H
huntinco
Guest
Does anyone know where one can find good reading/instructions on tool/bit grinding for lathes.
Thanks
Justin
Thanks
Justin
C
chuck furniss
Guest
Try machinerys handbook.Can't live without it.
Chuck.
Chuck.
One excellent resource is the book "How to Run a Lathe" published by South Bend Lathe. The book is now out of print, but there are copies floating around on the internet. The book has several pages on tool bit geometry. I recommend it as a general resource.
http://littlemachineshop.com/products/product_view.php?ProductID=1596
Clemson
http://littlemachineshop.com/products/product_view.php?ProductID=1596
Clemson
I'd second the "How to Run a Lathe" book. Great info!!! I got mine from Southbend. Lindsay publications sells "Southbend lathe booklets" that includes this tool bit sharpening section. They also have other great books available. Get on their mailing list for catalogs.
http://www.lindsaybks.com/
gunmaker
http://www.lindsaybks.com/
gunmaker
Although this is not instructional and there are many other shapes of tools it's a good quick reference:
http://littlemachineshop.com/Reference/RakeRelief.php
http://littlemachineshop.com/Reference/RakeRelief.php
P
phantom496
Guest
Lathe Tools . . .
I am a retired Tool & Die Maker - Model Maker - and General Machinist. The above post are dead on for information, but . . the general rule to grinding a cutter/tool is not to drag the heel of the cutter on the work, clearance is good. As long as you have a rake to the cutting edge (15 - 20 deg.) clearance under it (10 -15 deg), and a sharp edge, it will cut. There are no Limits to the design of the cutter, you can grind it to what ever you wish, that is why most machinist have a drawer full of cutters that are already ground to some application or another. The greater application to this is "Speeds & Feeds", faster is not always better . . If it don't cut- Re-Grind it till it does . .
You will only be limited to your grinding ability to make cutters to do anything you wish, and to make.
Phantom
I am a retired Tool & Die Maker - Model Maker - and General Machinist. The above post are dead on for information, but . . the general rule to grinding a cutter/tool is not to drag the heel of the cutter on the work, clearance is good. As long as you have a rake to the cutting edge (15 - 20 deg.) clearance under it (10 -15 deg), and a sharp edge, it will cut. There are no Limits to the design of the cutter, you can grind it to what ever you wish, that is why most machinist have a drawer full of cutters that are already ground to some application or another. The greater application to this is "Speeds & Feeds", faster is not always better . . If it don't cut- Re-Grind it till it does . .
You will only be limited to your grinding ability to make cutters to do anything you wish, and to make. Phantom
F
flatlander
Guest
As an illustration to the truth of phantom496's post above: I used to spend 30 min. or more digging through 5gal. plastic buckets full of surplus/used lathe tools every time I'd visit a surplus yard in Wichita. There were hand-ground tools of every description in those buckets - the purpose for some of them I could only guess at. I've picked out a handful that are practically perfect for one or more application(s) in gunsmithing, though most, if not all, were ground by toolmakers/machinists in the aircraft factories & custom machine shops in town. Many's the time I've envied the skill of the hands that ground some of these tools. I'd sure like to talk to some of the guys who ground a couple of them, and see what sort of grinders they used.
P
phantom496
Guest
Grinding a tool. . .
There is no particular talent to grinding a lathe tool, and the grinder is usually a pedistal grinder. Grinding a tool comes out of the necessity for the cut that you are going to make. A Threading tool is gound to a 60 deg. included angle set on a 30 deg. to the work piece, it is a given. But if you are going to need a .020 Radius in the work, then grind the tool to that radius, or stone it on. Remember you have to cut the material, not push it off. If you put too much of a rake on the top cutting edge of the tool you will get long chips that are hard to handle. If you work with the leading (Point) of the tool and grind it where the chip will push back into the material being cut it will curl or break off and will not require the chip maintanence that makes work out of turning a piece of material. Over the course of many years I found the best of the bunch for roughing and with a small radius on the end, finish, a cutter that will have about .100 of a 45 deg. angle on the tip. As I stated earlier, it must have about 10 degrees relief under the leading edge and 15 - 20 on the top. You can take a brand new tool bit and just grind a 15 or so deg. on the end and it will cut, but not well, the clearances need to be there to allow the material to be cut off. Think of it as a knife - cutting the material, same as using a knife, only this one is 60+ RC. The mistake most people make is to try to use too much of a point, don't grind it to a point, a Radius on the end of the tool will not heat up as fast and will cut longer - better. Even the threading tool should have a small radius on it, stone it on with an Arkansas Stone, but have a radius. The other mistake most people make with a lathe is to run it too fast for the tool and the material. I seldom take mine out of the lower speeds, usually around 350 to 450 rpm, unless I am polishing something. If the chip is turning blue, you are either going to fast or feeding too fast, gear it down - slow it down. The one thing a good machinist will have is patience with the machine....... I have made cutters that were .020 in diameter for the mill (single flute) and gone .750 and deeper with them, .001 and .002 at a pass, very time consuming. I wish I could post pictures here it would save a thousand words.
When I started as a machinist I would ask the ole guys questions, they would tell me go find it for yourself, I had too. Well I don't feel that way, I love to teach people that are interested in how to run a machine or make things, that is the fun part of the profession. I was a Lead in a Model Shop for many years and the part I loved the most was teaching the new guys in the shop. I taught one to do Trig. took me about 3 years, but by the end of that time he was correcting me . . I knew I had succeded then . . . If you have any more questions - we may want to find a different venue for this conversation.
Phantom .
There is no particular talent to grinding a lathe tool, and the grinder is usually a pedistal grinder. Grinding a tool comes out of the necessity for the cut that you are going to make. A Threading tool is gound to a 60 deg. included angle set on a 30 deg. to the work piece, it is a given. But if you are going to need a .020 Radius in the work, then grind the tool to that radius, or stone it on. Remember you have to cut the material, not push it off. If you put too much of a rake on the top cutting edge of the tool you will get long chips that are hard to handle. If you work with the leading (Point) of the tool and grind it where the chip will push back into the material being cut it will curl or break off and will not require the chip maintanence that makes work out of turning a piece of material. Over the course of many years I found the best of the bunch for roughing and with a small radius on the end, finish, a cutter that will have about .100 of a 45 deg. angle on the tip. As I stated earlier, it must have about 10 degrees relief under the leading edge and 15 - 20 on the top. You can take a brand new tool bit and just grind a 15 or so deg. on the end and it will cut, but not well, the clearances need to be there to allow the material to be cut off. Think of it as a knife - cutting the material, same as using a knife, only this one is 60+ RC. The mistake most people make is to try to use too much of a point, don't grind it to a point, a Radius on the end of the tool will not heat up as fast and will cut longer - better. Even the threading tool should have a small radius on it, stone it on with an Arkansas Stone, but have a radius. The other mistake most people make with a lathe is to run it too fast for the tool and the material. I seldom take mine out of the lower speeds, usually around 350 to 450 rpm, unless I am polishing something. If the chip is turning blue, you are either going to fast or feeding too fast, gear it down - slow it down. The one thing a good machinist will have is patience with the machine....... I have made cutters that were .020 in diameter for the mill (single flute) and gone .750 and deeper with them, .001 and .002 at a pass, very time consuming. I wish I could post pictures here it would save a thousand words.
When I started as a machinist I would ask the ole guys questions, they would tell me go find it for yourself, I had too. Well I don't feel that way, I love to teach people that are interested in how to run a machine or make things, that is the fun part of the profession. I was a Lead in a Model Shop for many years and the part I loved the most was teaching the new guys in the shop. I taught one to do Trig. took me about 3 years, but by the end of that time he was correcting me . . I knew I had succeded then . . .
If you have any more questions - we may want to find a different venue for this conversation. Phantom .
H
huntinco
Guest
Thanks for all the good info. I picked up Shelly Davidson's Victor lathe, replaced the fluids, cleaned it up bit, replaced a broken shear pin on the lead screw & just finished getting it leveled. Now it's time to grind some tooling and make a few chips.
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henrya
Guest
phantom 496,
(and others)
I'd love to see pictures of the tools you are describing. Do you have a friend with a digital camera?
I just bought a used lathe and will be using it soon. Its been over 15 years since I owned my last one and I barely knew what I was doing then. Grinding good tools was always a mystery to me. Sometimes I got it right but more often not quite there.
(and others)
I'd love to see pictures of the tools you are describing. Do you have a friend with a digital camera?
I just bought a used lathe and will be using it soon. Its been over 15 years since I owned my last one and I barely knew what I was doing then. Grinding good tools was always a mystery to me. Sometimes I got it right but more often not quite there.
C
chuck furniss
Guest
Justin.
Some info at this site. sherline.com/grinding.htm.
Also a good inexpensive tool grinder at harborfreight.com..item # is 46727.
Be careful.A tool bit flying around the shop at 3000+ fps can be very exciting.
Chuck.
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phantom496
Guest
Tools . . .
I am going to try to post a couple of pictures of some of the tools that I have made over the years, there is a drawer full of them but when I looked they are all pretty much a version of these in some way or another.
. . . This is a picture of the end of them, you can see the clearance grind on them. 
Next is a picture of some of the Small Single Point and double point tools that I have made over the years. The biggest tool dia. there is 3/8" and down to 3/16". Just thought I would add them incase some one thought I was blowing smoke . . . 
You have to have a special grinder to make these tools and it is a very careful grind to do. Some are double flute and some are single flute, and the small one on the end is a threading tool. I guess they will come out like they are supposed to. Perhaps this will help, any more questions feel free to ask. . . I'll check on this site daily . . .
Phantom
I am going to try to post a couple of pictures of some of the tools that I have made over the years, there is a drawer full of them but when I looked they are all pretty much a version of these in some way or another.
. . . This is a picture of the end of them, you can see the clearance grind on them. Next is a picture of some of the Small Single Point and double point tools that I have made over the years. The biggest tool dia. there is 3/8" and down to 3/16". Just thought I would add them incase some one thought I was blowing smoke . . . You have to have a special grinder to make these tools and it is a very careful grind to do. Some are double flute and some are single flute, and the small one on the end is a threading tool. I guess they will come out like they are supposed to. Perhaps this will help, any more questions feel free to ask. . . I'll check on this site daily . . . Phantom
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Grinding tooling is almost obsolete..
With replaceable tool bits grinding your own tools has almost become obsolete. Kinda like rolling your own smokes. I can't recomend enough Thin Bit tooling for gunsmithing. If you dont have an optical comparison scope you are only guessing on the geometry.
Rustystud
With replaceable tool bits grinding your own tools has almost become obsolete. Kinda like rolling your own smokes. I can't recomend enough Thin Bit tooling for gunsmithing. If you dont have an optical comparison scope you are only guessing on the geometry.
Rustystud
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phantom496
Guest
Ok - more explination . . .
Rusty, Some of these tools I have had for 40'ish years, and are still good. The problem with the replaceable tools is expence, keep it simple for the simple folks. If you have the tooling to check the tools you are grinding, it is not a problem getting them correct. The Threading tool is about the only one that I would conceve to use as a replaceable tool. I have used them, but not for a small one man operation. Most of them are carbide, and if you ding one of them you have to replace it - unless you are in the lucky group that are able to afford a diamond grind wheel set up. I still have a tool that I made up to do threading with that has a carbide insert on it, use it mostly for things too hard to use High Speed Steel cutters on. Carbide has it's application, but it has a negative rake and most of the high carbon steels (Barrels 4130-4140 @ 26-32 RC) don't like that rake on it, it has a tendency to push off the material instead of cutting it off, makes for a lousy looking thread. To each is own, but the question on this link was how to "grind tools" not buy them, not getting testy, just a point . . .
The other point to be made here is the cost of the set up tooling that goes along with the carbide inserts, that tooling is not always made for the smaller machines. Most of the machines we had in the shops were 14" - 36" lathes and that 1/2" - 3/4" tooling is very available, but some of the small lathes today are not set up for that size tooling. Several of the tools that I use I had to modify to use in my 10" lathe, even the 1/2", it sticks out too far making a cantaleavered tool that can catch and tear up a machine. If you have a milling machine and can modify the tooling that is good, but if you don't then you are at the mercy of the manufacturer. I have a cut off tool that I had to modify even to use in the shop when I was working, it "just" does work in my little lathe. Where - if you can grind your own tools, and get fairly profecient at it, you can buy 1/4" - 1/2" tools at a reasonable price and girnd them and re-use them for years. As you can see from the pictures posted that some of the tools are ground a long way back from the leading edge of the orginal tool, it keeps cutting every time I re-grind it. Some of these tools - I just dust them off to regain the sharp edge, I don't completly re-grind every time. And as I said, they are 40'ish years old, and they show the length of time in their grinds.
Phantom
Rusty, Some of these tools I have had for 40'ish years, and are still good. The problem with the replaceable tools is expence, keep it simple for the simple folks. If you have the tooling to check the tools you are grinding, it is not a problem getting them correct. The Threading tool is about the only one that I would conceve to use as a replaceable tool. I have used them, but not for a small one man operation. Most of them are carbide, and if you ding one of them you have to replace it - unless you are in the lucky group that are able to afford a diamond grind wheel set up. I still have a tool that I made up to do threading with that has a carbide insert on it, use it mostly for things too hard to use High Speed Steel cutters on. Carbide has it's application, but it has a negative rake and most of the high carbon steels (Barrels 4130-4140 @ 26-32 RC) don't like that rake on it, it has a tendency to push off the material instead of cutting it off, makes for a lousy looking thread. To each is own, but the question on this link was how to "grind tools" not buy them, not getting testy, just a point . . .
The other point to be made here is the cost of the set up tooling that goes along with the carbide inserts, that tooling is not always made for the smaller machines. Most of the machines we had in the shops were 14" - 36" lathes and that 1/2" - 3/4" tooling is very available, but some of the small lathes today are not set up for that size tooling. Several of the tools that I use I had to modify to use in my 10" lathe, even the 1/2", it sticks out too far making a cantaleavered tool that can catch and tear up a machine. If you have a milling machine and can modify the tooling that is good, but if you don't then you are at the mercy of the manufacturer. I have a cut off tool that I had to modify even to use in the shop when I was working, it "just" does work in my little lathe. Where - if you can grind your own tools, and get fairly profecient at it, you can buy 1/4" - 1/2" tools at a reasonable price and girnd them and re-use them for years. As you can see from the pictures posted that some of the tools are ground a long way back from the leading edge of the orginal tool, it keeps cutting every time I re-grind it. Some of these tools - I just dust them off to regain the sharp edge, I don't completly re-grind every time. And as I said, they are 40'ish years old, and they show the length of time in their grinds.
Phantom
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Paul Schmid
Guest
Phantom
Why is it that when you have a great set of special bits like that, you NEVER can find the one you want until right after you grind a new one.
Then there is is, laying there just laughing at you.
Why is it that when you have a great set of special bits like that, you NEVER can find the one you want until right after you grind a new one.
Then there is is, laying there just laughing at you.
P
phantom496
Guest
Good Question . .
As I said, most of the ones that I have in the "box" are variations of the ones I took the picture of. A couple of them are "Regulars", I use them all the time for just about every cut. There is one in that group a REX AAA - 2nd from the left end that is a Regular, (it's older than dirt) there is nearly no chip management with that tool, and will cut forever nearly. Then there are ones that I have to grind for a special application, not often any more, but had to. I have a shelf that I put most of the ones I use "often" on and just pick through them to find what I need. Most of my work is on barrels, so most of them are set up all the time. In tool & die work, we had special radi that had to be adheared to so we had the gages to do that kind of grind, then stone it to finish. Mind you there are always tolerances and you can get away with being off .004 - .006 or so. When they start checking your work with a Cordax Measuring machine, get the tools ground . . . Most of the work you will do in a Std. Machine shop will have to be "to tolerance" and "Apealing to the eye".
Phantom
As I said, most of the ones that I have in the "box" are variations of the ones I took the picture of. A couple of them are "Regulars", I use them all the time for just about every cut. There is one in that group a REX AAA - 2nd from the left end that is a Regular, (it's older than dirt) there is nearly no chip management with that tool, and will cut forever nearly. Then there are ones that I have to grind for a special application, not often any more, but had to. I have a shelf that I put most of the ones I use "often" on and just pick through them to find what I need. Most of my work is on barrels, so most of them are set up all the time. In tool & die work, we had special radi that had to be adheared to so we had the gages to do that kind of grind, then stone it to finish. Mind you there are always tolerances and you can get away with being off .004 - .006 or so. When they start checking your work with a Cordax Measuring machine, get the tools ground . . . Most of the work you will do in a Std. Machine shop will have to be "to tolerance" and "Apealing to the eye".
Phantom
H
henrya
Guest
Great pics!
Its great to hear your explanations too.
I'll likely be buying some of this stuff - http://www.arwarnerco.com/ (especially a threading and boring tool I think) - but like you suggested in your last post those little trinkets are expensive and if you break the last one and don't know how to grind something, there you sit all sad and disappointed.
Its great to hear your explanations too.
I'll likely be buying some of this stuff - http://www.arwarnerco.com/ (especially a threading and boring tool I think) - but like you suggested in your last post those little trinkets are expensive and if you break the last one and don't know how to grind something, there you sit all sad and disappointed.
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phantom496
Guest
Better order a Catalog before you buy . .
When I went to the site you listed it didn't show any of the insert HOLDERS. You had better check with them and see if they have any of the holders that will fit in your machine. I have used nearly all of the ones that they show there, mostly in Carbide, be careful that the tools you order have some rake to them or your work will look like C _ _ p.
Phantom
When I went to the site you listed it didn't show any of the insert HOLDERS. You had better check with them and see if they have any of the holders that will fit in your machine. I have used nearly all of the ones that they show there, mostly in Carbide, be careful that the tools you order have some rake to them or your work will look like C _ _ p.
Phantom
H
henrya
Guest
Yep, they make holders but call them "kits" I think.
Like this:
http://www.arwarnerco.com/warner_products_kits_boring.html
But I might not want this stuff - its just tempting to think I can have this for the tools that I've found hardest to make myself. Anyone here use anything from these folks?
Like this:
http://www.arwarnerco.com/warner_products_kits_boring.html
But I might not want this stuff - its just tempting to think I can have this for the tools that I've found hardest to make myself. Anyone here use anything from these folks?
D
DannyH
Guest
Thanks Phantom for showing true machinist quality