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  1. S

    Stupid question - programmable overhang boring bar holder?

    I'm sorry, clearly I've come to the wrong place. This thing has grown arms and legs. Thanks for all the fish!
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    Stupid question - programmable overhang boring bar holder?

    Prob a lot less than you, but approx 20 years before he became a salesman. He's given me nothing but sound advice so far. Anyways, according to the "Sandvik book" I think a full carbide bar somewhat close to the dimensions of my steel bar will do the trick. Generally good up to 6 x D, I need 5D...
  3. S

    Stupid question - programmable overhang boring bar holder?

    I asked "my guy" about holding my Kenna devibe bar with a regular set screw holder - he went ballistic:D
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    Stupid question - programmable overhang boring bar holder?

    Yeah, I get that, but bear in mind I had a good verified program that I've made probably 30 of these parts on before with no snags. Then six months later, I spend a day trying to tweak it to work again. Unknown reason, but I'm guessing the 316 is the culprit. If there's a high-tec $$$ bar that...
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    Stupid question - programmable overhang boring bar holder?

    Ok, I guess it doesn't have to be a devibe bar, but I want it to be good for 5D overhangs. Most people I have spoken to (and also in this thread) say that 4D is the general "no chatter" limit for steel bars. Do you have any tips for lead angles in regards to chatter? Pos/Neutral/Neg?
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    Stupid question - programmable overhang boring bar holder?

    Made incremental changes, they all had a positive effect but the nose radius was the most effective, you're right. It also wore down quite quick - it wanted more speed I think, but higher speed made the bar vibrate. Made nice chips regardless. I've only got approx 650 mm z-axis travel and...
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    Stupid question - programmable overhang boring bar holder?

    Just to close this out. Got there in the end. Hope it works on next batch we get too. Used tall soft jaws at 10 bar pressure. Reduced nose radius from .8 to .4 Reduced VC by 50% to 100 m/min. Turned on the SSV w/ +- 50 [email protected] Thanks for all help. PS: If anyone has tips for proven anti-vibe...
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    Stupid question - programmable overhang boring bar holder?

    Holy cow, think I paid closer to 2500 USD for my dampened KM bar, but think that was a 10xD bar. But, yeah - I understand what your saying and agree with that - we're doing alright and we love buying quality tools. Machines are still expensive though, yet we just ordered a mill not knowing what...
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    Stupid question - programmable overhang boring bar holder?

    Agree with comments here. Will make plastic a doughnut on the router, and whack it onto the Ø120 stock in the hope that it might kill off most of the harmonics once the the thing gets a hole in it and becomes a musical instrument. Attached is a picture of one of these that I made about a year...
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    Stupid question - programmable overhang boring bar holder?

    Hi @kenton , you're right- It was a typo - I use it for Ø50 drilled holes, but the bar itself is Ø40. You're right about the second one too. BTW - What's your opinion on the M38/39 thing if you've used it? Apart from not having a lot of luck with it, I'm thinking that it must add some wear to...
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    Stupid question - programmable overhang boring bar holder?

    Appreciate that Ox, will do that first thing in the morning! Beer drinking time her in Norway just now. It's a 40mm KM bar in a BMT65 split 40mm holder. don't remember the finer details top of my head. Ironically I was told to use the split holder instead of the simple just set screw holders in...
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    Stupid question - programmable overhang boring bar holder?

    Apologies for missing the question! No, my initial post boils down to; 1)Boring bar overhang is as long as it needs to be to finish the job, but it would be nice to have a shorter one too, to reduce chatter. 2) The bar is a PITA to change because the holder needs to come out and in, in the...
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    Stupid question - programmable overhang boring bar holder?

    Ouch, was close once myself. Think there's about 3" clearance to the back on mine if I remember correctly. Will look into the Capto. Don't mind spending the money as long as the tooling will be useable in a future, arguably better, mill/turn machine.
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    Stupid question - programmable overhang boring bar holder?

    I've got the ST30Y lathe, so I agree that I should probably get away with using larger drills. On OD turning larger (12") duplex parts I've seen 120-140% spindle loads without that causing any trouble, but I regret not going for the gearbox option. Tempted to try something different than the KM...
  15. S

    Stupid question - programmable overhang boring bar holder?

    Maybe once we get our mill🙂👍
  16. S

    Stupid question - programmable overhang boring bar holder?

    This is the de-vibe bar that I bought for another part we're making. As I said, probably just user error, I didn't use a split holder for that one, which I think it requires. But really sobering price for a dust collector, so need to get it right before I buy another one.
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    Stupid question - programmable overhang boring bar holder?

    Well, as I stated in first post - bear with me :D We (4 guys) are first, and foremost, engineers who happen to love solving operational problems, doing all the design work and, as it turned out, starting actually making our own parts. In the past two years the machining has moved from a "hobby"...
  18. S

    Stupid question - programmable overhang boring bar holder?

    Not a devibe one - just a regular Ø40 bar. I've got a smaller dampened one that I hardly use, not sure if I want to spend big bucks for a second one that I'll hardly use as well. For the cost I wasn't too pleased with results on my dampened one, but think I might just need to learn to clamp it...
  19. S

    Stupid question - programmable overhang boring bar holder?

    Nope, not a chance:-) But that KM "quick release" system that "Dan from Oakland" posted a picture of seems like a good way to go. I presume it maintains most of the rigidity of a solid boring bar, but could be mistaken. With 12 spaces for holders in my turret it would make things a lot easier...
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    Stupid question - programmable overhang boring bar holder?

    You're right Ox, there's an element of laziness in this equation 😀 That being said, the boring bar holder I use is a pain to adjust, it's the fully slit one where you need to take the holder out of the machine to get access, then tighten set screw to pry it open, then realign the boring bar...
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