Vermont Indexable Tooling - Editorial

Company Information Custom Tools

VIT PROVIDES A COMPETITIVE EDGE IN
BACK SPOT FACING

CHALLENGE:

In the early 80's Vermont Indexable Tooling was asked by a major valve manufacturer to find a way to economically solve their back spot facing operations. This manufacture's goal was to machine a valve body complete on a machining center, in an effort to maintain a competitive edge against the encroaching foreign market.

EVALUATION:

Vermont Indexable Tooling began by evaluating the back spot facing tools already on the market. The tools available were costly to purchase and/or maintain, primarily because they consist of several moving parts. We felt that their replacement carbide blades were expensive. Although the brazed carbide blades were somewhat more economical, they still cost approximately $38.00 ea., and the interchangeable blade cost about twice as much as the brazed carbide blade with one, and in some case's two cutting edges.

THE IDEAL TOOL:

As a result of Vermont Indexable Tooling's findings, we set out to design and manufacture a Back Spot Facing tool that would fill the void existing in the market:

A tool with no moving parts.

A tool with the strength to withstand the stress to which it would be exposed; and

A tool which would be cost effective to purchase and which would require little or no maintenance.

With no moving parts, the tool cannot malfunction. By designing the tool to suit the application, we can achieve maximum strength and rigidity. By designing the carbide insert pocket to utilize standard carbide inserts, we are able to provide an economical alternative to those tools currently available. In many cases, the savings achieved by using a few dozen inserts instead of costly blade replacements, more than covers the cost of our tool.

HOW IT WORKS:

Vermont Indexable Tooling's patented Back Spot Facing tool is designed to be used on a machining center that has spindle orientation capabilities. After the hole pattern has been drilled, the machine spindle orientates the Back Spot Face tool in a position that will allow for offset entry through the hole and then reposition on the hole's centerline far enough through so that the head of the tool does not hit the part when first rotated. Once this process is complete, the Back Spot Facing procedure can be completed. Upon completion of the cutting cycle the entry procedure is simply reversed for hole exit.

TEST & EVALUATION:

During the initial years of testing and evaluating, Vermont Indexable Tooling's Back Spot Facing tool has proven to be a cost effective way to solve back spot facing problems for manufactures throughout New England, and most recently the entire North American continent.

Our tests indicated that the best starting point for machining is .001 IPR, and 80% of proper SFM of carbide grade. It may be necessary to make further adjustments based upon machine, fixture and/or part rigidity.

It is important to keep in mind that most valves and pumps are sand castings. To date, we have not found an insert that will successfully machine sand pockets, however, the elliptical shape neck of our Back Spot Facing tool leaves a space within the drilled hole that allows coolant to pass through and is then forced outward by the rotary cutting action of the tool's eccentric shape. The coolant helps to flush away loosened sand located in these pockets and also aids in extending insert life. Through tool coolant is available on most sizes.

With any carbide insert cutting tool, operator awareness is essential for its longevity. When the insert shows signs of dulling, an alternate tool must be called up from the tool carrousel, allowing time for the operator to index the dull insert without jeopardizing productivity or causing damage to the tool.

ECONOMIC CONSIDERATIONS:

In considering the purchase of any new tool, economics plays an important role. Vermont Indexable Tooling manufactures it's Back Spot Facing tool to meet current industrial standards. One of the advantages of our tool is that, in many cases, it has been designed to use standard inserts and hardware the customer may already have in stock. In many instances, the customer has spent a great deal of time and money establishing which grades of inserts work best on their product. Thus, two good products combined (their inserts and our tool) potentially make a better one. By eliminating the expense of stocking additional inventory of clamps, screws and various grades and types of carbide inserts, a company can realize major savings. Many manufactures compare the initial cost of the tool itself, but the real saving is in the usage of inserts, and we do offer a quality line of inserts.

Consider the back spot facing tool that offers one cutting edge at a cost of approximately $38.00 vs. a tool that can utilize the customers stocked TPG carbide inserts with 3 cutting edges, at a cost of $6.00 ea., or $2.00 per cutting edge. This represents a saving of $36.00 per cutting edge. Multiply these savings by several dozen inserts and you can see that VIT's Back Spot Facing tool will pay for itself within a very short time. Another economical advantage to our Back Spot Facing tool is the ability to insure that the tool can enter and exit the hole without chips interfering. Such interference with the operation of this mechanism on other back spot facing tools can result in damage to the machine and the part, loss of set up time and even damage to the tool.

Our Back Spot Facing tool only requires spindle orientation and offset positioning to enter and exit a hole. The tool is easily manufactured for left hand or right hand rotation. (The standard being right hand like the twist drill). The elliptical shape of the tool's neck adds approximately 15% more support and the offset cutting head is designed to provide hole clearance and does not require piloted support of the machined hole. This procedure eliminates the possibility of galling and seizing or otherwise damaging a finished hole. Our tool eliminates the need for a manufacture to pilot the hole, stop the cycle, and manually attach the cutter to the arbor. In addition to the time saved, operator safety is increased, and the chance of human error reduced.

The compact design of the head and absence of moving parts make our Back Spot Facing tool perfect for use in hard to get places. A surprising development has been the popularity of our Back Spot Facing tool on N/C lathes for back boring and/or back recessing operations. Given the ability to rotate the position of our insert pocket during the tools manufacture we can achieve almost and endless variety of angles for back seat machining as well as standard chamfering front and rear of the through hole. This is a summary of some of the economical advantages to Vermont Indexable Tooling's Back Spot Facing tool, as well as some of the problem areas encountered during back spot facing operations with existing tools on the market and our ability to overcome these problems.

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