Help needed to lift bandsaw curse.

Posted by Bill Phinn 15/03/2022 22:27:12
Sadly, the bandsaw saga continues.
Earlier I was cutting a piece of 1" x "5/8" mild bright steel into T-nut sized chunks on
speed 1 on my Aldi Scheppach bandsaw. I was using a Tuffsaws Vario 14-18 blade
that has cut only about thirty pieces of steel and brass mostly smaller than the present
piece since it was fitted new around six months ago. I cut one chunk off without any
issues. I came to cut my second chunk off and the blade snapped instantaneously
as the blade contacted the work, even though I contacted the work ever so gently,
as I am always careful to do. The workpiece was very firmly clamped in the vice
and did not move. There are no broken teeth on the blade; the blade is
barely "broken in", in fact, and the teeth are virtually as sharp as they were
when the blade was first fitted.

Can any one suggest how this can be avoided in future? A lifespan as short
as this for a blade is clearly undesirable.

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I suppose the obvious answer is buy from a better supplier.

The better option is to buy blade on a reel and make your own.I have not bought
a made blade in over 20 years .

An article written by me appeared in Mew 166 August 2010
and shows how to do this just by Mig welding.
The fixture here is a piece of copper bar ,the blade is clamped in
the slot with some mole grips and mig spot welded through 2nd photo.
They last long enough sometimes to resharpen but if they do break
as in your photo you can just re weld them.

John

It may have been mentioned already, but new blades should be 'conditioned' before normal use. Conditioning slightly removes the sharpness of the teeth and lets the new blade 'bed in' without damage.

All you need to do is take 3 or 4 cuts through some large diameter mild steel bar whilst keeping a light load on the blade. The large diameter stock helps to spread the load amongst the many teeth in contact, thus restricting damage/chipping of the blade.

The various patterns you see are normal and what I get with my lovely Nebes bandsaw too.

Martin.

Thanks for the suggestion, Robin. I've done that.

I don't think Tuffsaws are bad suppliers, John. They're sending me a replacement blade in a different material to see how I get on.

It was suggested by them that the tooth pitch was too fine for the job, which I accept, but that this was the cause of blade breakage here I very much doubt.

This was their take on it:

"With the small portable bandsaws because the blades are so small then there’s not as much time between the teeth doing a cut and then coming back around for the next cut so if the tooth pitch is too fine it can put more heat into the blade than is ideal that will lead to micro fractures and blade breakage. "

Since the blade was being run at the lowest of six speeds and it was completely cool after the first cut and before the second was attempted, I don't think excessive heat can be a factor here. And, like I said earlier, the blade had cut very little material all told, so there was very limited opportunity for micro fractures to occur even if it had been overheated, which it never was.

Lastly the blade almost certainly broke at the weld, judging by the shinier metal at the location of the break.

Yes, this was done, Martin, before the blade was put into service.

Edited By Bill Phinn on 16/03/2022 18:14:10

I also have a Scheppach bandsaw bought from Aldi (internet) and it does a glorious job. I modified the vice which now is operated by a 20mm threaded leadscrew but once setup it appears to cut squarely on all I have cut with it which has mainly been heavy box section and big angle.

Just changed the blade for one from 'misterrbandsaw' (eBay) also 14tpi and cutting very cleanly. The only reason I replaced the original blade is because it had lost a tooth.

Alan

Yes, I did away with the vice's original cam clamping mechanism on mine as well, as seen here. I also made a work stop for repeat cuts using a modified mag base.

I've no problems with the saw cutting squarely; after a few initial tweaks, it cuts absolutely square. The only thing I miss is an auto downfeed. I might have to lash one up, somehow.

Last year I also bought one of these generic bandsaws (seems only the colour is different, mine is red). And I also broke the blade on a simple cut, It looked just as in Bill's picture above. Nothing to lose, much to gain I thought and used the technique of grinding the ends in wedge form and soldered the blade with silver solder. Lost about 12 mm in length, I think after a second incident it would be too short. I first was a bit afraid because the soldering looked not very reliable (gas bottle was almost empty), but after some grinding the blade moves now through the guides with only a slight thump. I did already some cuts and up to now all is ok. Two replacement blades (quite expensive here, about 9 blades equals the price of the saw) resting in a drawer now.

Kind regards,
Hans

Edited By Versaboss on 16/03/2022 22:06:27

I got my bandsaw when I changed workshop. The exiting tenant sold me his steel collection and his bandsaw at bargain prices. I failed to smell the rat.

I eventually decided some bandsaws are simply cursed.

After a year or so I managed to exorcise mine by becoming bored while waiting for Hermes and whiling away the time taking it apart. Once I uncovered the fault it was stupid and very easy to fix.

If you require divine intervention with your saw, I recommend Hermes. Buy something vital to your project with SpeedPAK Economy China mainland shipping. That should do it