Metal Cutting Saw

[BukitCase]

Willie, check the rated rpms on your saw (probably 3600 or so) vs. the rated max rpm of the blade you're looking at - I've seen a few that are rated at high enough speed for a normal chop or radial saw, but haven't tried 'em to see how long they last.

What I DID do, and it was a success (until it wasn't :=( was to buy a "closeout" blade from Hazard Fraught, it was a 14" carbide tipped "metal cutting" blade - it listed max rpms at around 2400 IIRC, and my abrasive chop saw is 3650 or so - I got stupid, put on my heaviest welding leathers/gloves and face shield, clamped a piece of square tube down, stood with ALL body parts AWAY from the plane the blade runs in, and gave it a shot -

The cut was perfect, no burrs, looked like it had been polished after cutting. Same with the second cut, up thru about the 15th or so (IIRC, it was 2" .095 wall tube) -

Then, it got harder/slower to make each successive cut.

By about #25, it was done. Blade was clearanced out @ $50, so each cut cost me $2.

Typical "cold cut" chop saws like DeWalt, Milwaukee, etc, run at around 1750 rpm and the blades are typically rated at maybe 2000-2500 -

Like I said, I've seen a couple 8-10" blades that are rated at high enough rpm, but they're anywhere from $60 to $100, and I'm not sure I want one bad enough to take the chance it will last.

I am, however, planning on keeping the blade option open on the "radial plaz" when I get to it, but it'll mainly be a "mini-track saw" for a plasma cutter, that will crosscut, miter, bevel, and cut radiuses for things like hoe and loader buckets, maybe "heavy duty hose hangers" for all my welding carts, etc. - I'm gathering notes and such, and will start a new thread in the Welding forum on the subject - of course, anyone who beats me to it will be encouraged to post pics, plans, results, etc, so that thread can be sort of a "one stop shopping" thing for converting a RAS to a "RAP" :=) Steve

 

[JKR]

If you want to cut metal get a metal saw. Milwaukee 8" saw will cut though 1 1/2" plate. I also use a 3/4" metal band saw, twin blade saw for pipe and rods that just need to be cut.
Using a wood saw on metal is just asking for trouble. It runs to fast an will take the teeth of the blade.
Be safe in your work and do it right. Or pay some one to do it for you.

 

[downsizingnow48]

I explained in Post #1 and Post #23 that the DeWalt turns at 3425 rpm which is compatible with the Makita 5 3/8" metal blade rated at 4600 rpm. Pls look at those notes and let me know if there is still something that concerns you about blade speed.

 

[muddstopper]

A milwaukee 8 saw is rated at 3700rpms, the RAS is rated at 3450rpms, a 8" Irwin metal cutting blade is rated at 5000rpms. Speed shouldnt be a problem as long as the blade you choose is rated for or above the speed of the saw. My problem with the RAS metal cutting conversion is climb out when cutting. The Milwaukee metal saw, as well as other skill type saws, all have a plate that keeps the saw flat on the material. Table saws work the same way except upside down and you push the material instead of the saw. The RAS is hanging in the air, free floating on a rail, with nothing except the operator to keep the blade from taking to big of a bite and hooking a tooth and climbing out of the metal.

 

[Willie B]

Is that perhaps something that sets the new to the market power hand saws for metal apart from conventional wood saws; speed? No, I hadn't studied up on rpm ratings yet. This thread planted a seed for thought, it hadn't yet germinated. A young fabricator friend swears by the metallic blades for abrasive saws. I guess I hadn't realized how slow they turn. I have a Milwaukee, quite an expensive saw, it seems painfully underpowered, especially with aluminum.

 

[BukitCase]

Blades - as long as your blade's rated speed is somewhat higher than the saw's rpm, it would be a non-issue. If you ignore this, the LEAST of your problems will be short blade life.

Saws - all the 14" cold cut saws I've seen have a speed in the 1400-1600 rpm range. All the 14" abrasive chop saws tend to run in the 3400-3700 rpm range. The one test I did showed that too fast a saw WILL dull these blades rapidly, and may also cause flying parts, which I did NOT experience.

One thing that will shorten the life of ANY blade is impatience - if you try to "power" through cuts on any material, you'll get crappy results and shorter blade life (in my experience)

Climb cuts on radial saws - with WOOD, using the saw on pull cuts is fine IF YOU'RE CAREFUL and don't let the saw get ahead of you - this takes technique and practice, and isn't for everybody.

On METAL, I would stick to PUSH cuts and a FAIRLY GENTLE approach with dual HOLD-DOWNS.

With adapting a RAS to metal, once you've found a rpm compatible blade there are also SAFETY issues -

1 - guarding. Flying metal, regardless of WHERE it enters the body, is arguably more dangerous than wood. And trust me, there are a LOT of small metal chips flying around that need to be controlled.

2 - Hold downs - chop saws have 'em, so should a RAS. I've not dug into options on this yet since MY main plan is converting to Plasma. Maybe something like a SLOTTED table with a couple of drill press hold-downs that can adapt to material size.

3 - Table - personally, I would NOT keep ANY wooden parts, either for blade or plasma use. I know the blades are called "cold cut", but still...

JKR, your concerns are noted and agreed with - but sometimes people wanna push the envelope and/or don't have the extra money available for the "real" deal - plus, this IS the "build it yourself" forum So some of us who can identify with some or all of these reasons will do our best to advise on the SAFEST way to do these (possibly un-safe) mods.

Unique operations - For metal cutting, I have two horizontal band saws, an abrasive 14" chopsaw I almost never use, thin cutoff blades for side grinders, two recip saws, hand hack saws, O/A cutting torch, plasma cutter, a Porta-Band, and they all have their uses/strengths/weaknesses, BUT

One thing NONE of them can do to my satisfaction, is to cut out ONLY THREE SIDES of a piece of square tube with left and right ACCURATE 45 deg. cuts, so the REMAINING side can be bent closed and welded, leaving a square corner with a perfectly smooth outer corner -

The only thing I'm aware of that CAN do that is one of the HIGH DOLLAR band saws that does NOT hinge at the rear, but instead the ENTIRE SAW floats up and down on linear ball bushings so the BLADE IS ALWAYS PARALLEL to the table - if you can find one USED, it'll still cost you anywhere from $1500-$3000. A bit much for a home shop

I think there's a way to accomplish that with a modified RAS, but to do it SAFELY isn't gonna come easy. Eventually I'm gonna try, but it isn't my MAIN goal - as stated earlier, it's a "poor man's plasma table" since the 4x4 CNC plaz I'd REALLY like to have is in the $10k range.

Man, this is getting long even for me :laughing: I probably forgot what I originally intended to say... Steve

 

[Willie B]

I think the radial arm saw will continue to serve the same purpose it has since new; a place to pile objects I have no other place to pile. Oh well.

 

[muddstopper]

I think the radial arm saw will continue to serve the same purpose it has since new; a place to pile objects I have no other place to pile. Oh well.

Thats exactly where mine has been for the last several years. I had to climb over a bunch of junk just to take the picture I posted

 

[sandman2234]

My step-father took me out to the garage one day, and told me that his radial arm saw was to be mine, when he was gone. Mom asked me what he wanted when I got back into the house, and was surprised when I told her. When he passed away, Mom said my brother wanted the saw to stay there so he could use it to "fix" stuff. I told her that wasn't what he wanted, but if she decided she needed it there, I would leave it there. Ten years later it is still there...lol!
David from jax

 

[ultrarunner]

^^^ Hear things like this a lot..

My Grandfather had given me an old clock that had been on the wall at his place of business when he opened in the twenties and it was old then... he also gave me an old 8" table top lathe.

When he passed, I was 13 and my Uncle claimed it and that was the end of it...

My neighbor wants to sell his Craftsmand circa 1980 Radial Saw... he brings it up every couple of months... never needed one yet and don't know where I would store it...