Freehand grinding of Lathe bits

Has anyone tried freehand grinding of lathe bits (those with inserts and without). The use would be a diamond wheel that cuts on the side.
I tried it with simple bits and it seems to work well, but maybe I am missing some finer points of grinding.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Generally diamond wheels at high speed and steel do not go together. The steel has an affinity for carbon which is what a diamond wheel is. Still, from hanging out on the Quorn groups and such, I see that people use diamond wheels on HSS.
CBN is the wheel for steel afaikt.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Wes, I may be very seriously confused and misinformed. What I was thinking about originally was carbide tipped lathe bits (with carbide tips brazed on). When I grind those, the objective is to grind carbide, but some steel gets ground, as well.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You can undercut the carbide (steel support) on a aluminim oxide wheel first.
Wes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

It's up to you to see that it doesn't. Use an aluminum oxide wheel to grind away the steel that will get ground. Unless you use the tools for extremely heavy cuts (unlikely), it's easiest to grind the steel at a greater relief angle, so even if you touch steel when grinding the carbide, very little is exposed to the diamond wheel. Do not seriously undercut the carbide, otherwise you risk tool failure.
Do not grind steel with a diamond wheel that runs at high speed, regardless of what foolish people tell you. Norton did extensive testing back in the 50's in regards to diamond and steel. They do not go together. If they did, all grinding manuals would suggest they be ground together with diamond.
Harold
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

From what I remember of reading Norton's publication on the subject: Yes, there is a noticeable degradation of the diamond, but only in terms of production rates. What I mean is that if you have a wheel that will last 10,000 hours grinding carbide, and it only lasts 1,000 hours grinding steel, that's not about to be a problem for a hobby (or even small production) user.
I don't think I'd sweat it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

From what I remember of reading Norton's publication on the subject: Yes, there is a noticeable degradation of the diamond, but only in terms of production rates. What I mean is that if you have a wheel that will last 10,000 hours grinding carbide, and it only lasts 1,000 hours grinding steel, that's not about to be a problem for a hobby (or even small production) user.
I don't think I'd sweat it. --------------------------------------------------------
It's not that simple. The wheel loses performance drastically, and it happens quickly. It's obvious if you know the difference. I'd sweat it, and plenty, as I have in all of my years in the shop. Why taunt the piranha? Would you also paint your car with a broom? Why not-----it's painted, isn't it? :-)
Harold
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 11 Aug 2009 05:05:29 GMT, "Harold and Susan Vordos"

Harold has it right. Ive seen newbies take bits to diamond wheels in machine shops...and toast em in a VERY short time.
The owners tend to get really really really pissed off.
Gunner
'In the first place, we should insist that if the immigrant who comes here in good faith becomes an American and assimilates himself to us, he shall be treated on an exact equality with everyone else, for it is an outrage to discriminate against any such man because of creed, or birthplace, or origin. But this is predicated upon the person's becoming in every facet an American, and nothing but an American... There can be no divided allegiance here. Any man who says he is an American, but something else also, isn't an American at all. We have room for but one flag, the American flag... We have room for but one language here, and that is the English language.. and we have room for but one sole loyalty and that is a loyalty to the American people.' Theodore Ro osevelt 1907
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 11 Aug 2009 05:05:29 GMT, "Harold and Susan Vordos"

Actually, I bought a mill that looked like it was painted with a broom. A very old, dirty one. Right over the spooge. Don't think I'd like it on a car.
Pete Keillor
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Harold and Susan Vordos wrote:

I saw a rusted old 57 Caddie that the owner painted orange and black with a roller and house paint. he drove it whenever his 67 Corvette was in the shop for bodywork, which was about half the time. He had me install a stereo system in it in the early '70s. Does that count?
--
You can't have a sense of humor, if you have no sense!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Chuckle!
Now that's a discriminating car lover! Nothing quite like a nice orange and black rolled paint job to set off a nice car! <sigh> Bet he painted the bumpers with aluminum paint, too, eh? <g>
Harold
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Harold and Susan Vordos wrote:

No. He still had some black house paint left...
BTW, it fit right in on Halloween. ;-)
--
You can't have a sense of humor, if you have no sense!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

drastically, and it

difference. I'd sweat

shop.
Question for you Harold. What can the HSM do to recover such a diamond wheel other than the white stick that comes with it? Got any tricks to reclaim? The first one I bought has been abused, not the second one......;>) I'd be nice to fix the first. phil kangas
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snip---

My only experience extends to the dressing stick, Phil. A lot depends on what they've done to the wheel. If it was run dry, and is heavily loaded, and dulled by having ground steel, but runs true, you may enjoy perfect success using the stick. What it does is attack the matrix, releasing the dull diamond and exposing new. The problem is, it shortens wheel life considerably, so you can't use it routinely. That's what's wrong with "clever" guys that think they know more than the folks that have done the research. I've never disputed that a diamond wheel will cut steel--but I know beyond doubt that it does so only briefly, and at considerable loss to the wheel.
If your wheel runs out of true, and has been badly abused that way, you may have some success mounting it such that you can rotate it slowly, with the back running dead true, then run a grinding wheel against the diamond wheel, barely making contact. Assuming it's a resinoid bonded wheel (the choice for brazed carbide, by the way), you may succeed in removing enough of the matrix to true the diamond wheel. Be careful, for some are only 1/16" thick when new, while others are 1/8". When you break through the matrix, what you have left is a piece of aluminum that is worth nothing more than scrap. I would use the grinding concept ONLY if the wheel is badly out of true.
Hope this helps, Phil.
Harold
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Harold and Susan Vordos" <> wrote in message >

such
it?
abused,
A lot depends on

heavily loaded,

enjoy perfect

matrix, releasing the

shortens wheel life

what's wrong with

that have done the

cut steel--but I

considerable loss to

that way, you may

slowly, with the

the diamond wheel,

wheel (the choice

removing enough of the

are only 1/16"

through the matrix,

nothing more than

is badly out of

Thank you very much for your input, Harold! phil
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snip--

Welcome!
:-)
Harold
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
OK, last dumb question, I swear.
Carbide inserts do not need grinding.
Brazed carbide bits cannot be ground with diamond.
Anything else can be ground with green wheels.
Why,. then, the need for diamond wheels?
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Who told you brazed carbide can't be sharpened with diamond? Better yet, who suggested to you that green wheels are an acceptable compromise for a diamond wheel? I'd recommend you stay far away from that individual, for he surely doesn't know what the hell he's talking about. Mean time, NEVER use a silicon carbide wheel for grinding steel. That is just as stupid as using diamond for steel.
You are very best served to take advice from those of us that have actually worked with these grinders. I have, and have extensive experience in hand grinding lathe cutting tools. My advice will serve you perfectly well and keep you out of trouble. I can, and do, grind toolbits that work, and work as they are supposed to work. I am not lost on the subject of grinding toolbits, and have many years to my credit, and have authored several documents that are available for those that care to learn the art of grinding toolbits.
Sharpening brazed carbide toolbits is very best accomplished with a diamond wheel. In order to achieve the desired results, you must relieve the supporting steel substrate. That's not a big issue, and is easily accomplished by simply grinding a slightly greater relief angle that that which is ground on the carbide. Using the existing carbide as a guide, grind the steel beneath the cutting edge until the wheel is grinding on the carbide. You'd use an aluminum oxide wheel for this task, which is too soft to move much carbide, so it is more or less self gauging. You now have prepared the tool to be ground on a diamond wheel, which should be run wet, and supported by a table that can be set for the desired amount of relief. If, in the process of sharpening the carbide, you must remove enough to make contact with the supporting steel once again, regrind the steel with the aluminum oxide wheel. None of this is difficult.
A good idea is to have a wet diamond on one end of a double shaft motor, with an aluminum oxide wheel on the opposite end. That way you are properly setup to sharpen both brazed carbide and HSS with one grinder. I have operated in that manner since 1967 with excellent results.
Harold
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

    They may in their production -- but you don't want to grind ones after they have gotten dull in use.

    They can -- if you *first* undercut the steel with standard grinding wheels, so the diamond won't touch the steel. The brazing is no problem to the diamond, just steel or iron. It would help to have fixtures to prevent the angle shifting which might allow the steel to touch the diamond wheel.

    Not well. You get poor edges with green wheels on carbide, and green wheels are too soft to work well on mild steels.

    To make a good sharp edge on the carbide -- either the brazed carbide inserts, or as a manufacturing step in the production of the replaceable carbide inserts.
    Listen to Harold -- this is his primary field.
    Enjoy,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 17 Aug 2009 01:24:16 -0400, "Michael A. Terrell"

A hot, sunny day and rattle cans is the way to go, great, pebbled finnish! Gerry :-)} London, Canada
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.