Sharpening system for a newbie

[Doug Freeman]

We're all a little loose in using the term "sharp". It's not a precise term. Sometimes I'll run my thumbnail down an edge as a judgement of sharpness, that really isn't a good way to judge an edge's ability to cut.

For example, grind a neutral rake scraping tool on a precision grinding machine. Neutral rake having an included angle of the cutting edge of 90 degrees (a square corner) and assume the thumbnail test indicates its smooth. I measured my favorite kitchen knife with an included angle of less than 5 degrees. Which would be better choice for whittling on a stick of wood? This is an extreme example of how the included angle should be included in any description of the sharpness of cutting edge. The lower the included angle the better the cutting edge.

When I talk about carbide inserts as being "high positive" it refers to a large back rake angle combined with a front relief angle which means a low included angle. They're used in automated, production woodturning because they do so well cutting both with and against the grain without needing much sanding. And, of course, being carbide they hold up longer than HSS. The insert manufacturers don't give any information on the included angle and it's not easy to measure, my guess is between 25 to 35 degrees. By canting their inserts down Hunter tools effectively increases the included angle making them a little less aggressive in cutting.

The cutter geometry plays a part too. The 30 degree diamond inserts shown in my previous posting are a factor too with a relatively small length of cutting edge removing material as oppose to a round insert.

I look at Hunter tools as a first big step forward in lathe tools.

So what choice do you make, wanting to rotate an insert to a new edge every so many hours or grinding a new edge every 15 minutes?

And, I still believe a carbide insert factory honed to mirror finish on a precision grinding machine using a 6,000 grit abrasive will have a better edge than a hand held HSS on a low budget Chinese bench grinder with a 180 grit CBN wheel.

I dont have one of those little string type sharpness gages that are well accepted as the scientific measurement method. They essentially measure the amount of force required to cut the test string.

What I do have is experience cutting the same piece of wood with carbide (flat and cupped cutters) and hss tools in the same type of cut. My hands are not instrumented, but they are capable of determining the carbide requires more force than the hss (new sharp edge).

The hunter style bowl gouge tools dont cut nearly as easily as my 60 deg hss gouge in a push cut, and my 40 deg hss gouge cuts even easier.

For hollowing I use a Jamieson system, and have the hunter cupped carbide cutter, which is tilted at ~45 deg. The holder also can use 1/4” square hss bits. It easy to tell which cutter uses less force when the cutter is 10 or 12 inches off the tool rest. When hollowing gnarly wood at depth, the hss cutter has significantly less reactionary force (cuts easier) vs the canted carbide cutter.

 

[john lucas]

All this talk of sharpening jigs, etc is fine. But as Natasha says she is using carbide so she already has cutters honed to a sharper edge than any turner in the world can do with the jigs.

I suggest she concentrate on learning how to use razor sharp carbide tooling. That may take some searching and practice since this forum does not generally give much support to turning with carbide. Most of the widely advertised carbide tooling I've seen doesn't look so good IMO. The Hunter tools do look good though.

Carbide cutters will not get sharper than hss tools. I was not able to to include carbide in my electron microscope tests but did compare relative 60 degree edges on my sharpness tester. Hss won every time over flat carbide tool that has a mirror polished edge.
The Hunter cutters are a different animal. That have a highly polished inside surface and cut extremely well. Because they are round I can't test them accurately on my sharpness tester. They have extremely small carbide particles which is why they can achieve a high level of sharpness.

 

[Doug Rasmussen]

Comparisons of cutting forces between round inserts and high positive, 30 degree diamond are not valid. Especially if you are talking about inserts angled downward. In the 4th paragraph of my previous posting I addressed this a bit mentioning cutter geometry.

A 30 degree diamond taking a cut removing 1/8" of material has a cutting edge of about .130". A 1/4" round insert taking the same depth of cut has a cutting edge of close to .300". That gives more than 2 times the force with the round insert, worse when it's canted down. Another factor I've mentioned is the high positive inserts have a very apparent tendency to self feed (which can be either good or bad depending how able the turner is to use and control them). I cautioned about that in another previous posting.

Another point.. just to clarify, I would call the inserts Hunter uses high positive. But when they're angled down you lose a good deal of the positive characteristics of the insert by effectively increasing the included angle..

I stand by my contention about the factory grind on the type inserts I use as a "better edge" than your hand ground HSS. If for no other reason because it lasts for hours. No re-grinding during a project. Plus, no expense of CBN wheels, grinders, jigs, etc, etc. The inserts can be an ongoing expense. Buying off eBay they're dirt cheap.

 

[Neil S]

My take, as has been mentioned already, is to invest in a system and get on with it. any of the systems mentioned will get you to an easily repeatable process that gets you back to turning quickly and with the same edge time after time. That’s all you need. Find the best deal you can on the Wolverine, Woodcut, Kodiak - any of those do essentially the same thing. You can add the niceties later after getting control of your tools with consistent edges.

Natasha

I'm in agreement with Jeff. You won't go wrong with any of the three systems identified by Jeff.

Use one of those on a bench grinder. More costly CBN wheels can replace the aggregate wheels later.

Although I think a slow grinding is unnecessary, I also don't think a slow grinder would be a mistake if you can get one at a good price.

Unless you have a lot of other uses for a wet grinder like the Tormek, which was developed for grinding non-HSS blades, then IMO that is an unnecessary expense at this stage.

And, unless you are able to take a class with someone on how to use a vector jig, I would leave that option aside for now as a new 'traditional gouge' user. That may be a transition that you could take later when you have a better understanding of the grind geometries that work best for you.

 

[Timothy White]

If you are considering a vector grind in the future get the wolverine system because the Vector grind does not come with bases.

 

[William Rogers]

Comparisons of cutting forces between round inserts and high positive, 30 degree diamond are not valid. Especially if you are talking about inserts angled downward. In the 4th paragraph of my previous posting I addressed this a bit mentioning cutter geometry.

A 30 degree diamond taking a cut removing 1/8" of material has a cutting edge of about .130". A 1/4" round insert taking the same depth of cut has a cutting edge of close to .300". That gives more than 2 times the force with the round insert, worse when it's canted down. Another factor I've mentioned is the high positive inserts have a very apparent tendency to self feed (which can be either good or bad depending how able the turner is to use and control them). I cautioned about that in another previous posting.

Another point.. just to clarify, I would call the inserts Hunter uses high positive. But when they're angled down you lose a good deal of the positive characteristics of the insert by effectively increasing the included angle..

I stand by my contention about the factory grind on the type inserts I use as a "better edge" than your hand ground HSS. If for no other reason because it lasts for hours. No re-grinding during a project. Plus, no expense of CBN wheels, grinders, jigs, etc, etc. The inserts can be an ongoing expense. Buying off eBay they're dirt cheap.

I never use to use carbides. However I have begun using them for roughing. I think there is a place for carbide tools, but they will never replace standard gouges IMO. You can turn to finish with carbide, but you will give up adding some detail and do more sanding. I have yet to see any carbide tool give will give you the finish on a spindle that you can get with a skew. Likewise the same for a bowl using a bowl gouge. Carbides are useful for roughing and especially for new turners, but they are not the sole answer to wood turning tools. You are stuck with the configuration being round, square, point, or radius. I cannot get anywhere near the finish using carbide tools that I can get using my gouges and spindles.

 

[Doug Freeman]

Comparisons of cutting forces between round inserts and high positive, 30 degree diamond are not valid. Especially if you are talking about inserts angled downward. In the 4th paragraph of my previous posting I addressed this a bit mentioning cutter geometry.

A 30 degree diamond taking a cut removing 1/8" of material has a cutting edge of about .130". A 1/4" round insert taking the same depth of cut has a cutting edge of close to .300". That gives more than 2 times the force with the round insert, worse when it's canted down. Another factor I've mentioned is the high positive inserts have a very apparent tendency to self feed (which can be either good or bad depending how able the turner is to use and control them). I cautioned about that in another previous posting.

Another point.. just to clarify, I would call the inserts Hunter uses high positive. But when they're angled down you lose a good deal of the positive characteristics of the insert by effectively increasing the included angle..

I stand by my contention about the factory grind on the type inserts I use as a "better edge" than your hand ground HSS. If for no other reason because it lasts for hours. No re-grinding during a project. Plus, no expense of CBN wheels, grinders, jigs, etc, etc. The inserts can be an ongoing expense. Buying off eBay they're dirt cheap.

Mixing insert shape/cutting edge length confuses the point - stick with edge sharpness, thats your original contention.

The hunter cupped carbide cutter, mounted on the arm, can be used in a scraping orientation, where the lower center of the cutter is presented to the surface, but its designed to use the angled side from ~7 to ~9 o’clock for a shearing cut. In both case it is less sharp than hss. Never tried a cupped carbide “straight up”, as it is self feeding by virtue of the inner bevel, becoming uncontrollable by hand. An acute diamond shape as you refer to obviates much of the self feeding by reducing the amount of edge presented to the wood, however the small edge also makes it very difficult to obtain a smooth, no line cut. Its a futile discussion to continue, I agree to disagree.

 

[Tim Otto]

does anyone remember these?

 

[Randy Heinemann]

nFor me, both carbide and HSS tools have their place. I treat woodturning just like my overall woodworking. I use what I feel gets the job done best for me. There is no right tool for any job except the one that gets the job done best, easiest, and safes for the person doing the work. them I have carbide insert tools mainly from when I started turning and still use them when I think they will help me get a part of a bowl done the way I want it. Could I spend time acquiring the skills to do all woodturning with HSS tools? Sure. However, sometimes I just want to enjoy my work and use the tool that I am comfortable with and works for me. So, sure sharp is relative. I have learned how to get my HSS tools very sharp. Does it match someone else's sharp. Maybe, maybe not, but it works for me.

 

[Neil S]

I have yet to see any carbide tool give will give you the finish on a spindle that you can get with a skew. Likewise the same for a bowl using a bowl gouge. Carbides are useful for roughing and especially for new turners, but they are not the sole answer to wood turning tools. You are stuck with the configuration being round, square, point, or radius. I cannot get anywhere near the finish using carbide tools that I can get using my gouges and spindles.

Let's not conflate the capacity of tungsten carbide to give a very fine finish off the tool with many of the tools made from TC that are mostly not optimised to give a fine finish off the tool.

A traditionally shaped bowl gouge made from a fine-grained TC can give as fine a finish off the tool as any of the HSS we use and for longer!

Here is the finish off a traditional bowl gouge made of TC after 50 minutes of use...

​

Try getting the same finish off any other HSS tool steel we use after 50 minutes of use. Most will refuse cut at all after 50 minutes of use!!!

 

[Bill Blasic]

Seeing that Mike Hunter and I are about the same age about the time he started working for a carbide company I started using that carbide when I started working for GE, that being 54 years ago. I have a metal lathe so I occasionally still use carbide and did early on in my woodturning voyage try using that carbide in woodturning, did not work at all. Obviously Mike has kept up with the knowledge of carbide because when I tried using his first carbide tools it was truly an eye opener and there is no comparison to that carbide and what was and is being sold as carbide for use in woodturning. Having used Thompson lathe tools since he started making them and helping sell them at symposia for the last 18 years I know these turning tools have no equal in steel. Now you will find in my turning arsenal both Thompson and Hunter tools, what you won't find is both of them at the same lathe at the same time. I wouldn't want to stop and have to make choices as to which I would use. So mainly I have separate jobs for each and it makes my turning life much easier. I'm not going to get into this sharpness argument per se but I sharpen my Thompsons with a 180 grit CBN wheel and I use the Hunters as is and they both do the best job in their class and I would not give up either.

 

[Brian Kopp]

Hunter carbide tools should do the job much better than some brands which use flat top inserts and look more like scrapers than shear cutters.

I have a Hunter Hercules #3 as well as a lathe chisel I made from scratch using the same cupped carbides as Hunter uses, from AZ Carbide. These cupped carbide chisels are one of the tools I use most often now, despite having a full set of HSS and flat carbide chisels.

 

[Gerald Rutledge]

I finally got to use the lathe I bought 15 months ago. I needed a disc sander to make some furniture pegs (to round over the corners at the ends) and decided to mount a block of granite-hard red oak to a faceplate. It needed some truing-up, which I did a horrible job of. Turning is more difficult than I remember... I gravitated almost instantly to scraping, which I seem to remember from the last time I turned anything... 28 years ago.

["What does this have to do with sharpening, Gerald?" Good question, I'm glad you asked...]

The granite oak dulled my bowl gouge and scraper within minutes, in reality it was likely just a minute or two. Budget tools, sure. But I also noticed that the shavings coming off the piece got warmer and warmer as things went along. My theory is that dull tools create more friction, thus heating up the chips.

Can this be used as a sort of "alarm" to tell a newbie when to head to the grinder? I also was able to tell just by the effort needed, and even the noise level, but the heat seemed like a confirmation, getting to the point of actual discomfort by the end of the short session. Is this a good indicator, or just a facilitator of bad habits? I think the tools were gettin' dull as the heat began, well before it got slightly painful. What says the collective?

 

[Dave Landers]

Dull tools will certainly cause heat, and you can notice that in the shavings. Although by the time the shavings warm up, you're well beyond the point where you needed to sharpen. So using heat as an indicator is more in the area of "facilitator of bad habits" as you say.
(Another heat generator can be rubbing a gouge bevel too hard against the wood - but that's for a different discussion)

 

[hockenbery]

Can this be used as a sort of "alarm" to tell a newbie when to head to the grinder?

Really difficult to see how you are using the tools from here.
Heat is not a warning it’s a cease and desist order. Heat from turning or sanding is telling you - you have been doing something wrong since everything was not hot.

If you can hook up with a local club and get some coaching a mentor can likely get you using an effective technique in minutes.

Cutting really hard wood takes a light touch. Some really hard wood will scrape better than it will cut.
A scraper relies on a burr to work well. Scrapers need to be sharpened often maybe every 30 seconds.

Turning is more difficult than I remember..

Turning is easy if you let the tools do the work while you cradle them in your hands. This takes a lot of practice - less with instruction or mentoring. When I started I held the tool way to tight. Once I learned to soften my grip the turning got easy.

We often try to solve problems by using more force.
With turning most problems are solved with less force.

 

[Bob Raasch]

Hi Natasha, Dennis Belcher who writes for the AAW journal recently published an AAW video that demonstrates how to sharpen a range of turning tools with the Woodcut Tru Grind and Woodturning Wonders sharpening products, here is the video link

View: https://www.youtube.com/watch?v=eLiWaM-nBiM&t=753s&ab_channel=DennisBelcher

 

[Bob Raasch]

Natasha,
I've had the Wolverine system with slow speed grinder and stone wheels for 15+ years. One problem is gouges easily slip off edges of 1" stone wheels, becomes increasingly challenging as we get older.

After researching options, I recently purchased the complete Kodiak system & 1HP Rikon grinder with CBN wheels from Ken Rizza @ Woodturners Wonders. For sure, it's pricy, but consider the importance of sharpening tools and use of very sharp tools, which is critical to producing quality wood turned items, the Kodiak should be on your look list. It's a solid system, provides easy/good repeatability for sharpening. The system, because of the presets, does not easily allow for slight changes in grinds. What I really like is the gouge sharpening fixture, does not physically allow the gouge tip to go off edge of the wheel.
For me, now older; consistency & sharpness is more important than making slight changes in bevel angle. The platform for scrapers, skews and the like has many similarities to the SB platform, and probably just a good & designed to fit the Kodiak. SB platform probably the gold standard.
Give it a close look.

 

[Bob Raasch]

Couple more pics my system.

 

[hughie]

Natasha, I use the Woodcut Tru-Grind System. To me, it does and can do everything the Wolverine system can, but takes up less room and, I think, stores more easily than the Wolverine. Price is competitive AFAIK.
Best of luck, which ever way you go.

I used the Woodcut jig for years couldnt fault it, in fact had a double set up one for each wheel, passed it on to a new turner.

 

[Peter Kaup]

I recently started turning with carbide tools and wood like to transition to traditional HSS tools. I am looking to purchase a slow speed grinder and will fit them with 80 and 180 grit CBN wheels. I can't seem to decide which jig system to use. I have narrowed it down to Wolverine and Tormek (with the bench grinder attachment). I may eventually get a tormek for other tool sharpening needs down the road. Any thoughts or suggestions?

I’ve been using the Sorby belt system for over five years. Very easy set up and very repeatable and quick.

 

[Mike Harman]

I recently started turning with carbide tools and wood like to transition to traditional HSS tools. I am looking to purchase a slow speed grinder and will fit them with 80 and 180 grit CBN wheels. I can't seem to decide which jig system to use. I have narrowed it down to Wolverine and Tormek (with the bench grinder attachment). I may eventually get a tormek for other tool sharpening needs down the road. Any thoughts or suggestions?

Hi Natasha After years of sharpening my tools by eye on all sorts of systems I have finally bought a true grind system which is the same as the wolverine system. I also bought a CBN 180 wheel and a new grinder I made the rest system myself out of some 20mm and 300mm box section steel.
You do not need an 80 gtit wheel the 180 does the job very well what I would buy if you dont have one is a linishing wheel with a leather band on it.
I wish that I had found this system years ago as when it is all set up it is so easy to use and very fast you do not need alot of pressure to sharpen and the angles are spot on.
Good luck
Mike

 

[Neil S]

I’ve been using the Sorby belt system for over five years. Very easy set up and very repeatable and quick.

I have a mate who teaches students in his workshop and he has one of those for them. He got that for them because some students are a bit more intimidated by the sparks coming off a regular bench grinder. He uses and prefers the CBN wheels on the bench grinder for himself.

One of the upsides of a belt system is that you can have as many different grit sizes as you might think you would like at minimal additional cost compared to another CBN wheel. The downside is also in the belts, which are a consumable compared the the CBN wheels. The cost of replacement belts can mount up over time depending on how aggressive you grind and how tolerant you are of worn and ragged belts.

Knife makers (as distinct from knife sharpeners) prefer belts to wheels, so if you are doing a bit of that or making other edge tools as well as wood turning the belt system might be the way to go.

If I felt the need to include a belt option I would just buy a cheap 2nd hand belt sander and adapt my jigs to swap them over when using that...

e.g. https://chico.craigslist.org/tls/d/chico-benchtop-disc-belt-sander/7631820298.html

https://reno.craigslist.org/tls/d/reno-bench-belt-disc-sander-ryobi/7624125172.html