Help needed to lift bandsaw curse.

[Bill PhinnParticipant @billphinn90025]

[Bill PhinnParticipant @billphinn90025]

After buying an Aldi Workzone bandsaw in 2019 and deciding to return it because I felt it wasn’t good enough for my needs

(**LINK**)

I some time afterwards decided I couldn’t live without a bandsaw so bought a more expensive Femi model, which, in some ways, was even more disappointing:

**LINK**

This too was returned (and subsequently lost by the courier, though that is another story).

Feeling I still needed a bandsaw, last week I bought essentially the same Aldi bandsaw as before but this time branded under the Scheppach name.

Like the first Aldi saw, out of the box the Scheppach would not cut perpendicularly to the vice/base. However, I managed to correct this by simply shimming the far side of the vice slightly. It now cuts perfectly square, even when what is being cut is something as thick as a piece of 4×4 timber.

In spite of my initial elation, I soon realised that my bandsaw curse has not yet been lifted; there is a very disconcerting clunk as the blade kicks downwards into the work every revolution.

You can judge for yourselves in a video a friend of mine has uploaded for me. For the record, I am cutting 6mm x 20mm hot rolled mild steel bar, the blade is fully seated on the wheels and bearings, properly tensioned, running on speed 2 out of 6, and not by any means being forced into the cut. There is no noticeable weld seam on the blade and no obvious (to me) reason why it kicks downwards.

Whether the surface finish I’m getting is anything to do with this kicking downwards I don’t know, but I do know that the surface finish on brass, aluminium or mild steel is poor. (Attached photo shows 6mm x 20mm hot-rolled steel bar).

Any suggestions on how to cure the downwards kick and improve surface finish would be greatly welcomed.

[JasonBModerator @jasonb]

Clunk that was not that easy to hear is likely to be the weld on the blade, a better quality blade may fix that though I can still hear the joint on my Femi and vertical woodworking bandsaws.

I tend to cut flat bar laid flat so there are more teeth in contact with the work which may also help with your finish.

[Ady1Participant @ady1]

Your speed sounds fine

Blade tension?

I dont use a lot of tension and get nice cuts

The nice bit is the bandsaw, the top bit milling

I use 10-14 tpi blades and dont let too much weight fall on the blade by supporting it via the trigger handle

 

Edited By Ady1 on 28/02/2021 19:26:28

[Martyn Edwards 1Participant @martynedwards1]

Although Scheppach manufacture very good Bansdsaws in their German Factory the smaller cheaper ones are badged Chinese ones so I would suspect if it's the original blade that came with the saw I would look at trying to get a better quality blade that's possibly made in the UK such Dakin-Flathers blades.

[John BaronParticipant @johnbaron31275]

I would check very carefully for missing teeth. The original Aldi bandsaw blade lost several teeth within a few cuts, the new blade is far better.

[John HaineParticipant @johnhaine32865]

I got a Femi 782L and it's brilliant! What problems did you have with it?

[martin perman 1Participant @martinperman1]

AS already said, check the weld and look for teeth missing, can you open the blade guides slightly because the weld might be slightly thicker when going between them.

Do you also have a guide pushing down the blade, the weld may not be flat along the edge catching the guide there also. 

Martin P

Edited By martin perman on 28/02/2021 21:31:43

[Bill PhinnParticipant @billphinn90025]

Many thanks to everyone for your replies.

I think the blade is almost certainly the problem, as Jason and others with experience of these things clearly sensed.

I took off the blade used in the video, located the weld seam and emeried it as smooth as I could get it, even though it was pretty smooth to begin with.

After refitting I expected at least some improvement, but there was none; it still jerked downwards disconcertingly. [In the video the jerking and clunking is more noticeable in the last half].

Fortunately, Aldi supply two blades with this saw [M42-grade steel, so perhaps a bit better than bargain bucket territory in their material at least?]. I fitted the second blade. There is a slight detectable deviation downwards once per rev., but this is much less than with the first blade, and there is no audible clunk.

As for cut quality, I've uploaded a couple of photos of steel bar showing the difference between cutting with the bar flat and cutting with it standing on edge, as initially. Lying it flat produces an obviously better cut.

There are still two minor issues. The picture of the brass bar [in the first image and 3/8" x 2", I think] shows the first: the two short patches near each end of the bar. I can't detect any difference in surface height with my finger at these points, so I'm not too concerned by it, but does anyone have a suggestion as to why these markings have occurred? There is nothing on the surface of the bar either side to explain their existence, and further cuts produced exactly the same result. The bar was cut lying flat.

The second issue is that now I have shimmed the vice on one side with washers [around 1.25 mm thick], the plastic guard on the inner side of the saw slightly fouls the angled side of the vice at the bottom of the cut. I can probably resolve this fairly easily, but why the clearance between the edge of the vice and the body of the saw has to be so small I don't know.

John Baron, there are no missing teeth.

John Haine, if you click on the second link in my opening post you should find my post about the Femi on that page.

Ady, the user manual shows the blade tension lever pointing almost vertically downwards when the blade is tightened according to the instructions ["to the stop"]. Are you saying it would be OK to use the saw with the lever backed off part way? I will back it off when not in use.

[Bill PhinnParticipant @billphinn90025]

Posted by martin perman on 28/02/2021 21:27:18:

AS already said, check the weld and look for teeth missing, can you open the blade guides slightly because the weld might be slightly thicker when going between them.

Do you also have a guide pushing down the blade, the weld may not be flat along the edge catching the guide there also.

Martin P

Edited By martin perman on 28/02/2021 21:31:43

Martin, good question about the blade guides. The gap between the pair of bearings distant from the cut direction is noticeably greater than the gap between the two bearings on the other side of the gap. Measured with a feeler gauge it is about 0.05mm wider. The blade inserts easily between these two bearings and is piggishly tight between the other pair. Not sure if this is how things should be, or how adjustable the bearing positions are [I suspect they're thread-locked; EtA: tried to undo one screw – tight as hell, and head of screw not very hard, so gave up for time being].

Sorry, I'm not sure what you mean by a guide pushing down the blade.

Edited By Bill Phinn on 28/02/2021 22:16:33

[Martin KyteParticipant @martinkyte99762]

I would change the blade. Most budget saws will be dispached with somewhat less than quality blades. Now't wrong with the saws but don't expect top quality blades to come with them.

regards Martin

[martin perman 1Participant @martinperman1]

Bill, your saw has two bearing guides either side of the blade, is there a third one sitting on top of the blade to stop the blade riding up.

Martin P

[John HaineParticipant @johnhaine32865]

Well, sounds like the Femi was broke when you got it. Several votes for them here including from me. Buy cheap, buy twice.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, the clunking could be as simple as the set of one tooth sticking out a little more than the rest, I've seen that on a big industrial band saw and it very often disappears with use.

Regards Nick.

[Bill PhinnParticipant @billphinn90025]

Posted by martin perman on 28/02/2021 22:30:41:

Bill, your saw has two bearing guides either side of the blade, is there a third one sitting on top of the blade to stop the blade riding up.

Martin P

Martin, yes, the third one is top right.

I suspect my problem is a combination of the first blade having a marginally too thick weld area and one pair of guide bearings [before and still] being marginally too close together.

If I can loosen off the screw going through one of the bearings that are too tight, will this allow me to retighten the screw with a bit more clearance? I ask because I can't really get to the bearing screws with the saw mounted on the pivot arm, and after the trouble I had mounting it in the first place [having to do the work practically one-handed] removing and remounting it isn't something I look forward to with relish.

[Robin GrahamParticipant @robingraham42208]

I had a very similar problem with an Axminster saw, supplied with one of their supposedly 'top notch' blades. After tearing my hair out trying to fix it I eventually bought a bimetal blade from Tuffsaws. The problem just disappeared. Still a faint click when the weld goes past, but no kick – which in my case was sometimes severe enough to unseat the blade.

Robin.

[Bill PhinnParticipant @billphinn90025]

Thanks for the further replies.

Robin, disturbing to hear about your Axminster saw – puts my problem in perspective.

I'd got Tuffsaws earmarked even before the present saw arrived.

Sadly, at the moment, I'm getting the following message on all pages of their website:

"Due to experiencing higher than usual levels of orders, the website is currently offline while we catch up but will be back up shortly.

Please check back later or email us at sales@tuffsaws.co.uk"

[WindyParticipant @windy30762]

I bought an Aldi Workzone portable bandsaw in 2019 apart from the vice which works better now after a few mods have been pleased with it.

The blade with it worked well and cut 100mmØ ally and en24t 50mmØ plus lumps of rectangular ally bar that stretched it to its size limit.

The cut finish was equal to a friends professional metal bandsaw.

After many cuts had to replace the blade as it broke as a cut piece moved it was a 2 metre lump of 50mmØ en24t.

Had bought a pack of 3 better quality blades as spares replacement blade had that annoying blade weld click but has not altered the quality of cut.

Did wonder if should try to smooth the blade weld but decided to leave alone.

[Martin KyteParticipant @martinkyte99762]

Posted by Robin Graham on 28/02/2021 23:22:52:

I had a very similar problem with an Axminster saw, supplied with one of their supposedly 'top notch' blades. After tearing my hair out trying to fix it I eventually bought a bimetal blade from Tuffsaws. The problem just disappeared. Still a faint click when the weld goes past, but no kick – which in my case was sometimes severe enough to unseat the blade.

Robin.

To be fair to Axminster, Their saws come supplied with the manufacturors blades. Their own brand which they make are superior.

regards Martin

[AJWParticipant @ajw]

Interesting post as I have only just ordered the bandsaw from Aldi which could be arriving today.

Viewing reports/reviews of this and similar I have basically assumed that the device will need some 'fettling' to allow it to produce what I'm after. These things are made down to a price but I think the engineer in us expects things to be right.

Nearly bought one a while back but resisted although since then I can't believe how much hack sawing I have been tackling!

Alan

[Leo F Byrne 1Participant @leofbyrne1]

Don't mess about – use Tuffsaw blades. I email, the chap sends me a PayPal invoice and the blade arrives very promptly. I have no connection etc etc.

[GeorgineerParticipant @georgineer]

Posted by Nicholas Farr on 28/02/2021 22:48:41:

Hi, the clunking could be as simple as the set of one tooth sticking out a little more than the rest…

That's my experience with woodcutting bandsaws in schools. I became quite expert at dressing wonky teeth in one school where I couldn't stop untrained staff using the bandsaw out of hours. After resetting the offending teeth with a light hammer and a dolly, holding an oilstone at the side of a running blade and just letting it touch any high spots would trim things up quite nicely. I rescued a number of blades that way.

George B.

[noel shelleyParticipant @noelshelley55608]

I was given an axminster saw that wouldn't cut true. A new blade and reset the blade support bearings and it was fine, though I had to file the bearing support to get one side right. You should have atleast 3 teeth in contact with the metal at any point, so for thin material finer blade. Keep the blade guides as close as you can to the work. If the overarm is too heavy on thin material or the blade is cutting to fast take some of the weight with your hand to ease the cut, a fast cut will often give a poor finish. Cheap blades are false ecomomy. Good Luck Noel..

[John BaronParticipant @johnbaron31275]

Posted by Bill Phinn on 28/02/2021 22:02:00:

There are still two minor issues. The picture of the brass bar [in the first image and 3/8" x 2", I think] shows the first: the two short patches near each end of the bar. I can't detect any difference in surface height with my finger at these points, so I'm not too concerned by it, but does anyone have a suggestion as to why these markings have occurred? There is nothing on the surface of the bar either side to explain their existence, and further cuts produced exactly the same result. The bar was cut lying flat.

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

[Howard LewisParticipant @howardlewis46836]

My bandsaw is the larger generic 4 1/2" one which was mediocre to begin with.

Don'tb know if any of what follows will be of any help.

The blade needs to be set so that it tracks correctly, (The Idler wheel does this on my saw )

One of the adjustments made was to set the each of the two guide wheels to bear firmly against the sides of the blade, and the upper one to bear against the back of the blade.

On my saw the "side" bearing are mounted on eccentric shafts which have to be rotated to set the bearing against the blade.bearings

If the blade loses any teeth it will jump!

Some time ago Engineering in Miniature carried an article on making a Blade Tension Meter.

I made one and used it to set blade tension.

Basically it is a DTI bearing against a pivoted lever clamped to the blade, whilst the other end of the frame carrying the swinging lever and DTI is also clamped to the saw blade. The blade is tensioned until the DTI shows that the blade has extended by a very small amount . From memory, on a 64" x 1/2 x 0.020" b;lade, by 0.05 – 0.06 mm.

After this "fine tuning" blades last much longer, and cuts are more accurate. One never to be repeated test showed a difference in the thickness of a 1.5 mm slice to differ by only 0.025 mm!

But that it not to be expected to happen very frequently..

Using an excess down force will cause the blade to veer, and produce a curved cut.

Some of the foregoing may be of assistance with your machine.

Howard

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