Indexable parting blade advice

[Sshire]

I've been thinking about an indexable parting blade, like an Iscar Tang- grip, Do-grip, IQ GRIP, some other kind of grip.
They have so many, that it's a bit confusing.
1. Are there any advantages over the standard HSS parting blades?
2. If so, flat blade or integral tang?
3. The Iscar blade holding block seems very expensive for something that looks like I could machine in an afternoon. Is there something special about it?
Thanks

 

[crankshafter]

Stan.
This is how I make a mountingblock for my cut off blade. Used a dovetail cutter to cut the slot.
As you can see this is a Seco-brand blade but you get the idea?
http://www.homemodelenginemachinist.com/f31/my-hoglet-5244/

CS.

 

[mc_n_g]

It depends upon your lathe, speeds and what you plan on doing.
Do you have a QCTP?
I use HSS P type blades in my QCTP all the time. I use 0.040", 0.062", 0.093", and 0.125" and swap them out depending upon what I am doing.
If you have a QCTP I would recommend you grind a small flat on top of the blade (it help curl the chips off for me and feeds easier).
The GTN (self locking style style) is a good proven series. The smallest I think is around 0.090"
They come in blade styles where you need a block and as an insert tool so it mounts on the lathe without a block. The problem with these is the limited depth of cut.
With all types set up is critical, how fast you feed in and use of cutting fluid (I highly recommend it) play a role in how each type cuts.
If you are cutting a large diameter you need a sturdier and wider tool so it will not bend a flex during cutting.
If you have no experience with indexable lathe tools I would not recommend you jump into them.

 

[Sshire]

CS
That's exactly what I'm looking for. I guess I'm not getting how you are clamping the blade in the holder and where the dovetail cutter is used. I've made blocks for the QCTP before so I get the big dovetail for mounting the block

 

[Swifty]

I have the same setup as crankshafter, but with a purchased holder. I have 3 and 4mm wide inserts and they last for ages. I still tend to use HSS for aluminium. I probably would not recommend the carbide parting system for smaller lathes though.

Paul.

 

[Sshire]

Paul
My intent is to use the carbide for steel and cast iron. I would stick with the HSS for brass and aluminum.
What would you consider too small a lathe?

 

[crankshafter]

Hi again Stan.
I use my parting tool on aluminum without prob. Power crossfeed and a squirt of W40 will do the trick. I do not know wath lathe you have but give it a try. Have a look on picture no. 7 from top in the link I provided in my first reply;D
Best regards
CS

 

[Swifty]

Stan, I would think that most bench top lathes would not be strong enough.
I think that the blade holder size will govern the lathe size that it will fit.
Paul.

 

[Niels Abildgaard]

Hello

The system described here

http://www.homemodelenginemachinist...arbide-partoff-tooling-long-10176/index2.html

is using nominal 4 mm blades to cary inserts of 2,3 and 4 mm .
Have parted quite a lot (max 130 mm) and only spoiled ONE insert cutting a grove in a hardened piston pin.Blades are unharmed.

A suitably mounted 7*10 lathe can be well served by nominal 3 mm blades carrying 2 and 3 mm inserts.

 

[Sshire]

Neils
Thanks for the drawing. It will be a help. I looked at photos of the various holders from Seco, Iscar and Kennametal and they all appear to be similar. Not a particularly difficult machining job. Even on EBay, they are $150+.
I've ordered the Seco blade and it should be fine in my 10x22.