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Welding a broken bandsaw blade. Bad idea?


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my bandsaw blade broke a few days ago and considering that hardware store trips are few and far between for me I decided to try welding my bandsaw blade which would not be to bad IF I KNEW HOW TO WELD!. I have already welded the blade, ground the weld flat and installed it. the weld seems to be holding but looks pretty scary would it be a bad idea to use it until Sunday when I get back into town?.

 

 

Lextin.

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Put it on and turn the wheels by hand. If it runs true just use it until it breaks the next time. Not dangerous at all!

 

I braze my bandsaw blades when they break. It is a bit tricky the get the joint well aligned, but if it is the blade does its job like before. If it is not the saw will run that noisy that you will stop using it just because of the noise and also because the cuts will be really awful.

But again, a blade that breaks or jumps off the wheels presents no danger at all to the saw operator  if all guards are in place and the fingers are in a reasonable distance to the running blade.

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At work we made our own blades. But we bought by the spool. First how long next squaring and welding, annealing. This was done using a fixture to keep it aligned. Now and then the weld was bad and have to start over. This shortened the blade by 1 inch each attempt. Buy a new blade it is safer.

David B

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They used to make up all the bandsaw blades where I used to work from rolls of blade stock. They were welded up on a bandsaw that had a blade grinder/welder unit built into it on the side of the machine. Provided it's annealed after welding it will be fine, that's how bandsaw blades are made! An alternative for home users are to braze the ends together which shouldn't need annealing afterwards.

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I remember bandsaws with a grinding wheel and welder built into the machine. But that was 50 years ago!!

 

Mark

It was similar to this one Mark.

 

16720_150939.jpg

 

It had a work light, blade grinder and clamping system. And had "weld" and "anneal" buttons on the panel. Not sure of the exact model of Startrite bandsaw it was or it's age but it was still in daily use when I left last year. It was mainly used to cut metal and they would quite often " "break" the blade, pass it through a drilled hole in the workpiece and then rejoin the blade to make the cut. The blade would then be "broken" again to remove it from the work. Fantastic machine, I'd have one any time except I expect it was three phase.

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Don't know what you meant by welding, there are numerous ways, but if you got the job done it must have been one of the methods that work, I would only add that you anneal that part of the blade. Run the thing, you were running it when it broke the first time. People used to know how to do a lot of things that modern man has been taught they are incapable of doing, a little fear also mixing into the teaching provides lots of jobs for people who should be doing something else. Band saw blades are cheaper bought by the roll, cut off what you need and roll your own.

jud

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I remember bandsaws with a grinding wheel and welder built into the machine. But that was 50 years ago!!

 

Mark

I am in the maintenance department where I work and we have 2 of the bandsaws with the built in blade grinder/welder to make your own blades. Most of us never seem to get it right, usually takes 2 or 3 times to get one to hold. Finally convinced the management to start buying the blades in the correct size.  SO MUCH BETTER.... Unless you are expert at brazing and grinding wait to get a new blade. With out the proper tools it is a pain.

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It realy comes down to just how many blades you use. I worked in a Tool and Die shop for the last 43 years,we had two bandsaws,with blade welders on each saw. They were electric and buttwelded the blades together.

 

The main things to get right are:

grinding the two ends square to each other

setting of the spring preasure that pushes the two ends together when the welding was done

annealing the blade after welding

grinding the weld seam down to even with the blade

Annealing the blade AGAIN after grinding

using the correct tension on the blade in use-too little will alow the blade to come off the wheels,too much will break the blade

 

I have worked with toolmakers that never could get a blade weld to hold. They just did not have an eye for seeing the right color of the blade when annealing-which is the heat range that you need to have-going thru blue to dull red,that's what worked out for me on our welders.

 

I have not seen them silver soldered,only electric welded by a blade welder.

 

A welder will not be cheap,so if you only use 5-6 blades a year,and do not saw out holes in parts,stay with the premade blades,find the correct lenght and maybe find a tool supplier in your area that makes up blades .They might be cheaper than ones that are premade one's.

 

The learning curve on bandsaw welding can be a long and fruitless indevore if you do not have the skill and luck in hitting the right combinations to welding a blade that wears outwithout breaking.

 

Note-a correctly welded blade should not break before it wears out,and even then it should not break.

 

AND MOST IMPORTANT_DO NOT USE YOUR FINGERS TO PUSH ANTHING THRU A SAW_ALWAYS USE A STICK THAT IS AT LEAST 4" THICK AND AWAY FROM WHERE YOU ARE PUSHING ON IT. THAT WAY IT WILL BE POSSIBLE FOR YOU TO STOP PUSHING AFTER IT GOES THRU WHAT YOU ARE CUTTING BEFORE IT GETS TO YOUR FINGERS AND HAND!!!!!!!!

 

i have been using machines in a shop since I was only 8 years old,and I still have ALL of my fingers and use of them. I have seen too many guys lose fingers and other parts to various machines. The saw is one of the most dangerous and unforgiving.

Just see how fast a frozen hotdog can be cut thru with a saw blade. A skip tooth will realy show you just how fast it can cut,faster than you can pull back from trying to push thru a wood part when it goes thru a soft spot.

 

Sorry about the lecture,but I have seen too many guys bleeding and having to order 5 beers using two hands instead of just five fingers on one hand.

 

Keith

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I made my living for more than 40 years as a welder and used band saws with built in blade welders in several shops. Those welders use resistance welding where electric current passes through the blade ends until molten then presses them together in an automatic process. I've broken and welded a lot of band saw blades. Like the previous poster I was the only person in any of those shops who paid enough attention to the details to get it right. There is no danger from using your repaired blade; if it breaks again the blade just stops like it did when you broke it the first time. Unlike a circular saw blade, a band saw blade isn't moving fast enough to throw shards of the blade around the shop.

 

Perhaps the best way to weld at home a broken band saw blade would be by using an oxy-acetylene torch with a very small torch tip. After cleaning and degreasing the ends, align and clamp the ends tightly together and run a fusion pass without filler metal (except perhaps a small touch at the end of the weld) on one side, let it cool, turn it over and run a fusion pass on the other side. Unfortunately, this takes a moderate amount of skill. On the plus side, there's no weld build-up to grind off and there's no need to anneal it afterwards because the torch will heat enough of the blade to allow it to cool slowly. Silver brazing won't be strong enough.

 

And please heed the safety precautions in the previous post. I got complacent with a band saw once and split a finger lengthwise from the tip to the root of the fingernail in a split second.

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Sorry, Dee Dee, but in spite of your background I don't believe you have more than minimal hands-on experience with a band saw. If you had ever used one enough to experience a blade break you would know that when a band saw blade breaks all that happens is that it stops moving, nothing else, at all, ever. I have used both vertical and horizontal band saws extensively my entire working life, have experienced uncounted hundreds of band saw breakages and have never seen nor heard of a broken band saw blade doing anything except just stop moving instantly. The entire blade except for the portion between the two sets of guide rollers where the cut is made is inside a closed box and blade guards. Using even a poorly rewelded band saw blade (as long as it's reasonably straight and properly ground) poses no more danger than using a new one.

 

Removing the broken band saw blade from the machine is more dangerous than breaking the blade. But the most dangerous part of breaking a band saw blade is unpackaging the new replacement. They are turned back into themselves to make a smaller, triple coiled, package. Have you ever seen those little round sun screens (fabric stretched over a spring wire frame) for use in a parked car that pop open into a large circle or rounded rectangle and are almost impossible to turn back on themselves into the smaller unit until you learn the trick? Same thing. The only way I've found to open those band saw packages without shredding myself is to hold the blade firmly in one leather-gloved hand while cutting off the cardboard bands securing it then toss the blade across the room and take cover. Band saw blades do not fail in anything like the near explosive, shrapnel throwing way circular saw blades can.

 

I'm in no way saying to ignore safety concerns, but I don't believe in exaggerating dangers out of ignorance. I believe that the truth serves best. I'm assuming that everyone wears safety glasses and/or a face shield using power tools. My own prescription glasses, which I need to wear all the time, have had safety lenses since I was in my 20s. Take no chances with your vision. After working for more than 40 years in a potentially very dangerous industry I have gotten into the habit of always asking myself "What if........?" before proceeding with a planned operation and changing it when needed to minimize potential dangers. I haven't stabbed or cut myself with an edged tool in many years. I learned my lessons from the safety mistakes I made on the job - and the resulting injuries and near misses - and apply those lessons to my hobbies. The best safety device is the one we have built in between our ears, but it needs education, training and consistent practice to work at its best.

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Keith: Abought only using 5-6 blades a year, I have gone though a the massive number of 3 blades in the past 5'ish years that I have had the bandsaw as I mostly use it for cutting very small pieces that put very little wear on the blade. "Note-a correctly welded blade should not break before it wears out,and even then it should not break." All of my broken blades have been sharp still when they break could I be over tension them? if so I have a bone to pick with whoever wrote the instruction manual :angry:.

 

David F: My experience with blades breaking is much the same as yours except that I usually hear the Tink.... Tink.... Tink.... sound that the blade makes just before snapping and open up the case thinking its an alignment problem, maybe I should make a sticker that reminds me that sound means the blade is abought to break.

 

 

 

Lextin.

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All of my broken blades have been sharp still when they break could I be over tension them? if so I have a bone to pick with whoever wrote the instruction manual :angry:.

 

David F: My experience with blades breaking is much the same as yours except that I usually hear the Tink.... Tink.... Tink.... sound that the blade makes just before snapping and open up the case thinking its an alignment problem, maybe I should make a sticker that reminds me that sound means the blade is abought to break.

 

 

 

Lextin.

 

Perhaps the bone to pick is with the blade manufacturer. I'd bet the blades all broke at the weld. This may be one of those items where the high dollar blade is actually the better value. You might try de-tensioning the blade one turn when finished cutting - and remember to re-tension when you go to use it again.

 

Can't comment on the Tink . . . Tink . . . Tink . . . I never worked in a shop where I would have heard it.

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You are correct a broken blade is not dangerous but getting the thing out can be.  New blades are sharp.  We use standard, metal, and serrated.  Of the lot the serrated are the most dangerous.  A razor sharp steak knife.  When changing in and out a good pair of gloves and and and safety glasses is always used.  I would yell at someone when they did not wear them..

David B

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I just looked at the broken blade and found at least 7 cracks other than where it broke, just a bad quality blade I guess.

David F: "Can't comment on the Tink . . . Tink . . . Tink . . . I never worked in a shop where I would have heard it." Did the bandsaws you worked with have guide blocks, or bearings?. I think the sound was the crack hitting the guide blocks just before snapping completely.

 

 

 

Lextin.

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All of the bandsaws, both vertical and horizontal, had roller guides as I recall. The great majority of the bandsaws were horizontal for use as simple cut-off saws. A few of the shops I worked in did a significant amount of fabrication in aluminum for which a vertical bandsaw was useful. These were the only bandsaws I saw that had blade welders.

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