Bandsaw blade busted in 2 - "BAM" but why??

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Forum topic by becikeja posted 12-29-2015 01:41 PM 878 views 0 times favorited 12 replies Add to Favorites Watch
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868 posts in 2779 days

12-29-2015 01:41 PM

This was a first for me. I was cutting out a template in cardboard. Was about 90% completed and “BAM” the blade busted in 2. Luckily the blade stayed completely inside the bandsaw housing so there were no safety issues.

In over 25 years of woodworking as a hobby, I have never had a bandsaw blade bust before, maybe I’ve just been lucky. But it does bring up a couple of questions.

1) Is cardboard extra hard on blades for some reason? This doesn’t seem reasonable, but curious.
2) My shop used to be in a basement with a relatively controlled temperature. This is no longer the case since moving south with no basement. The temperature in the shop fluctuates. I keep it around 60-65 in the winter when I am out there, but it gets as cool as 35-40 during the winter months when I’m not working. In the summer the shop gets to around 80-90 on really warm days. I try not to keep tension on the blade when not in use, but don’t always remember to take the tension off. Does this have a negative impact on the blades. Is there something I should change?

Appreciate any comments thoughts?

-- Don't outsmart your common sense

12 replies so far

View bigblockyeti's profile


5093 posts in 1686 days

#1 posted 12-29-2015 02:11 PM

Did it break at the weld or somewhere else on the blade? What size (width & thickness) is the blade? What make & model saw are you using? Pictures?

View becikeja's profile


868 posts in 2779 days

#2 posted 12-29-2015 02:26 PM

I have a Powermatic 14” bandsaw, 3/16” blade. The blade was made by Carter. I can’t find a weld, so maybe that’s where it broke, but it doesn’t look like there was weld there. Broke clean – straight across.

-- Don't outsmart your common sense

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5093 posts in 1686 days

#3 posted 12-29-2015 02:37 PM

Any idea how long the blade was run for before the failure?

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792 posts in 2364 days

#4 posted 12-29-2015 02:47 PM

becikeja – In the first place, yes, you have been extremely lucky. Blade breaks are scary aren’t they? Based on what you have stated the break was probably caused by metal fatigue especially if you have been running it for some time.

-- Roger M, Aiken, SC

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868 posts in 2779 days

#5 posted 12-29-2015 03:34 PM

Here is a pic of the break. I did find the weld, it’s about 6 inches down from the actual break. The blade is probably about 4 years old, no clue how many hours are on the blade, but I would say less than 20. I don’t use this one very often.

I guess I am pretty lucky, that I have not had to deal with a break before. It was scary, but the housing did it’s job.

-- Don't outsmart your common sense

View bigblockyeti's profile


5093 posts in 1686 days

#6 posted 12-29-2015 05:57 PM

Sometimes it just happens. The blade after breaking doesn’t carry much energy, the bang is the upper wheel suddenly being allow to jump to the upper stop after the tensioning spring is no longer held down by the blade.

View MrUnix's profile (online now)


6590 posts in 2164 days

#7 posted 12-29-2015 06:00 PM

A straight break indicates too much tension or fatigue. Fortunately, as you found out, breaking a blade on the band saw doesn’t do any real damage other than to your nerves when it scares the crap out of you :)


-- Brad in FL - In Dog I trust... everything else is questionable

View Sandra's profile


7207 posts in 2040 days

#8 posted 12-29-2015 06:14 PM

I went through this earlier this year. With the help of LJs I’ve concluded that I was over tensioning to make up for bad tracking and I had worked theblades past a normal life span. Im now keeping rough track of how many hours or linear feet the
blades are being used.

FWIW- thw third break scared me as much as the first two!

-- No, I don't want to buy the pink hammer.

View KWood75's profile


10 posts in 872 days

#9 posted 12-30-2015 12:50 AM

I had one go on me last year but it broke at the seam. I wasn’t even cutting anything at the time. I had turned it on and was getting ready to make a cut.

Looks like it’s time to test your brazing skills out on that blade.

View gfadvm's profile


14940 posts in 2655 days

#10 posted 12-30-2015 01:39 AM

I have broken blades on all my bandsaws. Widths ranged from 1/8” – 1 1/2”. I have never had a SHARP blade break.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Planeman40's profile


1152 posts in 2726 days

#11 posted 12-30-2015 04:44 PM

Blade breaks on bandsaw blades happen. It is nothing unusual. In this case most likely due to over-tensioning as mentioned above. Also, poor welding-annealing of the blade joint can be a factor. In any case, just install another one and move on. The blade CAN be re-welded if you take it to a place that has the equipment (and knows what they are doing). You can also silver-solder (braze) the blade back together yourself using a propane torch and REAL SILVER brazing wire (usually obtained at a welding supply store). You have to grind the ends of the blade to taper them for a “scarf” joint and carefully align them prior to brazing. This requires a home made jig of some kind. The usual process is to cut off a small piece of the silver wire and hammer it flat. Apply silver solder flux to the joint and position the blade joint in the jig aligned accurately. Insert the flattened silver wire between the blade ends. Then heat the joint with the propane torch until the piece of silver wire melts. Quickly clamp the joint together with a pair of pliers and hold the joint tightly until the melted silver hardens. A little work with a file to dress the joint true and smooth and you are back in business.



-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

View jumbojack's profile


1674 posts in 2589 days

#12 posted 12-30-2015 05:02 PM

The first one is ALWAYS the worst one but they all carry the ‘ohcrap’ factor. Just last night the belt sander belt broke. While not quite as nasty as the BS blade going it did elicit the ‘ohcrap’ response.
May 2016 bring you ever lasting BS blades and plane irons that never dull.

-- Made in America, with American made tools....Shopsmith

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