Getting Started with a Gorton Grinder

 

Copyright 2009 by James P. Riser

 

 

 


The Gorton 265 grinder is a fairly small but very massive unit. They are built to last several lifetimes. On this page I shall briefly describe the process I use for grinding a cutter for engraving using my restored Gorton 3U pantograph. I will assume that the reader has a grinder to refer to as I describe the steps that I use.

 

The grinderlooks like this. There is an arbor with a mounted grinding wheel and a swinging/angle adjustable holder to control the grinding.

In addition to swing back and forth, the adjustable tool holder can be moved left and right.

 

 

 

 

The motor is securely mounted behind the grinder itself.

 

The cutter that I am describing will look like this when done.

 

The angle on the pivoting tool holder is adjustable.

 

The rotation of the tool holder spindle may be locked with the sliding pin.

 

 

The cutter to be ground is rough ground freehand on a regular bench grinder.

It is not quite ground half way through the HSS.

After this grinding, it is mounted in the appropriate 4NS collet of the tool holder.

 

 

 

The angle of the tool holder is set to "0" degrees and

the rough grind is cleaned up and trued on the Gorton 265.

When tightening the collet, turn the ground flat towards the grinding wheel and lock with the sliding pin.

 

 

 

Before doing this, I dressed the grinding wheel to run absolutely true.

With my grinder I have two ways to hold the diamond tipped dressing tool.

 

I can either use a regular collet or an internal tapered collet.

 

The special collet and tapered dressing tool look like this.

This internal tapered collet can also be used for holding tapered shank cutters for grinding, as well as, the diamond dresser.

The taper may be seen here.

 

Together the collet and dressing tool look like this.

These internal tapered collets may easily be made with a lathe, mill, and special tapered tool (ground on the grinder itself).

 

The angle is adjusted as needed...

 

During and after dressing.

 

After dressing the wheel, the rough grind of the cutter is trued.

At this stage, I further grind, the cutter; but still not quite going to the half way through point yet. This is critical!

For this cutter I next set the angle to 30 degrees.

 

The tool holder is rocked back and forth while bringing it in contact with the grinding wheel.

 

Go gently here.

 

The cutter should be ground so as to

form a series of flats forming a point.

 

 

 

 

Two additional views.

 

Things should now look like this.

 

Now is a good time to fine tune the halfway through grind on the cutter.

Notice that the cutter has not quite been ground half way.

This needs to be corrected.

Set the angle to "0" degrees again and finish the halfway grind.

 

It is better to not quite reach half way through than to grind past the center line. If you go past the center line, the cutter will not work correctly. Be gentle and use a good lens to examine your progress.

Clearance will next be ground on the new cutter.

I like to set the angle to 25 degrees for this.

 

I like to start the clearance grind opposite the flat on the cutter.

 

As before, grind a series of flats but do NOT grind clear to the cutting edge.

 

To avoid accidently grinding the cutting edge off, rotate the cutter so that the edge never gets ground.

 

The cutting edge is toward the viewer here.

 

Looking directly at the flat, the cutting edge is at the bottom here.

 

Two additional views showing how things should look.

Note that the clearance has been ground smooth by rotating the cutter to eliminate the many small facets.

If the cutter were to be used for engraving in this delicate state, the point would soon break off. Therefore, the tip must be slightly "flatened".

Notice the angle (3 degrees or so) on the fine diamond "stone"

The leading edge of the tip must be longer than the trailing edge. This "flat" is very small.

Here is the finished cutter.

There are a number of grinding wheels readily available for this grinder. I prefer cup wheels for most jobs like the one just shown.

Ruby wheels are nice for grinding steels.

 

Green wheels will grind carbide.

 

Some cup wheels will have straight sides.

 

For ultra fine finishes and carbide, diamond wheels are available.

Click here to see images of my Gorton 375-2 grinder.

Click here to go to my Gorton 3U restoration pages.