difficulty cutting oak work top

[7777777]

yesterday i cut my new oak worktop 950mm x 3mt ,,, the saw i have is a skill saw 180 mm blade it says its 1 3/4 horse power ive had it 20 years it never fails to cut exteria doors etc ,,, the blade looked good and i think its had liitle use,,, i leveled the worktop and started to cut it strugeled to cut the 38mm thick worktop and even started to smoake,, i managed and i did cut it,,, when i looked at the cut there were a few burn marks but had cut well,,,, is this typical of cutting oak ??? is the saw not up to it? is it the blade ? i have just bought 3 new blades 20t,,,24t,,,,40t which is best ? i have 4 more cuts crossgrain and i need to take 25mm off a 4 mt lenth which worries me,, i see there are some expensive blades but as i dont make my living from this ,,, and use my saw occasinaly so the silver line tct look ok to me any advice

 

[delmel]

Blades need to be good quality and in great condition, also using a good saw. My friend is a fitter and you would be shocked how often he replaces blades. He also uses a router and the blades only last a few cuts before he replaces. This is why worktop cuts and joints are costly.
Also be patient when cutting, to fast will burn, to blunt will burn and probably give a poor cut or damage worktop.

 

[big-all]

assuming you using a guide baton lube the blade with ptfe spray and cut 20mm then set the teeth to 40mm no more
if the worktop is not fully supported it can sag and bind on the blade

yes a new blade is the best option but for a one off ??

 

[Dave54]

Oak is harder than most woods to cut. You should try ripping it! Having said that a good sharp blade as already said should crosscut OK. Unless you're experienced it can be difficult to tell when a blade is worn. They get quite small sort of chipping on the cutting edge of the teeth which isn't apparent with a quick look. I'd use a coarser blade with oak as long as it gives an acceptable finish.
Are you sure that the blade is parallel to whatever guide you are using?

 

[7777777]

the saw i used was a circular saw i do have a bench saw but as you know the weight of a 3mt x 950mm oak top comes in at 80 KILO,,,,, so i used a guide with the circular ,,,,, thinking about it,,,, im thinking the blade may have been binding or the blade not as sharp as i thought hence the burn marks mostly in the center of the wood.......at the moment due to the weight i cant try another cut as its inside the house and 80 kilos and its size... make moving it hard

 

[Dave54]

I know what it weighs alright!
I used to get "wany edge" 1, 2 and 3 inch delivered here as "slices from the log". As much as two of us could do to carry it sometimes!
As I say, do check that the blade is parallel to the guide used (I'm assuming you're using a guide of some sort) Even a small bit out can cause it to pinch, as the blade is trying to cut a slight angle/

 

[7777777]

dave can you explain what i do to check its parralle,,,,, what i did was to screw a baton to the under side and run the saw along ,, im a plumber not a joiner so i welcome any advice,,,,, i do think that it was some how sticking or binding

 

[big-all]

unplug the saw
take a metal ruler or bit off say 2x2" par[21x44mm]
blade fully out
retract the guard
lay the timber along the sawblade against the base
draw a pencil line along the opposite edge off the timber
measure the distance at each end off the sole plate and if they are different the blade and base may be out off alighnment or the blade could be badly seated or a slight wobble

 

[Dave54]

What big-all said. All you're trying to do is check that the blade is parallel to whichever edge of the saw you're using against the batten. Otherwise the blade is sort of "steering" the saw, either away from the batten, which won't jam, but won't make a square cut, or into the batten, which "pinches" the blade as it tries to get closer than the batten. You can tell when it's happening with a bit of experience, because the saw will start to slow down and be hard to push forward as the blade rubs.

 

[big-all]

if you look at the cut edges if the cut starts clean and un burnt on one side for a few inches then burns thats a tell tail sign its off line a bit