How to hone a lathe tool ?

[morrisman]

Hi

There seems to be many opinions on how to get a nice sharp edge on HSS lathe tools .

Some advocate stones of various types .

I know that it is easy to ruin an edge by using a incorrect honing method

So whats the most effective method ? And, what is your preferred abrasive eg, diamond or whatever .

Mike

[KBs PensNmore]

Hi Mike, In the last 2 editions of MEW there are plans to make a honing tool for lathe tips, I think they used a diamond plate.
Kryn

[morrisman]

Hi Mike, In the last 2 editions of MEW there are plans to make a honing tool for lathe tips, I think they used a diamond plate.
Kryn

Do you know the MEW issue numbers ? I have the latest issue and cannot see anything in it about honing . I will have a look at the recent on-line back issues .

BTW I have tried all sorts of honing methods on my lathe tools and I usually end up with a blunt edge ( my fault again ) ... I find it best to use the tool straight off the grinder !

There must be a easy way of doing the honing ......:C

[Bryan]

I used to use a bench stone but that's a PIA. Too easy to roll the edge off. Lately I've used a cheap diamond wheel for finishing. Except it's getting clogged. Anyway there's a couple of tricks that can help. One is to hollow grind on the face of the wheel (white alox is ideal). Then just give it a kiss on the side of the wheel to create two narrow flats. Apply the bottom edge to the wheel first and roll up to the cutting edge. Remove it the opposite way. Repeat the last part with your chosen finishing medium. There's an article about it somewhere. ... which is eluding me. I will look again later. Unconsciousness beckons...

[KBs PensNmore]

Hi Mike, MEW issue 201 page 14 and 202 page 16, titled a tool bit sharpening trolley. It describes the making process only at this stage, the last section is about the mounting of the diamond plates. Next issue I presume would be about using it.
Regards,
Kryn

[j.ashburn]

Hi seen my old man for years lap his edges on a piece of glass and then hone them on a leather pad like a razor strop with jewellers rouge oil sew /mc oil. Used to do his chisels and plane blades same way [shave your arm hairs] He told me he learned that as a Vict Railways apprentice elec fitter they used collet lathes there but never asked him what brand they were [damn]He also told me that the old boys with treadle lathes did this method as the difference in leg power soon showed up.we used hi carbon steel for years and then hss cemented carbide tooling was for industry then and expensive for us . John.
plate glass with fine valve paste.

[Abratool]

Mike
I agree with Bryans post on this.
Bench stones are too "soft" & too large & very easy to roll the cutting edge.
I have found are 1/2" square hard stone in alum oxide the best for this job. If a fine radii on the tool point say for a fine pitch screwthread is required, then a hard white arkansas stone in 1/2" square works well.
Personally, I would not put too much emphasis on honing lathe tools, my experience over my lifetime has been with HSS tools & as Bryan says they come off a white Alum Oxide grade 80 grinding wheel ready for work.
The only real honing that is needed is to hone the front rake radii on the tool.
Especially for screwcutting work, where it is critical to have a predetermined radii that will hold up during the screwcutting process. To do this just mount the tool bit in its holder in the toolpost, & then position the 1/2" square honing stone against the front of the toolbit & carefully give the front rake of the toolbit a few rubs, to take out the grinder marks & form desired radii.
The important thing is to have a "hard" honing stone, convential honing stones are too soft & will dubb over the cutting edge. Dipping the stone in kero will help the cutting action.
So in essence...
Do not over hone, just hone enough to remove grind marks otherwise it will be messed up.
Hold stone firmly against the front rake angle.
Do not rock the stone to alter the angle as this will dubb or dull the toolbit.
Use a "hard" stone of small size say 1/2" square, that can easily be held by hand.
These "Hard" alox stones can be obtained through toolmakers suppliers. I can give you a source if need be.
A final note, an old tooley gave me years ago, do not bother trying to hone HSS toolbits for turning brass. The microscopic burr left by the grinding wheel actually aids the machining process when turning brass.
This seems a long story on honing lathe tools, my suggestion if in doubt do not bother as it is easy to mess the toolbit, probably best to improve grinding skills first & to use a white alox grinding wheel, as they cut cool & clean, leaving a good edge.
Hope this may be of some assistance.
regards
Bruce

[Bryan]

Advanced Tool Sharpening (http://conradhoffman.com/advancedsharp.htm)

[cba_melbourne]

Mike,

if you use a fine wheel in your bench grinder, there is no need to hone HSS tools that are just used for roughing steel.
That said, HSS tools used for other metals do generally benefit from honing. And HSS tools used for fine finishing of steel to exact dimension do benefit from honing.

To hone lathe tools, you use smaller stones than used for say sharpening knifes. The very best I know of is a fine grade Hard Arkansas stone. These are not cheap. Here a pic of how these look like:

274796

274797

I bought these some 30 years ago, so you see they last a lifetime if properly used (then again, I stopped using HSS for anything other than special shape tools 20 years ago....).
You just apply a few careful strokes, with very little pressure, to polish the cutting edge. It is like if you look at the tip of a knife, you use it to impart a tiny small second bevel to the cutting edge itself. And of course, you use it to smooth off the tip radius.

Before using the Arkansas stones, it may be necessary to re-shape a tip radius, or to remove a burr, always stroking up onto the cutting edge. This I like to do either with an old and worn, very smooth and fine grain diamond hone, or with a Norton India oil stone. These come in many shapes, to touch up all sorts of cutting tools. Here some pics of Norton oil stones:

274798274799274800


After some practice, you will find that it does not take that much time to hone your HSS tools. HSS-Co tools stay sharp a lot longer than just HSS. And cheap low quality carbide inserts also benefit from a quick lap.


However, nowdays one can buy ready shaped carbide inserts, that are as sharp as a carefully honed HSS out of the box. I personally prefer to use such inserts for ordinary turning/facig/boring on small lathes. I personally feel that I can make better use of the time spent for shaping, sharpening and honing HSS tools. In the past, say 10 years ago, this was not so, only HSS had the keen edge needed for finest finishing cuts on light manual lathes. But now since inserts like CCGT-alu have become available for such tasks, I see no more reason to pamper with HSS. Unless I need a special shape... Chris

[wheelinround]

:2tsup:

[morrisman]

OK, informative info as usual .

I think my my main error has been overdoing it. I tend to attack the tool with gusto and hone away over the whole face until all of the grind marks are gone from the entire facet . Yes, I have discovered ( after lots of frustration ) that the normal grey hardware stones as used for chisels etc, are a waste of time . I did try diamond encrusted flat plates too, but the results were not that encouraging .

The problem is, many of the HSS lathe tool sharpening articles in books and magazines rave on about rake and angles an so on ,ad nauseum. But they do not go into great detail about describing the honing process. The author usually writes , yes , it is beneficial to hone a tool , but then he doesn't describe how he does the honing process :no:

Mike

[Pete F]

Mike I keep my lathe tools sharp by honing them regularly and almost never need to regrind them. I use small diamond stones and just keep them flat on each face, except for the nose, where I roll it around as needed. Since it's removing so little material there's no need to take them from the holders or reset the centre height. Normally a fine stone is enough to keep the edge crisp, although I sometimes use a medium, as I did today and reset the height of my parting tool as it was clearly becoming blunt. I don't worry too much about any grinding marks per se, but over time they naturally get honed away.

Pete

Edit: This is a packet I tend to use for this EZE-LAP DIAMOND SHARPENING SET- 3 pack/Super Fine, Fine & Med Grit (LP3) on eBay! (http://compare.ebay.com.au/like/111039639336?ltyp=AllFixedPriceItemTypes&cbt=y&_lwgsi=y&item_id=111039639336) however I also have some DMT stones and they're arguably better in my opinion.

[Combustor]

Agree with Pete F the diamond sticks he recommends work nicely. I mostly leave the bit in the toolpost and turn it round for easy access. A touch up after a few heavy cuts works better than waiting till it is blunt. The medium and coarse sticks seem to work best. Be sure the tool is clean and dry so you don't clog the diamond grit. Combustor.

[j.ashburn]

Hi seen my old man for years lap his edges on a piece of glass and then hone them on a leather pad like a razor strop with jewellers rouge oil sew /mc oil. Used to do his chisels and plane blades same way [shave your arm hairs] He told me he learned that as a Vict Railways apprentice elec fitter they used collet lathes there but never asked him what brand they were [damn]He also told me that the old boys with treadle lathes did this method as the difference in leg power soon showed up.we used hi carbon steel for years and then hss cemented carbide tooling was for industry then and expensive for us . John.
plate glass with fine valve paste. Still got a cigarette tin of his tool bits he made as a kid 1939 and some of his gravers ad scrapers mainly used files and are like glass hard.As he said the old blacksmiths at the railways were wizards at what they could make tools hard and work well after all is all they had in those days.some times that old tin has helped me out some nicely made stuff.
I ask where are our industrial skills going? Time we each got some one to mentor to share these things [at least find 1 you can get away from their cell phone ipad . They are out there some kids who want to learn and see.
In ref to the old man Railway days first 2 weeks on the job they went to the wood work shop made their fitters box out of timber[their bench top box.then down to the enamelers to make their own initialled name plate.those days are long gone now. and they used to buy their tools via a tool club that in turn had an account with Mc Phersons and could do bulk buy deals. still got all his Starret marking out stuff. cheers John.

[morrisman]

Hi

Well I bought a small arkansaw stone from a UK vendor for $15 - I thought I would give it a try . It is a fine , hard grade stone , 1" X 2" . First impression , it does the honing effectively . I have sharpened all my HSS lathe tools on it , it is easier and more effective to use than any other stone I have tried . Wish I had one of these stones earlier :clap3:

Mike

[texx]

well i would just like to know what mew is ..??

johno

[Michael G]

well i would just like to know what mew is ..??

johno

MEW = Model Engineer's Workshop (English model engineering magazine)
ME = Model Engineer (Sister magazine to MEW, but dealing with models rather than tooling)

Michael

[texx]

thank you for that .


johno

[bwal74]

Hi

Well I bought a small arkansaw stone from a UK vendor for $15 - I thought I would give it a try . It is a fine , hard grade stone , 1" X 2" . First impression , it does the honing effectively . I have sharpened all my HSS lathe tools on it , it is easier and more effective to use than any other stone I have tried . Wish I had one of these stones earlier :clap3:

Mike

Hi Mike,

Will you post a photo of your new stone and a link to the seller? Since I'm back to using HSS and Crobolt I'm honing again and my cheap Chinese stone I found at work isn't up to the task.

Thanks Ben.

[morrisman]

Hi Mike,

Will you post a photo of your new stone and a link to the seller? Since I'm back to using HSS and Crobolt I'm honing again and my cheap Chinese stone I found at work isn't up to the task.

Thanks Ben.

Hi Ben

No problem, this is what I purchased

Arkansas Hard OIL Stone Sharpening Tools Boxed Watchmakers Clockmakers Engineers | eBay (http://www.ebay.com.au/itm/200907737265?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649)

Another likely candidate

DAN'S Whetstone Arkansas Pocket Sharpener Stone W Pouch | eBay (http://www.ebay.com.au/itm/271125037389?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649)

[jack620]

I had an Arkansas stone identical to the Dan's one for about 20 years, then it broke in half one day. I'll buy another from the eBay seller. Thanks for the link. Any idea what grit the white Arkansas is equivalent to?
Chris

[jack620]

Actually,
Anyone tried these:

http://www.carbatec.com.au/dmt-mini-whetstones_c7370

Oops, disregard. I see Pete F uses them.

[bwal74]

Hi,

Thanks for the link.

I was also looking at these:

EZE LAP Diamond Knife Blade Tool Sharpener 5 SET NEW | eBay (http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=130945299459)

About $35 Ozzie delivered. But I do like Dan's stone.

Ben

[morrisman]

I had an Arkansas stone identical to the Dan's one for about 20 years, then it broke in half one day. I'll buy another from the eBay seller. Thanks for the link. Any idea what grit the white Arkansas is equivalent to?
Chris


The stone I bought ( in the little wooden box ) is a very fine grade , as you run a finger over it, it almost feels like glass .

BTW I followed Pete's suggestion. It only takes 6 or so light strokes to get a nice edge . With the tool edge facing away from you , pull the edge inwards .

Mike

[cba_melbourne]

...........Any idea what grit the white Arkansas is equivalent to? Chris

Novaculite is a form of microcristalline quartz only found near Hot Springs in Arkansas. It is said to be the finest grit natural stone known. According to this site, it compares to about 600-1000 grit: Hall's Pro Edge - Frequently Asked Questions (http://www.hallsproedge.com/FAQ.php)

Maybe you have used "Tripoli" polishing/buffing compound? That is just powdered Novaculite: Novaculite - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Novaculite)

[jack620]

Thanks Chris. Interesting that the 'grit' size of the various stones is the same. It's the density of the stone that varies.

I've ordered one of Dan's pocket Arkansas stones. Can't wait to try it. I've been missing my old stone.

[morrisman]

Hi

What would be the favourite honing oil in use ?

Mineral oil ( AKA Johnsons baby oil ) and kero in a 50/50 mix seems to be the way ?

Mike

[Bryan]

Diesel.

[cba_melbourne]

Hi

What would be the favourite honing oil in use ?

Mineral oil ( AKA Johnsons baby oil ) and kero in a 50/50 mix seems to be the way ?

Mike

I do not think it matters just for final honing a lathe tool or a milling cutter, you can use it dry. For adding a tip radius or sharpening a scalpel or the like any light mineral oil will do, I like "3in1" oil or even WD40 because of the pleasant smell. Stay away from all vegetable oils, as these polymerize and clog the stone.

But what IMO really matters a LOT is to carefully clean the stone after each use. I do this by spraying it with WD40, then with electonic cleaner/degreaser, and if necessary brush with a nail brush. All visible metal deposits/streaks have to go, or they clog the stone and become ever harder to remove. Keep it clean and it will outlast you, you will not wear it out in your lifetime.

[Ueee]

With porous stones i was taught to soak them overnight is a warm mix of 50:50 oil and kero. This soaks the stone through. Repeat every few years....
For my larger white and black Arkansas stones i use straight kero normally. You can dress most stones with carborundum powder mixed with kero on a piece of glass.

Cheers,
Ew

[Pete F]

Hi,

Thanks for the link.

I was also looking at these:

EZE LAP Diamond Knife Blade Tool Sharpener 5 SET NEW | eBay (http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=130945299459)

About $35 Ozzie delivered. But I do like Dan's stone.

Ben

Yes I use them Ben and they're fine. The DMT diamond is in my opinion better, and I've worn out a number of Ezy-Lap stones. It's not like they last just a week however! The DMT stones are normally more expensive from what I've seen, but the quality is excellent. On the other hand I find the Ezy-Laps are easier to use if I'm just honing tools so they're the ones I normally use.

When using them I will use whatever I have to hand as a lubricant, normally either WD-40 or kero from the parts washer. I don't think it really matters what you use as it's just there to to flush away away the swarf generated. They're not as fussy as natural stones for example, and you could use anything at all.

Pete