Bowl Gouge Flute Descriptors

[Neil S]

Adding a few photos of gouges not covered thus far.
First is a Carter & sons 5/8 deep fluted bowl gouge. A U-shaped flute. I find the transition from the round bottom to the straight cut upper difficult to have a grind without a bump. Certainly takes care.
View attachment 49793
Second is a Oneway master cut 5/8 bowl gouge. Looks elliptical to me, also deep and wide. I love this with a 40-40 style grind. My workhorse.
View attachment 49794

Marc

Excellent photos there of the profiles on those two gouges.

Thanks

 

[Neil S]

I will put my grind on one of the tools with the flute you are showing and see what it looks like.

Bill, no need to put your grind on it. The flute profile won't change with the grind. Just a direct end-on photo will do to confirm, or otherwise, if the shallowness of the Thompson Vs have changed over time.

 

[odie]

or for at least the flute and bar width be both stated.

^^^^^ This would be the obvious and very easy solution that seems to escape most vendors.

(From one who has been bitten by ordering the wrong gouge......more than once!)

-----odie-----

 

[Bill Blasic]

I believe that if you compare D-Way gouges to Carter you will find them exactly alike and there is a reason for that. That info is out there.

 

[Sarah S Elkind]

I'm not going to hold my breath on getting an agreement among tool makers on that, Karl. But, we can collectively put pressure on both the makers and retailers to provide clear end-on photos to inform our choices and also to avoid the confusion that arises from the sloppy use of descriptors.

Ideally I would like the commonly used descriptors to be as precisely applied as is the heat treatment that all of the mentioned makers use in making their excellent tools. Until then, let's at least have clear end-on photos to see what we are getting.

AAW could inject some standardized language via tool reviews

 

[hockenbery]

Perhaps AAW could host a discussion among manufacturers, vendors, and resellers and get them to agree on what to call their gouges

AAW could inject some standardized language via tool reviews

AAW did have one success with leading standardization - nearly every manufacturer added “Spindle” to the the name of the Spindle Roughing gouge.

standardizing Bowl gouge sizes- US makers had no interest in adopting flute dimension and European manufactures had no interest in adopting US standards. Both continue to sell lots of tools. I will likely Always call bowl gouge by the flute dimension.
it’s just natural for me. But I do often add the bar dimension parenthetically.

 

[Neil S]

I believe that if you compare D-Way gouges to Carter you will find them exactly alike and there is a reason for that. That info is out there.

Bill, I presume you are referring to Carter's standard V fluted BG and not their Mahoney parabolic, which of course will not be the same as the D-Way V flute. Does anyone have an end-on photo that they can post of their Mahoney parabolic BG? Also, it would be good to have one of the Carter V flute for comparison.

 

[Neil S]

AAW did have one success with leading standardization - nearly every manufacturer added “Spindle” to the the name of the Spindle Roughing gouge.

standardizing Bowl gouge sizes- US makers had no interest in adopting flute dimension and European manufactures had no interest in adopting US standards. Both continue to sell lots of tools. I will likely Always call bowl gouge by the flute dimension.
it’s just natural for me. But I do often add the bar dimension parenthetically.

The standardisation in naming Spindle Roughing Gouges was a safety issue for which there was unlikely to be any major pushback, just tardiness with implementation.

What I am increasingly seeing with BG sizes on websites is that the convention being used is being more clearly stated. Here are a few examples...

• We use the American method of measurement for the stated size - diameter of the tool, not flute size.
• Blade measures 5/8” outside diameter
• ⅝” bar ∅ bowl gouge
• Size: 1/2" Superflute Bowl Gouge (5/8" Bar Stock)
• English size is 1/2” across flutes. 5/8” is dia. of steel.

I expect that those that haven't done so already will in time fall into line.

I expect that getting more accurate flute profile descriptors will be more challenging.

 

[Joe Kaufman]

5/8" Bowl gouge profiles
Left: Carter - Mike Mahoney parabolic flute
Center: Carter "v" flute
Right: Ashley Harwood 40-40 parabolic flute

 

[Neil S]

5/8" Bowl gouge profiles
Left: Carter - Mike Mahoney parabolic flute
Center: Carter "V" flute
Right: Ashley Harwood 40-40 parabolic flute

Many thanks, Joe.

Those are very good examples and helpful additions to our flute profile gallery.

 

[Donna Frazier]

Although no longer available... Stuart Batty's SB Tools had manufactured a beam shape gouge with a parabolic flute. The description and photos can be seen in his old catalogue. https://www.dmwoodturners.com/wp-content/uploads/2016/11/Tools-Woodturning-CATALOG-AUG-2013.pdf

 

[hockenbery]

increasingly seeing with BG sizes on websites is that the convention being used is being more clearly stated.

In the 90s the craft supplies catalog alway used a 1/4 page to explain gouge sizing and the English sizing the used for BGs.

naming Spindle Roughing Gouges was a safety issue for which there was unlikely to be any major pushback,

agreed.
Its like preventing avoidable deaths. I am amazed at the enormous expense and inconvenience the US accepts to prevent avoidable deaths by lightning strikes. Used to be over a 100 a year now less than 20. No pushback from the lightning supporters.
i don’t chainsaw in a lightning storm.

most public safety avoidable death initiative fail when there is group that perceives benefit from letting the deaths continue.

 

[Neil S]

Although no longer available... Stuart Batty's SB Tools had manufactured a beam shape gouge with a parabolic flute. The description and photos can be seen in his old catalogue. https://www.dmwoodturners.com/wp-content/uploads/2016/11/Tools-Woodturning-CATALOG-AUG-2013.pdf

Donna, thanks for that link.

I didn't include Stuart's flute profile as there aren't too many of them out there in the wild. The other reason is that Stuart goes back to when Henry Taylor called their Superflute an elliptical flute profile and he and others who were exposed to that descriptor would be familiar with it, but otherwise it has fallen out of use and is a less understood descriptor. Here it is in Stuart's defunct catalogue ...

​

If Stuart had gone into production with that flute profile and called it elliptical (as he does in his catalogue) then I would have no quibble with that as it is in fact mathematically an ellipse. But in the absence of gouges out there with this flute profile I recommend we don't resurrect that defunct descriptor until there is a bowl gouge out there that does have an elliptical flute and is rightly called that. There is enough confusion with the current descriptors without another one looking for a home where is doesn't belong...

 

[hughie]

An impressive piece of writing, there's a few I haven't come across and the Oneway master flute looks interesting. I might try and include this form in my latest project.

 

[Doug Freeman]

My thought would be to create a permanent file (like the one’s at the top of this forum category) that has the pictures of the different mfr profiles and names, as presented in this thread, in the tips and tutorials section. No other posts, just the photos with mfr and whatever they call it, shaft and flute size, etc. something that could be used as a quick reference. Of course someone would have to manage it.

 

[Neil S]

An impressive piece of writing, there's a few I haven't come across and the Oneway master flute looks interesting. I might try and include this form in my latest project.

Hughie

Might we get a thread on your latest project when you are ready for that?

 

[Neil S]

Forum members may have images of other examples of bowl gouges with parabolic flutes that I don’t have that they might like to post here with a clear end view of the flute profile, eg Hamlet Masterflute

I have an orphan bowl gouge, which may be a Hamlet Masterflute, but I'm not sure. It got separated from its original handle a long time ago when I moved over to removable handles and it has no identifying makings on the gouge bar itself and I lost track of the maker. Here it is...

​

So, it has a 5/8" parabolic flute in a 7/8" bar. That flute size in that bar size is no longer offered by any of the gouge makers. Henry Taylor do offer a Hamlet with a 3/4" flute in a 7/8" bar, but this one definitely has a 5/8" flute width.

Does anyone have this gouge and can confirm that it is a Hamlet Masterflute, or Diamic, that is no longer offered.

I also had a Crown 1" BG (yes they identified it as the bar size and not the flute width, as does Henry Taylor in that size), so I am familiar with that BG alongside this gouge and it is definitely not the Crown 1". It is also possible that it is one of Henry Taylor's original Diamic gouge range that is no longer offered in that 7/8" bar size.

Anyway, Masterflute or not, going by that fulsome parabolic flute it is does look like it could be out of the Henry Taylor works in Sheffield somewhere along their gouge development.

 

[Neil S]

Crown 1" BG (yes, they identified it as the bar size and not the flute width, as does Henry Taylor in that size)...

Here is that Crown Pro-PM 1" bar BG and as you can see with its upper straight sides it has a different flute profile to the 7/8" Henry Taylor/Hamlet I posted above...

​

It doesn't qualify as a U flute as those upper straight sides aren't quite parallel. If I remember correctly, they diverge by about 10 or 12 degrees. So, it just gets pushed out of the U into the V flute category, where it doesn't look quite at home with the largest semi circular flute bottom in any BG that I'm familiar with.

 

[Rick Lowe]

Donna, thanks for that link.

I didn't include Stuart's flute profile as there aren't too many of them out there in the wild. The other reason is that Stuart goes back to when Henry Taylor called their Superflute an elliptical flute profile and he and others who were exposed to that descriptor would be familiar with it, but otherwise it has fallen out of use and is a less understood descriptor. Here it is in Stuart's defunct catalogue ...

View attachment 49819
​

If Stuart had gone into production with that flute profile and called it elliptical (as he does in his catalogue) then I would have no quibble with that as it is in fact mathematically an ellipse. But in the absence of gouges out there with this flute profile I recommend we don't resurrect that defunct descriptor until there is a bowl gouge out there that does have an elliptical flute and is rightly called that. There is enough confusion with the current descriptors without another one looking for a home where is doesn't belong...

Not sure if anyone wants to see a couple pics(apologies for the poor quality) of two of Stuarts 5/8” bowl gouge still running free in the “wild” One sharpened to a 40/40, the other unsharpened.

 

[Neil S]

Not sure if anyone wants to see a couple pics(apologies for the poor quality) of two of Stuarts 5/8” bowl gouge still running free in the “wild” One sharpened to a 40/40, the other unsharpened.

Rick

Thanks for posting those photos, particularly the end view of the flute profile on the SB.

I have attempted to extracted that image from your photo and rotated it...

​

Although difficult to see in detail, it does appear to be close to elliptical, as Stuart maintained.

As it is beyond the scope of this thread, I will refrain from commenting about the finish on the gouges.

 

[Rick Lowe]

Rick

Thanks for posting those photos, particularly the end view of the flute profile on the SB.

I have attempted to extracted that image from your photo and rotated it...

View attachment 49952​

Although difficult to see in detail, it does appear to be close to elliptical, as Stuart maintained.

As it is beyond the scope of this thread, I will refrain from commenting about the finish on the gouges.

Neil,
The bowl gouge that you focused on is the nonsharpend one, which has a less than ideal end.

While I really do get your point/comment regarding the “finish”. For me it was the chance to own an SB bowl gouge, seconds on looks quality or not. … Instead of pretending with a Oneway and or Sorby and or and or, jammed into the SB bolster.

I could not be happier than I am with the tools that I’ve got. Now I’m waiting and hoping that Stuart’s new endeavor is working out well for him and that we will be seeing new tools etc.

Best
Rick
































































L
Last year when I took Stuart’s class in Vegas, he was talking about getting his mani

 

[Donna Frazier]

Neil,
The bowl gouge that you focused on is the nonsharpend one, which has a less than ideal end.

While I really do get your point/comment regarding the “finish”. For me it was the chance to own an SB bowl gouge, seconds on looks quality or not. … Instead of pretending with a Oneway and or Sorby and or and or, jammed into the SB bolster.

I could not be happier than I am with the tools that I’ve got. Now I’m waiting and hoping that Stuart’s new endeavor is working out well for him and that we will be seeing new tools etc.

Best
Rick
































































L
Last year when I took Stuart’s class in Vegas, he was talking about getting his mani

That is why I introduced SB tools into your discussion. Stuart has had some interesting innovations and I too look forward to more developments in the future.
Reminds me of the Tucker car.... despite not many in the wild...it made history and changed how car manufacturers thought about safety and design.

 

[Neil S]

I never managed to get an original Jerry Glaser bowl gouge myself, but had hoped that someone might have one and be willing to post a direct end-on photograph of its flute profile here. Jerry's bowl gouges have an important place in the development of the bowl gouge and it would be good to have a photo of his flute profile included here.

 

[Neil S]

I put together the following list of bowl gouge flute widths for another purpose but it is also a bit relevant to this topic, so I have also added it here...

Bowl Gouge Flute Widths
Maker	Bar size	Bottom of flute to bottom of bar	Bottom thickness as % of bar size	Width of flute	Flute width as % of bar size
	mm	mm		mm
Crown	22.5	5.6	25%	16	71%
Thompson	19.5	7.5	38%	13.5	69%
Woodcut	19	6	32%	14.3	75%
Thompson	16	7	44%	10	63%
Thompson 15V	16.4	6.3	38%	9.75	59%
Thompson/Jamieson	16	5.5	34%	11.75	73%
Vicmarc	16.3	6.3	39%	11	67%
Woodcut	15.8	5	32%	9.75	62%
Henry Taylor	15.8	6.3	40%	10.5	66%
D-Way	15.9	4.9	31%	10.6	67%
D-Way	15.9	5.5	35%	10.25	64%
Crown - Ellsworth	15.9	5.2	33%	11	69%
D-Way	13.1	4.5	34%	9.4	72%
Henry Taylor	13	5	38%	8.6	66%
Woodcut	12.6	4.75	38%	7.5	60%
Thompson	9.8	4.5	46%	6.75	69%

Please measure and add any that you have that I haven't listed.

 

[Marc Banka]

I put together the following list of bowl gouge flute widths for another purpose but it is also a bit relevant to this topic, so I have also added it here...

Bowl Gouge Flute Widths
Maker	Bar size	Bottom of flute to bottom of bar	Bottom thickness as % of bar size	Width of flute	Flute width as % of bar size
	mm	mm		mm
Crown	22.5	5.6	25%	16	71%
Thompson	19.5	7.5	38%	13.5	69%
Woodcut	19	6	32%	14.3	75%
Thompson	16	7	44%	10	63%
Thompson 15V	16.4	6.3	38%	9.75	59%
Thompson/Jamieson	16	5.5	34%	11.75	73%
Vicmarc	16.3	6.3	39%	11	67%
Woodcut	15.8	5	32%	9.75	62%
Henry Taylor	15.8	6.3	40%	10.5	66%
D-Way	15.9	4.9	31%	10.6	67%
D-Way	15.9	5.5	35%	10.25	64%
Crown - Ellsworth	15.9	5.2	33%	11	69%
D-Way	13.1	4.5	34%	9.4	72%
Henry Taylor	13	5	38%	8.6	66%
Woodcut	12.6	4.75	38%	7.5	60%
Thompson	9.8	4.5	46%	6.75	69%

Please measure and add any that you have that I haven't listed.

Adding Oneway mastercut 5/8 bowl gouge. Neil, can you add these numbers to your chart?
Bar size 15.75 Flute to bottom 4.825 30% of bar. Flute width 10.795 68.5% of bar.

 

[Neil S]

Adding Oneway mastercut 5/8 bowl gouge. Neil, can you add these numbers to your chart?
Bar size 15.75 Flute to bottom 4.825 30% of bar. Flute width 10.795 68.5% of bar.

Thanks Marc.

Spreadsheet now updated with Oneway Mastercut included...

Bowl Gouge Dimensions
Maker	Bar size	Bottom of flute to bottom of bar	Thickness as % of bar size	Width of flute	Flute width as % of bar size
	mm	mm		mm
Crown	22.5	5.6	25%	16	71.11%
Thompson	19.5	7.5	38%	13.5	69%
Woodcut	19	6	32%	14.3	75%
Thompson	16	7	44%	10	63%
Thompson 15V	16.4	6.3	38%	9.75	59%
Thompson/Jamieson	16	5.5	34%	11.75	73%
Vicmarc	16.3	6.3	39%	11	67%
Woodcut	15.8	5	32%	9.75	62%
Henry Taylor	15.8	6.3	40%	10.5	66%
D-Way	15.9	4.9	31%	10.6	67%
D-Way	15.9	5.5	35%	10.25	64%
Crown - Ellsworth	15.9	5.2	33%	11	69%
Oneway Mastercut	15.75	4.83	31%	10.79	69%
D-Way	13.1	4.5	34%	9.4	72%
Henry Taylor	13	5	38%	8.6	66%
Woodcut	12.6	4.75	38%	7.5	60%
Thompson	9.8	4.5	46%	6.75	69%

 

[Neil S]

I'm adding a few flute profiles here from some DIY bowl gouge projects that fellow forum member Hughie and myself have been recently engaged in. These are customised flute profiles that we have ground ourselves. I would call at least the first three as parabolic flutes as they have continuous curved sides.

​

The next double image is a before and after photograph where we reground the flute from one profile to another. The regrind was done to better suit the characteristics of the gouge metal that we found didn't favour acute wing edges.

​

If you are adventurous enough to regrind the bevel angles on your gouges to a different profile, why not also experiment with adjusting your flute profiles. I have posted some information on how we went about grinding these flutes in a thread over in Tutorials and Tips, called Grinding short flutes to make new bowl gouges

 

[Adrian Wilson]

Outstanding thread; thank you. Very helpful in trying to understand this stuff. I agree that the manufacturers could and should be doing a better job in showing exactly what their geometry (type, anyway) is. Some are better than others; there is one I am thinking of that has almost no information about what they are actually offering.

 

[Doug Freeman]

@Neil S what about adding a “flute shape” column to your chart? Parabolic or V, you may have others you want to use. A dim that might be added is “nose radius”, though defining exactly how to determine it may be a challenge.

 

[Neil S]

@Neil S what about adding a “flute shape” column to your chart? Parabolic or V, you may have others you want to use. A dim that might be added is “nose radius”, though defining exactly how to determine it may be a challenge.

Doug

Good suggestion about adding the flute shapes to the chart, I'll do that when I can, but as you say, something like the "nose radius" would need to be defined. I expect it would be the measurement across the V flute at the point at which the wings become straight, as viewed end-on to the flute. I'll have a think about that.

I've always attempted to begin shaping the wing profile on a new (to me) bowl gouge flute by following the insight provided by Jerry Glaser that the wing profile when viewed from above mirrors the flute profile when viewed end-on. Here is an example of those two views of the same bowl gouge when juxtaposed...

​

BTW, this is independent of the bevel angle that is then later added or changed. Here is Jerry's own diagram of that stage of wing formation...

​

That is always my starting point with any new bowl gouge flute profile and I then may vary it from there.

But the nose profile, when viewed from above, can then be change by the way the turner grinds their bevels, however the end-on view of the flute remains constant. So, any dimensions from the end-on view would be the most useful.

And, of course, the parabolic flutes don't have a fixed diameter anywhere on their curve, instead having an F number (F= Focal point, as shown in my post #2) that determines the curve, but I'm not sure how readily I could determine the F number by just looking at the flute on any gouge or how useful it would be if I added that number. Not many of us could conjure up a visual image from a number like say F=1.25...

 

[Lennart Delin]

Dictum, a German company has exemplary description with shape of the flute and stating that the width is always the outer diameter. Could it be more clear and simple? The steel quality is also clearly stated.

Crown Heavy-duty Bowl Gouge, M42-Cryogenic, Blade Width 13 mm | Standard woodturning tools | Dictum

Crown Heavy-duty Bowl Gouge, M42-Cryogenic, Blade Width 13 mm from category Standard woodturning tools with 30-day right of return at Dictum

www.dictum.com

 

[Richard Hodsdon]

Interesting topic, one omission I noticed is the Sorby Bowl gouges,
Even omitted from the table , is there a reason that these gouges are omitted?

 

[Neil S]

Dictum, a German company has exemplary description with shape of the flute and stating that the width is always the outer diameter. Could it be more clear and simple? The steel quality is also clearly stated.

Crown Heavy-duty Bowl Gouge, M42-Cryogenic, Blade Width 13 mm | Standard woodturning tools | Dictum

Crown Heavy-duty Bowl Gouge, M42-Cryogenic, Blade Width 13 mm from category Standard woodturning tools with 30-day right of return at Dictum

www.dictum.com

View attachment 54637

Thanks Lennart.

Yes, that is a very clear description of what you are getting.

Specifying the bar dimension avoids confusion with the convention that was used back when gouges were forged in Sheffield and sized by their flute widths. The outer dimensions from the forging process could vary from gouge to gouge, but the width of the flute was more controlled and precise...

BG flute profile in P Child 1970s book


Deep forged BG as drawn by Roy Child
​

When gouges began to be milled later on from bar stock in the US the outer dimension of the bar was used to specify the size, but flute width continued to be used in the UK and in some other places like here in Australia. This has lead to frequent confusion. More countries have now adopted the bar size convention as almost all bowl gouges are now milled from bar stock, but where a gouge has been made in Sheffield the two dimensions are now often given to minimise the confusion. e.g. https://henrytaylortools.co.uk/diamic-gouges/

The reason I added the flute width to my chart is that, IMO, the flute is the a critical component of the bowl gouge's geometry about which we don't always get good information before we buy.

 

[Neil S]

Interesting topic, one omission I noticed is the Sorby Bowl gouges,
Even omitted from the table , is there a reason that these gouges are omitted?

Simply omitted because I no longer have one myself and nobody on the forum offered to add it to the list. Richard, perhaps you would like to rectify that with a nice clear end-on photo of the flute and some dimensions.

Going by the diagram of the flute on the following listing, it also has a parabolic flute...

Fingernail Bowl Gouge 842FLH by Robert Sorby - Olivers Woodturning

Buy a Robert Sorby Fingernail Bowl Gouge 842FLH. A flexible tool equally suited to pull cuts and fine shearing cuts. Fitted with an Ash Handle and made in the UK

www.oliverswoodturning.co.uk

 

[Lennart Delin]

Simply omitted because I no longer have one myself and nobody on the forum offered to add it to the list. Richard, perhaps you would like to rectify that with a nice clear end-on photo of the flute and some dimensions.

Going by the diagram of the flute on the following listing, it also has a parabolic flute...

Fingernail Bowl Gouge 842FLH by Robert Sorby - Olivers Woodturning

Buy a Robert Sorby Fingernail Bowl Gouge 842FLH. A flexible tool equally suited to pull cuts and fine shearing cuts. Fitted with an Ash Handle and made in the UK

www.oliverswoodturning.co.uk

So, is the width the diameter or width of flute? Traditionally British sizes are the flute width. Interesting is also that the forged Sheffield shape you show, is often referred to as European style by British writers.

 

[Neil S]

So, is the width the diameter or width of flute? Traditionally British sizes are the flute width. Interesting is also that the forged Sheffield shape you show, is often referred to as European style by British writers.

Yes, Robert Sorby are made in Sheffield in UK, so those measurements are flute width. So their 1/2" bowl gouge are the same size as bowl gouges made from a 5/8" bar.

There is one exception to that, which I won't muddy the water with here.

Not relevant to this thread are their spindle gouge measurement that are given as the full width of the bar! It's their shallow spindle gouges that are called continental gouges (who knows why). Those are still forged from flat bar stack, as are some spindle roughing gouges

 

[Richard Hodsdon]

Simply omitted because I no longer have one myself and nobody on the forum offered to add it to the list. Richard, perhaps you would like to rectify that with a nice clear end-on photo of the flute and some dimensions.

Going by the diagram of the flute on the following listing, it also has a parabolic flute...

Fingernail Bowl Gouge 842FLH by Robert Sorby - Olivers Woodturning

Buy a Robert Sorby Fingernail Bowl Gouge 842FLH. A flexible tool equally suited to pull cuts and fine shearing cuts. Fitted with an Ash Handle and made in the UK

www.oliverswoodturning.co.uk

Hi Neil
Did as requested , sorry for the delay but still trying to work out how to transfer photos from an iPhone to PC , it was easy with my old android phone.
Also note that we (wife and I) have 4 3/8th" Sorby bowl gouges and 4 1/2" Sorby Bowl Gouges , start the turning session with them all sharp and don't have to stop to sharpen mid bowl. They have been bought over the last 30yrs
Interesting to see the changes in dimension of the bar

Sorby 3/8 bowl gouge	Shaft/bar	Flute width	Thickness at base	Year purchased	markings
	12.65	8.8	4.32	2000	3/8
	12.6	8.6	4.0	2000	3/5tjh
	13.0	8.7	4.62	2018	10mm and /3/8
	13.0	8.85	4.72	2018	10mm 3/8
Sorby1/2inch bowl gouge					Purchased
	15.75	10.8	4.92	1992	S Africa
	15.95	10.6	5.5	2000	USA
	16.0	9.62	5.5	2004	UK
	16.0	10.00	5.5	2018	UK

3/8 Bowl Gouge !/2 inch Bowl Gouge difference bet 2018 and 1992 gouges

 

[Dan Blankenberg]

Very informational, thanks for taking the time.

 

[Neil S]

Hi Neil
Did as requested , sorry for the delay but still trying to work out how to transfer photos from an iPhone to PC , it was easy with my old android phone.
Also note that we (wife and I) have 4 3/8th" Sorby bowl gouges and 4 1/2" Sorby Bowl Gouges , start the turning session with them all sharp and don't have to stop to sharpen mid bowl. They have been bought over the last 30yrs
Interesting to see the changes in dimension of the bar

Many thanks for those photos and the excellent detail on the Sorby parabolic flute BGs, Richard.

And, yes, very interesting to see the evolution over time, not only in bar size but also in flute design.

I'll consolidate your data into my table when I update mine and use your most recently manufactured example for the two nominal bar sizes.

 

[Ron Solfest]

I’ve used parabolic bowl gouges for a number of years and wanted to purchase another one late last year. I chose to purchase 3 Robust gouges (3/8”, 1/2”, 5/8”). Errantly I assumed all parabolic grinds were essentially the same with 5/8” bar gouges all having 1/2” flutes, etc.

The 5/8” is my ‘go-to’ bowl gouge and I couldn’t figure out why I kept gravitating back to my Crown 5/8” vs the Robust 5/8”, especially finishing cuts etc. A week or so ago I started investigating further and found the Robust 5/8” flute was significantly narrower leaving the bar on each side of the flute significantly thicker. When I compared to an older Henry Taylor 5/8” I found that was also very similar to the Crown.

Interestingly this same relationship of the flute/bar did not carry to the 3/8” and 1/2” Robust gouges, their flutes were wider more like other parabolics I’ve used and much more comfortable to my use. In fact, the Robust 1/2” bar gouge has a flute nearly as wide as the 5/8” bar Robust gouge. The inconsistency within a manufacturer across bar sizes surprised me a lot.

I don’t know for sure, but I think this is the crux of my preference for the 5/8” Crown over Robust. I want to get another 5/8”, but think I’ll wait a little until I’ve used the Robust even more and see if I can force myself to be more comfortable with it, or if I keep going back to the Crown (I like some other attributes of the Robust including it’s flat top and where it comes from).

Attached are some pics I took before I remembered this thread and so didn’t follow @Neil S conventions. I also apologize for the screenshot pic but I’m having difficulty combining pictures

I’ll also add my thanks again to @Neil S for the info contained in this thread AND my support again of his summarizing all of this into an AAW article