Lathe Tool Clamping

The are a number of things to consider when clamping the lathe tool into the toolpost, lathe tool clamping:

  • clean surfaces
  • correct height
  • clamping base
  • overhang
lathe tool post

One of the first things to do when changing a lathe tool or fitting a new tool is to clean all surfaces.

You will be applying a lot of force to hold the tool in place and small metal particles can get embedded.

Particles will gradually build up and change the surface height.

The tool post shown is from a Warco WM240B, but most tool posts are similar in construction and use.

lathe tool clamping

After cleaning the next job is to shim the tool to the correct height. Tool cutting edge needs to align to the centre of the chuck.

It’s easy to check this by putting a centre in the tailstock and moving this to position it next to the tool. I then use a selection of aluminium, steel and brass shims. Old feeler gauges are great for this.

The overhang and clamping of the tool is important. As you can see I try and use two clamping points spaced apart. Ensure that any shims extend to line up with both clamps or you will rock the tool.

tool overhang

Tool overhang is a really important factor to consider. The longer the overhang the lower the resonant frequency of the tool and the more likely it is to vibrate and hence create chatter marks.

In every aspect of machining it is good to think about the the stiffness. How far the part extends from the chuck. A 4 jaw chuck increases rigidity in the clamping of the part. Of course the tailstock is also there to support and increase stiffness for machining.

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