Tool grinding angles

Hi All
I am new to machining work and looking for links to any good sites with info
on tool sharpening angles for lathe work.
Reply to
Paul D
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You should go to Ebay and buy a copy of "How to run a Lathe" for about 10 bucks or so. This will be a life-long resource.
Lindsay books has a few reprints that will also be very helpful. one called something like "machine tool work" and another called "advanced machine tool work.
Take this link:
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It has most of what is in the above book. Note that
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has a lot more than that for you.
Pete Stanaitis ------------------------
Paul D wrote:
Reply to
================ You want the older (1940s-1950s) lathe books as they get into sharpening lathe tools from a blank piece of M2 HSS. The newer books and texts for production machining give this little coverage as most production tooling is carbide or requires a special [expensive] grinder and lots of experience to sharpen, for example face mill cutters.
Lindsay books has reprints of these books. Be aware if you get reprints from earlier periods [which have many useful suggestions and hints] they will be covering forged lathe tools and carbon steel which has almost totally disappeared.
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I suggest Milne's Machine shop Methods as a good introduction to general machine work include lathes.
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Several items:
Getting the exact rake/relief angles on your tools is not as important as being able to get the same, slightly more and slight less rake/relief angles.
Tool grinding is an area where almost everyone has problems to start because the results appear to be inconsistent because of the inability to grind consistent angles and or with small known changes.
While "carbide" grinders [used also for HSS with a white wheel] are ideal for the professional shop, they are expensive for the hobbyist. I suggest using a combination disk/belt sander which you may already have. Suitable belts and disks are inexpensive [I like the blue zarconia oxide ones] and you can keep a coarse belt for rough grinding and a fine disk for finish grinding mounted.
I suggest you fabricate a tool holder/fixture for your belt sander so you can get repeatable results. Note that although the belt sander tables generally pivot, the degree graduations are coarse [5 degrees] and it is only by accident that the zero mark will be with the tables right angles. With a little care you when using a machinist's protractor or combination square protractor you can get 1/2 degree accuracy with a jig or fixture, and with an angle block set the table to similar accuracy. Lots of people try to free hand sharpen "bare" bits but few are any good at it.
for some suggestions see:
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With these jigs even our first term machining students were able to get "'line-out" fit Acme thread tools.
Regular M2 HSS is more than adequate for home shop use. The lathes typically used in home shops don't have the RPM, power, or duty cycle to justify cobalt tools. Not only are these more expensive, but they are also much harder to grind. As a general rule you will find that the harder and more wear resistant a tool material is, the more brittle and prone to chipping/breaking it is, and as starting machinists generally lose more tools to chipping and breaking than wearing out, the choice is obvious.
For good finishes the nose radius is critical, but too much will cause chatter.
Don't dunk hot tools in water to cool them off while you are grinding. This results in thermal shock and causes micro cracking which results in early tool failure. This is bad for HSS and death for carbide tools. Hot tools indicate a dull wheel or worn out belt, or pushing the work. Let the wheel or belt do the work and slow down.
One last tip is to use a plastic abrasive bristle brush to hone your newly ground lather tools to remove the razor sharp edges to improve surface finish and tool life. see:
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local hardware store will generally have these.
Unka George (George McDuffee)
...and at the end of the fight is a tombstone white with the name of the late deceased, and the epitaph drear: ?A Fool lies here, who tried to hustle the East.?
Rudyard Kipling The Naulahka, ch. 5, heading (1892).
Reply to
F. George McDuffee
Sherline has a nice 4 page PDF file that describes sharpening tools.
-- Why do penguins walk so far to get to their nesting grounds?
Reply to
Bob May
An old copy of machinery's handbook is a valuable resource, every hobby shop should have one
Reply to
Here is a link to their web page about it:
Reply to
Ron Thompson
Reply to
Gerald Miller

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