Lathe tool holder sizes

If you are machining long shafts are looking to reduce tool pressure then a great option is a 55° DNMG43_ Insert.  If you run into chatter or tool pressure issues on a part then the best way to fix it is by lowering the engagement angle or go with a Positive Single Sided Insert instead of a Negative Double Sided Insert.  The 55° angle of the DNMG Insert is a lot less tool pressure than the CNMG or WNMG Inserts above and is our first choice if tool pressure is going to be an issue or if you need to do profiling or undercutting in OD Turning.  The DDJNR and DDHNR Holders are available for ¾” Shank Holders and up.

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Inserttool holder types

The 80° WNMG43_ Insert is also popular for OD Turning.  The Trigon Shape gives you 6 cutting edges compared to 4 cutting edges on a CNMG43_ Insert giving you much better economy at a similar insert price.    If you are doing heavy roughing or have more critical dimensions you need to hold then the CNMG Insert is a better choice as there is more steel on the holder supporting a CNMG Insert compared to a WNMG Insert (shown below).  But in most applications the WNMG is plenty rigid! The DWLN Holder is available for ¾” Square Shank Holders and up.

Wood lathe tool holder

The SDJCR 55° Holder for DCMT21.5_ and DCMT32.5_ Inserts (as well as DCGT21.5_ & DCGT32.5_ Inserts) is the most popular Geometry for Swiss Machines.  The 55° angle makes this a free cutting insert that is capable of profiling at different angles as well as turning up to a square shoulder.  Plus the DCMT and DCGT Insert lineup gives you the most options of chipbreakers/grade and radius options.

However, they have nothing to say about Cr-V, so I don't know if Cr-V, while apparently a popular material for wood-boring bits, is considered a more or a less economical choice, and whether it's better suited for wood drilling than HSS

I know it's not just a matter of "cheap ones are HSS and expensive ones are Cr-V" (or vice-versa) - I see that a highly rated brand has individuals and sets in both materials and the prices are similar for similar sized bits.

The SCLCR/L 80°Holder for CCMT21.5_ and CCMT32.5_ Inserts (as well as CCGT21.5_ and CCGT32.5_ Inserts, CCMT and CCGT are the same geometry, the M stands for Molded Cutting Edge and the G stands for Ground Cutting Edge). This is the strongest insert geometry for positive inserts that go up to a square shoulder and can also be used on your boring bars (3/8” Shank and up for CCMT21.5_ Inserts as well as ½” Shank and up for CCMT32.5_ Inserts).  This Holder is popular in smaller shank machines as well as Swiss Machines and is available from 3/8” Shank and up.

LatheInsertHolder

You are comparing "apples to oranges". They are dramatically different ; HSS will cut steel while red hot ( in a dark room , 1100 F), and contains roughly 20 % alloys. Cr , V is a low alloy tool steel ( like grade L-2) and contains less than 3 % alloys . The V carbides will hold an edge longer than other low alloy tool steels , but not to a degree that a craftsman could notice. An indirect comparison is that HSS is hardened by oil quenching from about 2200 F and tempered at about 1100 F. Cr, V is hardened by quenching from 1600 F into oil and tempering at about 350 F ; I understand this info is no value to the user but it indicates these are significantly different alloys. If you are drilling wood , the Cr, V are fine . I you want to drill more than a couple holes in steel ,pay for the HSS.

The 80° CNMG43_ Insert is the most common and popular insert in OD Turning.  The 80 degree angle makes this a strong insert and the insert is held rigidly in the holder.  Plus you can Turn and Face in a Standard Holder.  This is our first choice for OD Roughing on a CNC Lathe as it is strong and there are many insert options. This DCLNR Holder is available for 3/4" Square Shank Holders and up as well as Boring Bars ¾” Shank and up.

Round CarbideInsertTool Holder

High-Speed Steel (HSS) is a popular material good for drilling into soft steels as well as wood and plastic. It’s an economical solution for most maintenance drilling applications.

RoundInsertTool Holder

*All Positive Inserts are available in a Molded Cutting Edge (the 3rd Letter in the description is M) and Ground Cutting Edge (3rd letter is G). The Molded Cutting Edge is stronger for roughing and these inserts are less expensive. The Ground Cutting edge is sharper for finishing or to reduce tool pressure and the inserts are a little more as there is another operation on these inserts to grind the cutting edge.

If you need to reduce tool pressure even more or have a lot of profiling to do on a part then a 35° VNMG33_ Insert is the best option. This insert is less tool pressure than a DNMG Insert and comes in 3 different holder options that allow you to OD Profile at all angles.  The DVJNR, DVPNR and DVVNN Holders are available for ¾” Shank Holders and up.

For brad point bits, the design and quality of production process are more important than the material when it comes to the quality of the hole. The quality of the material (given the same design) would contribute to the lifespan between sharpenings. Lifespan can also be dictated by the material you drill and the number of holes you drill(obviously).

Lathe Tool Holder types

AS already mentioned above, HSS should be a better material for making drill bits out of because it should be harder. I have owned bits with HSS stamped on them that were definitely not great bits.

The SVJBR Holder for VBMT22_ and VBMT33_ (as well as VCMT22_ and VCMT33_ Inserts. The VBMT has a 5° Side Rake Angle while the VCMT has a 7° Side Rake Angle so a VCMT fits into a VBMT Holder with no issues) is great for profiling into tighter angles or at a deeper depth than a DCMT Insert and will also lower tool pressure.

I did find this handy description but it focuses on drilling in metals, not wood, and is, therefore, off topic here. I'm sure some of it translates to wood working, but I'm not sure exactly how. At this link, they state:

I need to purchase a set of brad point bits (all I own are split point). I see some that are High Speed Steel (HSS) and others made of Chrome Vanadium (Cr-V), and I'm not sure how much the steel should factor into my purchasing decision.

If you will be drilling a few holes in soft/hard woods then don't worry too much about the bit material. If someone has shown you that they drill nice clean holes then go for it. If you are planning to drill thousands of holes in wood, MDF or plastics (plastics tend to generate more heat when drilling) then go for HSS (or if you're planning on living for a long time without buying more drill bits). You certainly don't need two sets of the same drill sizes in different steels.