Which bandsaw cool blocks and where from

[zeroseven]

I have a Blundell SBW 4300 (looks same as Axminster SBW 4300). I'm having problems with the blades twisting badly and my next attempt at remedy is new cool blocks. The current ones are circular and I cannot find anything similar.

Suggestions please?

 

[blackrodd]

Don't Quite understand you're question, In the Axminster SBW 4300 link below, The last pic is the side bearings and behind will be the thrust bearing, this pictured is a good system for blade support, side to side, and a stable blade cutting action, And with the addition of TUFF blades usually makes for an excellent combination for trouble free bandsawing!
Regards Rodders

http://www.axminster.co.uk/axminster-in ... saw-700355

 

[zeroseven]

My saw has side cool blocks which I am looking to renew. I am hoping this will help my problem of severe blade twisting when sawing anything thicker than a couple of inches. I've spent 6 months trying to solve this, new tyres, new blades from Ian, extremely careful positioning of teeth half way across the tyres, paper thick clearance between back of blade and the rear bearings. The only thing I've not tried is new cool blocks. I'm almost certain this won't cure the twist, but I need to try something I haven't tried before. I cannot find a source for circular blocks as are currently fitted, failing that am asking for alternative recommendations for good cool blocks

 

[blackrodd]

Sorry to hear you're bandsaw woes and frustrations.
As you say, it looks as though replacing the "cool blocks" is the way to go, if you've tried everything else,
Are the originals worn or damaged at all?
Are the bearings noisy and knackered? slack at all? Do you set these right beside the gullet each side?, fag paper clearance?
How wide is the blade, have you tried getting the blade to run Central on the wheel? some wheels/tyres have quite a
Crown and run better than on the edge.
Our hero, Mr Snodgrass is very good too as you are no doubt aware.
Have to say most other users are going over to the bearings system, as I posted a link for the last pic.
I learnt my trade in a joinery shop and saw mill and have bandsawn cart shafts, oars, Sweeps and cabriole legs,
and many other things. I've even sharpened them in my stint in the saw shop.
Otherwise, Sounds like a blade problem to me, set damaged or knocked off on one side
Regards Rodders

 

[zeroseven]

Thanks Rodders. Will continue my search for the cool blocks, if unsuccessful I'll buy a bearing setup.

I've also spoken to the ever helpful Ian at Tuffsaw who has recommended a Sabrecut blade so will try that

 

[sploo]

My saw has side cool blocks which I am looking to renew. I am hoping this will help my problem of severe blade twisting when sawing anything thicker than a couple of inches. I've spent 6 months trying to solve this, new tyres, new blades from Ian, extremely careful positioning of teeth half way across the tyres, paper thick clearance between back of blade and the rear bearings. The only thing I've not tried is new cool blocks. I'm almost certain this won't cure the twist, but I need to try something I haven't tried before. I cannot find a source for circular blocks as are currently fitted, failing that am asking for alternative recommendations for good cool blocks

If your blade is twisting under load when resawing it's likely you have insufficient beam strength (i.e. the blade isn't sufficiently tensioned). The tensioners on most saws are woefully inaccurate, so don't really help.

What is the width of the blade (1/2", 5/8" etc)?

How much height is there between your table and the guides if you move them all the way up?

If you do that (lift the guides) and press on the side of the blade with your finger with gentle-to-moderate pressure, how far does it deflect?

EDIT: Based on what information I can find on a "SBW 4300", a saw of that class should annihilate even thick resawing jobs. My ancient Record BS300 (with about half the power) will handle a 5-6" thick green maple resaw with a suitable Tuffsaws blade. Slowly mind, but it'll do it.

 

[zeroseven]

Image will not appear above....https://www.dropbox.com/s/9fkyj3tdoauvc ... 5.jpg?dl=0

My 'coolblocks' are in fact just metal disks.... sorry for the confusion

Any advice on an upgrade path appreciated

 

[zeroseven]

What is the width of the blade (1/2", 5/8" etc)?

How much height is there between your table and the guides if you move them all the way up?

If you do that (lift the guides) and press on the side of the blade with your finger with gentle-to-moderate pressure, how far does it deflect?

EDIT: Based on what information I can find on a "SBW 4300", a saw of that class should annihilate even thick resawing jobs. My ancient Record BS300 (with about half the power) will handle a 5-6" thick green maple resaw with a suitable Tuffsaws blade. Slowly mind, but it'll do it.

3/4" Blade
ABout 11 inches
about 1/4" deflection, its pretty tight......

 

[dzj]

"...Otherwise, Sounds like a blade problem to me, set damaged or knocked off on one side
Regards Rodders"

+1
Or a dull blade or too many tpi.
The "coolblocks" look OK.

 

[sploo]

3/4" Blade
ABout 11 inches
about 1/4" deflection, its pretty tight......

That does sound fine. BTW you can try to replace those solid discs with ball bearings or ceramic blocks but I don't think they'll solve the problem.

When you're ripping thick stock, what actually happens? Does the cut wander along the length? Does the blade start to bend? Are you using green or dry timber (and what blade with that timber)? Are you simply pushing too fast (IRC 1.4x the depth requires twice the power, and 2x the depth requires four times).

Are the blade teeth well in front of the side guides (i.e. not damaging the teeth and blunting the blade)?

Photos may help.

 

[zeroseven]

I'm pushing incredibly slowly, I'd tried as slow as 30 secs per cm, the result is always the same. Once the blade enters the wood, it starts to turn (standing with the teeth nearest me the blade turns to my left)

I spoke to Ian at Tuffsaws who said my blade is not ideal ...........


3/4" - SuperTuff Premium 3116mm - 3590mm
- Blade Length: ***CUSTOM LENGTH***
- TPI: 3/4 Vari-Tooth
- Custom Blade Length (optional): 3345
- Bandsaw Model No. (optional): Europac SWB430

So have ordered an alternative and will try it on some logs next week....it just feels like a setup problem though

 

[paulm]

Are the blade teeth well in front of the side guides (i.e. not damaging the teeth and blunting the blade)?

Photos may help.

+1 on the above, how are you setting the side guides in relation to the blade ?

The guides should be very close to the blade sides but not actually touching.

The side guides should be far enough back behind the gullets of the teeth so that when pressure is applied to the front of the blade when pushing the wood forwards, the gullet of the teeth still remain in front of the side guides, otherwise the side guides will take the set and sharpness off the teeth.

I wonder if this is what is happening as in your picture the bottom left guide looks like it has been ground away by the teeth near the outer edge ?

There are guide sets both above the table and below the table usually, are you setting the below table ones similarly ?

Cheers, Paul

 

[blackrodd]

If you have this set up, in the link below, I, and many others believe this to be the best, just ensure the bearings aren't worn, page 23, fig 68-68.
Thinking about this further, is you're bandsaw 2 speeds, this affect the cutting? @ around 390m/m and 840m/m makes a difference with materials and blade choice, wood, alloy =fast speed, and steel etc,= slower speed
Make sure Ian at Tuffsaws knows and may advise as to the better speed, using the blade suggested,when you speak.
Also fence alignment, has this been checked?
Regards Rodders

http://www.axminster.co.uk/media/downlo ... manual.pdf

 

[Wuffles]

I posted this link the other day for someone else: https://youtu.be/wGbZqWac0jU

Personally I believe it is worth a watch. Watch it, don't watch it, the basics are the same. Rip it all down and start over.

Each time I fall out with my bandsaw I remember this video and start over before any fettling, works every time, for me.

 

[sploo]

I'm pushing incredibly slowly, I'd tried as slow as 30 secs per cm, the result is always the same. Once the blade enters the wood, it starts to turn (standing with the teeth nearest me the blade turns to my left)

I spoke to Ian at Tuffsaws who said my blade is not ideal ...........


3/4" - SuperTuff Premium 3116mm - 3590mm
- Blade Length: ***CUSTOM LENGTH***
- TPI: 3/4 Vari-Tooth
- Custom Blade Length (optional): 3345
- Bandsaw Model No. (optional): Europac SWB430

So have ordered an alternative and will try it on some logs next week....it just feels like a setup problem though

Looking back at some previous correspondence I had with Ian: Sabrecut blades are recommended for deep ripping on green wood. Fastcut are better for ripping seasoned wood.

The Vari-Tooth is a good general purpose blade. I have lazily used the 3/4 vari-tooth for a 3" deep softwood rip occasionally and it was OK (but the FastCut is better).

If the blade is turning then there's two main things I'd think might be wrong:

1. One side of the teeth has been damaged/blunted
2. The fence isn't set up correctly to account for the drift

Move the fence out of the way, and gently try to cut a straight line (freehand) on thin sheet stock (3-6mm is fine). Once you're most of the way through, stop, and look at the angle of the sheet (and cut line). It'll almost certainly not be parallel to the edges of the table. Loosen the adjustment bolt(s) on your fence, and bring it to the material.

Occasionally I've found you can be a long way off square with some blades (to the point you think the fence setting can't be right). It always is though - and then pushing a thicker resaw job through is much easier as the blade isn't fighting against the angle of the fence (likely further blunting one side of the teeth faster than the other).

One other thought: when running but not cutting, the blade isn't rubbing against your rear or side guides? I suppose a really badly out of true arm on the saw would mean the blade was rubbing against the guides, and trying to twist it.

 

[zeroseven]

Are the blade teeth well in front of the side guides (i.e. not damaging the teeth and blunting the blade)?

Photos may help.

+1 on the above, how are you setting the side guides in relation to the blade ?

The guides should be very close to the blade sides but not actually touching.

The side guides should be far enough back behind the gullets of the teeth so that when pressure is applied to the front of the blade when pushing the wood forwards, the gullet of the teeth still remain in front of the side guides, otherwise the side guides will take the set and sharpness off the teeth.

I wonder if this is what is happening as in your picture the bottom left guide looks like it has been ground away by the teeth near the outer edge ?

There are guide sets both above the table and below the table usually, are you setting the below table ones similarly ?

Cheers, Paul

Hi Paul

Yes I've been extremely careful with the setting of the guides, using a bank note as my gapping guide, above and below, and setting the blocks just behind the teeth spacings.

The metal guides were already in the machine (think its a 2004 though it looks absolutely mint) so cant vouch to their previous history

 

[paulm]

That all sounds okay With the machine switched off obviously, if you press the front of the blade firmly with a piece of wood, does the blade flex backwards such that the gullet of the teeth then moves further back into the side guides, or have you got the back guides adjusted such that they stop the backwards blade movement before that happens ?

Sorry if it's grannies and eggs and all that, not sure how much experience you have and what you already know

Cheers, Paul

 

[zeroseven]

The gullets are still about 1mm clear.

Zero experience but YouTube has been very informative. I'm a bit of a nerd for such technicalities...more fun than makingvwonky tables

 

[paulm]

Okay, well it's great to eliminate as many possible issues as possible at least, even if the problem itself isn't sorted yet !

What is puzzling me is that I don't understand how you can get severe blade twisting in a 3/4" blade that is tensioned with little side deflection, and with the top and bottom side guides set very close to the blade ?

It just doesn't seem physically possible, the side guides would prevent it ?

When you are cutting the 2" timber, are you lowering the upper blade guide assembly to be reasonably close to the top of the timber ?

If you are then the only other thing I can think of is whether the whole blade guide assembly is loose and moving but that would be unlikely I would have thought.

Cheers, Paul

 

[custard]

What is puzzling me is that I don't understand how you can get severe blade twisting in a 3/4" blade that is tensioned with little side deflection, and with the top and bottom side guides set very close to the blade ?

+1

Maybe the fence is flexing? Maybe the feed rate is too fast and the gullets are getting chocked? Maybe it's gnarly, warped, salvaged, or wet timber that's releasing tension during the cut? Maybe some of the teeth hit a buried nail/staple and are twisted so the set is asymmetrical?