Photos of inserts for Aluminum ...

[tino_ale]

To set the height I face a piece. I start with the tool a tad low, it leaves a nipple artifact at the face center.

I then raise it slightly until the nipple dissapear completely and I get a nice flat center. It seems to be pretty precise.

As I have an ongoing issue with my motor (vibration/noise) I have halted any investigation related to surface finish. Once I get a smooth running motor, I hope the finish will improve!

 

[wquiles]

To set the height I face a piece. I start with the tool a tad low, it leaves a nipple artifact at the face center.

I then raise it slightly until the nipple dissapear completely and I get a nice flat center. It seems to be pretty precise.

As I have an ongoing issue with my motor (vibration/noise) I have halted any investigation related to surface finish. Once I get a smooth running motor, I how the finish will improve!

That is pretty good, specially since once set, they will (most likely) stay on center. However, note that you can't always use this method to center a tool, so you should have a "plan B" available. There are many tools, but one of my favorite ways of checking is to lightly "pinch" a straight orange piece between the work and the tip of the tool, and then look from the tailstock to see if it is tilted in or out. If it is tilting towards the chuck the tool is a little high. If it is tilting away from the chuck, the tool is a little low. The longer the piece, the more this discrepancy is "magnified". Here is one I just did really chick which is close "enough" for me (it is actually a tad too high):

Still, I agree with you that the vibrations you have now are not good towards achieving a good finish.

 

[tino_ale]

I tried this tip, actually before I used the nipple trick, but with a cutter blade.

Then my lack of experience spoke : I ran the insert too hard against the blade, and chipped my brand new Al specific insert.
Goobye, money.

Oh well live and learn I guess. What I need is to be much more carefull and/or use a plastic piece.

I had never seen an insert in person before, those tiny guys are actually quite fragile. Impressive how they can, used properly, remove a good amount of metal during the turning operation.

 

[wquiles]

Then my lack of experience spoke : I ran the insert too hard against the blade, and chipped my brand new Al specific insert.
Goobye, money.

LOL! Why do you think I am using a plastic piece to do it now?

I learned my lesson when I broke the tip on a "very" expensive PCD insert when I tried with a small metal ruler

I had never seen an insert in person before, those tiny guys are actually quite fragile. Impressive how they can, used properly, remove a good amount of metal during the turning operation.

Oh yeah. I recently was doing an OD pass at .150" on 6061 (removing .3" diameter per pass!), and I was feeding the carriage so fast that I could feel and hear the motor slow down a lot, yet the insert worked perfectly under that "abuse" :devil:

 

[tino_ale]

Well there must be a bunch of us that had that "Duh" moment! lol

When removing that much material, were you using the same kind of Al specific insert as mine ? Dit you do that with coolant or dry ?

I think I'm still babying my inserts so any data point of situations that work is interesting to me.

 

[wquiles]

Well there must be a bunch of us that had that "Duh" moment! lol

Oh yes. More times I care to admit

When removing that much material, were you using the same kind of Al specific insert as mine ?

No. I was using these, which are much stronger, yet sharp enough to work with Titanium. Good enough for Aluminum (although not optimal). In fact in this image you can see some of the BUE (built up edge) I got from running the insert to freaking hard:

Dit you do that with coolant or dry ?

Oh yes. Copious amounts of coolant - and I could smell the coolant burning up!

I think I'm still babying my inserts so any data point of situations that work is interesting to me.

For now, 100% agree. You will find on your own what your machine can do. Give it time, go slow, and be safe

 

[darkzero]

Sandvick's H13A grade is great for turning Ti but CNMG is more oriented for material removal. For a MCLN holder I use CNGG for finishing, uncoated polished like for aluminum, CNMP is good too. But I prefer to use a high shear positive insert for final finishing for Ti, I use CCGT or DCGT. With Ti you don't get BUE, since TI is not a good conductor of heat that is more of the issue.

 

[precisionworks]

A good guide for setting tool height is:

• .005"-.010" (.125mm-.250mm) LOW for OD turning & facing
• .005"-.010" (.125mm-.250mm) HIGH for boring.

The logic behind the low & high settings is to make sure the tool tip is the first point of contact. If the tool is at dead center when fresh the first point of contact will not stay at dead center as the tip wears down. Slightly low for OD turning/facing or slightly high for boring allows for a small amount of tool tip wear without adversely affecting surface finish.

YMMV.

 

[wquiles]

Sandvick's H13A grade is great for turning Ti but CNMG is more oriented for material removal.

Agreed 100%. That is exactly why I used that tool holder and insert to remove the material. I then used an insert with a sharper corner to do the finishing passes

If I want the Al to be mirror like, I then go to the PCD inserts - fragile, but great for the last pass

 

[precisionworks]

High shear (aluminum optimized) PCD wiper inserts can be effective in producing surface finishes better than Ra 0.5 microns, equal to a ground or super machined finish.

 

[ronboult]

Hi Will and precision works
I have been using Korloy CCGT 060204-AK ( CCGT21.51-AK) H01 Grade inserts on 6061 Alu with reasonable to good finish on final cuts using WD40 lubricant.
I noted that you both referred to PCD inserts whatever they are. Could either of you please explain what they are, and if they are avalilable to fit SCLR holders.
Thanks
Ron

 

[precisionworks]

Will is the expert on diamond coatings so I'll defer to him for the answer :nana:

 

[wquiles]

Will is the expert on diamond coatings so I'll defer to him for the answer :nana:

No, not the expert. Just that I "really" love them for Delrin and also Aluminum, since they are even sharper than Al-specific inserts - and they seem to last forever with Delrin and Al. That being said, I did try them with Titanium, and they did not last.

Some reading on PCD and its uses:
https://www.kennametal.com/content/dam/kennametal/kennametal/common/Resources/Catalogs-Literature/Metalworking/Master%20Catalog%20-%20Metric%20Sections/A-11-02679_MasterCat_stationary_PCBN_PCD_inserts_metric.pdf

http://www.mmsonline.com/articles/inserts-for-difficult-materials

http://legacy.secotools.com/template/start.asp?id=6642


Will

 

[ronboult]

Thanks Will
Interesting read. From your comments you seem to be using PCD because of its increased sharpness rather than its production capacity. I assume you are therefore using the finer grades of diamond (KD1400). Also if I read the Kennametal document correctly many of the inserts are available with different nose radii. Any suggestions as to what to try. Also they seem to come with one point, two points or entire top coat. Is there a major difference in cost for these variations?
Ron