Slitting saw runnout..?

rfrink · Feb 5, 2008

My slitting saws always seem to have a pulsing sound when the cut...caused from radial run out. Today I put and instrument on it ...and I see a TIR of about .002" on a 4" diameter. I've used this saw for years...and it works great...but sounds like it only cuts on one side of the circumference.

What is the run-out on your slitting saws??

-Rob

icehd81 · Feb 5, 2008

Pretty common. I've had the expensive to the cheap and they all seem to have some amount of runout. Probably has a lot to do with what position it is in when it is locked down on the arbor. They have to have some clearance to get them positioned.

gmatov · Feb 6, 2008

Unfortunately, I bought a couple blades and an arbor from the Griz.

Blades are snug on the arbor, arbor runs true, but when I try to slit brass bar stock, man the runout!!!

1/32 to 1/16, almost like a flycutter, cuts on about 4 teeth.

HSM, not critical. To you it might be. Have to make an arbor for it sometime soon. Mebbe caliper the hole to the tooth dim before I do that. It might actually be 1/32 offcenter.

Never have, but when you bring it close to the work at low RPM, you can see the eccentricity.

Have to admit, it DID and does do what I need to do. Cheaper than buying more brass stock closer to the size I am slitting to. But then, the work warps, so have to slit thick enough to allow a cleanup on both sides. Ah, well, it's still fun.

Cheers,

George

rfrink · Feb 6, 2008

Thanks for the responses. My arbor is shop made by yours truly...and I must say that it is pretty darn concentric (thank ya very much) ...and the saw blades squeeze on snuggly. I'm thinking that the blades have the majority of run out.

At only .002" TIR...I can't see it ...but can certainly "hear" it when it is cutting:
shing! shing! shing!

The sound smooths out with more agressive feeds. I always thought that it would smooth out as the high spots wore down, but that doesn't seem to be happening.

Even though I've always been very happy with the performance, I've always wondered about the run-out....So during a slow day, I fired the question out on the web.

Thanks again!!

-Rob

jims · Feb 7, 2008

saw runout

Think I'll made a set true slitting saw arbor.
jims

dsergison · Feb 7, 2008

my experience matches yours. mystery run-out.

set-tru arbor would be cool

AeroncaChamp · Feb 8, 2008

I've seen this on my old Burke H-mill. In my case it's part looseness of slitting blade on arbor, but mostly the arbor's being slightly off center. (This is an old MT-9 spindle/arbor, both probably a little worn.) I have determined a rotation of the arbor in the spindle that minimizes it, but it's usually not worth the effort. I figure each time I remount the blade it will probably be in a different orientation and over time, I'll use all the teeth.

Tejano · Feb 8, 2008

rfrink said:
Thanks for the responses. My arbor is shop made by yours truly...and I must say that it is pretty darn concentric (thank ya very much) ...and the saw blades squeeze on snuggly. I'm thinking that the blades have the majority of run out.

At only .002" TIR...I can't see it ...but can certainly "hear" it when it is cutting:
shing! shing! shing!

The sound smooths out with more agressive feeds. I always thought that it would smooth out as the high spots wore down, but that doesn't seem to be happening.

Even though I've always been very happy with the performance, I've always wondered about the run-out....So during a slow day, I fired the question out on the web.

Thanks again!!

-Rob

I have found the same results with saw arbors. Pretty much the only way to make one concentric or close to it is to make one yourself and have the saw fit as snug as possible. last one I made, I took the slightest bit off per pass and tried the saw on until it went on with an extremely tight fit.

I was thinking of making one that expands to fit snug on the saw somehow.

I might make that a project the next few months and see how it works.

Tejano · Feb 8, 2008

Another design I was kicking around was to combine a couple of small boring heads so that thee slide perpendicular to each other with the slotting arbor mounted on the end so that it can be precisely centered.

Greg White · Feb 8, 2008

Hard to recall but I am trying here,Even the bigger 12"dia. 1" wide ones will make that sound,and I do recall that most folks would not feed em hard enough,count the teeth and put a chip load per tooth X# of teeeth X RPMs,it mite scare you at first.
I usta run em on old monster K/Ts. fond memories.
GW

rfrink · Feb 8, 2008

Chip load and feed rate? Greg, yep, it would probably scare me.

I've never figured it out...I just run it by the "sound".

Let's see...I use a 4" x .062 in a CNC application and typically feed it around 8-10 ipm. It's HSS cutting CRS and has about 10tpi...or roughly 120 teeth around the dia. I think I run it at about 150 rpm.

What kind of chip load would you use?? Lets say .0005.

Feed = 150rpm X 120 teeth x .0005 = 9 ipm. HOLY SMOKES!!! that's where I run it!!

hmmm..... I only run it like this because is just "sounds" the best. In reality I have no idea what is a reasonable chip load. I guess it would also have something to do with the thickness of the workpiece...or cirumferential length of the cut such that the gullets in the saw don't over-fill with the chip. Basically, the amount that the saw is engaged in the work piece.

Then due to the run-out issue, some teeth may never cut...while other handle 2X the chip load.

It's all interesting to think about. And so many variables... good stuff for a slow Friday morning online!

Thanks for posting,

-Rob

metal_twister · Feb 8, 2008

wonkaa...wonkaa sound is the naute of the beast.

We used 8" x 1/8 saws mounted on peterson flush arbors to part of turbine blades after the mill work was done.

Out of the box, they would lope so bad it would actually stall the spindle at times.

We took to kissing the O.D. on a T/C grinder with the saw mounted in the flush arbor.

Greg White · Feb 8, 2008

Yep on the 9ipm #,that is what I am talking aboot,the feed rate will make the noise somewhat understandable ,you can hear them simmer down when the feed rate gets closer to right,I do remember not liking it all when things went wrong with a saw,we had em with hss adjustable inserts,real pain to get set,but you cut a 1 inch wide slot in short order,we used to make clevis's in bar stock then saw to lenght,you know for the ends of air&hyd. cylinders for automated sheet metal,clamping,weld gun swing ins,part shuttle.
GW

jims · Feb 9, 2008

set true slitting saw

I just got to thinking about a set true holder for a slitting cutter. And it dawned on me I have what it takes already. I have a set true one inch shank that takes one inch bar in other end. All I have to do is turn a short arbor inch dia and inch or so long and turn dia of saw on end use bolt and washer to hold blade to arbor and slip in in what I already have. Then turn saw backwards and indicate od true. Just like setting a 4 jaw chuck. But the one inch is too big for my BP. So I would have to make a new shank to fit my mill. I make my own id collets that I used to slit with a saw and the noise would kill my ears. Now I made a fixture that fits my 4x6 saw and that works great and it's faster.
jims

rfrink · Feb 9, 2008

Hmmm....that's pretty cool Jim!! Thanks for posting the photos of that tool.

Thanks to you, I'll probably lose a few hours of sleep while thinking about making something of my own.

-Rob

DWOOD · Feb 16, 2008

As long as we are discussing slitting saws:

I've noticed all the runout problems as mentioned by previous posters. My question involves the smallest slitting saws . . . the ones with bores less than one inch and without a keyway. It seems no matter how tight I install it on the arbor it continues to catch and slip, even with the lightest of cuts.

Any help?

howiesatwork · Feb 17, 2008

DWOOD said:
I've noticed all the runout problems as mentioned by previous posters. My question involves the smallest slitting saws . . . the ones with bores less than one inch and without a keyway. It seems no matter how tight I install it on the arbor it continues to catch and slip, even with the lightest of cuts.

Any help?

Could be your arbor is worn enough to not tighten down on the blade. Shim stock?

Walter A · Feb 17, 2008

Slipping saw

DWOOD said:
I've noticed all the runout problems as mentioned by previous posters. My question involves the smallest slitting saws . . . the ones with bores less than one inch and without a keyway. It seems no matter how tight I install it on the arbor it continues to catch and slip, even with the lightest of cuts.

Any help?

I solved the problem once by making an arbor spacer out of aluminum. I used it on the outboard side and tightened the nut real good. Also check all your steel spacers for parallel and surface grind if needed.

Make sure your nut does not bottom out.

Walter A.

Frank Ford · Feb 17, 2008

I made my own R8 arbor and to be sure of concentricity, I skimmed off the final diameter right in place on the mill by simply gripping a QC lathe tool holder in the vise and running the quill up and down, feeding the X-axis:

The slitting saw blade is TIGHT Fit on the arbor.

Every time I use it, whatever blade I choose just pulses away, cutting on only one section of the blade. . .

Cheers,

Frank Ford
FRETS.COM
Gryphon Stringed Instruments
My Home Shop Pages

wesg · Feb 20, 2008

My guess is these things are made by stacking a bunch of blanks on an arbor, with plenty of clearance in the bore so they don't have to wiggle each one on and off, and milling the teeth. Then grinding to thickness after hardening. So there's runout that could only be corrected by grinding the teeth too. Which they don't do because they'd have to set them up one at a time, or stack them on a loose mandrel ...

They're junk, basically.

If they absolutely have to run true, you have a choice of regrinding them yourself or buying carbide saws.

I've seen the same thing with sprocket blanks, the teeth aren't concentric with the stamped bore. They run much better if you indicate the teeth in and machine the centers off of that. Amazing how the chain tension stays constant as you rotate the wheel :-)

Slitting saw runnout..?

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