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View Full Version : Dif Beteen SCMSaw and Radial Arm Saw



Ivan in Oz
25th July 2003, 08:07 PM
People in the know;
To a basic Novice,
What are the differences between
a Sliding Compound Sliding Saw
and a Radial Arm Saw?

What size of one is the "Equivalent" to what size of the other.

What are the limitations of each?

Thanks,
Ivan
CounT4

Wayne Davy
25th July 2003, 11:16 PM
My 2.2c (inc GST)

From what I know, Radial Arm Saws are damn dangerous. They are also quite expensive in comparison to SCMS. Radial's will cut a wider board but I think you would be happier and safer with a SCMS especially, as you say, you are a novice.

soundman
25th July 2003, 11:30 PM
the radial arm was touted as the answer to all you wood work problems at one time. that seems to have calmed down.

the radial arm is usualy a medium sized machine wher the saw runs on an overhead arm.
They do a number of things very well. like angle cutting big boards.
But ripping with them is verry scary, dont do it.
They do have a number of dangerous tendancies that require propper care.

the sliding compound miter saw is a much more practical machine for most people cheaper, lighter and quite a bit safer.

all types of saw will cut off fingers with equal ease.

journeyman Mick
25th July 2003, 11:41 PM
I've got both, bought the radial arm years ago thinking "wow, this can do everything, 600 wide crosscuts, mitres, compound angles, ripping, bevel ripping". Yeah it can do them all, but it's not very good at any of them. When crosscutting the blade tries to pull itself forward and up and over the workpiece. If you don't hold it back it will try to climb over, jamming itself and stalling. You really need to use negative rake blades to minimise this but they're near impossible to find. I find that mine just has a trenching head permanently fitted and it gets used maybe once a year to run up saw stool tops for the year.

Comparison wise:
DeWalt 10" RAS will do 600 wide crosscut on 19mm stock (if you move the fence back to its rear position), cuts about 70mm deep, takes 2 people to lift. Constantly needs adjustment for accuracy.

Makita 10"SCMS Will do 300 wide crosscut (not sure how deep, but probably 50mm @ 300), cuts 90mm deep, easily lifted by one. Wont rip. Unless dropped, doesn't need adjustment for accuracy.

I wouldn't recommend a RAS at all, mine hasn't paid for itself yet and I've had it for more than 10 years, all my other tools generally pay their way in 3 - 12 months. I'd get rid of it if I thought I could actually get anything for it!

Mick

Iain
26th July 2003, 09:45 AM
Mick, SCMS's come with a 3 to 5 degree negative rake blade and even Bunnies carry them as a stock line.

journeyman Mick
26th July 2003, 05:52 PM
I've seen plenty of 8 1/4" blades with negative rake as the Elu SCMS uses them but none in 10", mind you I stopped looking a few years ago. At any rate I don't think anyone makes a 10" ripping blade with negative rake and that's really what I needed at the time. I managed to keep the saw from pulling itself through too rapidly when crosscutting by attaching a cable which ran through a wall mounted pulley and had a counter weight on the end (couple of brake drums). But ripping was such a totally hairy experience that I only tried it a few times, never had a mishap but I quit while I was ahead.

Mick

PS Neither of the two Makita SCMS's that I've had came with negative rake blades, and none of the replacement blades were either. Are you sure about the negative rake Iain? It shouldnt be neccesary on a SCMS as you are bringing the blade down into the timber and pushing it back against the direction of rotation. Whereas with a RAS you are pulling it into the timber with the direction of rotation so the negative rake is really needed here to minimise the blades tendency to "drive" into the cut.

Iain
27th July 2003, 08:29 PM
Mine has a negative rake blade and the Bunnies blades are Irwin.
Carbatec carry a range of CMT neg rake blades.
I thought the idea of a neg blade on a CMS or SCMS was to stop the workpiece being spat out at you, sort of a lateral thinking version of the RAS climbing over the work.
The blade tends to drop (cut) into the workpiece rather that attackking at an angle likely to produce a kickback, although I have managed to achieve this (we won't go into what I was doing or why, but I should have been using the bandsaw :( ).

journeyman Mick
27th July 2003, 11:18 PM
Can't say I've had a kickback as such on the dropsaw, but I have had the blade get pinched due to bowed stock or stresses in the grain, one was so bad I had to remove the bade from the saw with the timber still clamped around it! Don't know if the negative rake would have helped here. Must say that most of my replacement blades have been supplied by companies I've worked for, I try to chisel one out of the larger mobs on big jobs, so I haven't been that picky as they've been freebies.:D

Mick

John G
27th July 2003, 11:56 PM
I'm confused as to why RAS would suffer from kickback or try to ride over the timber, but a SCMS would not? The blades rotate the same direction yeah?
Is it for a SCMS you start the cut at the front and push it back, whereas for a RAS you start the cut at the back and pull it forward? Why can't you start the cut at the front too?

journeyman Mick
28th July 2003, 12:03 AM
[QUOTE]Originally posted by John G
I'm confused as to why RAS would suffer from kickback or try to ride over the timber, but a SCMS would not? The blades rotate the same direction yeah?

Is it for a SCMS you start the cut at the front and push it back, whereas for a RAS you start the cut at the back and pull it forward?
You got it

Why can't you start the cut at the front too?
With a SCMS you bring the blade down and then push it back. With a RAS the carriage only moves back & forth, it doesn't pivot up & down as well. You can bring the carriage forward, place the stock against the fence and then make your cut but it is awkward and you do lose some of your cutting capacity, the width of your stock plus the blade width plus a safety margin.

Mick

Don't know if I've got this quote stuff worked out yet.:confused: