# Slitting/Slotting Saw Noise



## ddickey (May 5, 2017)

I hade to make quite a deep cut. I used a .0625" saw ran it at teh slowest speed I can, 240 rpm. Used a lot of soluble cutting oil, that thing screetched and hollered like nobodies business. Just wanted to make sure this is normal. I needed ear protection.


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## bfd (May 5, 2017)

yes normal you need slower speed make sure you keep a load on the teeth. bill


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## mikey (May 5, 2017)

240 rpm is likely too slow. What kind of material were you cutting? How many teeth?

It varies with the material but I normally run a saw at about 1500-1700 rpm in aluminum and about 800-1000 rpm in steel and I get no screeching. I can hear the saw cutting but nowhere near the level that hearing protection is needed.


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## ddickey (May 5, 2017)

This was horendous. 20 times louder than ever before.
1018, 1" deep about 4" long. It was a 4" diameter blade. Not sure on the teeth but they were the larger not so not as many as the small type blades. Sorry I dont' know the correct terms.


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## darkzero (May 5, 2017)

With a 4" dia, coarse teeth, & 1018, you should probably run your mill as slow as you can. Not sure what RPMs you have available but max maybe 100 RPM.


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## ddickey (May 5, 2017)

That was as slow as my mill runs.


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## darkzero (May 5, 2017)

1/16" is pretty thin for a 4" slitting saw & that's also contributing for the singing. Normally I take cuts a full depth when using a slitting saw but if you have to make that cut again maybe try the next cut at only half depth & see what happens.


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## mikey (May 5, 2017)

In general, the fewer teeth you have, the higher the rpm you can use. That is a large diameter saw making a deep cut so there are no firm guidelines. Personally, I would try to go faster and see what happens. In my experience, there is a tendency to run too slow and feed too slow with slitting saws.


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## darkzero (May 5, 2017)

That makes sense, faster with less teeth, I got it ass backwards!  Still though, SFM still applies though somewhat.

I never had good results running slitting saw really fast except in aluminum & delrin. Could be just the ones I've use though.

Bottom line is experiment & see what works for you. Careful though, that's a big slitting saw & running at high speeds would scare the sheezo out of me.


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## mikey (May 6, 2017)

I just ran a 1/16" thick, 4" saw through aluminum at 1500 rpm a few months ago. Granted, it has a lot of teeth but it went right through without a hitch. 

I would try it in mild steel at 800-1000 rpm and lube it well and see what happens. If it works then good; if it seizes then blame Will.


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## ddickey (May 6, 2017)

Ok will do.


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## darkzero (May 6, 2017)

Blame me, ah hell no, now that's ass backwards!

800-1000 RPM, that's like in the neighborhood of 800-1000+ SFM. I'm not brave enough to try it but I am curious how the cutter will up in 1018 running that fast & DOC. Ya'll are crazy over there on that island (I tell "her" that all the time )!


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## ddickey (May 6, 2017)

Holy crap you're up early.


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## darkzero (May 6, 2017)

Haha, more like up late. 

But that's normal for me. My bedtime is usually like 3am. It's only 1:30am right now.


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## ddickey (May 6, 2017)

Oh yeah, west coast. Got it.


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## BGHansen (May 6, 2017)

From Tom's Techniques, the general "rule of thumb" for cutters for steel is "400 divided by cutter diameter" for RPMs.  If you have a 4" blade/end mill/drill, it should be run around 400 / 4 or 100 RPM.  Of course, rules of thumb are made to be broken depending on your machine and other variables.  I've had pretty good luck with slitting saws at slower speeds and wimpy feed rates.  Drag a chip brush on the blade to clear debris and drip oil.  Good luck!

Bruce


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## mikey (May 6, 2017)

Yeah, I know I'm suggesting some stupid speeds. Calculated speed for a 4" saw is somewhere around 100-130 rpm for steel but while the blade makers suggest speeds for their blades, they are usually for fine toothed saws with limited chip clearance. For coarser toothed saws I have found that higher speeds and higher feeds seems to work better, at least for me. 

Here is a 4" saw set up for taking a 1" deep cut, albeit in 6061. The rpm was 1700 rpm and the cut went clean. Calculated cutting speed for this blade is about 500 rpm.




Here is the cut:




This was a little rear mounted parting tool for a Sherline lathe. I've taken similar cuts in steel with this same saw at 800 rpm and got the same results in mild steel. 

Duane, give it a try. If you burn the blade up, I'll send you a new one.


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## Rustrp (May 6, 2017)

mikey said:


> Duane, give it a try. If you burn the blade up, I'll send you a new one.


WOW, experience and a good deal all in one.


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## EmilioG (May 6, 2017)

What about the arbor? Does the quality play a role in getting smoother cuts? Has anyone indicated the saw blade on the arbor?
How many teeth would be best to use in steel with a 3" saw blade?  From what I've read, fewer teeth are better for non ferrous metals and more teeth for steel.
There are so many variables.  DOC, size, abor, teeth, metal,......I suppose I'll just have to test them. (behind a thick sheet of plexiglass 
I have yet to test my slitting saws/arbor.  I'm waiting for my shipment of Martindale saw blades.


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## Cobra (May 6, 2017)

darkzero said:


> Blame me, ah hell no, now that's ass backwards!
> 
> 800-1000 RPM, that's like in the neighborhood of 800-1000+ SFM. I'm not brave enough to try it but I am curious how the cutter will up in 1018 running that fast & DOC. Ya'll are crazy over there on that island (I tell "her" that all the time )!



I would agree.  In steel I run the slitting saws (0.03-.125) at 70rpm.  Al at about 200rpm.


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## mikey (May 6, 2017)

EmilioG said:


> What about the arbor? Does the quality play a role in getting smoother cuts? Has anyone indicated the saw blade on the arbor?
> How many teeth would be best to use in steel with a 3" saw blade?  From what I've read, fewer teeth are better for non ferrous metals and more teeth for steel.
> There are so many variables.  DOC, size, abor, teeth, metal,......I suppose I'll just have to test them. (behind a thick sheet of plexiglass
> I have yet to test my slitting saws/arbor.  I'm waiting for my shipment of Martindale saw blades.



For arbors, accuracy, fit and a big enough cap are important. On good arbors the hole in the saw just barely fits on the arbor so I'm guessing we're looking at 0.0005" fits. The cap will be the same OD as the body. Of the designs I've seen, the Sierra American is the best one because it allows me to stack blades at need. I have not indicated the blade to date, sorry.

Hard to say how many teeth because the tooth count depends on the material, the depth of cut, the thickness of the material and so on.The more teeth you choose to have, the slower you have to run the saw. Personally, I use the coarsest saw I have for the job but I don't get too fussy about it. When I need a thin slot, I choose a thin blade and the number of teeth it has is what it has. More teeth slow the feed.

In my view, saws are meant to cut and not rub. In order to do that, your feed is more important than the speed. Like almost all cutting tools, there should be a slight positive resistance to feed. That feel, that you are just slightly pushing into the cut, means that blade is cutting continuously. When the blade is running fast, you are feeding pretty quickly and the blade cuts easily. For example, that cut in the aluminum block in the pics above took all of 30-40 seconds to do. As an aside, that parting tool will part mild steel at 1200-1500 rpm, three to four times the recommended parting speed; I've been told that it isn't possible but ... 

By all means, experiment and try things. For myself, I use recommended cutting speeds only as a starting point or guideline and take it from there. If I can keep up with the feed then I'll increase my speed until the saw cuts as efficiently as possible. My suggestions are a reflection of what I found to work well in my shop; I assure you that I am not pulling it out of the air.


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## mikey (May 7, 2017)

@EmilioG , I forgot to mention one very important thing - erect a guard of some type or you will have a band of dots across your chest from the cutting oil. I have a half-dozen T-shirts with this pattern so I thought I would warn you, and it doesn't come out in the wash! I cover my machine as well because it is messy.


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## EmilioG (May 7, 2017)

How much over do saws generally cut? Does a .078" wide saw cut .078" and how do you prevent burrs? Con. or climb milling?


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## mikey (May 7, 2017)

EmilioG said:


> How much over do saws generally cut? Does a .078" wide saw cut .078" and how do you prevent burrs? Con. or climb milling?



Slitting saws can be pretty accurate, within a thou or two of stated size. The little jewelers saws in particular are very accurate. However, a saw should not be considered a precision tool because you will always have a tooth or teeth that are not precisely aligned. You can tell this condition exists when you hear a knocking sound as you cut, and almost all saws have it.

In my experience, burrs are not a big issue with slitting saws. Any that do arise are easily handled with a scraper or file.

I only run the saw in a conventional manner, never a climb cut. Its the same situation with a wood cutting blade; if you ever tried or saw someone climb cut with a radial arm saw and have that blade chew its way toward the user in an instant, the event sort of stays with you.

Using a slitting saw is a non-event. It is a simple, routine job that goes easy if you do it right. Load the saw on the arbor, making sure that the saw and holder are free of debris and chips and that the teeth are pointing in the right direction (don't laugh; more than one of us has mounted a saw backwards). Torque the cap of the holder on firmly and bring the saw into position; again, slitting saws are intended to cut to full depth so set it to the full horizontal depth of cut. Pick a speed and let the saw enter the cut gently - you can dull the teeth if you ram the blade into the material. Once all the teeth have entered the cut, lube it generously and feed so there is a slight positive resistance to the cut. If you feel that feed pressure is excessive then increase your speed; a slitting saw should cut with very little resistance when the speed is right. Keep the blade lubed; heat from a dry blade will warp it and cause it to seize. Maintain your feed until the saw is clear of the cut. That's it, done.

Slitting saws don't require a lot of finesse but it does require us to listen to and feel our machine. It is the same feel when parting, turning, boring, sawing or anything else involving a manual feed. As you turn the feed wheel, you feel a definite contact as the cutter comes into contact with the work and you just need to maintain that contact as the cut progresses. If you feel the cut is lagging or that you are having trouble feeling the cut then try increasing your speed and the cut will go better.

Edit: I forgot to tell you to set the blade on a flat surface before you mount it and check to see that the blade is not warped. A warped blade will rock. If its flat and no teeth are obviously damaged then its okay to use.


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