Warco mill

Warco mill

Type	Machine Tools
Manufacturer	Warco
Model	Unknown

We have a Warco mill, which requires a induction to use, this tool is quite new and more documentation will be added here later

Workholding

Holding the workpiece to the bed is critically important, not only for creating an accurate part, but also for the safety of the operator and everyone else in the workshop. If improperly secured, a workpiece can be thrown out of the machine. If you are not certain the part is secure, do not try to machine it.

Vice

The standard vice should be the default for holding parts on the mill. It is useful for holding stock that has parallel sides, along with round stock with the use of V-blocks or the ER32 collet blocks.

Parts SHOULD NOT be left floating in the vice. Use parallels to raise them above the base of the vice where necessary. Ideally, both parallels should be tight under the part. If one is not, it should still be left under the part for support.

The vice should be re-trammed if the part needs to particularly accurate. This involves holding a dial test indicator in the spindle, zeroing it on the fixed jaw of the vice, and moving the bed to check how straight the vice is. It should be noted that the jaws are around 0.05mm out of flat. They may be re-ground at some point in the future.

Tooling

Selection of the correct tool for a given operation is important. While with some experience you will start to get a good feel for what is required to cut different materials, this is intended as an outline to begin with.

Correct feeds and speeds can be estimated from The Engineer's Reference Handbook on the shelves in the clean room. Please replace it on those shelves when you are finished with it.

End mills

End mills are the 'standard' tool for milling metal. They generally have different geometries, materials and numbers of teeth, but are general purpose cutters for almost any operation - but not necessarily the ideal tool for all of them. They are usually used for slotting, shoulder cuts, profiling and

Some endmills are designed to also do a limited amount of plunge cutting, while others aren't. If the cutting edge joins in the centre at the bottom of the cutter, it can be used for plunge cutting, though using a pilot drill is still advisable.

End mill selection

Carbide and High Speed Steel

High Speed Steel cutters have been used for decades as the standard for cutting tools on hobbyist mills, and are generally relatively inexpensive. They are very good for cutting softer materials, and can generally cut most steels with care and coolant. They are however susceptible to over-heating if run too hard, and the flutes will blunt over time. While the Tool and Cutter grinder next to the mill can re-grind the ends of the flutes, it cannot regrind the full spiral.

Carbide cutters are a more expensive option, but are run at much higher speeds and more tolerant of higher feed rates. They should still be run with coolant, but are capable of cutting harder materials. A note is that the correct cutting speed for smaller carbide end mills is generally outside of the spindle speed range of this mill. In these cases, depending upon what you are trying to machine, it is either suggested you switch to HSS or simply run the spindle as fast as it will go, and reduce the feed rate appropriately.

Two Flute Square mills

Two Flute end mills and slotting drills are generally ideal for cutting grooves or slots in aluminium and other soft materials, along with mild steel and cast iron. Generally, don't try using them for stainless, unless they are specifically designed for it, as stainless is much harder to cut. They can also be used for general milling of aluminium, particularly given the main limiting factor of the mill is rigidity, not necessarily the tooling.

Three Flute Square mills

Three flute end mills are generally used for cutting grooves and slots in steel, and general milling of aluminium and softer materials. Carbide is advised for most grades of stainless, as it tends to work harden.

Four Flute Square mills

Four flute end mills are ideal for cutting steels, and harder materials, but can 'gum up' in softer materials, due to having less chip clearance, and generally a different geometry of tooth. They can be used for most operations, but the increased chip clearance of three flute mills may make them a better choice for slots.

Finishing mills

Finishing end mills generally have more, smooth teeth than general purpose square ones. They are generally used to create a cleaner finish on sides that have cut, but should not be used to take deep cuts.

Roughing mills

Roughing end mills have varying numbers of teeth, but have a 'thread-like' pattern on the teeth, to assist in material removal. They are generally used for deeper cuts in steel, and to perform mass-material removal. They will not leave a particularly clean surface, and you will need to finish the cut with another end mill to get a good surface finish.

Ball Nosed mills

Ball nosed end mills are useful for cutting smooth, curved profiles. However, this is somewhat difficult with a manual machine. They can also be used to create round-bottomed slots, but ideally the majority of the material removed with a square end mill.

A note on slot drills

For the purposes of this page, I am treating slot drills as a type of 2 flute end mill, but they can also cut their own holes. I am not distinguishing between them and standard end mills that can plunge cut, as there are now sufficient different geometries of 'end mill' that it somewhat overcomplicates matters.

Face Mills

We currently have three face mills - all carbide insert - with three different types of insert. Face mills are used for facing and limited shoulder cutting, though the latter should be limited, due to the limited rigidity of the machine. Similarly, deep facing cuts should also be avoided in general, for the same reason.

The round inserts provide an excellent surface finish, and are probably a good substitute for a fly cutter.

Materials

The mill is a capable piece of equipment, with the rigidity and accuracy to cut many materials. However, it is not as rigid as many large, older machines such as Bridgeports, and thus some materials will take significant care.

Material	Machinable	Coolant	Notes
Aluminium	Yes	Advisable	Aluminium generally cuts well on this machine, though some alloys are better than others for machining.
Mild Steel	Yes	Yes	Mild steel is generally cut very well by this machine
Medium Carbon Steel	Yes	Yes	Medium carbon steels are generally cut very well by this machine.
Tool Steels	Yes	Yes	Tool steels are generally cut well, but they do create very small, sharp chips. Care should be taken to ensure you clean these up afterwards.
Stainless Steels	Care should be taken	Yes	There are many grades of stainless steel, some of which are easier to cut than others. However, they do many do work harden quite badly. You may be able to machine them, but it is generally advised against
Cast iron	Yes	No	Cast iron generally cuts very well on this machine.

Cooling

The mill has an air-powered mist cooler, which sprays coolant out of a small nozzle onto the part. This should generally be run coolant-rich to prevent the coolant from creating a fine mist in the room, which may not be particularly healthy to breath in. The coolant should be replaced regularly, as we don't have a particularly large bottle and it is used regularly, but if it has been left unused for multiple months, it may be wise to replace it, as bacteria can start to grow in it over a prolonged period.

Coolant is generally recommended for steel, and can help prevent aluminium and copper clogging the cutter. It is generally not used for cutting brass, and is discouraged for cutting cast iron.