Band Saw Blade flexes in cut

[Greg Caputo]

Title describes the problem I'm having and can't seem to correct. Whether ripping 3/4 inch stock or trying to resaw a 5 ince piece of cherry, the blade starts out just fine but quickly begins to flex in the cut. I've corrected for drift and I've tried different levels of tension. No help. Using a 1/2 inch, 3TPI blade, on a 14-inch Delta bandsaw with riser. Timberwolf blade. Relatively little use since I normally use a 3/8 inch blade for most things. Thanks for any thoughts you can send along.

Greg

[Richard Coers]

My first suggestion is to slow down the feed rate to see if that helps. Most folks I watch feed way to fast. If there is sawdust left in the cut, slow down. Cut is very clean, just right. Relatively little use doesn't mean the blade isn't dull. If you don't have the issue with a 3/8" blade, but do with the Timberwolf, the Timberwolf is dull. Is the flex in a side direction, or is the cut barrel shaped?

[Greg Caputo]

The flex angles in one direction, towards the front of the saw. I generally use a pretty slow feed rate, so perhaps it's a dull blade? Really appreciate the response.

[Myk Rian]

If the blade has so much as touched metal, then it's not going to re-saw.
I use hardwood guide blocks. That way I can bury the blade in them for great control.

[John Bailey]

This is just my opinion, but I don't think most of the Delta 14" and clones do well with 1/2" blades. Unless you've replaced, the tension spring with a more robust spring, it won't tension enough. I had the same problem when I had my Delta 14" when I tried using a 1/2" blade. One day, out of pure laziness, I cut an 1/8" slice off of a 5" piece of Teak using my standard everyday 1/4" blade. It sliced it off nicely.

You may want to try using the 3/8" for your resawing -- or even a 1/4". Also, it would be a good idea to replace the tension spring with one of the more robust springs available now. I just ordered one from Iturra Designs for my similar, but larger, Oliver 192-D, and Carter sells one called the Cobra Coil.

One nice thing about ordering from Iturra is you can ask for their catalogue. It's as much a reference source on 14" bandsaws as it is a catalogue.

Hope that helps.

John

[ian maybury]

Can't comment on tension as no experience of the saw type - but I went to considerable trouble to import a few of those blades a couple of years ago - and all had misaligned welded joints (flat and smooth looking, but angled backwards) which caused them to cut crooked. Perhaps not the case with yours, but worth a check. Unequal tooth set can do it too.

The other is to check that the blade is tracking at the same point on the crown of the wheels as worked before. If it's off to one side (has wandered down one side of the crown) the effect is to misalign/twist the blade away from the previous line of cut. Correcting for drift should have compensated for this, but it seems sometimes to be best with more highly crowned wheels to keep the blade centred or wherever has been working. i.e. to reposition the blade using the wheel alignment adjustments to correct drift rather than vice versa.

If the saw has been OK on other blades and is tracking right then the blade itself is probably a good first suspect...

ian

[Gus Dundon]

Are you sure you had enough tension on it? Is that a new blade?

[Jim Rimmer]

I don't want to blast the TW blade because they make good stuff but my experience with the blade was not good. Got 2 (free replacement for the first one with bad weld) and couldn't get a good resaw. Went to the Woodslicer and have great resaw cuts.

[Greg Caputo]

I replaced the tension spring several years ago with a heavier duty one. (From Iturra, I believe.) Do they wear out? I'm going to try John's suggestion about switching to a 3/8 inch blade to resaw. Thanks for all the great ideas.

[Sam Stephens]

my guess is the blade as well. if the saw is set up well, guides and what not, and other another blade doesn't have this issue, it's probably the blade. 3/4" thick wood should be like cuttin butta. you could double check your thrust bearings and make sure there's not a bunch of gunk/buildup creating a hang up as well.

[Myk Rian]

This is just my opinion, but I don't think most of the Delta 14" and clones do well with 1/2" blades.
Sorry, but you're 100% wrong.
I use a 1/2" blade on mine w/riser, and can re-saw all day long with it.
If you don't know how to set the saw up, you'll have a hard time with it.

I use a 1/2" 3-4tpi blade, and tension it with the flutter method. Been doing it for years.

[Lee Schierer]

I suggest you try tuning your saw the way this guys suggests. It worked wonders for my saw with a blade I thought was toast.

Bandsaw Tuning (http://www.youtube.com/watch?v=wGbZqWac0jU)

Try not to analyze what he is saying compared to what you may have read about bandsaw tuning and just try his method.......I think you'll be pleased.

[Noel Poore]

+1 on the video. The best cuts I have made were all after watching this video.

Noel

[Jack Gaskins]

14" bandsaws and the tensioning system are pathetic.........IMHO.

[Myk Rian]

Horse apples

[Gus Dundon]

I replaced the tension spring several years ago with a heavier duty one. (From Iturra, I believe.) Do they wear out? I'm going to try John's suggestion about switching to a 3/8 inch blade to resaw. Thanks for all the great ideas.


Yes, tension spring will wear out. 1/2" blade should be easy to tension on 14 inch bandsaw. Have you tried using different blade?

[Phil Thien]

Yes, tension spring will wear out. 1/2" blade should be easy to tension on 14 inch bandsaw. Have you tried using different blade?

Properly made springs don't really wear out. Stock springs may be insufficient, the Iturra replacement springs are certainly up to the task and won't wear out unless there were manufacturing problems.

[David Kumm]

There seem to be two schools of thought regarding spring life. Some say a spring fully depressed for a period of time loses strength, others say no. I have no clue so I revert to my answer for many things. I just don't do that. Interested in the right answer though. Keep in mind that a spring is only as good as the platform it sits on and some small steel saws can't handle much more than the stock spring. Dave

[Greg Caputo]

Thanks for the link to the video! Great demonstration.

[Mike Heidrick]

Sounds like dull blade to me. Buy a small laguna RSK and try it.

[Howard Acheson]

I replaced the tension spring several years ago with a heavier duty one. (From Iturra, I believe.) Do they wear out? I'm going to try John's suggestion about switching to a 3/8 inch blade to resaw. Thanks for all the great ideas.

That saw should work just fine with a 1/2" blade intended for re-sawing. It's trying to use a 3/4" blade on a 14" band-saw where problems occur. Many, many users over the past 50 years have been re-sawing using a 1/2" blade on 14" band saws like yours.

The type of problem you are seeing is almost always caused by a dull or damaged blade. I would purchase a new 1/2" blade, install it and carefully align your saw. You should not have to replace any springs. Over tensioning can cause a number of problems with small band saws.

[Gus Dundon]

Properly made springs don't really wear out. Stock springs may be insufficient, the Iturra replacement springs are certainly up to the task and won't wear out unless there were manufacturing problems.

That makes sense but I am not saying that Iturra spring will really wear out but what I know is that tension springs will eventually wear out. There are other possible reasons why his blade flexed while making his cutting , if it's not the tension ,the tracking or the blade or failure to adjust the guides .

Greg, I hope you'll figure out soon or find the solution to your problem . Goodluck :)

[Lee Schierer]

There seem to be two schools of thought regarding spring life. Some say a spring fully depressed for a period of time loses strength, others say no. I have no clue so I revert to my answer for many things. I just don't do that. Interested in the right answer though. Keep in mind that a spring is only as good as the platform it sits on and some small steel saws can't handle much more than the stock spring. Dave

If you compress a spring to solid height, it will generally lose some of its strength. I don't think they change much if you keep them partially compressed. However, it is always a good idea to de-tension a band saw between uses (if that will be a day or more) to prevent producing flat spots on the tires. YMMV.