Sharpening End Mills On The Lathe 

It’s always great when a plan works out. Rob was one of the very first RU-vid 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. 👍👍😎👍👍

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.

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

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

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.

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

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

Absolutely fabulous idea. Thank you.

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.

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

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

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

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

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

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

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

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 🙏

Great job mate. 🛠⚒

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

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

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

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

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

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

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.

Good job .

Brilliant. I'll try it.

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

Good idea.

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

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

Like that. Thanks for sharing 👍 🇬🇧

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

Nice one.

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 .

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... 🙂

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.

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.

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.

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

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"

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!

I should try this way

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.

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)

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

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!

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

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?

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????

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?

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...

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)

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

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

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

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

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

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

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.

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

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

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

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.

High speed steel you cab grind them red hot

use carbide my guy

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.

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.

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.

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.

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

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!

Super bro #luckytoolroomskills