Ordering a gundrill
 

What a gundrill user should “never” do: Better known as the seven deadly sins of a gundrill user !

• Think that a gundrill manufacturer can solve your gundrilling problems.  Remember, gundrill manufacturers sell gundrills not the gundrilling process so it is up to you to know how to use these drills.  Gundrill manufacturers are not responsible for the conditions of your machine (alignment, power, accuracy of motions, etc), proper coolant characteristics (brand, delivery parameters (the flow rate and pressure), purity and maintenance), suitable drilling regime, variation of properties of the work material etc.  It is true that the gundrill is “the weakest link” in the gundrilling system so it normally fails (does not produce holes of required accuracy, wears faster than you expect, breaks, etc).  Please do not hurry to blame the gundrill manufacturer for this failure – experience shows that 70% of the time it is not his fault. 
• Approve tool drawing as it is sent to you and/or make your own drawing using the prototype sent to you by the gundrill manufacturer.  This is probably the worst “sin” because by approving a drawing as it is or by making your own drawing using the one sent to you for approval, you automatically assume full responsibility for the performance of this drill. The manufacturer made the drill according to the requirements set forth by the drawing, approved by you and therefore would not be responsible for its failure.  If this drill does not work, you cannot even write a proper RMA because the drill is made exactly to the specifications YOU APPROVED.  Just remember - you are not a specialist in gundrill design or in the selection of the proper carbide grade for the application.
• Accept verbal guarantee of drill repeatability.
• If the gundrill you received does not perform as you expected, inspect the gundrill by measuring its essential parameters trying to figure out what is wrong with the drill.  First, the customer drawing you got for approval does not contain the most essential information so you do not really know what to inspect.  Second, you may not know the hidden correlation between these parameters and drill performance.
• Forget to pay close attention to the properties of the work material, their possible variation (for example, as after forging) within one workpiece and/or between different workpieces.  Forget to inform the gundrill manufacturer about the variations or about a change of your work material.
• When you start a new gundrilling operation, buy a machine, gundrills, coolant, fixtures etc. from different sources looking for the best deals.  Normally, you will have a lot of trouble trying to set them together. It’s like the old saying, THE RIGHT HAND DOESN’T KNOW WHAT THE LEFT HAnD IS DOING”. Remember there are no best deals, only smart choices. It pays to be smart.

WHAT EVERY SUCCESSFUL GUNDRILL USER SHOULD DO:

• Before contacting a gundrill manufacturer, formulate your objective clearly.  There could be a number of objectives so select the one most important to you. For example, to produce holes with maximum efficiency, to produce holes with maximum possible penetration rate (when your gundrilling operation is a bottleneck operation in your process), to produce holes with maximum gundrill life (when re-sharpening presents a problem) etc. 
• If you really want to achieve the highest efficiency, the biggest bang for your buck, then do not buy a gundrill – buy a hole.  To do that, you calculate the cost of a single drilled hole.  As such, do not pay attention to the particular prices of gundrilling system components as long as you achieve the highest efficiency.  Remember, you cannot achieve the performance of a Cadillac if you are willing to only pay the price for a Geo Metro.
• If you going to start a new gundrilling operation and thus ready to order a machine(s), go to a manufacturer that sells the gundrilling process (machines+gundrills+guaranteed requiring the best quality, highest productivity, best delivery etc.)
•  Before contacting a gundrill manufacturer, always do your homework by collecting information relevant to your gundrilling operation.  The prime attention should be paid to: (a) the properties of the work material and their variation within the workpiece, between different workpieces, between different workpiece suppliers etc., (b) kinematic scheme of drilling (what actually rotates: the drill, the workpiece, or both) (c) conditions of your machine including its alignment, ranges of speeds and feeds, (d) tooling, including drill holder, starting bushing, etc. (e) coolant: brand, ranges of the flow rate and pressure, purity, etc.
• While contacting a gundrill manufacturer, pay special attention to the questions he asks.  If no questions are asked about kinematic scheme of drilling, work material and the other above-mentioned working conditions, do not go with this manufacturer because you are not going to get what you need.  A gundrill is not a versatile tool but rather a very application- specific tool.
• Ask the gundrill manufacturer you contact what penetration rate he guarantees with his gundrill for your application and what is the tool life to expect.  Provide all information about your gundrilling operation. 
• Contact several manufacturers and go with one who gives you better ration penetration rate/tool life/const of gundrill.
• Always set a strict delivery date.  Don’t accept any excuses and uncertainties.
• Set your own requirements on a gundrill drawing before you approve it and send back to the manufacturer. Just check the drill diameter, length, driver suitable for your application. Don’t pay attention to other parameters – allow the manufacture to make these intelligent choices, remember, you are the user, you advise what you want, he should give you what you need, he should educate you not the other way around.  Set the requirements for the hole on your drawing: tolerances and other quality requirements the hole you need to drill (for example: surface finish of the drilled holes should not be worse than 1.6 micrometers (63 microinches), diametric accuracy +0.020/0.000 mm (+0.0008/0.0000 in), axis deviation should not be worse than 0.2mm/1000mm (0.008 in/3ft) etc); penetration rate (for example, 3 imp), tool life (can be in the number of parts produced or in the total length of the drilled holes per re-sharpening).  Don’t care if the drill is made out of maple wood or a plastic as long as it produces the holes you need with required productivity and tool life.
• If the drill does not perform as stated on the approval drawing, fill out an RMA form explaining clearly in a few words that the drill they recommended does not meet requirements stated on the approval drawing.  For example, “Tool life is 30% lower than stated on the approval drawing”  instead of “Drill has excessive wear”; “The diametric accuracy of the drilled holes are out of  tolerance assigned by the approval drawing”  instead of “Drill diameter is incorrect” etc.
• If the drill works as you expected, find a minute and drop a note to the gundrill manufacturer saying how many holes per sharpening you produced, what cutting regime and coolant you used and other information that might be relevant.  It normally helps the manufacturer enhance the performance of the next batch of gundrills.

  Understanding Terminology

Gundrill Master – a specialist who avoids all of the following.
Gundrill user – a specialist doomed to step on a garden rake.
Gundrill advanced user– a specialist who regularly steps on a garden rake.
Gundrill specialized user– a specialist who perfected stepping on the very same garden rake.
Gundrill general user – a specialist having more than two bumps on his forehead due to stepping on a rake.
Gundrill smart user – a specialist who manages to step on a rake even if it is hidden in a tool shed and properly locked.
A gundrill designer (gundrill machine designer) – a specialist who values first of all the result of stepping on the garden rake. Getting tired from stepping on garden rakes designed by others, so he designs his own.
An advanced gundrill (gundrill machine) designer – a designer who steps on the same garden rake no more than twice.
Copyright – a concept financially limiting gundrill producers and users to step on the garden rake designed by others.
GurStaHypeMast – known companies producing various garden rakes. Although brands can be quite different, a garden rake is still a garden rake. It could hurt no matter who makes it.
Design (carbide, machine) upgrade – a process of permanent money spending for buying new garden rake which hits more painful than previous.
Computer – a device that allows accelerating the process of garden rake production and stores information about all hits produced by the designed rakes.
Plotter – a compute devise allowing visualization of a garden rake before it is actually produced.
A 3D gundrill solid modeling – virtual stepping on a garden rake.You can see it but you cannot avoid it. Makes garden rakes more colorful and attractive on ad brochures and websites so one might think that it is not that bad of an idea to try to step on them.
Customer drawing – a drawing of a garden rake where only the handle is shown.
Drawing for approval (machine specification for approval) – a drawing (specification) of a garden rake to be used later to blame the customer every time he steps on it because he approved this action.
Trial tool (machine) batch – batch where garden rakes can be seen by the naked eye.
Serial tool (machine) batch – batch where garden rakes are covered by fallen leaves.
Non-reliable tool (machine) – a garden rake that hits your forehead even if you did not step on it.
Reliable tool (machine) – a garden rake that hits your forehead even if you face the opposite direction.
Friendly process controller – a rubber-covered handle for the garden rake.
Flexible process controller – a pad that can be moved over the garden rake handle adjusting for the height of the users forehead.
Graphical interface in the gundrill (machine) design and in the process control – a garden rake which allows adjustment of the color and spark intensity after the rake hits the forehead.
Manual – a book describing different ways for stepping on a garden rake.
Gundrilling automation – a concept that allows one to step on the same garden rake faster and faster.
Cooperation of gundrilling (gundrill machine) – a technology that allows you to be hit even if somebody else steps on the garden rake.
Foreign gundrill companies and machines – a technology that allows users to step on the garden rake made oversea.
Technical Service (Support) – a special department that recommends what has to be done when you step on a rake.
 

To be continued….