I need some advice from the turn & groove pros

[Kevangel]

Dave, I probably should have said "sorta gummy"since its copper..I wonder if anyone makes Cobalt HS inserts for cutting plastic. They may not wear as much as you think on this material..then again...

I use alot of cobalt HS boring bars for 4 inch deep close tol.holes in toolsteel and they hold up very well(cobalt is the secret). Use alot solid carbide ones also..not completely old school.

[Dave.L]

Hey Kevin,

 

I don't think you are old school at all and BTW, old school has some good tricks.

 

I just think you are a toolroom guy (nothin wrong with that) and actually my company started off doing all custom machines so we have used lots of tool steels over the years.

 

[gcode]

Sandvik has some new grades

rated for Ti.

The inserts have sharp edges and

high rake angles. I've found they

also work well in Inconel and Monel.

They might be a good choice for

gummy stuff too.

This being a production job,

you should probably break down and invest

in solid carbide bars.

[Kevangel]

quote:

---

I just think you are a toolroom guy

---

Soooooooo true on toolmaking, but I think of toolroom guys as slow:) ( I have always been job shop) .....I am thinking of buying a battery of CNCs this fall and hope this won't be fatal for me. Anyway what I am trying to say is "is this a negative rake tool you are using"?

[Dave.L]

quote:

---

is this a negative rake tool you are using

---

Nope, positive and sharp.

 

Tom,

 

I never need to "break down" to purchase the right solution. I am actually looking into dampend bars from Sandvik

[gcode]

quote:

---

I never need to "break down" to purchase the right solution. I am actually looking into dampend bars from Sandvik

---

maybe not.. but you'll break down and cry

when you get the quote..

They are world class tools, but man are they expensive.

 

We had one at my last job that cost $18K..

(Ø4" x 60" long)

It was a sad day when a careless rookie blew it up

[Kevangel]

quote:

---

We had one at my last job that cost $18K..

(Ø4" x 60" long)

It was a sad day when a careless rookie blew it up

 

---

and I felt bad when I did that to my .500 dia. carbide bar..in a programming wreck when in a hurry..

[chris m]

quote:

---

I am actually looking into dampend bars from Sandvik

---

Sandvik's "Silent Tools" dampened bars with the 570 style "comb" coupling work very well for vibration problems. The only caveat [other than the price, which will make you choke] is that you can NOT lean on them at all when machining or you'll bend them, so stay conservative with feed and DOC always with these tools.

 

C

[Kyle Waters]

I would check the edge prep on the insert. From the sounds of it, you need to be looking at a very small honed edge, if any at all. The downside is there will be a suffering because of the hardness.

m2c

[BBprecise]

Couple of other things to try. Not sure if this applies to your lathe, but you can try putting some thick rubber between the tool block and the turret. We have some 1/4" thick rubber strips with holes for the tooling block bolts that help alot with chatter. Tighten it down as you normally would.

 

Another thing to try that we've had good luck with are de-vibe bars. We make our own by drilling out the center and filling it with melted lead.

 

Can you get a heavy metal bar?

[chris m]

quote:

---

Not sure if this applies to your lathe, but you can try putting some thick rubber between the tool block and the turret.

---

[YoDoug®]

If you are still looking into dampened bars look at http://www.toolcraftinc.com/chatterfree.htm

We use their dampened bars at my last job with great success.