LittleMachineShop.com HiTorque 5100, Руководство пользователя

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Back rake The back rake produces the front cutting edge that cuts
into the workpiece.
Front relief Front relief provides clearance for the front cutting
edge. Without front relief, the front of the tool bit
would hit the workpiece and not allow the cutting edge
to penetrate the workpiece.
How to Grind Tool Bits
Use a bench grinder to sharpen your tool bits. Even an inexpensive bench
grinder can do a good job grinding lathe tool bits. In some cases, you might
want to purchase a higher quality fine grit wheel.
Keep a small cup of water near your grinder. Grinding generates heat, which
can cause two problems. The tool bit will become too hot to hold. Overheating
can also affect the heat treatment of the tool bit, leaving the cutting edge
soft.
Use a protractor to measure the angles. They are not super-critical, but you
should try to stay within one degree of the recommendations.
Grind the Front Relief
The first step in creating a tool bit is to grind the front relief. For most work, a
relief angle of 10° works well.
While you are grinding the front relief, you are also creating the front cutting
edge angle. Make this angle about 10° also, so that the corner formed by the
front cutting edge and the side cutting edge is less than 90°.
Grind the Left Side Relief
Form the left side relief next. Again, create about a 10° angle. You don’t need
to form a side cutting angle. The side cutting edge can be parallel to the side
of the tool blank.
Grind the Top Rake
The top of the tool bit is ground at an angle that combines the back rake and
the side rake. The side rake is most important, because the side cutting edge
does most of the work. For cutting steel and aluminum, the side rake should be
about 12° and the back rake should be about 8°. For cutting brass, the rake
angles should be much less, or even 0°.
Round the Nose
A small nose radius allows you to turn into tight corners. A large nose radius
produces better surface finishes. Create a nose radius that is appropriate for
the tool bit you are creating.