Dodgy blades

[Tim Creeper]

Alright can someone explain to me what causes a blade to cup when it warms and what the remedy is. I changed the blade to one that had been re teethed about 12 months ago and has been stored in the shed on edge. I made one pass of a short log. On the second pass the blade started to rise and bind. I brought the saw back and attempted another pass; same response and the teeth didn't even touch so I looked at the blade and it was cupped at least 2-3mm. I removed the blade and by the time I covered the machine and returned to the house to put a steel rule over it, it was almost perfect!
Whilst I have enough knowledge to be dangerous I am still very ignorant of a lot of stuff. I would love to learn a bit more. I would therefore like to thank in advance all the wise and experienced wood cutters who will pass to me there wisdom

[chambezio]

Without actually being able to watch you use the saw, its difficult to answer all your questions.
Don't take offense if I am talking about the obvious. ]
*Are you cutting logs? If so you could have a problem as you push the saw forward into the cut. The log may not be at 90° to the base plate/saw blade which translates to you binding the blade up against the saw cut. (Hope that makes sense)
*How hard is the timber? Pine or something else? sometimes really hard timber causes the saw blade to deflect as it is looking for an easier path to cut. Hence another bind/jamb
*Not enough set is another contributor but rare if using TC teeth.
*Then there is always....the grade of the blade. Cheap Chinese look alikes.
If the blade continues to cup....bin it. It could break and become a source of shrapnel.
You should never force a circular saw! You should always let it dictate the pace of the cut. In soft timber with a deep cut, it may cut really easy but you have to let the saw dust clear as the blade revolves.
Have a think about what I have written and feel free to cross examine me. As I said there are a lot of contributors to the dilema

[Tim Creeper]

*Are you cutting logs? If so you could have a problem as you push the saw forward into the cut. The log may not be at 90° to the base plate/saw blade which translates to you binding the blade up against the saw cut. (Hope that makes sense)
*How hard is the timber? Pine or something else? sometimes really hard timber causes the saw blade to deflect as it is looking for an easier path to cut. Hence another bind/jamb
*Not enough set is another contributor but rare if using TC teeth.
*Then there is always....the grade of the blade. Cheap Chinese look alikes.
If the blade continues to cup....bin it. It could break and become a source of shrapnel.
You should never force a circular saw! You should always let it dictate the pace of the cut. In soft timber with a deep cut, it may cut really easy but you have to let the saw dust clear as the blade revolves.
Have a think about what I have written and feel free to cross examine me. As I said there are a lot of contributors to the dilema

I'm here to learn. Oh and I forgot to say I'm using a lucas Mill.
*Yes: I'm cutting a Blackwood log. I always check the log is paralleled with the main rails both horizontally end vertically. Eg I think that's what you mean by at 90 degrees. Is it? If not I need more info.
*Its a log of 450mm diametre about 1.6m long. It was a live tree that blew over last august so it is only a little dry. I think it's a medium to dense timber.
*The blade is of unknown origin.
*Forcing a blade is something I understand. I never do and for a number of reasons I am quite slow and take my time.

[1thumb]

dont know tc saws but are you running water on it.also could be a lack of tension in the blade

[Tim Creeper]

dont know tc saws but are you running water on it.also could be a lack of tension in the blade

I should have said: yes it is a Tungsten Carbide Blade and it's the first time I've used it since it's been re tipped. I was wondering about tension. It is a subject I don't know much about. Is it Heat treatment of the blade??

[1thumb]

if the saw has been freshly retipped the tension should have been checked. as a circular saw cuts the edge warms and the tension runs to the edge keeping the saw cutting straight.not enough tension however and the saw can wander and dish. the saw doctor tensions a saw by hitting it with a special hammerin specific places generally closer to the centre of the saw don't know if that helps you as i am not very good with words. i would try running a little bit of water on it first ,if your not doing so already as this will help keep the saw cool.

[catpower]

Hi i had a blade do the same thing could not cut straight if you life depended on it,had it checked by a saw doctor said it was ok cut like a pile of #### ,threw it in the bin bought a new one no problems

[Tim Creeper]

if the saw has been freshly retipped the tension should have been checked. as a circular saw cuts the edge warms and the tension runs to the edge keeping the saw cutting straight.not enough tension however and the saw can wander and dish. the saw doctor tensions a saw by hitting it with a special hammerin specific places generally closer to the centre of the saw don't know if that helps you as i am not very good with words. i would try running a little bit of water on it first ,if your not doing so already as this will help keep the saw cool.

Thanks for that. I think a bit of research might be required re, tensioning. I'll give the water a try and see if it helps. Just wondering do I use just water or add anything to it? I guess if it doesn't work then the tension is all wrong?

[Sigidi]

OMG!!!! threw a blade in the bin?

saw should be tensioned after being tipped?

what planet are folkes living on?

TIM...listen up

did you send the blade to saw doctor, or did it come with teh millas a 're-tipped' blade? who is your saw doctor? how much experience do you have with the saw doctor? do you KNOW the saw doctor can 'tension' the blade? (FYI blades, shouldn't need 'hammering' now, they are roll tensioned using hydraulics and rollers like bearings - doesn't leave bullseyes all over your blade) he may say he does, but doesn't mean he does!!! fellow forum member Weisyboy has found that out the hard way, sent a lot of blades off to 'his' saw doctors here in brissy and slowly over time they have come back tipped but cutting like a hairy dogs #### - sent one to my saw doctor in gympie and Carl got it back said he's never had a blade cut that well even brand new. So first things first, you need to know what your saw doctor is capable of.

Secondly, Lucas blades SHOULD be dished/cupped/not flat! They are made like this so that at operating revs the blade 'stands up' or doesn't wobble, if they where flat to begin with then they would wobble like crap when cutting and you saw marks would be 2-3mm deep for individual teeth and your kerf would be twice the size, plus it'd take you all day to fight the blade through the log.

Thirdly dribble water on the blade the whole time it's in the log, if you think there may be a situation where the board will lie back and pinch down on the blade, use full water - BEFORE it happens, this will buy you time to shutdown and may save sending a good blade to the saw doctor. I use 1/2 water all the time and increase in situations that may pinch, but obviously I do everything I can to avoid any pinching.

Such a sort log shouldn't be a problem with tension so don't worry about that in this instance. Density of timber won't be a problem with our blades, I haven't come across anything including metal our blades won't cut - having said this irregular grain like that found around large knots needs to be treated with respect and feed rate slowed.

90 deg - no friggin idea what that is about??? even if your log is in the mill 20 deg to the blade, our blades will melt it like laser in butter

Never leave your blades lying down so the sun can heat them, this is an automatic trip to saw doctor, even standing up agaisnt vehicle tyre in direct sun = saw doctor trip. If you blade is ever more than cold to touch while milling = saw doctor trip... ie look after your blade.

Post some pics of the saw marks left by your blade on that log, I'll see what I can tell ya.

Hope it helps

[Tim Creeper]

OMG!!!! threw a blade in the bin?

saw should be tensioned after being tipped?

what planet are folkes living on?

TIM...listen up

did you send the blade to saw doctor, or did it come with teh millas a 're-tipped' blade? who is your saw doctor? how much experience do you have with the saw doctor? do you KNOW the saw doctor can 'tension' the blade? (FYI blades, shouldn't need 'hammering' now, they are roll tensioned using hydraulics and rollers like bearings - doesn't leave bullseyes all over your blade) he may say he does, but doesn't mean he does!!! fellow forum member Weisyboy has found that out the hard way, sent a lot of blades off to 'his' saw doctors here in brissy and slowly over time they have come back tipped but cutting like a hairy dogs #### - sent one to my saw doctor in gympie and Carl got it back said he's never had a blade cut that well even brand new. So first things first, you need to know what your saw doctor is capable of.

Secondly, Lucas blades SHOULD be dished/cupped/not flat! They are made like this so that at operating revs the blade 'stands up' or doesn't wobble, if they where flat to begin with then they would wobble like crap when cutting and you saw marks would be 2-3mm deep for individual teeth and your kerf would be twice the size, plus it'd take you all day to fight the blade through the log.

Thirdly dribble water on the blade the whole time it's in the log, if you think there may be a situation where the board will lie back and pinch down on the blade, use full water - BEFORE it happens, this will buy you time to shutdown and may save sending a good blade to the saw doctor. I use 1/2 water all the time and increase in situations that may pinch, but obviously I do everything I can to avoid any pinching.

Such a sort log shouldn't be a problem with tension so don't worry about that in this instance. Density of timber won't be a problem with our blades, I haven't come across anything including metal our blades won't cut - having said this irregular grain like that found around large knots needs to be treated with respect and feed rate slowed.

90 deg - no friggin idea what that is about??? even if your log is in the mill 20 deg to the blade, our blades will melt it like laser in butter

Never leave your blades lying down so the sun can heat them, this is an automatic trip to saw doctor, even standing up agaisnt vehicle tyre in direct sun = saw doctor trip. If you blade is ever more than cold to touch while milling = saw doctor trip... ie look after your blade.

Post some pics of the saw marks left by your blade on that log, I'll see what I can tell ya.

Hope it helps

Sigidi, Hi. Thanks for the info. I use a bloke here in Mt Gambier and he has a good reputation. He does most of the work for the big saw mills here and many others. He's always busy and getting busier which to me spells Good work.
I'll post some pics of the cuts. I've run it again with water on full flow and no better. If any thing it's worse. The vertical cut is running out to the right dramatically as I pull it through. So much so that it pushes the rails out and when it leaves the cut it jumps back in line 15mm or more!
07-05-13_1202.jpg07-05-13_1201.jpg07-05-13_1203.jpg07-05-13_1204.jpg
This made me wonder if when I hit a 3/8 bolt the other day (hence the blade change) that the set-up was thrown out so I've also measured off the blade to the engine frame from opposing teeth to see if the blade is parallel to the rails. tried adjusting via the right roller because the measure varied 4mm. No difference, probably worse run off. I put it back where it was -same result again.These next pics show the effect of adjustments to settings. While the cut was straighter it ran out to the right. 2 picks show the amount the thing jumped (sprang) back in line. Each of the 3 cuts were after an adjustment. To give an Idea the saw was set to cut 25mm.the left piece is 35mm thick at the end. You can see where the saw sprang back to leave 20mm after coming out at
08-05-13_1028.jpg08-05-13_1029.jpg08-05-13_1030.jpg

[Skew ChiDAMN!!]

That's significant "spring" at the end!

Just curious: you don't have another known, 'good' blade you can swap in to verify that it is the blade and not some alignment issue caused around the same time?

[Tim Creeper]

That's significant "spring" at the end!

Just curious: you don't have another known, 'good' blade you can swap in to verify that it is the blade and not some alignment issue caused around the same time?

My other blades are are in being repaired. He's so busy I don't know when I'll get em back.

[Sigidi]

Geese Tim!!!

whats ya current blade look like mate?, any pics of the teeth possible?

[Tim Creeper]

Geese Tim!!!

whats ya current blade look like mate?, any pics of the teeth possible?

Oh well let me start with an apology to those involved with this thread. Sorry. All the info above is correct cept 1 thing I didn't mention is the blade is set for stone cutting and I presumed that it would be ok since it hadn't been used yet. Well I finally got into town and saw the saw doctor today and He tells me that it will make a difference (pfffft, now who feels like a dill). I thought it would cut a little slower due the set but it seems there's a lot more than the set that's different. It's teeth are not face sharpened, The clearance of the top of teeth with the edge of the blade is 0. and the sides of the teeth are 90 degrees. Now I just need to wait for the other blades to be done. He promises next week.
Sigidi pics of teeth below.
10-05-13_0830.jpg10-05-13_0831.jpg10-05-13_0832.jpg
Always willing to learn but not always happy with the way I learn; but learn I will

[Skew ChiDAMN!!]

0 clearance on top and sides? No wonder it wandered wherever the grain led it...

Oh well, at least you can slab up any billets of aluminium or masonry left lying around while you wait for your new saw blades...