I an in need of some recommendations on inserts for tool holders already on hand. The various inserts we have leave too much to be desired for most the everyday materials and conditions we have at work. This has left me to grind brazed carbide tools to meet the conditions, and I have become quite good at it. But, while I want to train others to do much of what I do, I am still having to grind, and sharpen tools for them. Suitable inserts would make it easier for me to get others to cutting metal while I do other stuff. Haphazard trying this or that insert is not really in the budget, and is what, I think, has caused the assortment of unsuitable inserts in stock.
The first problem, is likely that the machines are old and do not have the horsepower, nor surface speed for many of the modern inserts. For example a lathe that swings 28 inches, has only a 7.5 Hp motor, and maximum speed of 900 RPM. Second, most of the machining is relatively dry. Flood coolant is not going to happen. A misting coolant is about as sophisticated as it gets. Brushed on cutting oil is more common, but is also sparingly used. Third, it may be due to the tool holders themselves being a bit incompatible with the realities of the conditions.
The materials that need to be bored and turned are as follows in order of frequency and quantity:
Grey Cast Iron in different hardness states but usually fairly soft,
Mechanical Tubing mostly seamless mild steel (ASTM A513 and A519) ( Note, this material is particularly difficult to get chips to break and not chatter. The final wall is often less than 1/8"),
Free Machining Steel in the form of unbored couplers,
Pure or nearly pure Copper (DC armature commutators e.g.),
1045 Steel Shaft material normalized,
Plasma Cut Mild Steel Plate,
4140 steel bar, and DOM tubing,
Bronze ranging from just copper/tin alloys to heavily leaded to phosphorous alloys (aluminum bronze is rarely encountered),
304/303 Stainless Steel,
416 Stainless Steel,
Aluminum of various alloys, including cast.
Linen filled Micarta,
Other plastics and epoxies.
The list of tool holders on hand are:
MWLNR-16-4W (tool holder not boring bar)
A16MWLNR3 (Hertel Boring Bar)
RTBAP-20-3 KM4 ( Sandvik Boring Bar)
MTGNR 16 3C L4M (tool holder)
No. TL 12 (Armstrong tool holder)
S32V-MCLNR-4 (Valenite Boring Bar)
The last thing to consider is the tolerances in which I need to work. The final finish should be better than 32 micro inches, and the size is often well within 0.001" and often within 0.0006".