Angle grinder for cutting wood

[tony sayer]

In article , Harry Bloomfield scribeth thus

Bet you go thru the blades doing that;!...

Which one have U got?..

73's

[Bruce]

Time you bought that pressure washer. :-)

[Harry Bloomfield]

tony sayer presented the following explanation :

No, none have worn out yet. I've managed to cut 12" trees down with it, lots of roots and cut 4" alloy bar stock.

The blue black Aldi variable speed one. The spring which closes the lever for foot adjustment seems to have weakened (may just be choked up with saw dust), other than that it works well.

[stuart noble]

A sawblade has individual teeth is so that the debris from the material being cut can be thrown clear of the next tooth. If the blade cannot clear itself, there is just friction but no cutting. In the old days B&D used to do a 5" circular saw blade as a drill attachment. Can't imagine what it could have been used for, but at least it wasn't spinning at 10,000 rpm

[Andrew Gabriel]

I have one of these on the shelf in the garage, but the drill gave up (the day I just bought several new blades for it, of course). It worked well for 10+ years, before dedicated circular saws were available at affordable prices. B&D had a load of drill attachments of that form. My father also had the circular saw one, but also the jigsaw and the hedgecutter attachments (and probably some I've forgotten).

However, this brings up an important point... An angle grinder spins much faster than the safe operating speed for a circular saw blade, so don't even think about going there.

[Bruce]

My father had the B&D circular saw attachment and the finishing sander attachment. I inherited them and used them for a few years.

When I finally got around to buying a Bosch circular saw, I wondered why on earth I had struggled on with the clunky B&D attachment.

[js.b1]

Fuckwit.

A diamond disc will not cut wood due to the mimimal depth of the cutting surfaces, it will instead burn through whilst spinning at circa 10,000 RPM.

A diamond disc with sintered tabs, several long teeth interspersed by gaps, will snag on the wood fibres - flinging unsecured wood at some function of the 80m/sec disc speed, kicking back off sufficiently immovable wood or shredding wood into a fibrous pulp rather than efficiently cutting. With sintered tab on wood there is some risk of ejecting a tab or a limited risk of catastrophic disc fracturing from a tab gap (most discs have the tab slot ending at a circular hole to reduce crack propogation across the disc causing separation which at circa 10,000rpm would be unpleasant).

A diamond disc that is continuous (does not have a tabbed perimeter) will just bounce off the surface or burn through.

This is exactly how someone killed themselves with a diamond disc in an angle grinder, it kicked back off a tree stump and embedded itself in their neck severing an artery. Most likely a tabbed diamond disc where the slots snagged on a particularly resilient group of wood fibres so launching the grinder up into the victim's neck.

Any blade for wood cutting at angle-grinder RPM will need to have a very robust disc construction, very robust teeth to resist the peak shear forces along with an appropriate tip cutting angle, and large inter teeth gap to handle the extremely high material ejection levels at such high RPM. That is to say teeth gaps of several millimetres compared to the sub-milimetre gap for diamond cutting brick particle ejection.

Alligator saw has double blades, demolition saw has single blade. An alligator saw is a lot more useful to a DIYer.

[Mike Marlow]

Potty mouth.

Don't use many angle grinders do you? Regardless of the 10,000 RPM, it still does not approach the speed of a simple circular saw or a sawzall.

It's clear you don't use an angle grinder much. Any wheel in an angle grinder is capable of kick back. All you have to do is contact the leading edge of the rotating wheel. To my point - it's not a matter of the wheel in use, it's a matter of where you contact it.

[stuart noble]

My simple circular saw RPM is less than half that. Peripheral speed unknown though

[Bob F]

And there's always harbor freight for a cheap source. Better than using an angle grinder and having an accident.

[Stuart]

Put it across a couple of bricks and stamp/jump on it.

[Stuart]

Same as me probably

Stuart

[Stuart]

Yup, had one of those

It was usefull for cutting sheet material or ripping down the odd floorboard :-)

[Bob F]

How about when you are trying to cart off that old firewood pile you don't need anymore?

[stuart noble]

Yes, I can imagine ripping a floorboard with that thing :-)

[John Rumm]

Multiply by the blade circumference... so for a 190mm blade at 4500 rpm that is 4500 x 0.19 x pi = 2686 m/sec

[stuart noble]

I knew I could count on you :-)

[dennis]

I have an even cheaper PPro one I bought in a clearance and it does roots really well. It says maximum cut 100mm but it cuts anything the blade fits, I have some

10" green wood blades and it works fine. For demolition I have some tungsten tipped blades and just cut through the wood and metal. The whole lot was ~£20.

[js.b1]

Heh-heh, blade tip travelling at beyond even rail gun projectile hypersonic speed would be fun.

RPS =3D 4500rpm / 60 =3D 75 Circumference is 2*Pi*R =3D 2 * 3.14 * 0.19/2 =3D 0.59m Circumferential speed =3D 75 * 0.49 =3D 44m/sec.

At 4,500rpm you have almost 100 miles per hour. At 10,000rpm you have

200 miles per hour. Quite a few angle grinders run 12,000rpm, still far below the sound barrier.

Due to the way an angle grinder is mechanically driven, stopping one in motion as with a tree root will hurl the saw at speed. A chainsaw will not do this hence eminently less dangeous than a freakin angle grinder.

Alligator saw is expensive but handles both demolition & general precise wood cutting, a jigsaw with a wood ripping blade is cheaper.

[aemeijers]

OP is in the UK- No HF over there, but they likely have something similar.