Adjusting set screws on boring bars to stop chatter

Tyler337 · Dec 15, 2022

I’ve seen experienced Cnc lathe machinist hang a boring bar out so far that they were only able to use 1 set screw on the top and bottom to hold tighten the bar. And it cuts great. No chatter at all. I’ve seen people tighten and loosen the set screw in many ways to stop chatter. What is the exact method or science that makes this work?

Tyler337 · Dec 15, 2022

I’m currently using a 2” steel bar that has flats on the bar for me to tighten the top 2 set screws directly onto the bar. And I can tighten the bottom 2 set screws as well but the sleeve I’m using only has holes at the top so I can tighten onto the bar. The set screws at the bottom tighten onto the sleeve. Btw I’m using a dnmg .0312 radius, 450sfm, .01-.013 feed, .081 DOC. I know every possible way to stop the chatter but I want to know how to use the set screws to find that sweet spot and let the chatter be gone!!

noname777 · Dec 15, 2022

but that depends on your particular machine geometry ( rigidity ) and how it can suppress mechanical resonance. It is not just your tool holder vibrates, carriage itself has free mechanical resonance frequency.

Tyler337 · Dec 15, 2022

noname777 said:
but that depends on your particular machine geometry ( rigidity ) and how it can suppress mechanical resonance. It is not just your tool holder vibrates, carriage itself has free mechanical resonance frequency.

Yes sir I’m aware of all this. I just want a solid answer to the right ways to adjust set screws.

noname777 · Dec 15, 2022

well than your solid answer is very simple, those people are using length of a tool holder and mounting as a mechanical resonance suppressor. It still resonates but they just move fundamental frequency up or down, and in this way u are only exposed to higher harmonical components and they are weak. Correct?

Tyler337 · Dec 16, 2022

noname777 said:
well than your solid answer is very simple, those people are using length of a tool holder and mounting as a mechanical resonance suppressor. It still resonates but they just move fundamental frequency up or down, and in this way u are only exposed to higher harmonical components and they are weak. Correct?

Yes sir that is correct. It’s just, I’ve heard so many different techniques that I’d like to know the science.

Tyler337 · Dec 16, 2022

And it’s no big deal bc today I ordered some rare earth magnets. That’s what they are called for some reason. they are about a .250 long and about .5 in diameter. SUPER strong and will take the chatter out of just about anything. If you stick two of them together you literally have to put one in a vice and find a way to wedge them apart.

Search

Largest Manufacturing Technology Community on the Web

Search

Adjusting set screws on boring bars to stop chatter

Tyler337

Plastic

Tyler337

Plastic

noname777

Cast Iron

Tyler337

Plastic

noname777

Cast Iron

Tyler337

Plastic

Tyler337

Plastic

Similar threads