Quick Tips

[i]Last Update: 03-02-2017[/i] This will be a collection of some simple tips and techniques that I have learned over the years and use regularly.

Regrinding carbide inserts for special operations - 03-02-2017
Using a ball bearing to hold rough and non parallel parts in a vice - 03-02-2017
Centering work on the rotary table - 03-02-2017

Regrinding carbide inserts for special operations

In some cases it is benefitial to change the grind on an off the shelf carbide insert.
This part was such a case, it has to be turned down do a 3,9mm diameter, 17mm long. With a normal finishing insert it did not work very well, I could not hold any reasonable tolerance because oft the cutting pressure.

I did also not want to come back with a second tool for finishing, as I had to make a bunch of them.

I decided that a normal CCMT06 finishing insert with a 0,2mm nose radius is a good starting point, but I ground a substancial back- and side rake to the top of the insert.
That way I was able to rough and finish with two cuts - First cut took it down to 4mm in diameter, second cut finished it to 3,9mm +-0,01mm.

The way the insert was ground is very primitive: I grab them with a needle nose vice grip.
Then the the top face of the insert is held freehand against a diamond wheel, eyeballing the angles - I tipped the top surface about 5° back and to the right, to create a nice, positive cutting action with very little cutting pressure. As the insert has already a nose radius of 0,2mm, it is also a very durable tool.

Using a ball bearing to hold rough and non parallel parts in a vice

The purpose of the flat is to protect your vice.

Centering work on the rotary table

If your rotary table has a morsetaper socket in its center, a morsetaper collet and a pin can be a simple way to center a workpiece that has already a hole drilled in its center (Conrods for model steam engines are a good example where this technique works well.
The collet with the pin is just pushed by hand into the morsetaper of the rotary tabel and then the work is placed on parallels (to clear the collet) over the pin and clamped in place.