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Slitting saw info

trlvn

trlvn

Ultra Member
Just wanted to share a helpful resource on slitting saws:


Pages 13 and 14 have a bunch of good information including a table of recommended rpms based on the blade diameter and material to be cut. They also suggest that the feed rate can be up to 2 thous per _tooth_! Not sure I'll ever push things that hard. I keep a copy of this page with my blades.

YMMV,

Craig
 
Screenshot_20250509_201916_Adobe Acrobat.jpg

So from 2.8 to 28 ipm on a 3 inch 56 tooth in mild with cutting oil. Saw loses temper when it turns blue lol. I'd be trying like 5 to start.
 
AIUI, and I'm very much a novice, a 56 tooth, 3 inch blade is considered a 'screw slotting' blade. Max depth of cut would be something like 3/4 inch but such a blade would typically be used in thinner materials as the larger number of teeth means smaller gullets to carry away chips. With a shallow depth of cut, I could see a fairly high feed rate but 28 ipm would have to be with some super-rigid, ultra-accurate production machine.

They recommend saws with fewer teeth for deeper cutting or slotting. Say 30 teeth on a 3 inch blade. That basically cuts the theoretical feed rates in half as the blade has about half the number of teeth per revolution. So with the example above, the feed rate could range from 1.5 to 15 ipm. In that case, it could presumably be taking a full 3/4 inch DOC. Would make an interesting experiment!

Craig
 
Dissenting voice here .... I wonder if the authors of such tables have ever used one?

Because of clearance required between cutter and arbor, they seem to always end up eccentric and cutting on a few teeth on one side. Unlike a horizontal mill cutter, they are too flimsy to get enough of a load to make that go away.

Ergo your 80 tooth cutter is cutting on say 4 teeth on one side ..... In my experience you need be aware of that else you'll have a crash. Feed based on a couple of teeth cut at one spot on the revolution. I usually feed by feel than math with these guys because of that.
 
^ Bingo. In my experience you need to take that into consideration and feed accordingly. I don't know about you guys, but I get into a cadence with feeding a slitting saw manually according to the eccentricities of the teeth. Like a musical timing almost. One of the reasons I always hated using them in the CNC. I always spent way too much time trying to adjust them to run true, and 9/10 would just pull the part at that point and run it in the manual mill anyway.

The PDF is nice info, but based on theoretical math of perfect world situations, Practical experience always has one adjusting federates accordingly. I find cutters to last a very long happy life living about 70-80% of manufactures suggested feedrates. If running high production crank it up, and bake in tool breakage and downtime to change and reset. For home shop and one off stuff, that's usually a deal breaker and day wrecker.
 
Mcgyver said:
Dissenting voice here .... I wonder if the authors of such tables have ever used one?
Click to expand...

Too often true.

I was doing some slitting work a while back and hit your issue. I was some pissed. I made a tight fitting arbour and got on with the job.

But I also put a tapered arbour on my ToDo list but never got around to it. The idea was a short taper and a nut with recessed threads that could fit over the taper until the blade jambed.

Over time I forgot about it. I guess I should add it to my ToDo list again.
 
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