Hi Keith, Its a dual grit bench stone made by Norton. Its similar to McMaster 4506A5. I think it came from MSC or J&L tools. The fine side is something like 320 and the coarse side is a little too rough for most things. Glad to hear you put something you saw to use in the shop. That kind of stuff makes my day. Thanks for the comment. Regards, Tom
Hi Straighthread, The stone on the left side is Aluminum oxide run of the mill bench grinder wheel. Probably 46 grit. The right hand one is Silicon Carbide, also fairly coarse. You don't need super fine wheels for most tool bit work in particular if you hand hone. Fine grit wheels are nice for holding form and sharp corners like you would need for detail work like chipbreakers. Regards, Tom
Hi Tyler, Great question. First I would have ground the chip breaker differently for steel to make it stronger. For the same basic tool in steel I would have run it at 250-300 rpm and the heavier feed rate on the 1.5 (50mm) diameter. Regards, Tom
I seem to have my own style of tool grinding, not that its any different than anyone else, but I have my own favorite tools and grinds that I use on the daily basis, most of which I picked up from my dad. I rarely use the positive lead angle approach, mine is usually set to turn to a square shoulder. I thought it might be of help to share with what I learned and how I grind my chip breakers. Im going to add it to my list of videos to make. BTW, I'll be posting up a large lathe work video soon.
Looking at the last part of the video, it looks like the reason the chip breaker isn't working is because the chips are never hitting it due to the relief angle on the front side of the blank. If you moved the chip breaker closer to the cutting edge it would work with less DOC.
Hi Fred, I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Very good video Tom; from your back catalog. All the tool angles are really confusing when starting out on the lathe. You took the edge of that with this video. Thanks. I noticed that your stone was pretty grimy. I was told that using oil on the stone transports all the metal particles away, and makes it easier to keep a "sharp" stone (or clean if you like).
Hi Arnljot, I clean my stones pretty regularly normally. They pick up metal from stoning off large surfaces. I guess I showed this one in a loaded condition. I typically use the stones dry. There are two points of view on stone sharpening dry or wet. Both have merits depending on the type of stone and the sharpening goal. Thanks for the comment. Cheers, Tom
Great video When i started turning i never found a good video like yours , the chip breaker maybe could be easy to made with a dremel or any other rotatory tool ,and a small cutting disc.
Hi Battle, Harder grinding wheels work well for chipbreakers. My wheels were too soft for a small one. A dremel would also work well. Thanks for the comment. Cheers, Tom
Hi Tom I believe that in your video you didn't show the honing of the top rake and this may have left some questions as to exact process in people's minds (like me!). Would it be fair to say the cutting edges lead in the honing stroke? Additionally, we have numerous reports of strange and calamitous events in locations where you have stuck pins in your maps. Where did you get those maps? ;-)
Heya Tom! Thanks for the clear demonstrations of each step. One thing I'm running into when turning 6061 is welding, i.e. the aluminum begins to adhere to and build up on the cutting edge. Any tips on dealing with that?
Very useful video for someone who just got himself a small hobby lathe. Thanks. I was thinking about using a angle grinder to cut the blanks. This will get you a flatter surface that you could sharpen on the bench grinder. But things can get rather hot with an angle grinder and I'm wondering if this will have a negative impact on the HSS steel. Any thought on that?
Thank you for your video! Ive had a very difficult experience breaking chips with CNC turning internal diameter aluminum with vcgt inserts on a 4" long part to a tolerance of 0.0006". had to add 3 stops on 3 different boring bars to manually clear the chips cause it can make trouble with the ATC. wonder if there is a good solution to it? of course with this fine tolerance and long thin boring bar you cant push the part to break the chip and are left with long stringy chips. the ap is only about 0.01" on diameter for the finish cut. ive tried to decrease it to 0.004 and no luck there too (trying to make dust like and have coolant wash it off). would love to hear your take on this matter. thanks!
I have watched a lot of video about large radius nose tools. They seem to work really good. Do you know what is the best large radius nose tool that give a very good finish? Thank you so much!!
Hi Sofyanas, Thanks for the comment. Feed rate is how much the tool advances per revolution on the spindle. I don't know what "Forage" is. Can you give me a time stamp in the video so I can understand what you mean. Cheers, Tom
Fabio Gobbo Hi Fabio, There are a few good ones out there. Some are available online as PDF's also. Everybody should have "How to run a lathe" By South Bend lathe works. The other good one but more scientific/engineering is "Tool Design" By Pollack. All the best, Tom
Hi Emil, I generally don't use any lube on the abrasive. I subscribe to the techniques used in the Razor edge book of sharpening. Thanks for the comment. Cheers, Tom
oxtoolco Thanks for the info Tom. I'm always on the lookout for sharpening and honing techniques. I'm going to try it "dry" even though my sharpening stones have soaked up enough oil to never be truly dry.
Obrigado professor! Não entendo muito o inglês, mas só de assistir seu vídeo aprendi muito. Poderia me responder se o suporte do esmeril tem algum ângulo específico? Saudações do Brasil. :)
Hey Celso, The stone is not a specific angle. The tool rest on the grinder is angled downward slightly on the side of the operator. Hope this makes sense. Cheers, Tom
khoa nguyen dang Hi Dang, My email address is on the whiteboard in the beginning of most of my videos. Send me an email with a picture of your tool and setup. Best, Tom
Ok Tom, I started watching the video this morning when I was getting ready for work, but I had to wait untill my 13 hour work day was finished to finish watching the rest. Good info on the tool grinding and honing, I enjoyed it. I have to say, I was planning on making a similar video myself, and hope you dont mind if I do so some time later. BTW, I noticed that NOGA holder is helping you get more closer to the action!!
Hi Steve, They are all interconnected. Surface speed, feed rate and tool geometry. Of all of the factors feed rate has the most effect on chip breaker performance. Best, Tom
Hi Chris, Great points. There is way to much weight is given to specific tool angles and geometries. The bottom line is a large range of configurations work. Take a look in a really old machining handbook at check out some wacky looking forged tools. In the olden days (when you were a lad) a blacksmith was an important guy in the machine shop. Many tools were forged and heat treated right on the shop floor. Regards, Tom
Hi Chris, Great points. There is way to much weight is given to specific tool angles and geometries. The bottom line is a large range of configurations work. Take a look in a really old machining handbook at check out some wacky looking forged tools. In the olden days (when you were a lad) a blacksmith was an important guy in the machine shop. Many tools were forged and heat treated right on the shop floor. Regards, Tom
Now THAT is a tool bit collection! The honing really makes a difference to the surface finish.... Just a few more of these videos and I should be capable of using my own hobby lathe :)
Hi Fred, I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
The bit got too hot and lost some of the hardness/El bits tomo demasiada temperatura y perdio parte de la dureza/Either way it is quite educational for beginners. For machining aluminum it will work quite well/De cualquier manera es bastante educativo para los principiantes. Para mecanizar aluminio va a funcionar bastante bien
Hi Chris, Another good point. In fact in this video I moved the leading cutting edge over after I ground the chip breaker. The wheels on my grinder have big corners so I was having a little trouble making a tight little chipbreaker. But I also really wanted to use the bench grinder and the lowest equipment investment tools. Best, Tom
Hi Fred, I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Hi Fred, I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Hi Flip, I took the chipbreaker all the way to the leading edge. It is very high positive cutting angle. The chip breaker is rather large which is somewhat realistic hand grinding on an average bench grinder. To make really fine chipbreakers you need a fine narrow wheel with a tight crisp dressing. Best, Tom
Hi Fred, I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Hi Fred, I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Hi Annoy, Not sure what you mean "away" from the edge. I push the tool in the direction that would make it cut. In other words the same direction the material would flow into the edge in question. Does that make sense? I think I might have said something like how you sharpen a knife in the video. I don't think it matters too much which is probably why I didn't blather on about it. Thanks for the comment. Best, Tom
Hi rhost, The chip breaker does go all the way to the edge. Its rather large for fine depth of cuts so that is part of the reason it performed poorly on the light cuts. The feedrate was the variable with the most effect on the chips breaking with the setup I showed. Thanks for the comment. Best, Tom
Hi Tom, Low carbon steel and in particular hot rolled is difficult to get a really nice finish on. My advice is use a nose radius and take a depth of cut radially that is equal to the nose radius or greater as a minimum cut. The hard thing is to take a really light cut and get a super finish on hot rolled steel. Regards, Tom
Hi Bill, I generally keep my toolpost at 90 degrees to the axes for everything. It is probably a habit from using DRO's on lathes for so long where you might have to retain five or six tool offsets. Moving the post around all the time monkeys with keeping tools calibrated. Regards, Tom
Hi Fred, I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Hi Dan, Excellent questions. The reason I lifted the tool was to get onto the more curved part of the wheel if that makes sense. I was holding the bit at a compound angle to do the top rake of the bit. So I tipped the right hand side of the tool in toward the spindle and down toward the tool rest. Its also easier to feel when you engage with the wheel if you are making full contact with the previous grind. Its water with a little soluble oil. Best, Tom
Hi Fred, I don't think I honed the top surface after the chip breaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Hi Hal, That's a good way to grind a small feature like a chipbreaker. I'm going to get a couple of finer harder wheels for my small bench grinder and get back in practice. Lawrence suggested a Dremel with a small cutoff wheel which I tried and it works well. Regards, Tom
Hi Sharg, I showed and insert similar to what you mention in another video. Several viewers requested a video showing honing and preparation in more detail. I also like the diamond hones for touching up tools for the same reason you mention. I wanted to show the lowest level of tooling investment needed to make good cutting tools. Thanks for your comment. Regards, Tom
Hi Sharg, I didn't take your comment in a negative way. You seem knowledgeable and experienced about metalworking and it shows. Thanks again for your comment that makes the channel content better. Regards, Tom
Hi Alex, If it works then that's all that matters. Its more important to make good parts than to do everything by the book so to speak. You are probably correct that the cutting edge will not last as long but if the results are controllable and reproducible then who cares. The word on tool angles is there is a broad range of angles and geometries that will cut metal. Don't get hung up on the "book" I would suggest trying your coworkers deal yourself and making your own assessment. Best, Tom
Hi Fadt, Most of the holders I've seen for inserts that have that much relief are flat also. That is horizontal to the machine center line. You could put some angle in the pocket to create some rake but I would not do it. If you get non flat top inserts that already have a positive geometry they may not perform at all. Stick with what the manufacturers are doing as they invest lots of time and money to get their tools to work. Hope that helps. Regards, Tom
Hi Fred, I don't think I honed the top surface after the chip breaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
Hi Jack, You are right. I generally grind my chipbreakers on my Deckel. The small diameter fine diamond wheel is the killer tool. Not everybody has that so I did it the lowest equipment investment method. I'm glad I got the point across. Best, Tom
Hi Fred, I don't think I honed the top surface after the chip breaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite. I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there. Regards, Tom
show me. how to grind tangential angels, on to the geometry on to a strat bit a Hss curating tool, 12-degree angels, Often refers to as A diamond shape & a dack angel of 12 degrees. represented in the normal Holding method.
Hi Lawrence, Thats a great idea! I'm going to try that out right away because I just picked up a nice corded Dremel for ten bucks. Thanks for the great idea. Do you just use the thin cutting discs or the diamond type? Best, Tom
Hi fgleich, Another viewer suggested the very same idea. I tried it myself and it seems like a way to put in a very small narrow chipbreaker that would work well for light depth of cuts and slow feedrates. Thanks for the comment. Regards, Tom
Hi Scot, As you said once you have a good tool its pretty easy to maintain it with some light honing or built up edge removal. Thanks for the comment. Best, Tom
Very informative. I feel It's one of those things that can be theorised reasonably easily but perfected via trial and error. I cant wait to try. Oh, and to all the comments about the danger of hands in the chips, obviously he's been doing It for years and still has all his fingers. I'll be damn sure to stay away until I naturally feel attuned to my task just like any trade.
Hey Tom another great Video, on making a chip breaker how about cutting it with a thin cut off wheel in die grinder, I find it's easier and creates a sharper edge for the chip breaker. The tool bit is held in the vice does not get hot and I have more control with a die grinder. Hal
Hi Adam, Thanks for the nice comment. I would really like to see you do a toolbit video also. In all the shops I worked in everybody had their own tricks for making good toolbits. I think you could do a great one and show some of the features you like to see in lathe tools. Yeah the Noga holder is working good. My camera is getting oily! Regards, Tom
This is a very neat demo. I just have one concern: At the end of the cut, the bit moves rapidly back along the surface, without retracting in the y-axis. By listening to the audio I can hear that it's scratching the workpiece during the retraction move, and that is probably spoiling the surface finish of the cut. It would be great to see the comparison without that happening.
Hey Jay, Give me a time stamp where you think this is happening. I looked at a couple near the end and non of those were dragging on the Z retract. The cross feed is the x axis on the the lathe. Thanks for the comment. Cheers, Tom
oxtoolco Oh yes you're right -- sorry, I meant x-axis. It happens once at 15:05, and to a lesser extent at 16:00 and 23:35. After honing the tool, when the feed rate was slow, it didn't happen nearly as much. For example it didn't seem to happen at all at 22:30, 25:00, and 26:38. That said, I really appreciate you making this video, and I learned a lot about tool grinding -- never saw how to make a chip breaker before, and it was great to see what high-speed steel can do! By the way, what model of lathe is this? It seems really nice.
Tom I been watching your videos for some time now so I decided to subscribe what type of wheel should I use on my bench grinder for high speed steel also stone for honing tool bit I really enjoy your videos
hi thanks for the vid -im struggling to get a mirror finish on aluminum on my old southbend 9 - possible my motor is worn? ive been trying using the back gear for more torque, tends to labor even on light cuts! really frustrating!
Starrett has a short but great section on saw blades, how they work, different teeth, and materials. and break-in (!) I had never heard of breaking in a saw blade. The teeth develop micro chipping until they are used enough to break the razor edge similar to how Tom explains tool bits. Small: www.starrett.com/docs/saw-resources/recommendations.pdf?sfvrsn=2 Big: www.starrett.com/docs/default-source/catalogs/starrett-band-saw-blades-(catalog-60)
If u want to learn tooling, then you need to burn your fingers while grinding high speed steel tool and do practice, then any one can make any kind of tool for cutting job.first thing is patience, then anyone can become master...I like it video😀
I just found your channel a week or so ago and it is a wealth on useful information. Most videos on toolbit sharpening spend too much time talking about angles and theory. I liked the fact that you created a toolbit and then used it in your lathe. Real life turning not just theory. Looking forward to the flycutter portion. Inserts are great but HSS will always have place in my toolbox. Thanks, Rich
Hi Dang, The geometry shown in this video will work well for plain steel. Cast iron would have less rake angles particularly on the top. Hope this helps. Cheers, Tom
Hey Tom, I turn alot of CW614N Brass and just can't get it to chip, I've tried ground tools of various geometry, negative geometry carbides, different feed rates and DOC but I'm either getting dust or splinters, not problem with surface finish but the mess is getting on my nerves, any suggestion? The finest feed rate on the machine is 0.004".
Hi Andrew, Have you tried a positive geometry? Many brasses and bronzes chip as you describe just for something to do. Increase your nose radius and try a zero or positive top geometry. Let me know how it works. All the best, Tom
Tom I lathe true my soft urethane (101 on the A-scale) roller skating wheels (62mm diameter). Not knowing how to grind cutters (3/8 square HSS) I decided to make it into a knife-edge. The front face is rounded with a steep rake done by hand. When I cut them, I end up with "rubber bands" that are seemingly endless. I'm not sure how to grind my cutter. Do you have any suggestions for me ?
Hi Roger, Funny you should ask that question. I designed some tools for cutting the OD of urethane skateboard wheels. We used to do thousands of them a week. The tool is actually a tricky thing to grind. The good news is it sounds like you're on the right track. You need a razor edge in contact with the diameter to be cut. The other thing we added was a sharpened edge where the ribbon came off the wheel which was used to split the ribbon up so you don't get the tough rings. I don't think I have one in my box anymore but I'll take a look. Mess around with the lead angle the edge comes into contact with the urethane. Angle it so your razor edge is not parallel with the diameter. See if that helps. All the best, Tom
Homo Sapiens the tool maker. Watching you carefully make these tools from observational skills and long term experience I can't help but think about our Ice Age Ancestors (as modern as we and perhaps more intelligent, their brains were actually larger than ours today) sitting around the fire Flint Knapping a variety of specialized tools from the materials found in their environment, who's very lives and their families depended on their quality.
Hi Titus, If you read about Ishi a California Indian they were able to study at close range. They noted he was very careful and meticulous when knapping and making tools and articles he depended on. I think you are right about their craftsmanship was more of life and death for them. Thanks for the comment. Cheers, Tom
does anybody still sell solid carbide blanks tool blanks like half inch by 4 inch or 5/16 by 3 inch or 4 inch? I bought an old ways actually about a couple of plays that came with them boxes and boxes of old crap most of it junk but I did get a bunch of blanks some of which were solid tungsten carbide they're a pain in the ass to sharpen but once you got a nice tool bit less virtually forever. I suppose that's why I'm having a hard time finding anybody that supplies and stuff because they last forever and it's not good business practice I really would like to get a few more if anyone knows what I'm talking about please comment
Hi Clown, I have not seen solid carbide squares for tool blanks. Generally you would see a chunk brazed into a steel shank. For boring tools solid carbide is the top choice. Over a certain size most of the carbide is going to waste just doing nothing but supporting the edge that is doing the work. There would be no advantage in my mind unless you like to grind a lot of difficult stuff. Thanks for the comment. Cheers, Tom
Good vid and informative. I see you use grey stones on your grinder and you can grind for a while before the bit gets to hot. when I grind HSS the bit gets hot quickly so I can only grind for a couple seconds before too hot to hold. would a courser stone be better. I always read that a blue or white stone is the one to use? maybe your stones are better quality then the ones I have.
Most of the video was good, BUT, if you made your chip breaker much smaller or narrower you would have improved the chip breaking effect, Then I also do not like to see someone dragging their bit back across the job cut after one has finished the cut, it ruins the finish, and dulls the bit and with different steels can chip break the tool bit.
Hi Tom, today I practiced your tool grinding techniques and I am astonished about the result. The cuttingsound was smooth and I meet had so many curls when cutting so now I need to make the chip breaker. I have been facing off a 5 inch diameter disc and it was peanuts. Thanks for the great video. Regards, Ritchie
Haven't finished watching this yet, but i thought id say that i normally skip honing stones and just give my tools a lick on the balder buffing wheel before I use them and it does essentially the same thing, leaves a nice finish at least with aluminum. Its something I started doing years back with wood carving chisels and the cutters I used on my old wood lathe and I've just carried the practice over in my shop for metal work. And if you find yourself up in humboldt county sometime, stop by. Be cool to meet you and talk shop one of these days.
Small lathe, but I am having trouble getting good finishes, mostly I think because of my tools. Also I would like to better understand the difference between roughing and finishing, both in terms of tool geometry and feeds and speeds. Thank you for this.
Hi Scott, First off I can tell from your questions you need to buy the Southbend book "How to Run a Lathe" This book is a must have for anybody that has a lathe, period. They are readily available and cheap. So a couple of quick words on roughing and finishing. Remember these guidelines. Rough ugly. Its to remove material quickly, nothing else. Feedrates from .015 down to .008. Finishing is for size and finish. Sharp honed tools and feedrates from .005 down to .002 per rev or less on certain operations. For a small lathe that is not rigid then lean toward the finishing side of things with sharper lower pressure tools. Hope this helps. All the best, Tom
I am fascinated by the process of grinding one's own tools. It seems like an absolutely essential and entry-level skill for anyone who wants to get in to metal-work handicrafts on a lathe, especially as an amateur or hobbyist. 'thisoldtony' also has an excellent video on the same topic and when combined with this, slightly more in-depth study the two give a very comprehensive grounding on the techniques required. One aspect that occurs to me is--don't the blocks of tool steel get hot while you are grinding them?
I would recommend this video to anyone wanting to learn toolbit grinding. Great video. Keep making chips.
Thanks for the comment.
Cheers,
Tom
Hi Keith,
Its a dual grit bench stone made by Norton. Its similar to McMaster 4506A5. I think it came from MSC or J&L tools. The fine side is something like 320 and the coarse side is a little too rough for most things. Glad to hear you put something you saw to use in the shop. That kind of stuff makes my day.
Thanks for the comment.
Regards,
Tom
This video explains the inconsistent finish quality. This is priceless for a beginner like me. Thank you so much.
Hi Jeffrey,
Glad you had some success. Thanks for the comment and participation.
Cheers,
Tom
Hi Straighthread,
The stone on the left side is Aluminum oxide run of the mill bench grinder wheel. Probably 46 grit. The right hand one is Silicon Carbide, also fairly coarse. You don't need super fine wheels for most tool bit work in particular if you hand hone. Fine grit wheels are nice for holding form and sharp corners like you would need for detail work like chipbreakers.
Regards,
Tom
Hi Tyler,
Great question. First I would have ground the chip breaker differently for steel to make it stronger. For the same basic tool in steel I would have run it at 250-300 rpm and the heavier feed rate on the 1.5 (50mm) diameter.
Regards,
Tom
I seem to have my own style of tool grinding, not that its any different than anyone else, but I have my own favorite tools and grinds that I use on the daily basis, most of which I picked up from my dad. I rarely use the positive lead angle approach, mine is usually set to turn to a square shoulder. I thought it might be of help to share with what I learned and how I grind my chip breakers. Im going to add it to my list of videos to make.
BTW, I'll be posting up a large lathe work video soon.
Thank you for the video! I just discovered your channel last week or so. Great channel and I am enjoying your videos!!
Great video Tom, you have sparked my interest and I'm going to have ago at grinding my tool bits now. Thanks John
Hey John,
Go for it. Its important to understand how tool geometry relates to the cutting action. Thanks for the comment.
Cheers,
Tom
Hi Zippy,
Thanks for the comment.
Regards,
Tom
Looking at the last part of the video, it looks like the reason the chip breaker isn't working is because the chips are never hitting it due to the relief angle on the front side of the blank. If you moved the chip breaker closer to the cutting edge it would work with less DOC.
Hi Fred,
I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Very good video Tom; from your back catalog. All the tool angles are really confusing when starting out on the lathe. You took the edge of that with this video. Thanks. I noticed that your stone was pretty grimy. I was told that using oil on the stone transports all the metal particles away, and makes it easier to keep a "sharp" stone (or clean if you like).
Hi Arnljot,
I clean my stones pretty regularly normally. They pick up metal from stoning off large surfaces. I guess I showed this one in a loaded condition. I typically use the stones dry. There are two points of view on stone sharpening dry or wet. Both have merits depending on the type of stone and the sharpening goal. Thanks for the comment.
Cheers,
Tom
Great video When i started turning i never found a good video like yours , the chip breaker maybe could be easy to made with a dremel or any other rotatory tool ,and a small cutting disc.
Hi Battle,
Harder grinding wheels work well for chipbreakers. My wheels were too soft for a small one. A dremel would also work well. Thanks for the comment.
Cheers,
Tom
Hi Tom
I believe that in your video you didn't show the honing of the top rake and this may have left some questions as to exact process in people's minds (like me!). Would it be fair to say the cutting edges lead in the honing stroke?
Additionally, we have numerous reports of strange and calamitous events in locations where you have stuck pins in your maps. Where did you get those maps? ;-)
good video! but i would like to add that the chip breaker can be done more precisely with a dremel tool ...
Heya Tom! Thanks for the clear demonstrations of each step. One thing I'm running into when turning 6061 is welding, i.e. the aluminum begins to adhere to and build up on the cutting edge. Any tips on dealing with that?
Very useful video for someone who just got himself a small hobby lathe. Thanks.
I was thinking about using a angle grinder to cut the blanks. This will get you a flatter surface that you could sharpen on the bench grinder. But things can get rather hot with an angle grinder and I'm wondering if this will have a negative impact on the HSS steel. Any thought on that?
+U3erpru7ser Hi U3,
High heat will not cause any problems. High speed steel retains its hardness at red heat. Thanks for the comment.
Cheers,
Tom
thanx
I am finding some kind of lathe tools that make a smooth finish. Can you recommend some? Thank you so much!!
Hi Dang,
The video will show you how to make your own smooth cutting toolbits. Thanks for the comment.
Cheers,
Tom
Thank you for your video! Ive had a very difficult experience breaking chips with CNC turning internal diameter aluminum with vcgt inserts on a 4" long part to a tolerance of 0.0006". had to add 3 stops on 3 different boring bars to manually clear the chips cause it can make trouble with the ATC. wonder if there is a good solution to it? of course with this fine tolerance and long thin boring bar you cant push the part to break the chip and are left with long stringy chips. the ap is only about 0.01" on diameter for the finish cut. ive tried to decrease it to 0.004 and no luck there too (trying to make dust like and have coolant wash it off). would love to hear your take on this matter. thanks!
I have watched a lot of video about large radius nose tools. They seem to work really good. Do you know what is the best large radius nose tool that give a very good finish? Thank you so much!!
Hi Tom,
What kind of a stones are you using on your grinder?
A chain saw blade sharpening wheel makes good chip breaker grove.
thanks for video,, it's the best for study lathe machine.. how to get a smooth finish like your video?? what do you mean for "forage" and feedrate??
Hi Sofyanas,
Thanks for the comment. Feed rate is how much the tool advances per revolution on the spindle. I don't know what "Forage" is. Can you give me a time stamp in the video so I can understand what you mean.
Cheers,
Tom
Great vid but maybe not a good idea to try and clear the stringy chips with the chuck still turning. Not trying to be clever here, just safe.
Hi, Are there any books that show some of the different HSS tool bits one can grind?
Fabio Gobbo Hi Fabio,
There are a few good ones out there. Some are available online as PDF's also. Everybody should have "How to run a lathe" By South Bend lathe works. The other good one but more scientific/engineering is "Tool Design" By Pollack.
All the best,
Tom
oxtoolco thanks for the recommendations, Tom, and thanks for these videos, they are are very well shot and very informative :)
Do you recommend not using any lubrication on the stone?
Hi Emil,
I generally don't use any lube on the abrasive. I subscribe to the techniques used in the Razor edge book of sharpening. Thanks for the comment.
Cheers,
Tom
oxtoolco Thanks for the info Tom. I'm always on the lookout for sharpening and honing techniques. I'm going to try it "dry" even though my sharpening stones have soaked up enough oil to never be truly dry.
Obrigado professor! Não entendo muito o inglês, mas só de assistir seu vídeo aprendi muito. Poderia me responder se o suporte do esmeril tem algum ângulo específico? Saudações do Brasil. :)
Hey Celso,
The stone is not a specific angle. The tool rest on the grinder is angled downward slightly on the side of the operator. Hope this makes sense.
Cheers,
Tom
I tried to grind the tool just like yours but I didn't succeed. Can show me detail about the tool?
Thank you so much
khoa nguyen dang Hi Dang,
Email me a picture of the tool you ground. Perhaps I can help you by looking at what you did.
All the best,
Tom
Thanks
The bar is Aluminum? Thank you Ox!
khoa nguyen dang Try a radius of about 1mm and polish it with your sharpening stone. Hope this helps.
Cheers,
Tom
How can I give you the pictures Ox? I have just taken them today. I hope will receive some comments from you! Thank you
khoa nguyen dang Hi Dang,
My email address is on the whiteboard in the beginning of most of my videos. Send me an email with a picture of your tool and setup.
Best,
Tom
I'm sorry Tom, I cant see the whiteboard. :(
khoa nguyen dang Try a Meatloaf episode. Its at the top of the whiteboard. Look at meatloaf 79 and pause at the ten second mark.
Best,
Tom
Do it on 316 stainless Tom and you would really have something..--Stainless defeats me..E
Hi Adam,
Can't wait to see your next video. You are so smooth on the lathe its a pleasure to watch.
Best,
Tom
Ok Tom, I started watching the video this morning when I was getting ready for work, but I had to wait untill my 13 hour work day was finished to finish watching the rest. Good info on the tool grinding and honing, I enjoyed it. I have to say, I was planning on making a similar video myself, and hope you dont mind if I do so some time later. BTW, I noticed that NOGA holder is helping you get more closer to the action!!
Watching old Tom videos in 2024 for fun. Youve taught me much, starting with your book when it was new. Thanks, Mr Wizard!
Hi Steve,
They are all interconnected. Surface speed, feed rate and tool geometry. Of all of the factors feed rate has the most effect on chip breaker performance.
Best,
Tom
Hi Chris,
Great points. There is way to much weight is given to specific tool angles and geometries. The bottom line is a large range of configurations work. Take a look in a really old machining handbook at check out some wacky looking forged tools. In the olden days (when you were a lad) a blacksmith was an important guy in the machine shop. Many tools were forged and heat treated right on the shop floor.
Regards,
Tom
Hi Chris,
Great points. There is way to much weight is given to specific tool angles and geometries. The bottom line is a large range of configurations work. Take a look in a really old machining handbook at check out some wacky looking forged tools. In the olden days (when you were a lad) a blacksmith was an important guy in the machine shop. Many tools were forged and heat treated right on the shop floor.
Regards,
Tom
Now THAT is a tool bit collection! The honing really makes a difference to the surface finish....
Just a few more of these videos and I should be capable of using my own hobby lathe :)
Hi Fred,
I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
The bit got too hot and lost some of the hardness/El bits tomo demasiada temperatura y perdio parte de la dureza/Either way it is quite educational for beginners.
For machining aluminum it will work quite well/De cualquier manera es bastante educativo para los principiantes.
Para mecanizar aluminio va a funcionar bastante bien
Hi Chris,
Another good point. In fact in this video I moved the leading cutting edge over after I ground the chip breaker. The wheels on my grinder have big corners so I was having a little trouble making a tight little chipbreaker. But I also really wanted to use the bench grinder and the lowest equipment investment tools.
Best,
Tom
Hi Fred,
I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Hi Fred,
I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Hi Flip,
I took the chipbreaker all the way to the leading edge. It is very high positive cutting angle. The chip breaker is rather large which is somewhat realistic hand grinding on an average bench grinder. To make really fine chipbreakers you need a fine narrow wheel with a tight crisp dressing.
Best,
Tom
Hi Fred,
I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Hi Fred,
I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Hi Annoy,
Not sure what you mean "away" from the edge. I push the tool in the direction that would make it cut. In other words the same direction the material would flow into the edge in question. Does that make sense? I think I might have said something like how you sharpen a knife in the video. I don't think it matters too much which is probably why I didn't blather on about it.
Thanks for the comment.
Best,
Tom
Hi rhost,
The chip breaker does go all the way to the edge. Its rather large for fine depth of cuts so that is part of the reason it performed poorly on the light cuts. The feedrate was the variable with the most effect on the chips breaking with the setup I showed.
Thanks for the comment.
Best,
Tom
Hi Tom,
Low carbon steel and in particular hot rolled is difficult to get a really nice finish on. My advice is use a nose radius and take a depth of cut radially that is equal to the nose radius or greater as a minimum cut. The hard thing is to take a really light cut and get a super finish on hot rolled steel.
Regards,
Tom
Hi Bill,
I generally keep my toolpost at 90 degrees to the axes for everything. It is probably a habit from using DRO's on lathes for so long where you might have to retain five or six tool offsets. Moving the post around all the time monkeys with keeping tools calibrated.
Regards,
Tom
Hi Fred,
I don't think I honed the top surface after the chipbreaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Hi Dan,
Excellent questions. The reason I lifted the tool was to get onto the more curved part of the wheel if that makes sense. I was holding the bit at a compound angle to do the top rake of the bit. So I tipped the right hand side of the tool in toward the spindle and down toward the tool rest. Its also easier to feel when you engage with the wheel if you are making full contact with the previous grind. Its water with a little soluble oil.
Best,
Tom
Hi Fred,
I don't think I honed the top surface after the chip breaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Hi Hal,
That's a good way to grind a small feature like a chipbreaker. I'm going to get a couple of finer harder wheels for my small bench grinder and get back in practice. Lawrence suggested a Dremel with a small cutoff wheel which I tried and it works well.
Regards,
Tom
Hi Sharg,
I showed and insert similar to what you mention in another video. Several viewers requested a video showing honing and preparation in more detail. I also like the diamond hones for touching up tools for the same reason you mention. I wanted to show the lowest level of tooling investment needed to make good cutting tools. Thanks for your comment.
Regards,
Tom
Hi Sharg,
I didn't take your comment in a negative way. You seem knowledgeable and experienced about metalworking and it shows. Thanks again for your comment that makes the channel content better.
Regards,
Tom
Hi Alex,
If it works then that's all that matters. Its more important to make good parts than to do everything by the book so to speak. You are probably correct that the cutting edge will not last as long but if the results are controllable and reproducible then who cares. The word on tool angles is there is a broad range of angles and geometries that will cut metal. Don't get hung up on the "book" I would suggest trying your coworkers deal yourself and making your own assessment.
Best,
Tom
Hi Fadt,
Most of the holders I've seen for inserts that have that much relief are flat also. That is horizontal to the machine center line. You could put some angle in the pocket to create some rake but I would not do it. If you get non flat top inserts that already have a positive geometry they may not perform at all. Stick with what the manufacturers are doing as they invest lots of time and money to get their tools to work. Hope that helps.
Regards,
Tom
Hi Fred,
I don't think I honed the top surface after the chip breaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
Hi Jack,
You are right. I generally grind my chipbreakers on my Deckel. The small diameter fine diamond wheel is the killer tool. Not everybody has that so I did it the lowest equipment investment method. I'm glad I got the point across.
Best,
Tom
Hi Fred,
I don't think I honed the top surface after the chip breaker was put in. The reason is if that surface is honed after it can very easily be damaged since its a fine edge. I lead with the cutting edge as you say but many people go the opposite.
I bought the maps at a local voodoo shop. What city were you in again? Looks like I need to stick another couple of pins there.
Regards,
Tom
show me. how to grind tangential angels, on to the geometry on to a strat bit a Hss curating tool, 12-degree angels, Often refers to as A diamond shape & a dack angel of 12 degrees. represented in the normal Holding method.
Hi Lawrence,
Thats a great idea! I'm going to try that out right away because I just picked up a nice corded Dremel for ten bucks. Thanks for the great idea. Do you just use the thin cutting discs or the diamond type?
Best,
Tom
Hi fgleich,
Another viewer suggested the very same idea. I tried it myself and it seems like a way to put in a very small narrow chipbreaker that would work well for light depth of cuts and slow feedrates. Thanks for the comment.
Regards,
Tom
Hi Scot,
As you said once you have a good tool its pretty easy to maintain it with some light honing or built up edge removal. Thanks for the comment.
Best,
Tom
Hi EF,
I'm sure you will find some electrolytic honing method for your toolbits. Still waiting for your next video installment mate.
Regards,
Tom
Hi Rick,
Thanks for the swell comment. Its all in the results right? There are no prizes for talent just results.
Regards,
Tom
Very informative. I feel It's one of those things that can be theorised reasonably easily but perfected via trial and error. I cant wait to try.
Oh, and to all the comments about the danger of hands in the chips, obviously he's been doing It for years and still has all his fingers. I'll be damn sure to stay away until I naturally feel attuned to my task just like any trade.
+Tristan Patterson Hi Tristan,
Thanks for the comment.
cheers,
Tom
Tristan Patterson
Hey Tom another great Video, on making a chip breaker how about cutting it with a thin cut off wheel in die grinder, I find it's easier and creates a sharper edge for the chip breaker. The tool bit is held in the vice does not get hot and I have more control with a die grinder. Hal
Hi Adam,
Thanks for the nice comment. I would really like to see you do a toolbit video also. In all the shops I worked in everybody had their own tricks for making good toolbits. I think you could do a great one and show some of the features you like to see in lathe tools. Yeah the Noga holder is working good. My camera is getting oily!
Regards,
Tom
Hi John,
Thanks for the kind words. Looking forward to the next project in your shop. Did you sort your camera issues?
Regards,
Tom
Thank you so much for giving back to the field and to the hobby. As a "greenhorn", I certainly appreciate your time, effort and experience!!
Hi Andrew,
Thanks for the comment. Now watch the video.
Best,
Tom
I might not choose that particular word to describe it.........
Happy Friday,
Tom
I might not choose that particular word to describe it.........
Happy Friday,
Tom
This is a very neat demo. I just have one concern: At the end of the cut, the bit moves rapidly back along the surface, without retracting in the y-axis. By listening to the audio I can hear that it's scratching the workpiece during the retraction move, and that is probably spoiling the surface finish of the cut. It would be great to see the comparison without that happening.
Hey Jay,
Give me a time stamp where you think this is happening. I looked at a couple near the end and non of those were dragging on the Z retract. The cross feed is the x axis on the the lathe. Thanks for the comment.
Cheers,
Tom
oxtoolco
Oh yes you're right -- sorry, I meant x-axis. It happens once at 15:05, and to a lesser extent at 16:00 and 23:35. After honing the tool, when the feed rate was slow, it didn't happen nearly as much. For example it didn't seem to happen at all at 22:30, 25:00, and 26:38.
That said, I really appreciate you making this video, and I learned a lot about tool grinding -- never saw how to make a chip breaker before, and it was great to see what high-speed steel can do!
By the way, what model of lathe is this? It seems really nice.
oxtoolco
15:08
Tom I been watching your videos for some time now so I decided to subscribe what type of wheel should I use on my bench grinder for high speed steel also stone for honing tool bit I really enjoy your videos
hi thanks for the vid -im struggling to get a mirror finish on aluminum on my old southbend 9 - possible my motor is worn? ive been trying using the back gear for more torque, tends to labor even on light cuts! really frustrating!
Starrett has a short but great section on saw blades, how they work, different teeth, and materials. and break-in (!) I had never heard of breaking in a saw blade. The teeth develop micro chipping until they are used enough to break the razor edge similar to how Tom explains tool bits.
Small:
www.starrett.com/docs/saw-resources/recommendations.pdf?sfvrsn=2
Big:
www.starrett.com/docs/default-source/catalogs/starrett-band-saw-blades-(catalog-60)
If u want to learn tooling, then you need to burn your fingers while grinding high speed steel tool and do practice, then any one can make any kind of tool for cutting job.first thing is patience, then anyone can become master...I like it video😀
I just found your channel a week or so ago and it is a wealth on useful information. Most videos on toolbit sharpening spend too much time talking about angles and theory. I liked the fact that you created a toolbit and then used it in your lathe. Real life turning not just theory. Looking forward to the flycutter portion. Inserts are great but HSS will always have place in my toolbox. Thanks, Rich
Hi Zippy,
Thanks for the comment.
Regards,
Tom
Hi Zippy,
Thanks for the comment.
Regards,
Tom
Hi Zippy,
Thanks for the comment.
Regards,
Tom
Hi Zippy,
Thanks for the comment.
Regards,
Tom
How can I make a lathe tool for a smooth finish on steel or iron? Thank you so much!!!
Hi Dang,
The geometry shown in this video will work well for plain steel. Cast iron would have less rake angles particularly on the top. Hope this helps.
Cheers,
Tom
Thank you so much :):)
Hey Tom, I turn alot of CW614N Brass and just can't get it to chip, I've tried ground tools of various geometry, negative geometry carbides, different feed rates and DOC but I'm either getting dust or splinters, not problem with surface finish but the mess is getting on my nerves, any suggestion? The finest feed rate on the machine is 0.004".
Hi Andrew,
Have you tried a positive geometry? Many brasses and bronzes chip as you describe just for something to do. Increase your nose radius and try a zero or positive top geometry. Let me know how it works.
All the best,
Tom
HSS is a machinists friend. I use it daily!
I have never seen a site where theres replies to comments without knowing what the comment was in the first place. A bit strange.
Tom
I lathe true my soft urethane (101 on the A-scale) roller skating wheels (62mm diameter). Not knowing how to grind cutters (3/8 square HSS) I decided to make it into a knife-edge. The front face is rounded with a steep rake done by hand.
When I cut them, I end up with "rubber bands" that are seemingly endless.
I'm not sure how to grind my cutter.
Do you have any suggestions for me ?
Hi Roger,
Funny you should ask that question. I designed some tools for cutting the OD of urethane skateboard wheels. We used to do thousands of them a week. The tool is actually a tricky thing to grind. The good news is it sounds like you're on the right track. You need a razor edge in contact with the diameter to be cut. The other thing we added was a sharpened edge where the ribbon came off the wheel which was used to split the ribbon up so you don't get the tough rings. I don't think I have one in my box anymore but I'll take a look. Mess around with the lead angle the edge comes into contact with the urethane. Angle it so your razor edge is not parallel with the diameter. See if that helps.
All the best,
Tom
MrCrispin has a great tool sharpening video... he's a Rolls-Royce engineer.
Thanks for the video. I’ve just started making my own HSS tools and I really enjoy it. I’m no good at it yet but I am having fun!
Homo Sapiens the tool maker. Watching you carefully make these tools from observational skills and long term experience I can't help but think about our Ice Age Ancestors (as modern as we and perhaps more intelligent, their brains were actually larger than ours today) sitting around the fire Flint Knapping a variety of specialized tools from the materials found in their environment, who's very lives and their families depended on their quality.
Hi Titus,
If you read about Ishi a California Indian they were able to study at close range. They noted he was very careful and meticulous when knapping and making tools and articles he depended on. I think you are right about their craftsmanship was more of life and death for them. Thanks for the comment.
Cheers,
Tom
does anybody still sell solid carbide blanks tool blanks like half inch by 4 inch or 5/16 by 3 inch or 4 inch? I bought an old ways actually about a couple of plays that came with them boxes and boxes of old crap most of it junk but I did get a bunch of blanks some of which were solid tungsten carbide they're a pain in the ass to sharpen but once you got a nice tool bit less virtually forever. I suppose that's why I'm having a hard time finding anybody that supplies and stuff because they last forever and it's not good business practice I really would like to get a few more if anyone knows what I'm talking about please comment
Hi Clown,
I have not seen solid carbide squares for tool blanks. Generally you would see a chunk brazed into a steel shank. For boring tools solid carbide is the top choice. Over a certain size most of the carbide is going to waste just doing nothing but supporting the edge that is doing the work. There would be no advantage in my mind unless you like to grind a lot of difficult stuff. Thanks for the comment.
Cheers,
Tom
Good vid and informative. I see you use grey stones on your grinder and you can grind for a while before the bit gets to hot. when I grind HSS the bit gets hot quickly so I can only grind for a couple seconds before too hot to hold. would a courser stone be better. I always read that a blue or white stone is the one to use? maybe your stones are better quality then the ones I have.
Most of the video was good, BUT, if you made your chip breaker much smaller or narrower you would have improved the chip breaking effect, Then I also do not like to see someone dragging their bit back across the job cut after one has finished the cut, it ruins the finish, and dulls the bit and with different steels can chip break the tool bit.
Hi Tom,
today I practiced your tool grinding techniques and I am astonished about the result. The cuttingsound was smooth and I meet had so many curls when cutting so now I need to make the chip breaker. I have been facing off a 5 inch diameter disc and it was peanuts. Thanks for the great video. Regards, Ritchie
Hi Chippie,
Glad you had a good outcome. This is the stainless steel you were machining correct? Thanks for the comment.
Best,
Tom
Haven't finished watching this yet, but i thought id say that i normally skip honing stones and just give my tools a lick on the balder buffing wheel before I use them and it does essentially the same thing, leaves a nice finish at least with aluminum. Its something I started doing years back with wood carving chisels and the cutters I used on my old wood lathe and I've just carried the practice over in my shop for metal work.
And if you find yourself up in humboldt county sometime, stop by. Be cool to meet you and talk shop one of these days.
Small lathe, but I am having trouble getting good finishes, mostly I think because of my tools. Also I would like to better understand the difference between roughing and finishing, both in terms of tool geometry and feeds and speeds. Thank you for this.
Hi Scott,
First off I can tell from your questions you need to buy the Southbend book "How to Run a Lathe" This book is a must have for anybody that has a lathe, period. They are readily available and cheap. So a couple of quick words on roughing and finishing. Remember these guidelines.
Rough ugly. Its to remove material quickly, nothing else. Feedrates from .015 down to .008.
Finishing is for size and finish. Sharp honed tools and feedrates from .005 down to .002 per rev or less on certain operations.
For a small lathe that is not rigid then lean toward the finishing side of things with sharper lower pressure tools.
Hope this helps.
All the best,
Tom
I am fascinated by the process of grinding one's own tools. It seems like an absolutely essential and entry-level skill for anyone who wants to get in to metal-work handicrafts on a lathe, especially as an amateur or hobbyist.
'thisoldtony' also has an excellent video on the same topic and when combined with this, slightly more in-depth study the two give a very comprehensive grounding on the techniques required.
One aspect that occurs to me is--don't the blocks of tool steel get hot while you are grinding them?