10.8 Tool Setup
Micky R. Jennings
Setting up tooling on a lathe requires some checks and adjustments to make sure the cutting process will be successful. When using modern inserted tooling and a quick change toolpost on a manual lathe, it is ideal to set the tooling up like it was designed to be used. Setting the tooling up in this manner will give adequate clearance where it is required. The first check will be to the insert itself. The next step will be the correct orientation of the tool. Then check the height or the tool. Lastly, tools are set up in the tailstock. Each of these components is important, and when any one of them is neglected, the operator may have difficulty with the cutting process.
Insert replacement
It is important to check cutting tool edges from time to time to ensure they are sharp, free from damage, and in good working order. Often, an experienced machinist can tell something is wrong with a cutting edge by noticing a difference in the part, the sound the machine is making, or the chips that are coming off the tool. For tooling like HSS, this would mean taking the entire tool out of the toolpost, resharpening it, and redoing the setup of the tool. With the use of modern carbide inserts, much of that headache is gone. Carbide inserts have multiple cutting edges per piece and often repeat their location with an accuracy of less than .001. This allows the operator to rotate an insert in much less time than it would take to fix a dull HSS tool.
Step by step process for replacing indexable inserts:
- Leave the tool on the toolpost and in the quick change tool holder.
- Clean all the chips, oil, and residue from the insert, clamp, and screw heads.
- Inspect the insert.
- Use the appropriate tool to loosen and move to the side, the hold down clamp. If this is really dirty, the hold down clamp may need to be completely removed and cleaned. Some tools may not have this clamp.
- Use the appropriate tool to loosen and remove the alignment screw holding the insert and insert backing plate in place.
- Clean the insert seat meticulously. A little cleaning solution on a cotton swab helps to get into the small crevices.
- Clean the insert and backing plate with a rag. Some insert holders may not have a backing plate.
- Clean the screws by holding them tightly with a rag and rotating them with the hex key.
- Inspect the insert, looking for an unused cutting edge. If one can’t be found, the insert needs to be replaced.
- Start reassembling the tool by setting the backing plate on the bottom of the pocket.
- Start the thread of the alignment screw. Do not tighten.
- Place the insert over the alignment screw and press it down onto the backing plate.
- While holding downward pressure on the insert, gently tighten the alignment screw. Do not overtighten! This screw is easily stripped and is only used to position the insert in the pocket and not to hold it.
- Replace the clamp and screw in the opposite fashion; it came off. This screw can be a