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Small milling cutters

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philf:

--- Quote from: DavidA on January 24, 2016, 12:51:32 PM ---
On removal, the very tips of the cutter were showing signs of wear, but the rest of the edge was ok. no apparent wear on the flutes. So really it needs sharpening before any further use.

Dave.

--- End quote ---

Dave,

If you haven't got a tool and cutter grinder just take the corners off on a bench grinder. A 45 degree (ish) chamfer with about 5 degrees clearance will give your cutter a new lease of life.

Phil.

DavidA:
Phil,

That would be one way to go; thanks for the idea.

But as this is a very low power machine I really aught to aim for a nice crisp edge with minimal contact area.

I could take the cutters down to my old work and get them touched up.

As I am gradually 'rationalizing' my numerous time consuming pursuits (aka hobbies) and starting to get my machining into some kind of order, I have a cutter grinder pretty close to the top of my wish list.
Meanwhile I may have a go at H Hall's grinding rest.

Dave.

DavidA:
Phil,

Going back to the original reason for me creating this thread.

I just received my copy of 'Milling:a complete guide' by Harold Hall.

I think that all of the items he covers in the book have also been presented in Model Engineer's Workshop; but I reasoned that it would be more convenient to have all this stuff in one place.
The items covered and the techniques used are very interesting,

But what immediately struck me was the speeds he uses.

He is recommending free cutting mild steel for his projects. But running a 12mm HSS cutter at 500 rpm.

Agreed, he does indicate  that there is some leeway in this, but 500 rpm is less than half the recommended speed.

I do tend to wonder if many people have taken this advice too literally and wonder, as I did, why they were having problems milling with small cutters.

Dave.

chipenter:
At lower speeds less heat is generated and the cutting edge lasts longer , and you don't need to use coolant .

DavidA:
Jeff,

I appreciate the above points.

However, it would perhaps be a good idea to point out to the reader that the speeds used are not the same as the ones to be found in standard tables.

After all, the book is entitled 'MILLING; a complete course'.

Dave.

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