Thread: Educate me on slitting saws?

Originally Posted by carlherrnstein

That looks like a job for a bandsaw............. but hey mill it just cause you can.

Exactly my thought. :-) It's only a clamping slot.
Bandsaw and a strip of emery paper.
...lewie...

Personally I haven't had any problems running slitting saws once I started paying attention to SFM and cooling/flushing. I like to put a paper washer under the arbor clamp for extra clamping. Choose a saw that has more than three teeth into the cut. Smaller diameters will be slightly more accurate.

Originally Posted by eKretz

I'm not sure that applies to slitting saws, but just a couple days ago I was standing 10 feet away from a young kid using a cutoff wheel on a 5" hand grinder at a friend's shop. The wheel got misaligned in the midst of cutting and grabbed, exploded.

Metabo and probably others have a clutch to stop the spinning when choked, saved me several times.

Had a buddy who lost the key to his garage (pad lock) so he grabbed a grinder with a thin cut off wheel that had been sitting Loose behind the seat of his truck.

It didn’t have a guard on it, I said that’s dangerous man it’ll kick back and cut you pretty bad, he said I’ve used them for years “I know what I’m doing”.

And to my surprise about 10 seconds into the cut the thin wheel EXPLODED and blew the meat off 4 fingers.

The doc fixed him up good, had to do surgery.

A few years later he overdosed and passed, he was the rare breed of addicted, worked his body to death to feed his habits, wasn’t the zombies that run around stealing and causing trouble.

Rip Higgins, miss ya buddy.

Originally Posted by Homebrewblob

Rip Higgins, miss ya buddy.

That sucks (all the way around, it seems).

Sometimes we think with our lizard-brains rather than the big one. When that goes wrong it can get ugly.

Originally Posted by Milland

That sucks (all the way around, it seems).

Sometimes we think with our lizard-brains rather than the big one. When that goes wrong it can get ugly.

It can get ugly but it seems we still consult the lizard brain because when it does work, it works great.

Higgins told me a really good True story.

He was in the 3rd floor window of a old brick house Doing some kinda Stone Lentil or mantle work,

he consulted the lizard brain and determined he could save some time by chucking the crumbling stone into the bed of his 94 F-150 from the window.

He said he tossed a football sized of stone into the bed and sure as shit it blew a hole in the bed and busted his driveshaft clean off!

Amazing the truck didn’t roll away (automatic transmission).

Was a fun crude honest friend.

Originally Posted by Homebrewblob

He said he tossed a football sized of stone into the bed and sure as shit it blew a hole in the bed and busted his driveshaft clean off!

Was a fun crude honest friend.

Sounds like a gent who'd give you a lifetime of memories. As long as he didn't suggest you stand on the bed of the truck and catch the stone bits...

As long as it was his truck and not mine...

Originally Posted by Homebrewblob

He said he tossed a football sized of stone into the bed and sure as shit it blew a hole in the bed and busted his driveshaft clean off!

How did we get here from slitting saw speeds/feeds? Yall still honoring the great American tradition of whiskey on thanksgiving? I think your friend must not be from the West Coast...Out here even the dummies make sure to throw stones only at the other guy's truck.

To summarize, sounds like I want to calculate the same SFPM as I run my endmills, but super light feeds, a ton of coolant, and some safety glasses.

safety glasses might not be enough. stand so shrapnel wont hit you. (i never found the "chip".)

If you're into thin saws eg 1/64" thickness, then it helps to go really easy- make the first few passes at about the thickness of the saw, so the kerf doesn't wander because of the saw warping in the cut. That can be unnoticed early on, then later on deep in the cut the saw starts binding and flexing till you push too hard and it shatters. After the kerf is a few saw thicknesses deep then I start ramping up the doc but no more than 3 to 4 times the saw thickness. Thicker saws are a lot stronger can can be pushed a lot harder. "Pecking" the cut this way can help if the piece is prone to closing up on the saw; leave only a thin strip for the last cut lets the rest of the cut go easily.

Coolant to wash out the gullets is very important on the small tooth saws. The small teeth can quickly go from cutting well to packed off and burning. If parting something circular its helpful if you can rotate the part while cutting so you only need half its diameter- smaller saws better than larger ones.

Consider also keeping rpm and feed low, I run at 50% indicated by speed/feed on thin saws- a sharp saw gives a feel of freely cutting, even slighly blunt saws considerably increase cutting effort. That said I saw on a manual horizontal with lever feed so "cut feel" is easily observed and feed can be tailored to how the cut is progressing- much harder to sense on a screw fed axis or cnc. Taking care, I generally hit .001" flatness and perpindicularity with thin saws in steel or AL on total cut depth up to about an inch- I've sawn up to maybe 2" depth but mostly around 1/2". If you go easy the cut face can resemble a blanchard ground surface.

One more tip - for the feed it helps to figure out the actual number of teeth cutting. On larger saws where the rpm isn't high you can pretty much count the thunk thunk thunk as the teeth come around and hit the work. If there are only a few hitting you might want to calculate the feed per rev for the cutter as though it has only a single tooth. Or better yet, put in the effort to get it running more concentrically.

The multiple cuts starting with a shallow one can't be stressed enough IMO. That's the way to go for good saw life and straight cuts. Lowering cutting speed for deep cuts is good too: it's hard to get coolant in deep through a narrow kerf.

Originally Posted by catalytic

In my whole time machining I have never used a slitting saw. I have needed them, but always found a way to get the job done with something else. I finally picked up a set of Sierra American arbors yesterday. Is there anything to know about selecting/using them?

-Is it correct to think that I want the thickest saw with the least overhang over the arbor support for each job?
-Does more overhang/larger diameter for the same arbor tend to result in chatter?
-Now that I bought various arbor sizes, I see McMaster sells the vast majority of saws in 1/2" or 1" arbor sizes. Why have other arbor sizes? Just for 'fitting in' places?

-I expect I'll be using HSS saws, as parts are one-offs on manual machines and unless I'm working on the lathe I don't use much carbide.

-Any preferred brands/styles/tooth counts? Most jobs will be slotting aluminum to depths of no more than 3/8" with a slot that can be 3/32" wide.

If your depth of cut will allow it use a woodruff cutter they tend to make much straighter cuts and you can get them in many sizes, I always choose a woodruff cutter over a slitting saw if possible. Less run out is also a plus, you do not get the added run out of an arbor and the fit of the saw to the arbor and that results in better cutter life and far less chatter.