resharpened circular saw blades seem wrong.

[RossJarvis]

I also posted this on the Mafell forum.

I've recently had my 12 teeth Mafell blades sharpened (rip blades). At the time I thought they looked wrong but the chappie said "I've been doing this 30 years and that's right'. I thought they looked at too much of an angle and should be much squarer. Although they did have some alternate angle originally. The reason I ask is that I couldn't get through a knot in an oak board and had to come out and plunge into it. I'd never needed to do that before.

Anyone know how I could find the correct angles. They are noticeably angled as you look down the blade through the centre and along the teeth (if that makes any sense). At 60 quid a pop for a new one it angers my wallet.

 

[RossJarvis]

Having worked out how to get pictures out of my camera, this is what the teeth look like now;

 

[siggy_7]

There's no right angle I think, but ATB blades I've used have 12-15 degree top angle. The steeper the angle, the sharper the cut will be - you can get fine cut HATB blades with about 30 degree top angle. The higher angles cut better and I think with a little less effort on the motor. The disadvantage of higher top angles is they blunt quicker.

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[dzj]

I don't think rip blades should have alternating beveled teeth.

 

[Beau]

Not sure on angles but looks like a right dogs dinner of a grinding job in the second picture. 30 years experience?

 

[RossJarvis]

I've checked the packaging and it does say alternating teeth, however something makes me think they didn't look so steeply cut before re-grinding.

It also seems to me that it's harder to push the thing along when doing rip cuts.

If it were a hand saw it would have "chisel" teeth square in two planes, but I'm not sure about circular saw blades.

I think the picture of the top grind is a bit out of focus and the teeth on that blade had had a bit of a hard life. (One had to be replaced as I somehow managed to leave one of them stuck in the aluminium track )

 

[Neil S]

I always thought that rip blades didn't cut but more scraped the wood shavings out therefore they were a flat top grind. Usually with fewer teeth as well. Cross cut or combination blades usually have more teeth and are alternate top bevel grind as they cut the wood fibres.

-Neil

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[RossJarvis]

I've been to Elliott Bros and compared it to the stock one on their example. The angles are noticably different, the stock blade is cut much squarer. I've had a moan at my local tool shop who sent them off for sharpening and have had a chat with the owner of the sharpening firm over the phone. He does seem to know his stuff. Unfortunately, despite having phoned Mafell in Germany we can't get any information on what the angles should be. The sharpening boss and Mafell chappie seem to think it may be fine with the steeper angles, but as it's a non standard blade who knows. What with my other worries I'm just thinking it's one of those months and I shouldn't get out of bed.

All I know is that it doesn't feel "right" on rip cuts and I couldn't get through a knot, at all, in green oak at 3 1/2" deep cut, maybe I'm over-reacting?

 

[Chrispy]

I've been to Elliott Bros and compared it to the stock one on their example. The angles are noticably different, the stock blade is cut much squarer. I've had a moan at my local tool shop who sent them off for sharpening and have had a chat with the owner of the sharpening firm over the phone. He does seem to know his stuff. Unfortunately, despite having phoned Mafell in Germany we can't get any information on what the angles should be. The sharpening boss and Mafell chappie seem to think it may be fine with the steeper angles, but as it's a non standard blade who knows. What with my other worries I'm just thinking it's one of those months and I shouldn't get out of bed.

All I know is that it doesn't feel "right" on rip cuts and I couldn't get through a knot, at all, in green oak at 3 1/2" deep cut, maybe I'm over-reacting?

Seeing as your having such a bad day, you have got the blade in the right way round haven't you? silly I know but it has been done before.

 

[harvestbarn]

It might be worth checking the width of your riving knife in case the grinding has altered the cut width and it is now binding a little.

 

[RossJarvis]

Ha ha, blade wrong way round :lol: No, I've checked that, I wouldn't put it past me but that at least is okay.

We've checked the teeth and the re-grind has not changed the cut width.

I've actually been to the sharpening company who have been incredibly helpful, they've re-ground to the original 5 degree bevels and I'll see how it goes.


I'll be putting a good review of the saw doctor as they have been very good.

 

[RossJarvis]

As mentioned in my review of the sharpening company I've now tried the new grind and the saw's working fine now. I know next to nowt about circular saw blade technology and it does seem that rip blades can be angled noticably, I'm now not sure whether it was the blade or operator error

I am however coming to the conclusion that Mafell blades are probably over-priced and it's worth switching to other brands. Mind you the size and style of the one I've got does seem unique. 237mm or 9 5/16" anyone?

 

[Jamesc]

Would you mind mentioning who the re-grind company is please (PM me if you want to keep it private).

I am not too far away from you (Southampton) and have been struggling to find a decent company to sharpen my blades locally

James

 

[RossJarvis]

Would you mind mentioning who the re-grind company is please (PM me if you want to keep it private).

I am not too far away from you (Southampton) and have been struggling to find a decent company to sharpen my blades locally

James

Its in Eastleigh and called Saw Tec. I don't know if you've tried them but I had great service.;

http://www.sawtec.co.uk

 

[Jamesc]

Thanks,
Strangely enough they were the ones I had problems with, admittedly it was a number of years ago and they did not have the fancy CNC machine shown on their website. I will give them another go.

 

[RossJarvis]

Thanks,
Strangely enough they were the ones I had problems with, admittedly it was a number of years ago and they did not have the fancy CNC machine shown on their website. I will give them another go.

I know what you mean, sometimes you get great service and others dreadful from the same people.

 

[andersonec]

Have a look at some of the angles on the Axminster site, I think they are explained on there, or even Atkinson Walker, they are very helpful and have re-ground blades for me to different dimensions and angles.

http://www.awsaws.uk/

Andy