be a bad blade.

I set the tension to the 1/2” mark but without the cool blocks literally almost touching each side of the blade it twists a lot when cutting.

- abehil

Regarding the above, the cool blocks are supposed to be as tight as you can get them without them actually pinching the blade. The closer the better but just make sure the blade still moves freely through the guides.

-- See my work at http://remmertstudios.com and http://altaredesign.com

View abehil's profile

abehil

104 posts in 801 days


#11 posted 12-05-2015 10:51 PM



coplanar is critical with drift , sounds like the bottom wheel needs to be shimmed outward

- webwood

Ok, I took off the lower wheel which as it turns out is way easier than I thought it would be. A 1/2” long Philips head screw in the center was all that was holding it onto the shaft.

The shaft measures at 20mm so I picked up a hardened washer 20mm id, 35mm od and that moved the wheel out about 3/32. So now the blade is running on the center of both tires. The drift is mostly all gone but the blade still turns when cutting anything over about 1”. I’m noticing that the blade teeth seem to catch more on the left like right side wore down somehow. It’s a used blade that came with the saw.

I want a new blade to be able to resaw for 3-1/2 inches, maybe 4 inches thick.

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abehil

104 posts in 801 days


#12 posted 12-06-2015 12:30 AM

I’ve ordered a 1/2” Wood Slicer. Can’t wait until it gets here.

View Jimbo4's profile

Jimbo4

1432 posts in 2225 days


#13 posted 12-06-2015 03:23 AM

You really need to watch the video that mmax suggested. like johnstoneb says, coplanar is not the problem.

-- BOVILEXIA: The urge to moo at cows from a moving vehicle.

View rwe2156's profile

rwe2156

2192 posts in 943 days


#14 posted 12-06-2015 12:47 PM

Wandering cuts when resawing: two most common factors: blade guides set incorrectly, tension too low. Also caused by feed rate too fast, incorrect blade (heating up and flexing). After you get your resaw blade, you will see a huge difference.

That video is great with one exception: blade drift. I think he is oversimplifying that. I’ve owned several bandsaws and I have never been able to eliminate drift with blade tracking. It might be the tires or the wheels, but in the machines I’ve owned I can’t do it.

I’ll give you my opinions based on my meager experience.

If the blade is not square to the table (either way) adjust the table NOT the tracking.
A lot of people don’t pay attention to squaring the blade edge, just the side.
Don’t make any adjustments to the table until you’ve got the blade sorted out and set.
Check your table frequently ESPECIALLY after changing blades.

When adjusting the tracking make SURE you got the rear blade guides backed off or you will end up flexing the blade with will wreak havoc with blade tracking when sawing.
OR, adjust it so the blade is definitely forward of the rear guide, then gradually bring it back by adjusting the tracking inward.

You definitely need to tension the blade way past the manufacturer’s mark.
If you’re concerned about wearing out the spring by leaving it compressed, you can back it off between uses.

Referring to what I said before, 90+% chance you will have to adjust your fence for drift, but it shouldn’t be more than a few degrees off. If you’re having to make extreme adjustments in your fence, I would check the alignment of your blade guides.

If you’re machine has guide blocks, take them out and make sure they are square. You can sand them back to normal or change ends.

-- Everything is a prototype thats why its one of a kind!!

View webwood's profile

webwood

626 posts in 2713 days


#15 posted 12-07-2015 04:35 PM


coplanar is critical with drift , sounds like the bottom wheel needs to be shimmed outward

- webwood

Ok, I took off the lower wheel which as it turns out is way easier than I thought it would be. A 1/2” long Philips head screw in the center was all that was holding it onto the shaft.

The shaft measures at 20mm so I picked up a hardened washer 20mm id, 35mm od and that moved the wheel out about 3/32. So now the blade is running on the center of both tires. The drift is mostly all gone but the blade still turns when cutting anything over about 1”. I m noticing that the blade teeth seem to catch more on the left like right side wore down somehow. It s a used blade that came with the saw.

I want a new blade to be able to resaw for 3-1/2 inches, maybe 4 inches thick.

- abehil


new woodslicer and adjust all your guides

-- -erik & christy-

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