Thread: Help! Big problems with Carbatec CTJ-3501

Woodenink has the same model as this too I believe and the same problem, in the end he ordered shorter blades from C & S Saw Service which fixed it.

I'll go and have a look for the thread on it

Here you go, thread is here

Contact for

C & S Saw Service
17 Stewart Street
Mount Waverly VIC 3149
PH 03 9802 1040
FAX 03 9887 9950

Looks like the tension isn't working at all. Probably because the blade is too long and the top wheel is up as far as it can go without putting any tension on the blade. Perhaps measure the length of the blade and compare that to the specifications then go back to the seller. For cross reference call a bandsaw maker in your area and ask what length blade they make for your machine. If it turns out the you do have the correct length blade then have a close look at the tensioning mechanism. It is likely that somthing is preventing the top wheel from travelling up as is should. PS the blade tension guages are pretty useless on small machines, tension is best judged by feel or sound. i.e. pluck or press the blade sideways and it should deflect a little with firm pressure.

The blade's too long. If the tensioner were faulty you wouldn't get a reading on it; the reading is obtained by the wheel physically moving up.

If I were you I'd reduce the tension to minimum, measure the diameter of either wheel (both should be the same size) and then measure the height from the centre of the top wheel to the centre of the bottom wheel.

The (diameter x 3.14) + (2 x height) will give you the minimum length of blade that BS will accept. I'd add another 20mm or so to make it easier to slip the blade on & off. What's the betting that this won't add up to 2553mm?

It'd make the tension guide useless/inaccurate but, frankly, I've always found it useless anyway and prefer the "twang" test.

'Sides, yours can't be any more useless than it is now!

Over time and from experience, I have learnt to ignore the tensioning devices and gauges, they are often a stick on placard (used to indicate tension), what is there to say that the placard is in the correct position?

Blade tension should always be determined by the pluck and watch test. Using the longest unsupported side of the blade pluck the blade and do two things, watch the amount of vibration and listen to the resultant sound. If there is excessive vibration keep on tightening. I can't describe the most desired sound from a plucked blade, I guess it is a matter of experience. But you can rely upon the vibration test, the least vibration the better.

What is there to loose by overtightening the blade, contrary to the manufacturer's recommendation? In my opinion none!

For further advice ~ Bandsaws and Blades information sites

And, it is also possible that the shape (crown) of the tyres is not suitable for a 6mm blade, on the large bandsaw a 6mm will slip off the wheel, despite the amount of tensioning.


Good Health

Thanks every one for your help. I think these forums are GREAT!
I have ordered a couple of blades from C&S saw Services, who are in walking distance from my home.
Using Skews method I calculated the minimum blade length as 2547. Thanks for the tip because it was proving very frustratingly @#$%^ impossible trying to get a tape measure around the wheels and through the saw guides!

I had nothing but problems with bades from CarbaCrap blades were all to big and never fit properly anywhere else should be ok even hare and forbes blades fit perfect.

All Fixed!
The new blade works great.
The guys at C&S Saw Service were very helpful and for $4 they will even cut the old Crap blade down to the correct size for me

C & S Saw Service
17 Stewart Street
Mount Waverly VIC 3149
PH 03 9802 1040
FAX 03 9887 9950

Thanks again to all the helpful people who posted!

Originally Posted by Sculptured Box

.

What is there to loose by overtightening the blade, contrary to the manufacturer's recommendation? In my opinion none!


And, it is also possible that the shape (crown) of the tyres is not suitable for a 6mm blade, on the large bandsaw a 6mm will slip off the wheel, despite the amount of tensioning.


Good Health

Um. No. Not always anyway. My 24" saw will easily run 1/4" blades, and I have almost no crown at all. A larger saw's tensioning mechanism is more than adequate to snap the weld on a blade. I wrecked a brand new blade when I first got my saw following similar advice.

Greg

Originally Posted by steck

All Fixed!
The new blade works great.
The guys at C&S Saw Service were very helpful and for $4 they will even cut the old Crap blade down to the correct size for me

Originally Posted by gregoryq

Um. No. Not always anyway. My 24" saw will easily run 1/4" blades, and I have almost no crown at all. A larger saw's tensioning mechanism is more than adequate to snap the weld on a blade. I wrecked a brand new blade when I first got my saw following similar advice.

Greg

The smallest blade I can run satisfactorily is a 1/4", anything smaller falls off!

And yes there is a limit to the amount of tightening, thats why the pluck and watch test is important.

man .. ok this post was decade ago .. but I have just taken mine apart before finding this post ! thanks mate -

Originally Posted by JohnnoP

man .. ok this post was decade ago .. but I have just taken mine apart before finding this post ! thanks mate -

...as would be suggested if there was an honest design of bandsaw being made.

You might as well see if you can align the wheels whilst the table is off.
That is, if you can't afford to buy another ,or pay someone to repair wheel bores.
It's a bit of a lottery if you don't check that IMO.

A quick explanation, as to the method.
The upper wheel on most modern design sheet metal saws being the same, what's a rendition of sorts of the Italian saw...
(bar anything $h1te) made today, are all 99% the same concept.

That being that the upper wheel is fixed in one axis, and only allows to tilt on the other,
whilst the lower wheel can be adjusted in both.
So the method below, gives a projected datum line of the upper wheel, scribed on the base,
and thus gives one a line to adjust the lower wheel to.

Not being sure if the upper wheel may have some play on some, it might not be possible to
simply mount a block with a pen style laser onto the upper wheel shaft,
perhaps worth doing, well more so if the wheels have a groove or walls to keep the tires located.


SAM_7704.jpg



If not, then below using the scribing beam against the wheels might be chosen instead, to get the datum line drawn,
Perhaps more guaranteed as the machine is under tension, using preferably an old blade, what's narrow enough to track
on centre without the teeth scuffing the accurately prepared timber.
(sloppy upper wheel owners may have to rinse and repeat)
Scribing beam.jpegSAM_7271.jpgDatum scribed.jpegSAM_7773.jpg

Note in the other thread, the wheels need to be accurate enough for the scribed line not to pick up an error.
SAM_7151.jpgSAM_7152.jpg

Important...Now one better have adjusted their drive belt as loose as they can,
(making sure they actually can have both the belt loose, and making sure there is good clearance between pulley and hub)
as a misalignment can damage the motor bearings in an instant.

Prob a fair bit I left out, but it's on the last page of my tire dressing thread, which is most likely too much misery to go through from the start,
and best read backwards, unless one is having sleeping troubles.

You might not be happy, should you also decide to scribe a line from the pulley, what's the path of the belt,
as they don't make face or flange mounted motors adjustable.
Well not on any decent machine anyways, and it's a bit of a joke really.
Attachment 535072

All the best
Tom