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Tony Ennis
09-13-2010, 12:10 AM
I'm looking into getting a set of indexable turning tools. There seems to be an awful lot of choices.

The tool holders I'm looking at use "TCMT 21.51" inserts. I think "TC" stands for tungsten carbide. I don't know about the rest.

Where are these things defined?

Dr Stan
09-13-2010, 12:24 AM
Tony,

I recommend you contact Travers Tool and request their catalog as it has lots of technical information including charts that "decode" inserts. One example is:

http://www.traverscatalogs.com/lg_display.cfm/catalog/master_2010/page/331

Stan

JRouche
09-13-2010, 12:28 AM
I'm looking into getting a set of indexable turning tools. There seems to be an awful lot of choices.

The tool holders I'm looking at use "TCMT 21.51" inserts. I think "TC" stands for tungsten carbide. I don't know about the rest.

Where are these things defined?

The T there is for triangle. I think. JR

Jerry
09-13-2010, 12:38 AM
Get a copy of the "Engineers Black Book" (USA Edition) It has exactly the information you are looking for (as seen in the photo), and more! I have various books that I use in my shop, but this one is always nearby.

This pocket book is a great resource for anyone working in a shop. It’s designed for metal workers and machinists, but the information contained within comes in handy in lots of situations. Best of all, it’s durable enough to survive in a shop environment, and every page is coated in a glare-free laminate that resists tearing and won’t get all filthy.

Inside there’s a wealth of practical information like conversion tables, hardening and tempering information, engineering drawing standards, tolerances, bolt and nut standards, and keys and keyway standards. You’ll also find the weights of metals, tapping drill sizes, lubricants/coolants for cutting tools, speeds and feeds for twist drills, G codes, and lots, lots more. I have to say that this little black book has become my go to book lately. Try it, you'll like it.



http://www.jerryclement.ca/Machines/Machine-Shop/2010-05-22/875232452_E5mqa-L.jpg

KiddZimaHater
09-13-2010, 12:51 AM
Here's the link you need Tony:
Carbide Insert Info (http://www.carbidedepot.com/formulas-insert-d.htm)

Tony Ennis
09-14-2010, 10:51 PM
That perfect KZH.

For a small lathe (Atlas 12") is there a benefit to using 1/2" indexable tools versus 3/8" tools? We just cut with the tip of the insert, right? So what's the benefit of a larger insert?

fishfrnzy
09-14-2010, 11:15 PM
1/2 square shank tools will hold the 3/8 IC ( inscribed circle ) triangle inserts. They should be a good size for your lathe. Larger insert / shank = more rigidity but should be matched to the lathe. Make sure you get inserts with at least a 7 degree clearance angle because if you dont have alot of horsepower you'll need that clearance for them to work properly.

Bill Pace
09-14-2010, 11:19 PM
Pardon for getting off topic - question for Jerry (you dont have a way in your profile to PM)

In your photo/s of the book, how did you do the multiple pix? assume its some photo program? Thats neat...

PM me --- or, answer here, maybe someone else likes the process too...

Jerry
09-14-2010, 11:43 PM
Pardon for getting off topic - question for Jerry (you dont have a way in your profile to PM)

In your photo/s of the book, how did you do the multiple pix? assume its some photo program? Thats neat...

PM me --- or, answer here, maybe someone else likes the process too...
Its dead simple, download Picasa, its free and has a "Collage" option.

Bill Pace
09-15-2010, 12:07 AM
Aw jeez, I've had Picasa for some time - knew it had all kinds of bells & whistles, but missed that one --- thanks.

Jerry
09-15-2010, 12:21 AM
Aw jeez, I've had Picasa for some time - knew it had all kinds of bells & whistles, but missed that one --- thanks.
With Picasa open, select your photos and hold them in the tray, then click on the "Collage" button on the bottom of the page. After messing with it for a while, you'll get a feel for what you can do with it, like expanding, spinning, as well as dragging photos out of the work area and so on. Once you save your collage, you can do further edits, including cropping the photo if required.

PaulT
09-15-2010, 01:06 PM
Your are looking at a good insert for home shop usage, the TCMT insert has a highly positive rake and works well on HSM sized machines.

I prefer the CCMT insert over the TCMT though. Its from the same family but is an 80 degree design instead of triangular. With a SCLCR type holder (this is a standard industry designation) this orients the insert with 5 degree clearance in both the facing and turning planes.

This means with the same holder and without swapping its position you can both turn and face. This is great for quicky projects, just mount one tool and turn and face your part. If $ is tight it also allows you to get started with insert tooling with only one holder. You get one less cutting edge with these insert, but the design and quality of these inserts is very high, they last a long time. The 80 degree design is also more rigid than the triangular design, making the insert tougher for interupted cuts and longer lasting for roughing cuts.

There are a wide variety of insert types in this size. They make very sharp and polished ones for aluminum that work very well, they are almost as sharp as a well sharpened HSS tool. I also use these inserts for finish cuts on steel and they work well for that also.

The guy that runs www.latheinserts.com handles these sharp aluminum inserts. He also sells some "starter kits" of tooling using these inserts targeting HSM shop users.

Good luck-

Paul T.
www.power-t.com

dp
09-15-2010, 01:21 PM
Give the HSM advertisers a chance, too: http://Glacern.com/indexable_milling as they help keep the lights on.

djc
09-15-2010, 03:45 PM
I prefer the CCMT insert over the TCMT though....

You get one less cutting edge with these insert...



I'm not sure what typical sizes you would use, but Glanze make a holder for 06 (metric designation) CCMT inserts that uses the two normally unused edges of the insert. See

http://www.glanze.com/indexable-tool-holders/mc-ccmt-set-of-7-tools.html
http://glanze.co.uk/acatalog/Single_Turning_Tools.html

I fully echo the comments about the super sharp aluminium inserts; they are superb.

PaulT
09-15-2010, 06:38 PM
An additional plus of the CCMT insert (and I believe this applies to TCMT also) is that there are also a wide array of boring tools available that use this insert.

They work really well for boring because the highly positive design minimizes the side forces required on the insert, so you get less flex of the boring tool.

Paul T.
www.power-t.com