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Why Does My Blade Drift?

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Forum topic by kaschimer posted 02-01-2012 06:54 PM 2207 views 1 time favorited 17 replies Add to Favorites Watch
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kaschimer

89 posts in 1856 days


02-01-2012 06:54 PM

Topic tags/keywords: question bandsaw scroll saw scrollworking

OK so I have an issue. It’s probably me, but I wanted to get some input because I honestly have no clue…

Proble occurs with both my bandsaw (cheapie 10” Craftsman I inherited) and scrollsaw (cheapie craftsman I inherited).

Whenever I am cutting, the blade tends to drift to the right of the cut. To the point where I have to turn the wood radically to straighten out, then turn back.

The net result is, my cuts look like they were done when I was 3 sheets to the wind!

What the heck could possibly be wrong?

-- Steve, Michigan - "Every piece of work is a self portrait of the person who accomplished it - autograph your work with excellence!" - Author unknown


17 replies so far

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cloakie1

204 posts in 2022 days


#1 posted 02-01-2012 06:58 PM

if you have an old blade in there the chances are that there isn’t much set on one side hence the drifting…or the fence hasn’t been set to accomodate the drift…others will be able to explain how to set it better than i can…but for a start try a new blade

-- just get stuck in and have a go!!!

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Ripthorn

1406 posts in 2452 days


#2 posted 02-01-2012 06:58 PM

I’ve been fighting this some too. On my bandsaw, I think it is a combination of a 30 year old tensioning spring coupled with a cheap blade and poor guides. Consider me subscribed.

-- Brian T. - Exact science is not an exact science

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Bill White

4457 posts in 3427 days


#3 posted 02-01-2012 07:15 PM

Set up and tensioning coupled with quality blades go a long way in solving these problems. It takes some time and study to get these accomplished, but the effort is worth it.
Sometimes the saws just can’t be “fixed”.
OR: (my humor for the day)
Get three more sheets, and don’t worry about it…..................BOOOOOOO! Just couldn’t help it.
Bill

-- bill@magraphics.us

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SnowyRiver

51452 posts in 2947 days


#4 posted 02-01-2012 07:26 PM

I agree with everyone. The blade tension may not set up correctly, the blade guides could be worn or not adjusted correctly, or you might have either a slightly bent, or dull blade. Another thing to check is the tires on the wheels to be sure they arent worn.

-- Wayne - Plymouth MN

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kaschimer

89 posts in 1856 days


#5 posted 02-01-2012 07:33 PM

Well, regarding the tires… yeah it turns out they are fairly well dry-rotted…. so, I guess I will replace those first, then try adjusting the blade guides and tension to see if it will correct. I adjust the tension now and the blade pops off the wheels. Had me to the point where I was ready to throw it out the basement window.

Hopefully the advice will help with the bandsaw, but I’m not so sure about the scroll saw. I tried adjusting the tension on the blade. No help. I tried a new blade, and that seemed to help it cut straighter, but then after a little while of cutting, it would go back to the same problem. Is it possible that a scroll saw blade could dull that quickly (like in the neighborhood of 10 minutes or so)?

-- Steve, Michigan - "Every piece of work is a self portrait of the person who accomplished it - autograph your work with excellence!" - Author unknown

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MrsN

975 posts in 2993 days


#6 posted 02-01-2012 07:41 PM

The way scroll saw blades are manufactured produces a burr on the right side of the blade (it might be the left, but the concept stays the same) this burr causes the blade to drift slightly. So when making a straight cut, you actually are turning slightly to the left. It is one of the reasons cutting a straight line on a scroll saw is so difficult. so it isn’t you, it is the blade.
When cutting on a scroll saw the exact size isn’t usually critically important, it just needs to look straight/smooth. It is usually best to not quickly change direction to get back to the line, rather slowly correct the cut. if you make lots of straight cuts on a scroll saw (I use mine all the time) you get used to the angle that you need to use to make a straight line, and can cut a pretty straight line.

-- ----- www.KNWoodworking.com ----- --

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kaschimer

89 posts in 1856 days


#7 posted 02-01-2012 07:47 PM

Ah! Yes, I do have to turn the piece to the left in order to make a straight cut!

To be honest, I was using the scroll saw because of the issues with my bandsaw, and the cuts I was making were for flooring that we put in this weekend. Luckily, the cuts I made will go under show molding, so my “drunken” cuts will be hidden. AND, I’ve not really used the scrollsaw much before this weekend.

It was just very frustrating. I did, however, get really good at making cuts to go around door trim… lol

It’s old, too. The boots that are supposed to cover the arms are dry-rotted. I think I need to take some time and restore both tools.

-- Steve, Michigan - "Every piece of work is a self portrait of the person who accomplished it - autograph your work with excellence!" - Author unknown

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Dallas

3599 posts in 1954 days


#8 posted 02-01-2012 07:49 PM

Maybe not much help but are you certain that the blades are perpendicular to the table?

On the band saw, if the blade pops off the wheel it sounds like, (to me at least), that the wheels aren’t concentric.
I have a 1970’s vintage Craftsman 12” band saw that had a problem with blades coming off. I looked at a lot of different fixes until I figured out that the wheels weren’t lined up with each other. They were about 1/16” off. Once I fixed that they stayed on and the problem went away.
As was stated above, look for a weak tensioning spring. There was a thread not to long ago about tensioning. I extolled the virtues of using a digital caliper clamped to the blade to set the tension and have since learned a it more, although I have learned a few things about doing that that may make some differences using smaller or larger blades, the basic principal is still the same.

Good Luck to ya’!

DF

-- Improvise.... Adapt...... Overcome!

View hhhopks's profile

hhhopks

645 posts in 1844 days


#9 posted 02-01-2012 08:44 PM

I agreed that it is a tuning issue. You should able to gooble about band saw setup. All the bearing guides and guide blocks requires proper setting. As mentioned previously by others, the tires and wheel alignment impacts your cut as well.

I was told not to trust the gauage that comes with the saw for tension. I believe the old timers go by deflection.
Anyone know what that is?

-- I'll be a woodworker when I grow up. HHHOPKS

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BilltheDiver

250 posts in 2353 days


#10 posted 02-01-2012 09:38 PM

If your scroll saw will accept blades with no pins in the ends, you might try the “PGT” blades from Olsen. These blades do not have the burr that MrsN referenced and will cut a straighter line without drifting. They are a bit more aggressive than standard blades also.

-- "Measure twice, cut once, count fingers"

View DamnYankee's profile

DamnYankee

3297 posts in 2029 days


#11 posted 02-01-2012 10:03 PM

Get a book. a manual, or similar for setting up the BS
That said…
New tires
Make sure your wheels are co-planer
Check guides – make sure they are not pushing left/right

Older BS will have drift and all you can do is minimize it. However, there are ways to figure out what yuor drift is and set you fence to compensate.

-- Shameless - Winner of two Stumpy Nubs Awards

View stefang's profile

stefang

15512 posts in 2801 days


#12 posted 02-02-2012 12:34 AM

Good advice about getting a book on how to set-up your BS

If your bandsaw is adjusted properly:
1. guides adjusted (loosen top & bottom guide before you tension your blade).
2. wheel tires in good shape (dirty or worn out?).
3. Tension correct
4. Sharp blade
5. Top and bottom wheels planar. this can be hard to check, but if your blade is centered on the top wheel it should be centered on the bottom too. or check it with a straight edge if that is possible.

And lastly and very important that your blade is near perfectly centered on the middle of the tires. In all but the larger machines the tires are crowned and if the blade isn’t centered it will be runing at an angle. If this last item is done properly you will probably not have to adjust your fence for drift.

-- Mike, an American living in Norway.

View JAAune's profile

JAAune

1646 posts in 1784 days


#13 posted 02-02-2012 04:52 AM

Stefang’s point about centering the blade on the wheel is key. Ever since I learned that trick I’ve never adjusted a bandsaw fence a second time. If the table hasn’t been knocked out of position you should be able to just align the fence to the miter slot, center the blade on the upper wheel and be done.

If the blade is dull (leaves burnt sawdust) then you’ll probably get drift no matter how much the saw is adjusted.

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

View William's profile

William

9906 posts in 2309 days


#14 posted 02-02-2012 05:08 AM

Here is a good article on the right leaning blade drift you mention on the scroll saw.
And here is a good article on how scroll saw blades are made.

-- http://wddsrfinewoodworks.blogspot.com/

View cloakie1's profile

cloakie1

204 posts in 2022 days


#15 posted 02-02-2012 07:30 PM

i usually check the tension by placing my thumb on one side and index finger on the other and then squeezing them together…if the blade moves easily then it needs more tension.but i found that it doesn’t want to not move at all either or you will starting breaking blades but a good squeeze and feel a very slight movement and it is about right.i don’t use tension guides at all actually i don’t think our machine has one come to think of it…
anyhow works for me

-- just get stuck in and have a go!!!

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