Help needed to lift bandsaw curse.

[KEITH BEAUMONTParticipant @keithbeaumont45476]

I have the Scheppach/Aldi saw. Looking at your" video I would suggest you are putting a lot of down pressure on the cut.This afternoon I have cut a piece of Ali 2.5 x1.5" without any feel of jump . If I increased the down pressure it did cause a jump every revolution. Slackening off the pressure to my normal "feel" stopped it. The blades that came with mine are M42 and look well finished. I cannot visually detect any sign of a weld in either of the two blades supplied.

Keith.

[Bill PhinnParticipant @billphinn90025]

Thanks to everyone for your replies.

Howard, thanks for that information. I think my blade is set up pretty well even without the use of a DTI, but a DTI test of the kind you mention would certainly be useful, I'm sure. I'm also pleased with the accuracy of the cuts as things currently are. Time will tell whether the blades are long-lived in my hands; after a couple of dozen cuts in steel I can't detect any appreciable wear yet.

Keith, I can say with some confidence* I wasn't cutting with excess downward pressure; if anything I was holding the saw up in the cut; what's more, on other tests, whether I held the saw up or let it sit on the work under more of its own weight made no difference to the downwards kick. I did also mention that a change of blade improved the situation considerably, and downward pressure was the same (i.e. minimal) with the second blade as with the first.

* My right arm [the arm that was holding the saw] has functioning biceps but no functioning triceps or deltoid muscles [among others], so pressing down even remotely firmly with my right arm is something I'm physically incapable of; the outcome of a bit of a bad show on a motorbike many years ago.

[Bill PhinnParticipant @billphinn90025]

Posted by John Baron on 01/03/2021 13:19:21:

Those marks suggest a bad tooth on the blade, actually two or three bad teeth that distance apart !

John, could you explain this further? The brass was cut lying flat, so I'm not sure how a few bad teeth could have caused those marks even if there were any, which by all appearances there aren't.

[JasonBModerator @jasonb]

The blade gets pushed sideways as the bad teeth enter making the one on the opposite side cut deeper on the side. You then get the opposite effect as the bad tooth exits and the blade goes back to it's normal tracking position. Could be a badly set tooth or more likely the teeth either side of the joint slightly out of line.

Bit like using a 4-flute cutter to cut a slot as the cutter deflects the following flute taks a bit of a cut.

[John BaronParticipant @johnbaron31275]

Posted by Bill Phinn on 01/03/2021 21:51:21:

Posted by John Baron on 01/03/2021 13:19:21:

 

Those marks suggest a bad tooth on the blade, actually two or three bad teeth that distance apart !

 

 

John, could you explain this further? The brass was cut lying flat, so I'm not sure how a few bad teeth could have caused those marks even if there were any, which by all appearances there aren't.

Jason got it right ! 

The fact that there are two marks in the same spot tells me that the bad tooth/teeth are on the blade in one place, coming round at the same spot each blade revolution.

Also give me a clue as to how far apart the bad teeth are.

 

Edited By John Baron on 02/03/2021 08:11:13

[Bill PhinnParticipant @billphinn90025]

Many thanks, Jason and John. Good to know this strange crop-circle-type effect has such a simple explanation.

Since this problem is with the second blade and the first is already known to be defective, I take it this means that both the blades supplied with the saw are a bit sub-standard.

Tuffsaws replacements beckon fairly soon.

[John BaronParticipant @johnbaron31275]

Posted by Bill Phinn on 02/03/2021 17:44:27:

Many thanks, Jason and John. Good to know this strange crop-circle-type effect has such a simple explanation.

Since this problem is with the second blade and the first is already known to be defective, I take it this means that both the blades supplied with the saw are a bit sub-standard.

Tuffsaws replacements beckon fairly soon.

Hi Bill, Guys,

Not necessarily defective, its far from uncommon, particularly if the blade weld is slightly out. More often you can bend a tooth just by letting the weight of the arm rest on the work when starting a cut. I've ripped teeth off forgetting to start the saw before lowering onto the work.

[BrevaParticipant @breva]

Bill,

One thing not mentioned above is that the blade may not have been welded straight. It is something that I have found on my saw when purchased. You can only really check it with the blade off the saw. Lay the back of the blade down on a dead flat surface and check that the back edges on both sides of the weld are in line, ie tight to the flat surface.

A slightly crooked weld could cause your bump.

John

Edited By Breva on 02/03/2021 20:25:52

[Alan Waddington 2Participant @alanwaddington2]

Femi NG120 ABS bandsaw is one of the best workshop investments iv’e ever made, never had a minutes bother with it, cuts clean and square every time, no matter what the material being cut. Makes all those generic Chinese clones look like junk……and i had several different flavours of them before the Femi.

Am interested to hear why you sent yours back OP ?

[Alan Waddington 2Participant @alanwaddington2]

Ah ok, followed your link to the Femi saga……..surely that is a courier issue rather than a faulty saw ? 

 

 

Edited By Alan Waddington 2 on 02/03/2021 21:07:47

[Bill PhinnParticipant @billphinn90025]

Posted by Alan Waddington 2 on 02/03/2021 20:59:02:

Ah ok, followed your link to the Femi saga……..surely that is a courier issue rather than a faulty saw ?

Alan, technically it was both, though the faultiness was almost certainly courier-induced rather than the manufacturer's doing. Amazon UK were also hardly blameless for sending out a saw to a UK consumer with a two-pin plug. The foul-up with the return was the icing on the cake.

I would have given a Femi another go if either Amazon or Stakesys had had a replacement in stock, but both suppliers were clean out for a long time. After a brief window of availability in the New Year, Stakesys are now out of stock again, not just of the model I bought but of virtually all 230v versions.

John B., it's useful to know how common problems of this kind are with bandsaw blades. For the record, the blade that cut the piece of brass was fresh out of the box and the teeth were definitely not brought into contact with the brass until the saw blade had reached its operating speed.

John (Breva), I have checked the first blade, which is currently removed from the saw; there is indeed a very slight though gradual dip around the weld line at the back edge of the blade.

[Bill PhinnParticipant @billphinn90025]

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.

[Ady1Participant @ady1]

I changed the twist angle of the blade drive wheel tyre by 45 degrees to try and increase blade life

Out of the box has 90 degrees of twist

I think they should have no blade twist at all, like a vertical bandsaw, which is the best system IMO

I think things have improved but 0 degrees would be best

Edited By Ady1 on 15/03/2022 23:16:50

[Bill PhinnParticipant @billphinn90025]

Thanks, Ady. I'm having a look at and slowly digesting your project.

I know what you mean about blade twist. It does seem extreme, but I assumed this was standard for portable bandsaws. Maybe it isn't.

[Ady1Participant @ady1]

I put a teeny bit of oil on my blades now too

Sometimes this throws the blade from the tyre at the start, but I think a little bit of lube does more good than harm

Iron tyres would be best, then you can lube it properly, some of the good italian saws have iron tyres

[Robin GrahamParticipant @robingraham42208]

Bill, it might be worth reporting your experience with the Vario blade to Ian at Tuffsaws – he's very approachable, and knows a lot. He'll probably be interested. When I was struggling with setting up my own saws I emailed him and had about two pages of good advice. I buy nowhere else now!

Robin.

[John PParticipant @johnp77052]

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.

—————————————————————————-

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

[blowlampParticipant @blowlamp]

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.

[Bill PhinnParticipant @billphinn90025]

 

Posted by Robin Graham on 15/03/2022 23:55:51:

Bill, it might be worth reporting your experience with the Vario blade to Ian at Tuffsaws – he's very approachable, and knows a lot. He'll probably be interested. When I was struggling with setting up my own saws I emailed him and had about two pages of good advice. I buy nowhere else now!

Robin.

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

Posted by John P on 16/03/2022 12:44:58:

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

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.

Posted by blowlamp on 16/03/2022 13:00:24:

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.

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

 

 

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

[AJWParticipant @ajw]

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

[Bill PhinnParticipant @billphinn90025]

Posted by AJW on 16/03/2022 20:17:31:

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.

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.

[VersabossParticipant @versaboss]

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

[RobinParticipant @robin]

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

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