Cutter grinding

A useful reference is "Machine Engravers" C.Harerwood-Matthews ISBN 09520696 01.

This book assumes the use ofcommercial cutter grinders. For home brew the easiest strategy is use a setup method similar to that used by the Deckel cutter grinders.

Hold cutter in a jig that can present cutter to the face of a cup grinding wheel at the desired cone angle - say

Jig must allow rotation through more than 180deg but must have a positive stop at the nominal 0deg position.

If a cutter already ground with the basic 180deg flat is located in the jig with the flat lined up at the 0deg position, rotation against the grinding wheel face will produce the basic

At the 0deg stop position the flat face of the cutter is normal to the grinding wheelface so this results in 0deg cutter top rake

Now rotate cutter within the jig forward of the 0deg position enough to give the required clearance angle.

With the cutter jig locked at the 0deg stop position feed the cutter in until the tapered clearance flat generated just intersects the cutting edge.

Now, at the same infeed position, SLOWLY rotate the jig to grind away the the remainder of the cutter to the same depth as the centre of the already ground clearance flat.

If you're aiming for the very large clearance angle needed for some materials the second step removes rather a lot of material and it's easy to overheat the cutter. If so, remove the material at lighter infeeds but finishing up at the original infeed position.

The point of the cutter must be finally be given an end cutting clearance. This only removes a tiny amount of material and I usually do this by hand.

Jim

Many thanks Jim, i will scout around for Deckel info and order the boo

you have said. I have never seen one of these gadgets so it looks a interesting project, the cutters will be used on engraving qualit brass for clock dials, regards Dav

-- DCree

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And the following pages.

Don't try to get a used one. Here, a S0 would cost 1500.- EUR. :-(

Nick

Chronos do a "chinese" copy of the Deckel machine with the name "Universal Cutter Grinder" - a look at this may help you.

Jim

I have a somewhat battered SO toolroom model which I find very useful - it's as versatile as the Quorn but easier to use.

A home brew fabricated version is possible but castings would make life easier.

A few things that may not be obvious from the illustration.

The large knob at the far left is calibrated control of axial movement of the horizontal bar. 0.050" per turn, spring loaded for zero backlash.

The bar is free to rotate until it hits a stop controlled by the front knob.

The Tee shaped device at the top is a single point diamond dresser. When swung into use, infeed is controlled by the knurled knob on the left of the wheel guard.

The small knob at the top of the cutter mount casting is a 3 position plunger which is the detent for rotary location. Full out is free rotation using a 360 deg scale. Halfway in is 2 detents 180 deg apart. Fully in is 24 detents 15 deg apart.

The complete cutter holding casting sits on an axial dovetail slide which controls the radius generated by movement of the top swivel. There is also a second small dovetail at right angles to this which makes it possible to generate a radius offset from the centre of the cutter.

Jim

Hi Nick, i dont have that sort of money to splash around and even th

Chronos version is near a grand, so home made it will be. Hi Jim, man thanks for the useful information, i will print out your detaile instructions, i might have a look at a lathe top slide version, a least with this idea i can control the infeed of grinding withou having to make a new slide. I wonder if anyone has an exploded view o one of these gadgets, as i said earlier, i have never seen one of thes animals and this would be a great help, regards Dav

-- DCree

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DCreed,

I've sent you a PM at your RC Forum - have a look and give me a shout.

f147