Slitter saw on a horizontal mill
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    Default Slitter saw on a horizontal mill

    I'm running a K&T 205 SA that I bought this year. Amazing machine, does all I ask and more.... except.... today I went to cut a slit with a 1/16" x 5" HSS slitter saw and sheared through the key on the horizontal arbor.... twice. Using recommended speeds and feeds, cut went well until it didn't.

    Technique wise, is there something I should do differently with a slitter saw? I was running a much lower feed rate the second time, and it wasn't a heavy cut.

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    You need to use a hardened key. Your current setup with the hardened arbor and slitting saw functions as a impact shear. The soft key is being sheared as expected.

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    none of my slitting saws of this size have a key. so yes, what you are doing wrong is not tightening the nut enough.

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    Quote Originally Posted by Dannno View Post
    I'm running a K&T 205 SA that I bought this year. Amazing machine, does all I ask and more.... except.... today I went to cut a slit with a 1/16" x 5" HSS slitter saw and sheared through the key on the horizontal arbor.... twice. Using recommended speeds and feeds, cut went well until it didn't.

    Technique wise, is there something I should do differently with a slitter saw? I was running a much lower feed rate the second time, and it wasn't a heavy cut.
    With the appropriate side clamping force and care as to loading, you should not need a key at all.

    A 1/16" thick saw... nowhere near as thin as they CAN be.. just CANNOT have as much resistance to force from a key at minimal radius as it has ability to generate force loading out at the periphery.

    Simple leverage thing.

    Better bolsters. Greater clamping pressure. Pay attention to insure gullets never overload with chip and that they cleanly evacuate. Metal wedged into a full gullet will not easily compress. Apply coolant and even air blast if need be, but keep them clearing.

    Not new news.

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    Thank you for the replies. I'm new to the horizontal mill, and thought about throwing a hardened key in, but assumed that if it overloaded the key with a hardened key it might create a real train wreck. I can see where the narrow cross section of the saw concentrates a huge force if the key comes into play vs the larger contact area of a milling cutter.

    Quote Originally Posted by thermite View Post
    Pay attention to insure gullets never overload with chip and that they cleanly evacuate. Metal wedged into a full gullet will not easily compress.
    This (and the bolsters) seems like where I need to focus. I didn't consider that with the narrow kerf, that the chips wouldn't clear as cleanly as with a milling operation. Probably should have moved one of the air blast nozzles to make sure the chips cleared as the teeth exit the cut.

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    Keeping the teeth clear is critical on the thin saws, particularly when the teeth are small. I use flood coolant- air blast might work as well. I find tool pressure breaks the thin saws, even easy to overload them on a production feed mill using hand pressure on the lever- it doesn't take much and going well until it doesn't is a good description. A higher rpm might help but ultimately SFM rules. Backing off the feed a bit is probably a good move in any case.

    I tend to shatter the tool, haven't sheared a key.


    on edit: forgot to mention, with the thin saws its helpful to limit DOC to .010 or maybe a bit more until the kerf is a bit deeper than the teeth. Helps to avoid the cutting pressure from flexing/warping the saw which makes the cut diverge and is prone to snapping the saw if the cut is deep enough. Once the kerf is deep enough it helps keep the blade straight and planar. On thin saws I generally limit the max DOC to a few times the thickness of the saw.
    Last edited by Greg Menke; 10-22-2021 at 10:39 AM.

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    Thermite mentioned coolant or air for clearing chips. I generally flood with cutting oil and have no problems, never use a key and have never spun a blade. I do not think anyone asked but are you sure you are conventional milling and not climb milling? If you do not know the difference ask before going any further.

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    Quote Originally Posted by Greg Menke View Post
    I find tool pressure breaks the thin saws, even easy to overload them on a production feed mill using hand pressure on the lever- it doesn't take much and going well until it doesn't is a good description.
    That is certainly true! About 15 months ago, I did a job on my hand-lever Nichols which called for 4" diameter, 0.0355" wide, slitting saws (slot width 0.035-0.036).

    I started with three HSS landed ATB saws ground to order by Martindale (recommended). I didn't look closely enough at my arbor spacers, and dished the first saw fairly badly, to the point where the cut ran noticeably out of true with the table axis. After regrinding my spacers, I managed to totally shatter a second saw. It was going well until it didn't! I still have about 85% of that saw in a small plastic box, but haven't yet found the other 15% that went flying around the shop. (Wear your safety glasses, folks.) Fortunately, I was able to finish the job with the remaining cutter.

    BTW, this is the kind of job and machine for which HSS was a superior choice over carbide. I'm sure I would have broken all three saws had I ordered carbide.
    Last edited by sfriedberg; 10-22-2021 at 05:35 PM.

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    all ,,
    plus be sure the holding fixture does not pinch the saw at near through the part.

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    Have not yet totally sheared a key, but have done one partway through, that took a half hour to get off the arbor, it was so tight.

    "No key" is often recommended, but I am not a fan since the time the saw stopped and the feed continued... same problem of busted saw, and did not take long either.

    I keep a key in it, and not a hardened one. But I do keep the feed down to accommodate the reduced capacity of gullets. And also to prevent the feed driving the saw off-course.

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    Flood coolant usually works when cutting steel. Oil usually works better cutting aluminum since it helps prevent the chips from "sticking" to the cutter and filling up the gullets. Lighter chip loads help with either material. +1 on making sure the material isn't pinching the cutter as it cuts through.

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    Quote Originally Posted by JST View Post
    "No key" is often recommended, but I am not a fan since the time the saw stopped and the feed continued... same problem of busted saw, and did not take long either.
    Saws are consumables. Like it or not.

    So are arbours.

    If you charge-ahead, no key might save the keyway... but bend the arbour.

    Not having either problem in the first place?

    Well.... that's part of why an Old Skewl mill-hand was started out on a horizontal mill.

    They tended to be stout enough to survive .....whilst the new hand learnt sense. Touch. Feel. SOUND...

    THEN you could trust we chik'n s to not simply destroy yer fragile BirdPorts ...and only BARELY stouter Toolmasters, Trees, Wells, XLO's.. etc.!



    FWIW-not-much? Saws are all too often not run FAST enough as to rim speed vs feed on older horizontals. The RPM just ain't there.

    They do better "live tooled", CNC world, where their speeds can be better matched to the needs of the tasking and "many., many" light passes to clear gullet - if need be - do not strain a human operator's greed for feed nor impatience-budget.

    If one comes in via THAT door and has notions of saw performance?

    Dropping back to the limited high-end and limited uber-slow feeds of most older horizontals can get yah into trouble.

    QED

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    Perhaps you are near the top of acceptable feed for the material or the the holding fixture. Cutting 10 or 15 % may be the solution.

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    Quote Originally Posted by michiganbuck View Post
    Perhaps you are near the top of acceptable feed for the material or the the holding fixture. Cutting 10 or 15 % may be the solution.

    Very likely. Works for me every time.

    I'd rather keep the key and control the feed. Saw speed is generally not a limitation, but getting the feed right with respect to how much of the saw periphery is cutting is important. There isn't just one speed, nor feed for it.

    Deeper cut means longer length of cut on the saw, means teeth need to have bigger gullets, unless the feed is so slow as to nearly be rubbing. Then you have the wrong saw, and need one made for deeper slotting. Maybe you get away with it, maybe not.

    If the mill is a universal, and you have an alignment error setting the table, that's an issue too. Thin saws do not like chewing through at an angle unless they have side cutting teeth, and even then it's not the right way. Same if the saw is not true on the arbor, but I assume most would see that.

    "Slitting" saw? Terminology can catch a person..... saw made for cutting on the periphery only? Or was it one with side cutting teeth? Saw relieved in the middle, or straight sided?

    Depth of cut relative to tooth size & gullets?

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    I didn't see whether the op climb or conv cut
    I try and stay away from climbing on thinner blades

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    On the thin saws if I have to climb cut its only a few thous maybe at most .005- its still easy to feel the saw pulling on a production feed. On a style a/b arbor I always use a key OTOH I have a low profile saw arbor which doesn't have a key- haven't had a cutter slip in it yet.

    I tend to set rpm for about half the rated SFM on saws, but also depending on material. If its enough of a job to experiment, and the saw is happy then maybe up to 75% but thats about it. Once SFM is comfy and the cut deep enough then maybe up the DOC, but ease off the feed when doing that. Pushing the work is a quick way to shatter the saw or burn the teeth. Aluminum is easier to push a bit than steel. I run as much flood coolant as I can drain off the table and workpiece without making a mess.

    +1 as per previous post to make sure the workholding isn't going to pinch the saw as the cut progresses.

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    Quote Originally Posted by mjk View Post
    I didn't see whether the op climb or conv cut
    I try and stay away from climbing on thinner blades
    'Climb" isn't "horrible" as saws - thinner ones most of all, actually - tend to have way to Hell and gone more teeth and take finer nibbles rather than big bites of the average milling cutter, hence "hold what they got" with a high ration of consistency ...once wear/backlash has been pulled-up. IOW, one can deal with it OK. Mostly.

    It is still all about whether there is space in the gullet for the material removed, right IN that active cutting pass AND THEN ALSO that each approaching gullet enters clean and empty for its turn.

    If so, it works as planned.

    If not, yer plucked. Regardless. "Calculated' SFM & such don't do the do.

    You have to make certain for each material, blade, and operation.

    Up to the mill-hand, IOW.

    It's why they pay us the big bucks, after all.



    As to progressive workholder "squeeze" as material is removed?

    Oy! Basic woodchopper / sawdust maker cuts shudda taught yah all ABOUT that part as a pre-teen!

    If THAT ain't obvious as all get-out to be avoided?

    Yer in the wrong craft altogether!


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    Quote Originally Posted by sfriedberg View Post
    That is certainly true! About 15 months ago, I did a job on my hand-lever Nichols which called for 4" diameter, 0.0355" wide, slitting saws (slot width 0.035-0.036).

    I started with three HSS landed ATB saws ground to order by Martindale (recommended). I didn't look closely enough at my arbor spacers, and dished the first saw fairly badly, to the point where the cut ran noticeably out of true with the table axis. After regrinding my spacers, I managed to totally shatter a second saw. It was going well until it didn't! I still have about 85% of that saw in a small plastic box, but haven't yet found the other 15% that went flying around the shop. (Wear your safety glasses, folks.) Fortunately, I was able to finish the job with the remaining cutter.

    BTW, this is the kind of job and machine for which HSS was a superior choice over carbide. I'm sure I would have broken all three saws had I ordered carbide.
    glasses wont help much, stand completely clear of the process. i found shrapnel stuck in cardboard boxes over 20 feel away. especially so with full hss blades.

    btw, 1) make a shallow firs cut (full lenght) to guide the blade. 2) to locate part/blade put a test indicator on the side of the blade and touch the work.


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