Boring bar speed?

[MRogersII]

So, I bought these because that was what came with the boring bar when I bought it. I've done some reading on the cutter nomenclature. I have a better understanding of what the numbers represent....but still dont have a real clear understanding of which is better for which application. I was beginning to think that this was an issue of having the wrong (or less than ideal) cutter.

Cobra Carbide 40142 Solid Carbide Turning Insert, CM02 Grade, Multilayer Coated, CCMT Style, Molded Chipbreaker, CCMT 32.52, 5/32" Thick, 1/32" Radius (Pack of 10): Amazon.com: Industrial & Scientific

Cobra Carbide 40142 Solid Carbide Turning Insert, CM02 Grade, Multilayer Coated, CCMT Style, Molded Chipbreaker, CCMT 32.52, 5/32" Thick, 1/32" Radius (Pack of 10): Amazon.com: Industrial & Scientific

www.amazon.com

I don't have any lie in me.....so I'll go ahead and tell you that it took me a minute to get the "V4".

 

[aliva]

I don't know of any tables suggesting speeds. I run around 600 RPM and get a good finish on CS , Aluminum, brass and SS.
Get some scrap and experiment. I'm sure someone on the forum will give their recommendations.
When I finish to the target size I run the bar in a few thousands so as not to mare the finish on the way out.

 

[mattthemuppet2]

those inserts are for roughing steel - they have a larger nose radius (the xx.x2 in the code) and they're molded (xxMx in the code). You need a CCGT 32.51 (or CCGT0904) insert for what you're doing, like:

10Pcs CCGT09T304-AK H01 CCGT32.51-AK H01 Aluminum Blade CNC Inserts Cutter C# | eBay

Find many great new & used options and get the best deals for 10Pcs CCGT09T304-AK H01 CCGT32.51-AK H01 Aluminum Blade CNC Inserts Cutter C# at the best online prices at eBay! Free shipping for many products!

www.ebay.com

unfortunately all mine are the size (0604) smaller than that

 

[MRogersII]

Thank you for taking the time to help identify which one I need, I appreciate it. I'll see if I can find it on Amazon.

 

[MRogersII]

I appear to have found them on Amazon. Ordered. Thank you again.

I need to buy a boring bar to fit the other inserts I have. I bought a very large lot of milling machine/lathe tooling from the family of a retired machinist. Mixed in with those items are 7 or 8 trays of new bits, triangle shaped. I need to look those up and see what they are intended for and then buy a boring bar to use them.

 

[mattthemuppet2]

you're very welcome! Glad I could help. Those CCMT inserts are still useful, but on steel or cast iron. They also take more force to cut, so you're more limited on how far the bar can stick out of the boring head or tool post, otherwise you'll get crazy chatter. The CCGT inserts are crazy share and can take of a teeny tiny amount of metal, but they're much less robust. I think I've gotten through a couple of boxes of the CCGT in the last 4 years and perhaps 2 CCMT inserts

The triangle inserts are probably TCMT or TT inserts if they're single sided, or TNMG if they're double sided. Double sided inserts have sides that are perpendicular to the face, single sided inserts have sides that are at an angle (typically ~7 degrees). Boring bars - STUFR from memory, maybe STUFPR. Depends on the clearance angle at the front of the insert, but that should get you started. You want ~3-5 degrees clearance at the front so that there's clearance to both bore the hole (the sides) and face the end. That's one reason CCxT boring bars are so useful, as they do that by default. Have to be a bit more careful with the triangle inserts.

 

[MRogersII]

Good morning. So I went to the Kennametal website and found a catalog that more or less explains the insert numbering system, but I have yet to really understand what the ideal application is for each of the inserts that I have, and whether or not it makes sense to buy a boring bar that can use them. Any suggestions here would be greatly appreciated.

Thank you

Michael

Here is what I have:

Kennametal TPMT3252LF KC730 - 3 trays (30 inserts)
Kennametal TNMP331K KC910 - 1 tray (10 inserts)
Kennametal SPG422 KC850 - 1 tray (10 inserts)

These three all have a hole in the center for mounting.

The next two are triangle inserts that do not have a hole and, I assume, use some type of clamping mechanism.

TPEE-730 C5 (x 10)
TPG:320 C5 (x 10)

These are round inserts, also with no hole in the center.
REHR1605M0T-M14 T25M (8 inserts)

 

[mattthemuppet2]

12-STFPR-3

.750

is what you want for the 32.52 TPMT inserts. Smallest shank I could find was 3/4". Bars are less common/ more expensive than for the TCMT style inserts.

eg https://www.shars.com/products/indexable-cutting/boring-bar?insert_size=32.51&insert_style=TPMT
(they have a good way to sort by insert type)

TNMP is a double sided positive insert, couldn't find much for them

SPG is a square insert, not much for them either

TPG is the old style triangle insert, often used in face mills or turning tools.

My advice - sell the lot on eBay and use the proceeds to buy a couple of SCLCR carbide shank boring bars to match the CCMT/ CCGT inserts you already have. If you buy holders to fit those inserts you'll be stuck with buying expensive inserts to keep them running if/ when those ones run out. Also depends on what machines you have. if you have a 10" or smaller lathe, those inserts won't be the most suitable, partly because they'll force you to buy larger holders than you need. That's not as big an issue, the main one is cost and availability.

 

[MRogersII]

I'll take that as good counsel and put them up for sale. Thank you, Sir

Michael

 

[MRogersII]

Just as a side question, what is there to minimize/counter out of balance vibration? That is, starting at 3 or 3 1/2" in diameter, my boring head is going to be significantly off center, and will carrying a bar with 7" of steel sticking out of it. I would think that vibration would become an issue at some point?