Thread: Whats the best smooth cut blade for radial arm saw

Hi Tim,

I am no authority on the Radial Arm Saw but one thing I find that helps on critical cuts is to have a new sacrificial piece of MDF on top of the saw bench so that you get a nice new clean kerf in the MDF top that gives better support to the work. As opposed to an old top that usually has a wider kerf and therefore does not have support right beside the blade under the work piece.

Others may be able to comment on saw blade selection, but I am surprised that the 60 tooth is giving worse results to a 40 tooth blade, particularly if it is a crosscut blade.

Cheers
Pops

G'day Tim,

What Pops suggests will work or you could try what I do - when the kerf gets chewed out a bit then the tear out will get worse - mix and fill this kerf with Plastibond [not the type whch is reinforced with glass fibre] - let it go off almost and clean up excess with a sharp chisel leaving it slightly proud - let it go off completely and clean up any excess using a ROS.

You can then recut an "original" kerf which will eliminate almost all of the tear out - if the timber is laminated [ply] or you are crossing the grain you may find it useful to use a good quality sticky/masking tape on the underside of the cut as this will help further.

Hope it helps,
Regards,
Bob

Hi Bob,

Doh !! I forgot about using tape. Good call. However I had not thought of filling the old ragged slot in my table as you have noted. This is brilliant !!! Well done, Thanks for that idea. Will write that down before I forget it.

Tis a terrible thing, one's brain getting old before its time.

Tim,

Are you sure that you have a crosscut blade and not a fancy tripple chip blade for laminate or some other type. I really am surprised at the blowout / tearout with a new 60 tooth blade, even with a ragged/wide kerf in in your table top.

Anyway give us an update on how Bob's tips work out for you.

Cheers
Pops

Tim
whilst I'm no expert, not all 10" blades are the same.

as I understand it, the 10in 60 tooth blade used in a mitre saw needs a different hook angle to that on a 10in 60 tooth blade used in a radial arm saw and a cross cut blade used in a table saw might differ again. Something like a sliding Mitre saw needs a 5° rake and a radial arm saw needs a 15° rake. Please don't take these rake angles as gospel, I just know they differ.

then there's suport under the cut as mentioned by others

Just my way of dealing with this type of problem.
Run a Stanley knife along the cut, instead of a pencil line. (before cutting).
Works for me on all saws and the jig saw.

Paul.

One thing that will improve the cut from any blade is working out the optmum amount of penetration and this will vary from blade to blade and from material to material.
Sometimes you want the whole tooth thru the material, somtime half the toothe and others the tooth barely comming thru.

In general terms for cut quality on a radial arm or dropsaw, a negative rake tripple chip, with lots of teeth blade is the way to go......typicaly something intended for cutting aluminium.

But it wont be fast.

cheers

Originally Posted by soundman

One thing that will improve the cut from any blade is working out the optmum amount of penetration and this will vary from blade to blade and from material to material.
Sometimes you want the whole tooth thru the material, somtime half the toothe and others the tooth barely comming thru.

In general terms for cut quality on a radial arm or dropsaw, a negative rake tripple chip, with lots of teeth blade is the way to go......typicaly something intended for cutting aluminium.

But it wont be fast.

cheers

Soundman, I'm not having a go, but have you used both a radial arm saw and a sliding mitre (drop) saw?
My understanding is that because the radial arm saw is PULLED through the cut, and a sliding mitre saw PUSHED through the cut, the desired tooth rake angle is radically different for each saw. IIRC, the rake angle ideal for a sliding drop saw is positively dangerous if used on a radial arm saw.

In fact I have used both extensivly and a negative rake is generally considered best and safest for a radial arm saw, because it has far less tendancy to grab and self feed.

I have however seen and used radial arm saws with positive rake blades .....certainly not my preference, extreem care is required, but it is often done.....radial arm saws have some inherant risks, no matter what blade is used on them....no one should approach a radial arm saw without understanding the specific dangers inherant with them.
I have neary been the victum if some one who failed to understand one of these specific risks.

That does not make a negative rake blade inappropriate for a drop saw or a sliding compound mitresaw, an electric hand saw OR a table saw for that matter.

Negative rake blades can and are used very effectivly and safely on all these machines.

cheers

Originally Posted by soundman

In fact I have used both extensivly and a negative rake is generally considered best and safest for a radial arm saw, because it has far less tendancy to grab and self feed.

I have however seen and used radial arm saws with positive rake blades .....certainly not my preference, extreem care is required, but it is often done

thanks soundman
the OP is looking for "the best" cut-off blade to use in a radial arm saw.
I'm concerned that they not be led astray by people who only use mitre saws

The quality of a blade is also important. Cheap generic saw blades have a lower grade of tungsten carbide teeth and a lower grade of steel body. This results in the teeth not being as sharp and not holding the edge for long as a good quality sawblade. And the sawblade body flexing more, also causing a poor cut.
I'd recommend going to a good trade store that sells quality tooling. They could recommend a proper sawblade for your saw. Leuco or Lietz blades are the best in the world, and would cost more. They will last longer and give a cleaner cut.

You could rout out a strip on the table for a sacrificial board in there, so when it gets worn out, you just replace it.