Sharpening End Mills On The Lathe

In this video I show you how I sharpened my dull end mills on my lathe. I setup the end mill in the correct position and use a makeshift tool post grinder to grind the flutes.
Full credit goes to Rob from the Xynudu channel for posting his end mill sharpening video which I used as a guide. You can see that video here - • How to sharpen a HSS e...

[@joell439]

It’s always great when a plan works out. Rob was one of the very first KZbin machinist I found when I started on this journey as a hobby machinist almost a decade ago. His kind and humble delivery is much like yours. I especially appreciate that you always give credit to the others that have helped you along the way as well. 👍👍😎👍👍

[@thehobbymachinistnz]

Rob is a great guy. He was my first subscriber and actually did a plug for me on his channel when I first started which I really appreciated. Yes, it is only fair to give credit to other youtubers where I have used their ideas etc. Thanks for watching.

[@markkoons7488]

On the high lonesome prairie where aspiring sharpeners may botch your sheep shears, this video is especially valuable to aspiring machinists. Thank you

[@thehobbymachinistnz]

No problem. Thanks for watching.

[@markhedquist9597]

Not a machinist here, but I like watching machining videos and learning as much as I can about it. This was genius! Thanks for sharing the method.

[@thehobbymachinistnz]

Glad you enjoyed it.

[@Xynudu]

Good result Jon. Thanks for the shout out. The perfectionists will always complain, but they probably have more money than sense ;) Cheers Rob

[@thehobbymachinistnz]

No problem, and thanks Rob.

[@edsmachine93]

Looks pretty good, I must say. Great idea. Necessity is the Mother of Invention. Well done. Take care, Ed.

[@thehobbymachinistnz]

Thanks Ed.

[@kevinwatts73]

Great video, JP. Really brings those End Mills back to life.

[@thehobbymachinistnz]

Yep. With just a bit of time it saves me going out and spending good money on new end mills.

[@scottb8175]

One thing that breaks the corners off end mills, especially those expensive carbide ones, is starting the cut at full feed speed on a hard square edge or corner of the material. Its like hitting the corner of the cutting edge with a sharp hammer blow. Unless I'm in a big hurry to get some mass production work out the door (and I have end mills I use for only that kind of quick and dirty work), I always start conventional milling cuts very gently. Start the cut by slow hand feed and then engage the feed drive. Same for breaking through the end of the cut. Disengage the power feed and gently ease the tool through the violent interrupted cut. When climb milling, I try to keep the impact angle of the flutes shallow to avoid the hammer effect. I rarely get broken corners on my end mills this way.

[@thehobbymachinistnz]

Those are great tips, thanks Scott.

[@MattysWorkshop]

Gday, I seen the video Rob did showing this, it’s a brilliant idea and it works, good quality cutter’s aren’t cheap and it’s frustrating when they dull off, brilliant job mate, Cheers

[@thehobbymachinistnz]

Thanks very much Matty.

[@jeffarmstrong1308]

Great video. I just had a look at Rob's video and I think your method is an improvement. It's given me an idea to clamp my rotary table sideways on the lathe bed so I can use the cross slide to drive the grinder.

[@thehobbymachinistnz]

It is good that you got some ideas from the video. Thanks for watching.

[@3in1Machining]

Dam it, im same as you..... loads of damaged end mills and wondering how im going to get this sharpened. Brilliant idea. Its so obviously simple we tend to over complicate things . Thank you, really appreciated 🙏

[@thehobbymachinistnz]

No problem, glad I could help.

[@jonsworkshop]

Well done, really good tip from Rob, typical Rob as well, incredibly simple but effective. Cheers, Jon

[@thehobbymachinistnz]

Thanks Jon. Yes, Rob does show a lot of simple, yet effective ways of doing things in his videos.

[@fredford7642]

Thank you for a great video. Very helpful and informative!

[@thehobbymachinistnz]

Glad it was helpful!

[@ypaulbrown]

this is fantastic, Bravo, cheers from the USA, Paul

[@thehobbymachinistnz]

Thanks for watching.

[@jerrypeal653]

Looks like a V10 lathe I have the 8 . 3 I believe with the mill attached. Handy . Good method for sharpening.

[@thehobbymachinistnz]

Thanks for watching. Yes, it is a V10-P. But, unfortunately it did not have the milling attachment when I brought it secondhand. It is a nice lathe but the spindle bore size is its biggest limitation. I purchased a larger lathe, but I'm also hanging on to this lathe as well.

[@jerrypeal653]

@@thehobbymachinistnz I also bought a bigger lathe but surprisingly I use the EMCO quite a bit . It’s just so convenient for small work.

[@hernandezmay3117]

Almost makes me wanna dedicate my baby 7x10 harbor freight lathe into just an Endmill sharpener!

[@thehobbymachinistnz]

Thanks for watching.

[@neffk]

I have been doing similar touching up on some of my endmills. I have a D-bit grinder, though, so the relief angle can be set directly. However, many grinders use height adjustment and wheel diameter to set the relief angle, as you have done. The larger size mills are a good place to start because they're a lot more expensive to replace and, frankly, it's easier to see what you're doing. HSS is also a good choice. A non center-cutting endmill makes thing easier, too. If it's center cutting, you need a 3rd bevel and a narrow wheel to gash all but one of the cutting lips. I've been experimenting with a 0.035 diamond cutoff wheel. So far, I've sharpened up a 3/8 in solid carbide cutter. Your primary relief looks too wide but the cut looks fine. If you put marker on the primary grind and then do a cut in steel, rubbing will be revealed. Thanks for the video.

[@thehobbymachinistnz]

Thanks for your comments and suggestion.

[@bulletproofpepper2]

Thanks for sharing! I watch Robby also but I guess I missed that one. Great results.

[@thehobbymachinistnz]

Thanks for watching. I think Rob's video was released 9 years ago.

[@hootinouts]

Superb video. I have to try this out as I have a lot of old end mills that need sharpening

[@thehobbymachinistnz]

Thanks for watching. You will be pleasantly surprised how easy it is, and how much of a good result you get when you do your first one. I was only taking light cuts so it took some time for each end mill. Just be patient.

[@jamienewman5419]

Cheers from me here in the Waikato, I'm going to give something like this a go this weekend.

[@thehobbymachinistnz]

Great. Let us know how you get on.

[@shinyribs2178]

Buddy, I've got a shoebox full of worn end mills. You just saved me a mint!

[@thehobbymachinistnz]

Glad I could help!

[@nilegod1]

i have an old lathe with a bad motor and bearings. i use it for something like this, but i do it with old damaged drills to make flat bottom drills for blind holes. now ill use it for endmills too

[@thehobbymachinistnz]

Good idea. It will save you a lot from having to buy new endmills.

[@timbarlow1674]

Absolutely fabulous idea. Thank you.

[@thehobbymachinistnz]

No problem.

[@Rustinox]

I will give this a go one of these days. For sure.

[@thehobbymachinistnz]

Thanks for watching. Surprisingly it works very well. Don't throw away your old end mills. Save them up, then setup the lathe and grind them all in one session.

[@almacdonald2506]

Your resharpening looks good and any plunge cutting should work well if there’s a pilot hole (non center cutting end mill shown in your video), however as you move the material past the end mill it’s the teeth on the side of the end mill that are doing the cutting so hopefully they are still sharp.

[@thehobbymachinistnz]

Thanks for watching.

[@tano1747]

You're welcome.... And more so, thanks for the effort that went into the video

[@thehobbymachinistnz]

Thanks.

[@jaquimboaz]

Great job mate. 🛠⚒

[@thehobbymachinistnz]

Thanks 👍

[@HuFlungDung2]

I like your spindle indexer. FWIW, you can make a lot of headway by roughing in the end flutes on a bench grinder before you get to the final grinding stage. In particular, grinding the secondary relief (farthest from the cutting edge) can be done by hand, and leave just a narrow zone about 1 mm wide to grind the primary relief without using up your little stone too quickly. But you need a good wheel with a square corner so as to get near the center. In practice, a CBN wheel is a great investment for grinding HSS, as it will hold its shape for a long time, and grinds cool, if you get it in a coarse grit like 100 or so. I never bother with grinding the OD of the flutes, as this often results in reduced gullet depth that clogs too easily with chips. Also, you are changing the rake of the tool as you reduce it's diameter, so it doesn't cut very well if you have taken much off. I only shorten worn endmills and regrind the end clearances. In actual fact, it really doesn't matter a hell of a lot if all the flutes are the exact same length. ONE of them will produce the finish on the surface anyways. and most guys aren't feeding the tool so hard that they'd notice any scalloping effect whatsoever. You actually buy commercial inserts for face mills and install ONE wiper insert (along with several normal quality cutting inserts) on it to produce the finish you want, so that shows how having them all 'the same' is really just a pipe dream. A slightly worn or damaged endmill can be brought back into service by grinding a corner chamfer on it, sufficient to remove the dulled tip. Yes, you do have to think about whether that is suitable for a particular job, but there plenty of selections you can make to save some money buying new.

[@thehobbymachinistnz]

Thanks for the tips.

[@KathrynLiz1]

MMM... I have done big ones freehand with reasonable success but this is better. I do have a little pencil die grinder, so it should be easy to set up. Thanks for the Video... 🙂

[@thehobbymachinistnz]

No problem.

[@daveys]

That’s pretty impressive, will have to give that a try

[@thehobbymachinistnz]

Thanks for watching. It actually works really well.

[@ls2005019227]

Just found your channel {subscribed}, excellent video! Not sure that I've caught Rob's video on this, but have seen Stan Zinkosky (shadonHKW) & This Old Tony sharpen end mills in various methods (mill, surface grinder, etc). Thanks

[@thehobbymachinistnz]

Hi, thanks for the sub. Yes, I have seen This old Tony's end mill sharpening video. I will do it that way if I'm ever lucky enough to find a cheap surface grinder.

[@samdude1953]

Great info, thanks! It appears you use a variable speed grinder turned up to full speed. Have you experimented with slower speeds? Also, it appears that a finer stone would produce a better surface finish on the cuts. Nevertheless, it's clear your current setup produces the desired results. Thanks again!

[@thehobbymachinistnz]

Hi, thanks for watching. That is at about 70% of its top speed. I initially tested it at 100% but there were some vibrations at that speed, so I dialed it back a bit.

[@Steviegtr52]

Thanks for showing. I have a few Clarkson HSS cutters that could do with a refresh. But some of them have wear on the side flutes too so would need reducing in size. I think some have been done in the past as the sizes are smaller than the size shown. Subbed Regards. Steve.

[@MIck1-10]

It may pay to chamfer the corner.obviously it will change the profile of the slot but could save it for roughing operations.

[@thehobbymachinistnz]

No problem. Thanks for watching.

[@TROUROCKS]

i dont have a lathe ,,,, only a mill and a rotary table with a 3jaw chuck .. soooo grinder in the mill . end mill in the 3 jaw on the rotary on a rightangle plate .. yes????

[@thehobbymachinistnz]

That could possibly work. But, don't turn on your mill...

[@draganarc0131]

Yes I’ve done it that way.

[@martinwade7824]

It didn't make sense until I played banjo music to your video... ; )

[@thehobbymachinistnz]

Thanks for watching. I use to know an old man with a mandolin.

[@BensWorkshop]

Good work there. All I have to sharpen my end mills is a purpose built tool cutter grinder made by a former club member.. (Sorry for bragging) I see the black looking end mill. That might be carbide in which case it is very expensive and will need a diamond wheel or a green wheel rather than the standard HSS grindind wheels. (That said your wheel was green)

[@thehobbymachinistnz]

Thanks Ben. Yes, I think that end mill is carbide.

[@boltonky]

Like the inventive way to do it :) and here's me wanting a tool cutting machine cause i am lazy haha

[@thehobbymachinistnz]

Thanks for watching.

[@nairdacharles9492]

Nice. Thanks. Never thought of it. I think I'll make a tool post spindle to hold a slightly bigger wheel, maybe a 3 inch, with a universal motor. I think my tool post grinder might be too cumbersome and slow speed for this.

[@thehobbymachinistnz]

Thanks for watching.

[@1957mrbill]

Would using the top face of the grinding stone give a smoother grind? It would also eliminate the curve of the wheel.

[@thehobbymachinistnz]

It probably would give a better finish, but its the curve of the wheel and raising the center height of the wheel which gives the 5 and 30 degree clearance angles. Well.... that probably also depends on the diameter of the wheel as well.

[@TheRecreationalMachinist]

Like that. Thanks for sharing 👍 🇬🇧

[@thehobbymachinistnz]

No problem. Thanks for watching.

[@josejaviercalatayud8338]

great video thanks a lot for share , some question: 1. how many rpm ?? 2.which diameter stone do you think is better?? 3.height variation , do you use for the diferent part of end mill?? 4 some expirience whir cardide end mill?? excuse me for the numbers , and thanks a lot again .

[@thehobbymachinistnz]

Hi, the tool ranges from 8,000 to 23,000. I think this was on 8, 000 when I made the video. The stone I used is around 20mm diameter. That seemed to work fine. I use 2mm above center for the cutting edge and lifted the stone up a lot higher for the back relief grind. I have not sharpened carbide end mills. You would need some type of diamond wheel, CBN wheel or a hard stone specifically for grinding carbide if you need to sharpen carbide end mills.

[@johnlovett8341]

Daddy. Where's my dinosaur blanket??? 🦖 🦕 😭 Nice vid!

[@thehobbymachinistnz]

I think that was from a sheet my now 22 year old Son used when he was around 5. We had a clean out of the cupboards about a month ago and I scored some good rags.

[@JamesDoylesGarage]

Brilliant. I'll try it.

[@thehobbymachinistnz]

Thanks for watching

[@Carlos230023]

People can say what they like, proof in the puddin's in the eatin'. That looked like a really easy clean pass at the end there, might try this on a dovetail cutter I managed to blunt trying to do a single pass on some thin wall Carbon Fibre tubing (I know I know, should'a used carbide)

[@thehobbymachinistnz]

Yes, it may work on dovetail cutters as well. Let us know how you get on, and thanks for watching.

[@michaelunderwood5138]

Great job mate. Its always a good thing when you are able to resurface your own cutting tools. Now question is was that just beginners luck or will it be consistent with the other end mills. Have a great day mate and as we say it in the south "yall be good now ya hear"

[@thehobbymachinistnz]

Hi, thanks for watching. Yes it was consistent. I sharpened all of the end mills in the red container.

[@RotarySMP]

Nice one.

[@thehobbymachinistnz]

Thanks for the visit

[@Wiking419]

I guess you can probably sharpen HM end mills using the same method but diamond stone.

[@thehobbymachinistnz]

Yes, possibly.

[@edsmachine93]

I just subscribed to your channel. Take care, Ed.

[@thehobbymachinistnz]

Thanks for the sub!

[@MethMeister23]

great idea & video. just a quick question, why do you tighten down a nut on the top of your tool holder? does it help with holding tolerance? just curious. thank you!

[@thehobbymachinistnz]

Hi, thanks for your question. That is just a locking nut to lock the height of the tool holder. The black round thumb wheel below the nut adjusts the height of the tool holder. When you have the height set, you tighten the lock nut so that the black wheel cant move. That allows you to keep the same tool height when you remove and replace the tool holder. I hope that helps.

[@MethMeister23]

@@thehobbymachinistnzoh, that makes sense. thanks for the answer!... im a manufacturing student in highschool so im not that knowledgeable in how to be precise😅

[@bradwiebelhaus7065]

Good idea.

[@thehobbymachinistnz]

Thank you.

[@jerrypeal653]

Good job .

[@thehobbymachinistnz]

Thanks.

[@Jannemanne007]

I have not read all comments. I was wondering if it is an option to turn the grinder 90 degrees and use the flat front side so it will give a non curved grinded side? As i was watching an idea sprung to mind to use my rotary table on the mill with the grinding stone in the mill head. I can tilt my FB2 milling head. Anyway thanks for this great idea. Cheers, Janne.

[@thehobbymachinistnz]

No problem. Thanks for your comments.

[@vandalsgarage]

If you're planning on using the face of a grinding wheel, you need to make sure it's designed for that use. A cup wheel, for example. Grinding on the side of a wheel that is designed for grinding on the circumference is dangerous, the wheel can shatter.

[@Jabba410]

Why not spin the endmill before "backing off" with the desired clearance? Its how I was taught in the toolroom during my apprenticeship. Roughing it out first negates any wheel wear as you'd change to a finer wheel for finishing while having a visual tiny "land" to finish with that improves edge life.

[@thehobbymachinistnz]

That could work, thanks for watching.

[@zukjeff]

I was thinking you needed to take off the point on the ends of the cutting faces. maybe not. did they chip off ?

[@thehobbymachinistnz]

Thanks for your question. No, I have not had any chip off at this stage.

[@antonhuman8446]

Darren Conway is correct. But the machine has to be protected. Very nice work. Sir!

[@thehobbymachinistnz]

Thank you kindly.

[@volksdeutschewaffenss9670]

there is a better easy way to grind endmills by Harold hall, useing a square block and a bench grinder, its so simple and much easier, also no grinding dust on your lathe, google Harold hall, he shows the plans for a simple jig used with a home bench grinder, cheers mate

[@thehobbymachinistnz]

Thanks. I will take a look.

[@taranson3057]

I’m in need of sharpening some end mills. Would it be better to use an ER32 or ER40 chuck instead of a 3 or 4 jaw chuck?

[@thehobbymachinistnz]

An ER32 or ER40 chuck may have less run out than a 3 jaw chuck if the 3 jaw chuck is worn.

[@taranson3057]

@@thehobbymachinistnz I have a Chinese made 3 jaw P.O.S.

[@terrycannon570]

I really do like the idea. I have some that I need to sharpen and repair. My only concern is this method leaves a radius cut rather than a flat cut, How does that affect the way they cut if any?

[@thehobbymachinistnz]

Thanks for your question. I have not noticed any issues with the radius. Note that it is only the front edge that does the cutting. The flat (or radius in this example) is at an angle for relief so it technically should not touch the material being milled.

[@terrycannon570]

Fantastic. Thanks very much for the rapid response. What did you use for the tool post grinder. I bought myself a new Makita router to make one from. @@thehobbymachinistnz

[@Сутьділа]

Доброго дня,Какой угол лезвий которые закрашены, 5 градусов?

[@thehobbymachinistnz]

Я не знаю точного угла. Поднимаю точильный камень на 2мм. Это означает, что резка выполняется в нижней половине колеса, а форма колеса дает вам угол. Например. колесо большего диаметра даст меньший угол.

[@gvet47]

So when can I send you my dull mill cutters for a grinding job since you have the setup and I don't? 😉

[@thehobbymachinistnz]

Send them through anytime and don't forget to send your credit card number as well!!

[@roberttownshend3050]

@@thehobbymachinistnz And tell him you won't need his address as you won't be sending them back 🤔

[@maco8799]

hi have you made forming tools for the lathe? I want to make a couple of internal interrupted cuts but I am having a devil of a job grinding the hss...

[@thehobbymachinistnz]

I have ground up some forming tools. It does take a while to grind HSS. The stone I have is quite course as well. It would take longer if you have a fine stone. I have used a cut off wheel in an angle grinder to cut the bulk off some tool blanks. But, I don't know if that would work for the shape that you want.

[@bobengelhardt856]

How much more did you lift the stone for the 2nd facet grind?

[@thehobbymachinistnz]

I don't recall, but it was not a lot. A little movement is enough to grind the second algle.

[@rameshbharakhada5497]

How you will grinding the centre

[@thehobbymachinistnz]

The end mills I have don't have a center to sharpen.

[@timhofstetter5654]

Is that a green silicon carbide stone? For STEEL? Big mistake, if so. Never use silicon carbide for grinding steel. Never use diamonds for that, either.

[@nairdacharles9492]

I know about diamond, but never heard that about silicon carbide. What's the reason why not?. What should we use?.(actually I think those cheap little wheels are just green Al.oxide, but I'm not sure)

[@thehobbymachinistnz]

I don't know what it is. It came in the kit with the grinder. If silicon carbide is expensive, then this is probably not silicon carbide as it was one of the cheaper kits.

[@timhofstetter5654]

@@thehobbymachinistnz Keep an eye on it. It might work out OK. They usually make the green ones from silicon carbide, which erodes badly when it gets hot next to steel sparks. Alumin(i)um oxide (pink stones) stays together well against steel. You'll know very soon if this is a silicon carbide wheel by the way it erodes away. You can keep a pink stone sharp without dressing for a long, long time but a SillyCarb stone will wear off and blunt and glaze over badly as the carbon crystals melt and are absorbed by the iron, leaving only the substrate behind. SiC isn't expensive, but it gets to be a PITA to keep it in stock when it wears away almost as fast as the steel you grind with it. 8) You may do five hundred end mills with a pink stone but only five with a SiC stone. The more end mills (and other stuff) you sharpen in one swat, the more important it becomes... because... If your stone wears appreciably as you do one flute, then it'll be smaller when it does the next flute, and smaller still when you do the fourth (or sixth). That means that one flute will always be appreciably longer than the others and will do the bulk of the work, wearing out worse than the others. Your goal is to try to make all the flutes the same length within some ridiculously small tolerance, so you want a long-wearing stone and you want to make one final pass on all flutes, just kissing the steel lightly, to level them up.

[@irishwristwatch2487]

You want the blue ones for steel, theyre absolutely brilliant

[@hdisah7508]

Hi bro and thank you for your video, but I wanna say that buying an end mill sharpener is much better because sharpening with hand can't be done precisely.

[@thehobbymachinistnz]

Yes you could use an end mill sharpener. The issue in NZ is that machining equipment costs are very high here. Note that I am using an index plate so all flutes are ground exactly the same.

[@hdisah7508]

@thehobbymachinistnz Hi again bro Like the same in my country, Iran, everything is expensive so I appreciate your reasons. Unfortunately because of madness of our government in Iran, inflation is on the rise and the costs are going higher and higher. I checked your profile picture and found out you have a cute and loveable daughter. God bless her. 🥰 With the wish of a rosy future for everyone 💞

[@thehobbymachinistnz]

@@hdisah7508 Thank you. Yes, everything is going up over here like crazy as well. All the best.

[@Bugsy0333]

When you sharpen and end mill are you reducing the diameter ?

[@thehobbymachinistnz]

Hi, no not with this method. The end mill will get a little shorter depending on how much grinding is required to clean it up. We are grinding just the ends of the end mill so the diameter remains the same.

[@Bugsy0333]

@@thehobbymachinistnz Thanks

[@groot9976]

I should try this way

[@thehobbymachinistnz]

Thanks for watching.

[@ryanclarke2161]

I spent 800 on carbide endmills today, none of this for me.

[@timothyhackett7372]

until you chip it...

[@thehobbymachinistnz]

Thanks for watching. Carbide is nice to work with.

[@chuckbeckley7894]

Until you wear them carbide end mills out and they get dull. 🤣🤣🤷

[@samuelsnyder5169]

Man and here I am sharpening them with an angle grinder and a cutting wheel

[@thehobbymachinistnz]

I guess any bit of sharpening is better than a blunt end mill. Thanks for watching.

[@Preso58]

Great way to turn munted tooling into sharp tools. I have lots of munted tools!🙄

[@thehobbymachinistnz]

Thanks Mark. Also, I saw you put a note and photo on Instagram about your visit to my shop. Thanks for that.

[@Preso58]

@@thehobbymachinistnz Jon, I put a link to your channel on my latest video (I also pinched a screenshot of your home page and some clips of the vice). Hope you don't mind😉

[@thehobbymachinistnz]

@@Preso58 I don't mind at all Mark. Thanks for doing that, most appreciated.

[@guyfranks4354]

You need to use the Orange Grinding Stone that is for Steel as used in Dremel Rotary Tools. The Stone you are using is for non ferrous metals, not for steel.

[@thehobbymachinistnz]

Thanks for your advise.

[@darrenconway8117]

Really bad idea to use any sort of fabric around any moving machinery. If it gets tangled, it quickly turns into a rope that can pull something into the machine. Much safer to use any sort of paper. If I want to capture grit, I spray the paper with oil to make it sticky.

[@thehobbymachinistnz]

Thanks, that is a great tip.

[@assyholey4224]

I rub Cosby sauce on my 4 lathe's.

[@EitriBrokkr]

He wasn't running the lathe, settle down Mr. Health & Safety

[@darrenconway8117]

@@EitriBrokkr Are you forgetting those that watch these videos to learn? They should learn never to have fabric near a spinning thing.

[@EitriBrokkr]

@@darrenconway8117 stop trying to be the internets mom. No one cares. And your opinions are nonsensical. If someone can manage to hurt themselves with an abrasive stone on a dremel, and a towel...well that's just darwinism.

[@KlasJanzen]

Your grandson is gona be so mad when he finds out about his blanket.

[@thehobbymachinistnz]

That was my son's blanket. He is now 24 so I don't think he will miss it.

[@danhayward9186]

High speed steel you cab grind them red hot

[@thehobbymachinistnz]

Yes, HSS can take a lot of heat. Although I don't think there is as much heat here as there is with hogging out a HSS lathe tool on a bench grinder. About that comment re discoloration from Linda Vasserman, I wonder if she has confused the blue sharpie marks with over heating?

[@danhayward9186]

@@thehobbymachinistnz Use black sharpie for the dull ones amounst us

[@timhofstetter5654]

You really beat up your end mills, don't you? 8) It's good to see someone else using a Donegan Optical OptiVisor. You need an inspection mirror. You'd do well to make a tent and set up a box fan to suck the grinding swarf out of the tent.

[@thehobbymachinistnz]

Thanks. Yes, the optivisor really helps. I saw a video from MrPete222 so decided to get one. I should have got it years ago.

[@timhofstetter5654]

@@thehobbymachinistnz I own three of the darned things now... I bought my first... oh, heck. Forty years ago? Something like that. Before I saw the Southern Lights for the first time. 8)

[@Raul28153]

in a three jaw? It'd be bad enough in collets. At least ya protected the ways. That itty bitty stone is going to wear too dramatically to be consistent across four faces.

[@thehobbymachinistnz]

Thanks for watching.

[@Bob_Adkins]

That's why he sparks out a couple of times.

[@Dior9000]

use carbide my guy

[@thehobbymachinistnz]

Thanks.

[@guytech7310]

Not a good idea to grind in your lathe as the abrasive will get into the ways and spindle bearing. If you must grind on your lathe. put towel down in the ways and use a vaccuum when your grinding.

[@thehobbymachinistnz]

Yes that is true. Thanks for watching.

[@timmer9lives]

Great Video. And of course….It’s not a good idea to do a ton of grinding on a lathe and not to use pressurized air to clean debris and etc….etc…etc. That said, I’ve got a War Time South Bend lathe. And I use a rag when I grind around my lathe. And if I remember, I also wipe down everything to remove any oil present so that dust doesn’t stick. So, I grind stuff on my lathe and I use an air gun for my chuck at times. And I break rules. “Long story short”…..in the end, I’m sure that my lathe will be just fine. I’m 62 and a hobbyist. I’ll be six feet under and somebody else will be using my lathe when I’m gone. Damned thing works fine and it’s 75 years old. God only knows the abuse it has already seen.

[@thehobbymachinistnz]

@@timmer9lives Thanks for your comments Tim. Yes, taking precautions when grinding on the lathe will enhance its life.

[@dannyzuko1843]

It sure is amazing that Mr. Dumore sold as many tool post grinders as he did. Do you suppose he was getting kickbacks from the major lathe manufacturers?

[@Bob_Adkins]

Funny thing about grinding grit, it won't hurt ways or precision equipment 1 bit just laying on them. Wipe the grit off the ways before using them, and no harm is done. Only thing moving is the cross slide and head, which are (I assume!) protected from grit.

[@Migman2020]

i hope you know that is a good way to destroy the lead screws in your lathe... that dust is horrifically abrasive bud

[@thehobbymachinistnz]

Thanks. I had some rags there, but I will go and clean the lead screw just in case.

[@littlejackalo5326]

It will be just fine. Doing a bit of grinding every once in a while isn't a big deal. The amount that gets around the protection is inconsequential.

[@Migman2020]

@@littlejackalo5326 its the dust that is too small to see which is the problem.. trust me it gets everywhere.

[@thomasjeffersoncry]

That doesn't sharpen the flute edge! A milling cuter without a sharpened flute edge is NOT a sharpened cutter!

[@UptownSport]

Every used a mill before? Every single insert or end mill dulls on the edges just as his had. WHY is there always one who has to p*ss on everyone's Wheaties?

[@thomasjeffersoncry]

@@UptownSport Not sure what you are trying to say here, your english isn't good. Milling into steel most commonly uses the flute edge, sharpening the bottom is only good if you're using it as a drill bit. without a sharp bottom and sharp flutes the cutter is really no good. Who is P**ing in wheaties? simply facts.

[@UptownSport]

@@thomasjeffersoncry You've obviously never used a mill before.

[@thomasjeffersoncry]

@@UptownSport used many! Enough dull one as well to know what I am saying. you must be confused.

[@thehobbymachinistnz]

Note that I'm sharpening the ends of the flutes, not the spirals. I ensure you that after sharpening the ends these end mills are sharp and cut very well.

[@Маскс-н8ь]

This is a poor and incorrect method of sharpening a cutting edge. The worst thing is the discoloration on the tool, this indicates that the metal has been overheated, which means that its cutting properties have deteriorated and subsequently it will become dull again faster. Second, an emphasis is needed for precise positioning of the tooth. The stop will make the correct fixation of all the teeth of the cutter. Thirdly, the lathe chuck for sharpening cutters is not suitable as the lathe itself, the lathe chuck will not provide the maximum allowable runout for a 0.02mm universal tool. The dremel spindle itself does not have rigidity, but these are additional vibrations and beating of the grinding wheel. Sharpen the tool correctly, on the appropriate equipment and do not do amateur work!

[@williamclark77]

I love when a know-it-all Internet troll with no channel content shows their ignorance. 1. Incorrect. It's high speed steel. It's still just as hard now. It wasn't affected enough to be noticed by use in the home shop. 2. Incorrect - if I'm deciphering your "Engrish" correctly. He used a stop for accuracy. But, as long as the cutting edge gets sharp and clearances are there so no dragging, then it will cut fine. 3. Incorrect. A three jaw law chuck, even a worn out one with .008" of runout, is plenty accurate enough for sharpening the bottom face of an endmill. 4. His setup was plenty rigid for grinding something so small. Very little tool force is applied. Comment on things you understand, in an appropriate way, and do not be a troll.

[@Маскс-н8ь]

@@williamclark77 You shouldn't be concerned about my lack of content. If you don't like something, you shouldn't open the comments under the video.

[@jaredrattray]

@@williamclark77 Yes how dare us poors re-sharpen our endmills without using a proper T&C grinder worth thousands of dollars! I have personally used Rob's method and it works great, costs next to nothing - and believe it or not without wringing your hands and grinding your teeth about the suitability of the lathe for the job or the maximum allowable runout.

[@bowez9]

Guess hand sharpening a drill is wrong too.

[@littlejackalo5326]

Thanks LiNdA. Just what we all needed, your armchair expertise, about something that obviously worked out just fine. Derrrrrp.

[@luckytoolroomskills]

Super bro #luckytoolroomskills

[@thehobbymachinistnz]

Thank you.