These tools are used for finish machining the many accurate bores needed in the crankcases- transmission bearings, crankshaft journals, and cylinder bores. Because many of the bores are deeply recessed in the casting I felt a normal extended boring bar would not be able to achieve the required accuracy and surface finish.
The tools are from Microbore, a custom tooling house in the United Kingdom. I wanted to use domestic US suppliers for as much of this project as possible but all of the US tooling vendors I sent a RFQ to declined to quote the project. Microbore has done similar products in the past and their high quality, experience and reasonable pricing easily convinced me to choose them.
The boring bars are of the Devlieg adjustable insert style with an integral CAT40 shank. This will maximize accuracy and rigidity versus a boring bar held in a collet or end mill style holder.
Each bar has an angled machined pocket at the extreme end that receives a Devlieg Micro-Adjust carbide insert holder.
These Devlieg insert holders allow fine diameter cutting adjustment using the latest carbide insert cutting edges. We will use a test part to dial the cutting diameter to size for each bore then lock them in place.
In the next week or so we'll be machining the first castings and post some video and images of the results.
That's all for now.
Chris
