Parting Blade Question

[umahunter]

I've tried those what I've liked the best is an indexable parting block kit I got from shars one thing I've found works really good for me I'm not sure if this is proper but if I'm parting something that's not right next to the chuck and it it has a hole I put my live center on there to stiffen it up to start the cut then toward the end remove it for the last lil bit it really helped stiffen things up you just have to be careful

 

[NortonDommi]

Some HSS part off blades are tapered from top to bottom on one or both sides. One side is the most common. These ones can only be fitted one way and need to have the appropriate tool holder or be shimmed oat the bottom or they will skew first cut and break. A piece of broken blade inverted work in a straight face tool holder

 

[WarrenP]

I bought a T shaped blade and used a feeler gauge to take up the difference in my tool holder. Still have to try it, but im sure it will work as it should.. Hopefully my lathe will too.

 

[pdentrem]

Some parting blades have to fit a holder that has a angle cut top and bottom. Look at this photo. Note the top and bottom of the tool holder. It is cut like this to stop the parting tool from being pushed out of the holder.
http://www.abmtools.com/product/parting-tool-holder-quick-clamp-parting-tool-holder/

 

[9t8z28]

I have 3 of their parting blades in various thicknesses. 2 are T15 and 1 is HSS. They are the best T-blades I have ever used. I’ve never bought a Somma blade new. I was lucky enough to find a bundle of them for $5 but I would purchase them new if I needed a particular size

Some interesting parting blades.
https://www.sommatool.com/catalog/pdf/Somma_Catalog-Cut-Off.pdf

 

[9t8z28]

Nice find ! I like this style and it would be easy to make

Some parting blades have to fit a holder that has a angle cut top and bottom. Look at this photo. Note the top and bottom of the tool holder. It is cut like this to stop the parting tool from being pushed out of the holder.
http://www.abmtools.com/product/parting-tool-holder-quick-clamp-parting-tool-holder/

 

[Bob Korves]

2 are T15 and 1 is HSS.

T15 is also HSS. There are two basic types of HSS, one based on Molybdenum (for instance M2, M42, etc.) and the other based on Tungsten (T1, T-15, etc.) (Also a third based on Cobalt, Stellite.) Tungsten HSS has often been superseded by Moly HSS in more modern times for cost reasons in a changing metals market. Simply stated, Molybdenum is cheaper than Tungsten today. There are also some other subtle reasons why one type might be picked over the other for certain tasks, they are not identical in their properties. I have a pretty good selection of different HSS tool bits of different alloys from different manufacturers, and it is interesting to see the differences in how they act in the cut under different conditions.
https://www.asminternational.org/do...yNow.pdf/b8f2e317-5089-44bc-a14d-af31f80e33a5
http://www.crucibleservice.com/eselector/prodbyapp/highspeed/highspeedapptitle.html

 

[Larry42]

There are also P type blades. I think the defining feature is that they are hollow ground on the sides.

 

[ddickey]

What does hollow ground mean?

 

[mikey]

P-type blades have a 5 degree side relief on both sides.