Testing Tungsten Carbide Bowl Gouges

[Neil S]

Why tungsten carbide bowl gouges not available is raised on woodturning forums from time to time. Various reasons are usually given and here is a good summary of those reasons provided by Bill Boehme…

• A carbide profile can't be changed
• Even just a carbide tip would be prohibitively expensive
• Carbide is extremely brittle so an entire carbide bowl gouge would be hazardous
• Without specialized equipment, carbide couldn't be sharpened
• If you've ever dropped a solid carbide router bit, you know not to look down ... it will only make you cry.
• Other than the multitude of drawbacks, it's a great idea ... seriously ... but just isn't a practical idea.
• https://www.aawforum.org/community/threads/carbide-gouges.21247/post-221147

Ignoring those potential downsides identified for tungsten carbide I have undertaken a series of controlled tests using traditional styled tungsten carbide bowl gouges to find out how well they perform compared to some of the other more commonly used HSS woodturning tool steels.

Of course, we do already have the flat and cupped screw on carbide tips and like most of us I have a few of those for particular purposes, but being a traditional bowl gouge user those carbide tipped tools just don’t work the same way for me as a well made bowl gouge.

If the screw-on flat and cupped carbide tips are working for you mounted in whatever you have them mounted on then what follows is unlikely to be relevant to you.

And, if you are more than satisfied with the various traditional HSS bowl gouges you are currently using, for whatever you are using them for, then the following may also not be of particular interest to you.

But, if you think that a traditional style of bowl gouge made from tungsten carbide might be something that you could use, or maybe you are just curious, read on…

For those who would just like to see a summary of the results,
here they are...

The traditional style Tungsten Carbide bowl gouge that I used in these test runs was made by myself from a sub-micron TC. The bowl gouge labelled V10 in the graph above was a 10% Vanadium HSS and the one labelled M42 was a HSS with approx. 9.5% Molybdenum, 8% Cobalt and 4% Chromium.

The woods used for these test runs were:

Difficuty	Wood	Estimated Janka (kN)
Extremely Hard/Abrasive	Redgum recycled railway sleeper	14
Very Hard	Redgum - very seasoned	11
Hard	Oak - hard & tough	12
Medium Hard	Eucalypt	7.5
Medium	Ash & Maple	6.5/4.6
Medium Soft	Blackwood - recent	5.1
Soft	Pine	3.1

After the above test runs I then experimented with some other diamond grit grades to see if that made any difference to the performance of the TC. There was no measurable difference using a #240 or #320 diamond abrasive. The only other diamond grit abrasive that I had available was a #1,000, which I then used to re-sharpen the TC bowl gouge.

Selecting some more blanks of the tough oak that troubled some of the gouges in the previous test runs shown above I got a significant jump in performance with the TC gouge sharpened on the #1k diamond giving a 3.5x better endurance.

I then repeated the test runs on the oak with the other two HSS gouges resharpened on the #1k diamond. The V10 bowl gouge did about the same as before, but the M42 had a big improvement of about three fold, but along with the V10, it still significantly underperformed the TC.

I then went back and tested all three gouge metals re-sharpened on #1k and repeated the test runs on the hardest/toughest/most abrasive wood I had (recycled river redgum railway sleeper) and also on the softest I had, Radiata pine, with the following results.

The results for the TC on that old abrasive filled river redgum railway sleeper may not look significant when seen against its performance on the medium to softer woods, but it was still two to four times better than the other two, albeit with all of them struggling with that task. Previously the TC had not always outperformed the other two gouge metals on the medium to soft woods, but it pulled away from the others after being sharpened on the #1k diamond.

A brief note on my testing method before going on to the nitty gritty for those that might be interested in the details. The gouges were used in short stopwatch timed rotations to ensure all got equal exposure to any of the more difficult areas of the blanks. A bevel contact push cut was used on all of these test runs with just the first 4-6mm of the cutting side of the gouge nose engaged in the cut. By limiting the cut to just that area of the gouge I was reducing the time it took to become too dull to cut.

Each gouge was used until it could not cut any longer. This isn't how we normally turn, but this eliminates individual preferences for when a gouge needs to be re-sharpened. The ability of the gouge to continue to remove wood (its endurance) and not the quality of the surface finish left was what was being measured. However, having specified that, I can attest to the fact that the TC was capable of leaving a very nice surface finish off the tool long after the other two test gouge metals had been retired altogether. For example, here is the finish off the TC after the other two gouges had given up on one of the hardest woods I get to turn, Buloke (which is up there with the top ten of the hardest woods on some lists), which isn’t shabby at all …

​

So, the performance of TC as a bowl gouge metal is attractive going by the metrics from my testing. There are, however, some issues with it that I will address later in this or in separate threads.

For those that want to have more detail on the nitty gritty of how I went about my testing I will add more shortly on that in my follow up posts to this thread.

–-o0o—​

 

[Alan Weinberg]

I had started that thread asking about carbide gouges that you referenced so your science is of particular interest and I thank you. Fascinating.

 

[Neil S]

This and subsequent posts provide more detail about my testing protocol and results.

The motive for undertaking these test runs was to satisfy myself that I had the best bowl gouge metals available to me for turning the types of wood I get to turn using a ‘traditional’ style of bowl gouge, which I prefer to use.

I’ve been doing this type of controlled testing for over a decade now and I come back to it from time to time if I think there is an option I don’t know enough about yet to be confident in my judgments (and pronouncements) about it.

Having turned with most bowl gouge developments over the last 50yrs I stopped taking manufacturers and marketers claims about their gouges at face value a long time ago and do my own due diligence by doing my own methodical testing to find out how well an option performs against other options under controlled conditions that you don’t always get from day to day use in the workshop when your focus can be on many things at any one time.

The focus of these particular test runs was to see how well sub-micron tungsten carbide (TC) compares to some other commonly used woodturning tool metals across a range of wood hardness, toughness and abrasiveness.

A considerable number of blanks were ‘consumed’ during this testing that ranged from the hardest woods I had, like Buloke (Allocasuarina luehmannii, some specimens of this species have tested as hard as Janka 5060 lbf, which would put it up near the top of the list of the hardest woods) and some of the most abrasive I had, like recycled railway sleepers that are full of ballast dust, right through to the softest I had in sufficient quantities to exhaust the cutting edge on the test gouges, for which I used Pinus radiata (Monterey Pine).

The test blanks began like the following with little preparation other than what you can see here…

​

Plus a few that were pre-turned, like these…

With most ending up looking like this, lots and lots of them

I can’t honestly say that no wood was harmed in carrying out these test runs. At last count I am close to fifty very good wood blanks or pre-turned pieces that have been sacrificed to the cause!

~~~~​

 

[Neil S]

I had started that thread asking about carbide gouges that you referenced so your science is of particular interest and I thank you. Fascinating.

So, Alan, your the one...

Not so much science, just methodical testing in a real workshop with real wood and tools.

 

[Neil S]

As described briefly in my initial post, my testing protocol involves freshly sharpening all of the gouges and then using them in short stopwatch timed rotations to ensure that each gets equal exposure to any of the more difficult areas of the blanks. For the hard to medium woods the rotations are in timed intervals of 30sec. I disengage the cut on hearing the buzzer and record it and repeat with the next gouge, and so on in rotation until a gouge can no longer raise shavings and remove wood, at which point it is eliminated. Here is a typical score sheet for the 30sec rotations…

​

The score sheets were transcribed into tables like this…

TC vs HSS - Push cut in Oak
Bowl Gouge Metal	Cut well - minutes
TC #120	24
V10 #120	13
M42 #120	4

And a graph produced from that for each wood…

The intervals were increased to 3 or 5 minutes with the softer woods.

A bevel contact push cut was used on all of the test runs with just the first 4-6mm of the cutting side of the gouge nose engaged in the cut. By limiting the cut to just that area of the gouge I was reducing the time it took to become too dull to cut.

For the initial test runs all of the gouges were sharpened on a #120 diamond wheel using a jig set at 42° nose bevel. All of the test gouges had very similar parabolic flute profiles.

Here is the traditional style bowl gouge that I made from TC to use in these test runs…

​

After completing the first round of testing I consolidated all of my test results into one table that looked like this…

Series of tests with gouges off #120 diamond ​

	RG sleeper	RG	Oak	Eucalypt	Ash/Maple	Blackwood	Pine
Bowl Gouge Metal	Extremely Hard	Very Hard	Tough	Medium Hard	Medium	Medium Soft	Soft
TC	9	30	24	34.5	24	39	36
V10	1.5	5	13	13.5	16	19	33
M42	0.5	3	4	10	16	14	33

From which the graph in my initial post was derived.

For completeness I should say that the #120 that I used to sharpen in the first round of tests was an 8” resin diamond matrix wheel that I have been using for many years. Although #120 is relatively coarse grit by today’s standards; the resin matrix doesn’t expose as much of the grit as a sintered diamond (or CBN) wheel or disc and is probably why the #240 and #320 sintered diamond discs didn’t provide any performance improvement over the #120 diamond resin matrix wheel.

I subsequently ordered a #600 and a #800 sintered diamond lapping disc hoping they would perform as well as the #1k and possibly remain aggressive for longer. Although, with the low cost of these diamond discs replacing them isn’t a big consideration.

When the #800 diamond disc arrived I tested the edge off that against the #1k and found that the edge off the #1k was the standout performer there. Without a metallurgical microscope I don’t know what benefits the $1k is providing over the #800.

I won’t bother doing a summary of my findings on how the TC bowl gouge performed compared to the other bowl gouge metals as that should be obvious enough from the graphs in my first post. I’m sufficiently convinced and already enjoying the benefits from using the ones I made for day to day use in my workshop.

I will post a separate thread on the economical setup that I used for sharpening the TC bowl gouges that I used used during the testing as that is one of the often referred to challenges that come up with TC.

I will also attempt to address some of the other issues identified for TC in subsequent posts, but it being bedtime for those of us that live down this side of the rock that will have to wait for now.

 

[Doug Rasmussen]

A lot of interesting information to digest.... Thanks.

Am I correct in concluding M42 more than doubled its cutting time in oak when sharpened with the 1,000 grit wheel? If so, that would suggest the so often recommended 180 grit CBN wheels are far too coarse for a touch up sharpening.

 

[Darryn Achall]

A lot of interesting information to digest.... Thanks.

Am I correct in concluding M42 more than doubled its cutting time in oak when sharpened with the 1,000 grit wheel? If so, that would suggest the so often recommended 180 grit CBN wheels are far too coarse for a touch up sharpening.

A lot of interesting information. I have a 600 grit cbn wheel for touch ups, maybe need to change that out for 1,000 grit. Now where can I find a TC bowl gouge?

 

[Doug Rasmussen]

A lot of interesting information. I have a 600 grit cbn wheel for touch ups, maybe need to change that out for 1,000 grit. Now where can I find a TC bowl gouge?

Neil's testing brings up some significant differences between tool gouge materials. Neil tested M42 gouges, most users probably have plain HSS gouges. And even the term "HSS" is not a precise definition. I would be careful buying anything that was only described as HSS. There are precise definitions like M2, M3, etc. How does an M2 gouge compare to M42, maybe not so well?

As to where to buy a TC gouge, Neil may have a source. Or you could pull out your wallet and have one made in any of several shops in the Seattle area. A gouge tip could be made on a CNC tool grinder and silver soldered onto a mild steel shank. Or a wire EDM shop could cut one. MY choice might be the EDM shop because their machines are versatile in multi-angle work. Either way is going to be expensive.

 

[Neil S]

Am I correct in concluding M42 more than doubled its cutting time in oak when sharpened with the 1,000 grit wheel? If so, that would suggest the so often recommended 180 grit CBN wheels are far too coarse for a touch up sharpening.

Doug

The improvement was closer to a three fold improvement for M42 off #1k sintered diamond over #120 diamond resin matrix.

Here is the data for the three steels. All sharpening for these tests was done on diamond.

Improvement in performance with #1,000 over #120​

Wood	TC off #120	TC off #1k	V10 off #120	V10 off #1k	M42 off #120	M42 off #1k
Ext Hard Redgum	9	18	1.5	4.5	0.5	8
Oak	24	84	13	12	4	11
Soft Pine	36	100	33	50	33	35

And, shown here as a graph...

​

However, as I didn't use a #1k CBN wheel to sharpen the M42 shown in these tests results I can't say if M42 would have a similar improvement of almost three fold in cutting time if sharpened on CBN.

 

[Alan Weinberg]

this is so cool.

 

[Neil S]

Now where can I find a TC bowl gouge?

As to where to buy a TC gouge, Neil may have a source. Or you could pull out your wallet and have one made in any of several shops in the Seattle area. A gouge tip could be made on a CNC tool grinder and silver soldered onto a mild steel shank. Or a wire EDM shop could cut one. MY choice might be the EDM shop because their machines are versatile in multi-angle work. Either way is going to be expensive.

The reason I made my own TC bowl gouges for these test runs is that, as far as we know, nobody is currently making a traditional style TC bowl gouge to sell. That is in part why fellow forum member @hughie and myself are doing this. You have to have one before you can find out if they are worth having...

Knowing what we do now, we can now asses what the break even point (no pun intended) would be on the cost of making them and address the other issues raised about TC.

 

[Doug Rasmussen]

Great charts Neil, makes it much easier to make comparisons.

While your grinding was done on composite diamond wheels do you have any reason to believe the grinds would perform differently if done on CBN wheels. My experience grinding tiny precision metal cutting tools for my Swiss lathes tells there shouldn't be much if any difference. Occasionally, when in a hurry we used diamond on HSS when CBN would not wear the wheels so much.

Now I wonder if there'll be a run on 1,000 grit plated CBN wheels (if such a thing exists). Or, instead of a plated wheel a composite 1,000 grit CBN might be best.

Have you done any tests using honing between grinds? I've said previously touching your expensive gouge on a 180 grit wheel for touch-up sharpening was not a wise thing to do.

 

[Neil S]

Great charts Neil, makes it much easier to make comparisons.

While your grinding was done on composite diamond wheels do you have any reason to believe the grinds would perform differently if done on CBN wheels. My experience grinding tiny precision metal cutting tools for my Swiss lathes tells there shouldn't be much if any difference. Occasionally, when in a hurry we used diamond on HSS when CBN would not wear the wheels so much.

Now I wonder if there'll be a run on 1,000 grit plated CBN wheels (if such a thing exists). Or, instead of a plated wheel a composite 1,000 grit CBN might be best.

Have you done any tests using honing between grinds? I've said previously touching your expensive gouge on a 180 grit wheel for touch-up sharpening was not a wise thing to do.

You can grind TC on CBN, but there a good reasons to not do that as a regular thing. I've started another thread on how I sharpened the TC that will explain why...

Sharpening tungsten carbide gouges with diamond

. One of the drawbacks for gouges made from tungsten carbide (TC) is that it is best sharpened with diamond. Many of us now have CBN grinding wheels for sharpening our HSS turning tools and although those could be used to sharpen TC that would be both inefficient (something like only 67%...

www.aawforum.org

No, Doug, I didn't do any hand honing of the TC during my testing as that could have brought in a variable that may have had an effected on the results. All the gouges were sharpened in a gouge jig with the same settings each time so that they all stated each test run exactly the same.

The improved performance off the #1k diamond was an unexpected outcome for all of the gouge metals tested. I did use the #1k diamond on all three metals so that I was comparing apples with apples, but as we know diamond supposedly doesn't like the iron in HSS, so I'm unlikely to continue to do that as a regular thing and will continue to use my current CBN wheels for those.

However, Someone else might like to pursue whether a #1k CBN might provide a better performance for their current HSS tools.

 

[Neil S]

Returning to the identified issues with TC being used as a traditional bowl gouge metal...

A carbide profile can't be changed

Perhaps not quite as readily as some HSS metals, but having made half a dozen so far with different flute profiles, bevel angles and grinds I can confidently say that it could be re-profiles by most woodturners.

Even just a carbide tip would be prohibitively expensive

That may be the case, but at least we now know how much better the TC performs as a traditional bowl gouge as a basis for assessing any additional cost involved.

@ Hughie and I are currently exploring manufacturing options and costs, but don’t have definitive figures yet. We are hopeful!

Carbide is extremely brittle so an entire carbide bowl gouge would be hazardous

An entire bowl gouge made with TC is not envisaged for many reasons. But, a TC bowl gouge tip mounted on a steel shaft partly overcomes some issues.

However, brittleness will always be an issue with the grade of TC that is most suited for woodturning, having as it does a Rockwell Hardness (HR) on the A scale up around 90HR(A), or more. At that hardness it will be brittle. Its hardness is what gives it its edge durability but that comes at the expense of its low toughness (brittleness). It’s a trade-off!

If you think of these grades of TC as being more like a ceramic than a steel and treat it accordingly its brittleness becomes less of an issue. You just can’t throw it about as I’m a bit inclined to do with my HSS tools.

Having said that, I used the TC for many hours during my testing on all manner of woods without incident.

It is also worth pointing out that HSS metals are not entirely exempt from issues with brittleness despite their much lower HR. Here is what can happen to A11/10V…

​

Without specialized equipment, carbide couldn't be sharpened

During testing I experimented with ways to economically sharpen with diamond on the setup that most turners currently have in their workshops. I have written that up and posted it in a separate thread…

Sharpening tungsten carbide gouges with diamond

. One of the drawbacks for gouges made from tungsten carbide (TC) is that it is best sharpened with diamond. Many of us now have CBN grinding wheels for sharpening our HSS turning tools and although those could be used to sharpen TC that would be both inefficient (something like only 67%...

www.aawforum.org

So, that leaves cost and brittleness as the outstanding issue.

Hopefully, the cost question will be answered soon.

The brittleness will remain so, but if it is thought of and handled like it is a piece of ceramics it should survive most of us. It may not be tough in itself but if used with reasonable care it can do some very tough jobs for us!

 

[Neil S]

I will post a separate thread on the economical setup that I used for sharpening the TC bowl gouges that I used used during the testing as that is one of the often referred to challenges that come up with TC.

Here is that thread that I have now posted on the economical setup I used to sharpen the TC gouges...

Sharpening tungsten carbide gouges with diamond

. One of the drawbacks for gouges made from tungsten carbide (TC) is that it is best sharpened with diamond. Many of us now have CBN grinding wheels for sharpening our HSS turning tools and although those could be used to sharpen TC that would be both inefficient (something like only 67%...

www.aawforum.org

 

[hughie]

Food for thought, and for those who are not so familiar with our species I have included links to what I consider to be authoritative sites, especially https://www.ttit.id.au/index.htm

The background to all this effort came about to some degree with my frustration with many of the current turning tools and early sharp edge failure, as I find sharpening although necessary, it interrupts the creative flow of ideas. As many of you know, we have more than our share of hardwood species in Australia. All of them will argue with HSS and some will win. When Doug Thompson came out with range of cryo tools its was an 'aha moment'. I immediately bought a couple of gouges 5/8 and 1/2, and they have never disappointed me. They are and remain my go-to gouges but a couple species namely Buloke [ https://en.wikipedia.org/wiki/Allocasuarina_luehmannii ] , Inland Rosewood [ https://www.ttit.id.au/treepages/rosewood.htm ] with these species they struggle and edge retention can be similar to non cryo tools.

But it gets a little more complicated as we have areas where the soil has silica and the tree seems to take it up to the extent of matching the Buloke or Inland Rose wood. Here are a couple in have in my stash Gidgee [ https://www.ttit.id.au/treepages/gidgee.htm ], Deadfinish [ https://www.ttit.id.au/treepages/deadfinish.htm ] and the silica content takes me back to square one .

TCT tips, Neil and I have teamed up out of mutual interest to try and overcome this problem, realising if we are successful then all can benefit from this research even if we cant bring it to market and that is definitely food for thought.

So gentlemen chime in with your thoughts and experiences with hardwood, we can all benefit.

 

[Gord Cameron]

While the markedly extended cutting times with the higher grit sharpening of HSS might have been a (mere) side issue in your effort to develop a TC gouge, I find your data on that point very interesting. In the world of knife sharpening, the data show that, for a given apex, an edge sharpened to a higher grit will cut longer (cut more material before ceasing to perform). It is interesting to see that this effect might apply in woodturning despite the exposure of the edge to huge amounts of tough material in a very short time.

I find that, once I have shaped my tools on lower grit wheels, the 600 grit wheel is all that I need: a few seconds on a 600 grit wheel puts on a new edge with minimal loss of steel. I don't keep track of whether this edge cuts longer than an edge from my 180 grit wheel, but your data suggests that it probably does. I hadn't thought a 1000 grit wheel would be useful, but if data like your comes out for CBN wheels, a 1000 grit wheel might be in order.

 

[Neil S]

In the world of knife sharpening, the data show that, for a given apex, an edge sharpened to a higher grit will cut longer (cut more material before ceasing to perform). It is interesting to see that this effect might apply in woodturning despite the exposure of the edge to huge amounts of tough material in a very short time.

Good points there in your post, Gord.

I'm very familiar with that knife sharpening data as I spend a lot of my time sharpen many different types of cutting edges, including some top-end hand forged Japanese kitchen knives on some very expensive waterstones, but as you say, we woodturners are rapidly cutting through large volumes of much tougher material than most knife would would be expected to handle, so only some of that knife data applies.

I find that, once I have shaped my tools on lower grit wheels, the 600 grit wheel is all that I need: a few seconds on a 600 grit wheel puts on a new edge with minimal loss of steel. I don't keep track of whether this edge cuts longer than an edge from my 180 grit wheel, but your data suggests that it probably does. I hadn't thought a 1000 grit wheel would be useful, but if data like your comes out for CBN wheels, a 1000 grit wheel might be in order.

I think I might know why there was a quantum leap in edge durability when the TC is taken down to #1k on diamond, but it is a bit beyond the scope of this thread to go into that here other than to say that I found it to be the case during my testing.

In the case of the TC, I took it through both #600 and #800 diamond without any observable improvement before the #1k diamond, where there was a definite two to three fold improvement.

With the two HSS gouges that I used for the test runs, I went straight from #240 diamond down to #1k diamond. Having found the sudden improvement with the TC off the #1k I wanted to see if it was just an anomaly for the TC or if there would be a similar improvement for the HSS at #1k, which there was to varying degrees.

What I didn't do was step through the #600 and #800 diamond with the HSS gouges, so I can't say unless I went back to do that that the same quantum improvement which was observed with the TC would apply to the HSS gouges going from #600 and #800 diamond down to #1k diamond.

Also, none of the test data was off CBN sharpened gouges. The results off CBN could be very different for HSS. Many like yourself, Gord, who have a #600 CBN wheel report the benefits of going down to that grit with their HSS gouges.

An economical way for anyone who would like to experiment to see if going down to #1k CBN would provide any further benefit over #600 for their HSS would be to get a #1,000/1,200 CBN hone and just hand hone the bevel with that. And, we can all do with another hand hone!

Note: Gouge flutes should be taken down to as fine a grit as that used on the bevel side of the edge. I took the flutes on the TC gouges that I used in my tests runs down to a 5micron finish with loose diamond powder suspended in wax, which is equivalent to #1,200 grit. This is what gave them that mirror finish you can see back in post #4. You wouldn't need to use loose diamond for the HSS flutes, but it is much cheaper than you would expect if you look for a reasonably priced source.

 

[Brian Gustin]

Note: Gouge flutes should be taken down to as fine a grit as that used on the bevel side of the edge. I took the flutes on the TC gouges that I used in my tests runs down to a 5micron finish with loose diamond powder suspended in wax, which is equivalent to #1,200 grit. This is what gave them that mirror finish you can see back in post #4. You wouldn't need to use loose diamond for the HSS flutes, but it is much cheaper than you would expect if you look for a reasonably priced source.

I was actually thinking about it after researching the loose diamond powder on Amazon... but what I had in mind was a custom-fit gouge hone , where you would set your preferred grind and then make a casting of the gouge end and flute, and use that casting to make a 3-piece mold (external block shape, and top & bottom flute/bevel shapes), and then mix some suitable epoxy and mix in your loose diamond grit , keep the whole thing by the lathe and when you wanna hone, just stick your gouge in your custom mold and give it a few twists back and forth.... and go back to cutting with a nicely honed edge... epoxy profiled hone could help retain and polish your grind so well that you may never need to go back to the grinder unless you nicked your gouge badly, or wanted to change profile (in which case you'd need to make a new custom hone)

But, I just have not really had the free time to mess around with the idea (And epoxy costing more than the diamond grit, I haven't been willing to spend the money on it yet either)

 

[Neil S]

what I had in mind was a custom-fit gouge hone

That is what I do for power honing the flutes on all of my gouges and in the case of TC the abrasive just needs to be diamond rather than chromium oxide, etc...

​

 

[Michael Nathal]

Terry Martin wrote "Rethinking Sharpening" in the June 2014 issue of Am Woodturner. He describes his own experience with using the Tormek, which I believe is similar to a 1000 grit diamond finish. He is convinced that polishing a gouge to a higher finish lasts longer. He also refers to an article by R Farrance with sophisticated tests that show a finer edge lasts longer.

 

[Alan Weinberg]

a finer edge lasts longer.

only logical if you are starting finer that it takes longer to get to dull—just like if you are driving faster, it takes longer to get to zero.

 

[hughie]

I was actually thinking about it after researching the loose diamond powder on Amazon... but what I had in mind was a custom-fit gouge hone , where you would set your preferred grind and then make a casting of the gouge end and flute, and use that casting to make a 3-piece mold (external block shape, and top & bottom flute/bevel shapes), and then mix some suitable epoxy and mix in your loose diamond grit , keep the whole thing by the lathe and when you wanna hone, just stick your gouge in your custom mold and give it a few twists back and forth.... and go back to cutting with a nicely honed edge... epoxy profiled hone could help retain and polish your grind so well that you may never need to go back to the grinder unless you nicked your gouge badly, or wanted to change profile (in which case you'd need to make a new custom hone)

But, I just have not really had the free time to mess around with the idea (And epoxy costing more than the diamond grit, I haven't been willing to spend the money on it yet either)

Definitely food for thought here Brian

 

[hughie]

That is what I do for power honing the flutes on all of my gouges and in the case of TC the abrasive just needs to be diamond rather than chromium oxide, etc...

View attachment 55957​

I have developed something very similar, finding MDF ideal for conforming to the shape I require.

 

[Neil S]

Terry Martin wrote "Rethinking Sharpening" in the June 2014 issue of Am Woodturner. He describes his own experience with using the Tormek, which I believe is similar to a 1000 grit diamond finish. He is convinced that polishing a gouge to a higher finish lasts longer. He also refers to an article by R Farrance with sophisticated tests that show a finer edge lasts longer.

only logical if you are starting finer that it takes longer to get to dull—just like if you are driving faster, it takes longer to get to zero.

Michael and Alan

I have responded to your posts over in the companion thread on sharpening TC gouges because it relates more specifically to that sharpening thread...

Sharpening tungsten carbide gouges with diamond

. One of the drawbacks for gouges made from tungsten carbide (TC) is that it is best sharpened with diamond. Many of us now have CBN grinding wheels for sharpening our HSS turning tools and although those could be used to sharpen TC that would be both inefficient (something like only 67%...

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[Neil S]

When the #800 diamond disc arrived I tested the edge off that against the #1k and found that the edge off the #1k was the standout performer there.

I have since tested the use of a #1.5k diamond disc compared to #1k disc, which I have reported on in the companion thread on sharpening TC…

Sharpening tungsten carbide gouges with diamond

. One of the drawbacks for gouges made from tungsten carbide (TC) is that it is best sharpened with diamond. Many of us now have CBN grinding wheels for sharpening our HSS turning tools and although those could be used to sharpen TC that would be both inefficient (something like only 67%...

www.aawforum.org