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  #11  
Old 03-09-2019, 08:27 PM
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MetalWolf MetalWolf is offline
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Right now I am just starting out with this fairly cheap set.
If this tells yall anything. For me it might as well be in Chinese

CCMT060204
SNR0012M11 12 150 11 IR
SER1212H16 12 100 16 ER
SCL1212H06 12 100 CCMT060204
MGEHR1212-2 12 100 MGMN200
SDNCN1212H07 12 100 DCMT070204
SDJCR1212H07 12 100 DCMT070204
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Last edited by MetalWolf; 03-10-2019 at 02:03 AM.
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  #12  
Old 03-10-2019, 01:54 AM
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TriHonu TriHonu is offline
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Here are a few points to consider:

1. Negative Rake Tooling - Even though the insert is tipped down, you can still have a positive angle on the cutting edge. Lets say the holder is -7°. If the insert has a 12° positive cutting edge, the effective cutting edge angle is 5° positive.

When you look up the inserts top geometry (chip breaker), most manufactures will describe the cutting edge style and angle. They will also specify the range of feeds and depths of cut that chip breaker is designed for.

This leads me to the second point...

2. If you have been using HSS in a home shop, what you probably consider Roughing Depth of cuts and feeds, is no where near what Roughing means in terms of carbide.

For example, typical depths of cut and feeds for carbide are:
a. Extreme Finishing: .010 - .080 depth of cut, Feed: .002 - .006" IPR
b. Finishing: .020 - .080 depth of cut, Feed: .004 - .012" IPR
c. Light Roughing: .080 - .160 depth of cut, Feed: .008 - .020" IPR
d. Roughing: .160 - .400 depth of cut, Feed: .015 - .040" IPR
e. Heavy Roughing: .240 - .790 depth of cut, Feed: > .040" IPR
f. Extremely Heavy Roughing: .310 - .790 depth of cut, Feed: >.028" IPR

Many of our machines are not capable of "Roughing" cuts in the carbide world.

When you look at inserts, use the definitions above to narrow your search for inserts designed for the cuts your lathe is capable of performing.

When I first started, I bought a bunch of roughing inserts. The cutting edge is designed for strength, no sharp edge, in fact the edge is purposely dull so it won't chip. My lathe does not have enough HP to take a deep enough cut for the chip breaker to be effective.

The inserts that work the best on my lathe are classified as Finishing inserts.

If you want/need to take very fine depths of cut on steel, you can effectively use inserts designed for Aluminum turning. The ones I bought are not coated and have a very sharp cutting edge with a lot of positive rake. They will not be as durable as a steel finishing insert, but will allow you to take very fine cuts.

3. Note the combination of insert shape and tool-holder style effectively defines the work area/features that can be machined.

4. Shape and Rake of the insert determines how many cutting edges an insert provides. Negative Rake inserts normally provide twice as many cutting edges per insert compared with Positive Rake inserts. Good economy can be had with Negative Rake inserts with High Positive Cutting Edge chip breakers.


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  #13  
Old 03-10-2019, 02:18 AM
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MetalWolf MetalWolf is offline
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Quote:
Originally Posted by TriHonu View Post
Here are a few points to consider:

1. Negative Rake Tooling - Even though the insert is tipped down, you can still have a positive angle on the cutting edge. Lets say the holder is -7°. If the insert has a 12° positive cutting edge, the effective cutting edge angle is 5° positive.

When you look up the inserts top geometry (chip breaker), most manufactures will describe the cutting edge style and angle. They will also specify the range of feeds and depths of cut that chip breaker is designed for.

This leads me to the second point...

2. If you have been using HSS in a home shop, what you probably consider Roughing Depth of cuts and feeds, is no where near what Roughing means in terms of carbide.

For example, typical depths of cut and feeds for carbide are:
a. Extreme Finishing: .010 - .080 depth of cut, Feed: .002 - .006" IPR
b. Finishing: .020 - .080 depth of cut, Feed: .004 - .012" IPR
c. Light Roughing: .080 - .160 depth of cut, Feed: .008 - .020" IPR
d. Roughing: .160 - .400 depth of cut, Feed: .015 - .040" IPR
e. Heavy Roughing: .240 - .790 depth of cut, Feed: > .040" IPR
f. Extremely Heavy Roughing: .310 - .790 depth of cut, Feed: >.028" IPR

Many of our machines are not capable of "Roughing" cuts in the carbide world.

When you look at inserts, use the definitions above to narrow your search for inserts designed for the cuts your lathe is capable of performing.

When I first started, I bought a bunch of roughing inserts. The cutting edge is designed for strength, no sharp edge, in fact the edge is purposely dull so it won't chip. My lathe does not have enough HP to take a deep enough cut for the chip breaker to be effective.

The inserts that work the best on my lathe are classified as Finishing inserts.

If you want/need to take very fine depths of cut on steel, you can effectively use inserts designed for Aluminum turning. The ones I bought are not coated and have a very sharp cutting edge with a lot of positive rake. They will not be as durable as a steel finishing insert, but will allow you to take very fine cuts.

3. Note the combination of insert shape and tool-holder style effectively defines the work area/features that can be machined.

4. Shape and Rake of the insert determines how many cutting edges an insert provides. Negative Rake inserts normally provide twice as many cutting edges per insert compared with Positive Rake inserts. Good economy can be had with Negative Rake inserts with High Positive Cutting Edge chip breakers.


Thank you!
I'm glad i asked because i for sure would of just bought a bunch of inserts not knowing really what I was doing or needing and as my luck usually turns out with buying tooling I tend to overbuying or buy stuff I can not use... for many reasons one being, I am very new to the machining world...

and am still in the pre-k stages of learning what is what and what is useful at first I bought a lot of tooling and devises that I am in no way ready for due to lack of skill level

I found it will be no doubt a good many years before I'll even need such tooling fixtures... but if I do ever get to that point I'll have them...

so now I rather ask than to invest money in to tooling that will just sit as it is way to easy to spend a lot of money really fast and I now understand this is a trade and or hobby that you need an unlimited supply of cash as the buying never stops... well until I'm broke and the next paycheck comes around

I think I'm getting to understand the insert thing a bit better still not completely sure about all of it but its an eye opener and with help from good people like you guys I'll get a better grasp of it and be able to do a little more turning...
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  #14  
Old 03-10-2019, 08:45 AM
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MetalWolf MetalWolf is offline
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Ok, so one problem I ran into it finding the insert for the one threading tool I bought this set of BG and at least want replacement inserts for the tooling I have so far been able to find the same inserts that come with this 7pc set...

but the replacement inserts that eludes me in the search on BG.... as I don't yet fully understand all the numbers yet...

So maybe for someone who is familiar with BG and inserts might be kind enough to help me out here to a link on BG site for suitable inserts to this one particular holder...

The tool number is: SNR0012M11 Says for the insert it's a: 11IR 1/4"

https://www.banggood.com/7pcs-12mm-S...r_warehouse=CN

Thanks'... I appreciate any help I can get...
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  #15  
Old 03-10-2019, 11:50 AM
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toprecycler toprecycler is offline
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Randell, I went to this link and looked at the description of the holders and found a list of recommended tool inserts. I then did a search on each insert # in the BG search bar and it came up several items for each one, some just different inserts , coated and
Un coated for example.

Here are some screen shots.

I also was able to cross some of the insert numbers to Keith’s above PDF of insert descriptions.

You have entered a world of somewhat very confusing terminology. It is hard ( at least for me ) to make sense of it yet. And the more I learn, the more I realize there is to learn.

I know Kieth says inserts are well worth the cost, but i also think you need to know what your lathe is capable of doing before you stock up on a lot of inserts. And there is a lot of confusion in learning the proper feeds and speeds in using them.

For example, I was learning from the senior machinist before he retired, and he told me that I needed to use a special ceramic insert to turn this particular inductioned hardened rod. I had to turn 6” long down for threading. Take a .250” doc (depth of cut), at about 150 rpm, and I think about .005” feed. Oh and the insert will break about halfway into the cut. Don’t worry about that, just put a new one in. Cost of doing the job. He was right. About 3 and 1/4” into the cut, the insert shattered. It broke the insert so bad I could not use the other 2 cutting edges. So had to use another new insert. I’m told these inserts cost about $30 apiece. (I’m not sure, but maybe the boss was exaggerating a little).

That seems like a big waste to me. When I finished that job, I chucked up the old rod, and practiced redoing that job again, this time only using the older brazed carbide tooling that I sharpen however I like. I cut the same part out changing the speed and feed and DOC and did it faster overall, but with more correct settings, and all with one bit. That I can reshape, and resharpen again for the next job.

Bottom line, it is going to take actual making chips with your lathe before you can really figure out the best tooling for it, also depending on the material you are actually working with too.

IMO, it would be cheaper ( less cash outlay) to stick with HSS and maybe Carbide brazed tooling that you sharpen yourself, then you can experiment with what works best for you and your lathe. Then you can start moving into the inserts if you would like. If you have to hand sharpen your own bits, then you will learn the basics of why certain clearances are necessary and so on.

Even after a year of machining daily, I feel I am still at the beginning stages of understanding the cutting action of the lathe I am using at work. ( I can be a slow learner too) It is frustrating to me that I might be getting great chips and finish on this one part, then I cannot duplicate that again in the next part. But, I am not afraid to break the mold, and do something differently from the way the old guys did, in order to find a better faster way. But sometimes, it is ok to go with the old way too.



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