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Munty Scruntfundle

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Hi folks. I need a little help with a band saw. (Axminster AC2602. Bleeping thing!) It's a decently built machine but I'm having trouble getting a true cut. Let me give you some info...

It's never cut quite right, the supplied fence was a joke at best and more like an insult to any sane person and adjusting anything is impractical at best. However, I have made some progress.

Recently I purchased a fence upgrade kit which is more substantial than I need, but it's not going to fall apart. That's fitted. It took a bit of fettling and I had to mount it on a steel plate to spread the load over the cast, but it's on and I reckon you could stand on it! Also purchased was a new mitre slide as the original was awful.

This has been my setup methodology:
Band fitted, teeth running nicely in the middle of the tyre, tension taken up correctly, cold block guides 'just' touching the blade, rear guides have around 1mm gap. Runs lovely.
Table checked square to vertical blade, it is.
I checked the mitre slide is square, it is.
Fence checked square against mitre slide, it is.
And last, table rotation checked in line with the blade. Now, I'm pretty sure this is the problem area. I have one of those aluminium bars with magnets in the middle, it sticks to the side of the blade an gives a magnified view of the blade axis. You rotate the table to match and job done. However when I use this bar I have to rotate the table to one of it's extremities which doesn't seem right to me. The bar is perfectly flat, but I have no way to check the inset magnet position which may be out. I have checked the blade axis with a rule, but of course the splayed teeth cause a problem and I'm relying on touch and eye balling.
Each micro adjustment of rotation requires unlocking the table, tilting it 45 degrees, undoing the 4 locking bolts underneath, tapping the table, then reverse to lock it again. While I'm being as careful as possible there's room for error and things not quite seating the same.

And the problem symptoms...
No matter where I put the table the blade tries to cut inward towards the fence. As the blade is twisting slightly the work is then pushed away from the fence. (Which would suggest (to me) the table needs to rotate anticlockwise) You have to keep a lot of pressure on the work to get a straight cut, but the first inch is always wavy.

I've been at this for hours in between using for rough cutting. I do have a little table saw but I'm working with small things and the blade width wastes as much wood as I'm using.

I know a band saw shouldn't be classed as a high tolerance machine, but it should be doing better than it is. You're probably going to suggest changing the blade which I must admit I haven't done yet. Could you suggest a really good blade for wood and non ferrous?

Sorry for the long post, but I want to get everything in!

Many thanks.
 

samhay

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What shape is the blade in? Can you cut in a straight line freehand, without the fence?
 

CHJ

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As above suspect Blade, may be teeth are not cutting equally on both sides of the set.
The problem you are describing is my first indication that a blade needs changing because I have damaged it on a wood inclusion or in some way worn the teeth on one side of the blade.

Within reason don't over indulge in the blade (teeth) position on the top wheel, main criteria is that it runs at 90 deg, north south & east west with the table and its mitre slot, if your fence is set up to align with your mitre slot then moving it close to the blade should give you a pretty good eyeball check on the blades alignment with the table & mitre slot, certainly well within its clearance kerf dimensions so that it should not be influenced by the cut slot.
 

Steve Maskery

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There is a tracking knob on the back of the machine. Adjust that until it cuts true north.

There are lots of resources online (not just mine) which show you how to do this properly.
 

sunnybob

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Wavy first cut means you are pushing too hard. With the correct pressure the blade HAS to cut in a straight line.... Unless the teeth are damaged.
The one thing you dont mention is where on the blade the guides rest. If the blade can be pushed back far enough for the teeth to get squeezed between the guides, even for a couple of seconds run time, you have flattened the teeth and the blade is ruined.
Its very easy to do this when first learning the bandsaw
(yes, that includes me :roll: )

Adjust the blade tension so that it will follow a straight pencil line down the middle of a piece of wood. Stop the machine when youre halfway along, and let the scrap wood stay there. Then adjust your fence to the wood.
 

Steve Maskery

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sunnybob":1tl3tfzi said:
Adjust the blade tension so that it will follow a straight pencil line down the middle of a piece of wood. Stop the machine when youre halfway along, and let the scrap wood stay there. Then adjust your fence to the wood.
No, no, NO!

The fence should be parallel to the mitre slots and the blade tracked to that direction. Altering the fence mucks up crosscutting and jigs and stuff.
Learn to do it right from the get-go.
 

Munty Scruntfundle

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First to last...

The blade looks fine, no shiny edges, tips in place, nothing obviously out of whack. I'm not aware that I've pushed it beyond it's limits, it's quite a full depth blade so I haven't used it for anything curved.
The tracking knob on the back of the machine sets the position on the tyres, as far as I can see from the mechanism this twists the blade on the y axis, not z.
The guide bushings/bearings are set back from the teeth, just in alignment with the rear of the blade.
Certainly not pushing too hard, have tried all sorts of pressures. It will cut straight freehand, I could do with a laser line, but that's a different matter!

A new blade set was delivered yesterday, woohoo! So I'll be fitting one of those after bloody Christmas bloody dinner at a bloody friend's house with loads of bloody kids. Blade fitting will be a total relief!!

Otherwise it looks like I'll have to persevere with the table alignment.

Thanks so much for your replies, all great pondering material.
 

sunnybob

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Sorry for late reply, been away and dont do internet while I'm out and about.
Youre right about my method screwing with the mitre slot.
I dont use the mitre slot on my bandsaw for anything precise, so did not consider that. :roll:

But having said that, its a good starting point to get a straight cut. Once the blade is cutting straight and level with the fence, its not too difficult to edge the blade back or fore on the wheel to change the angle and make it square to the mitre slot and then match up the fence.
The main problem with fault finding on a bandsaw is there can be several things wrong at the same time.
 

Munty Scruntfundle

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Thought I ought to add a note for anyone interested in my minor life problems...!

About a month ago I bought a pack of 5 bands from Axminster, they have good reviews so thought I'd give it a go. I fitted one of them today, not sure exactly which model number, it's outside and it's cold.

First thing I noticed was my previous work to true the table and cross slide was perfect, everything nuts on 90'. Secondly, it cuts straight!! Yay! What a bonus.

So I'd been struggling with the damn thing for months and it was all down to the blade it was supplied with. I doubt I'll ever find out exactly what that old blade is/was, there isn't one with the same tooth profile in the pack of 5.

Anyway, all good. (Big smiley face)
 
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