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Roughing gouges

M

Mike Darlow

Joined
May 1, 2019
Messages
19
Likes
23
Location
Exeter, NSW, Australia
In the AAW books Lathes and Turning Tools and Getting Started in Woodturning several authors promote that roughing gouges should be called spindle roughing gouges to warn turners not to use these gouges when turning bowls. While I sympathise with the intention, it has too narrow a focus.

Most of the roughing gouges made by forging a flat piece of HSS are rendered unsafe for bowl turning by having a narrow and shallow tang. They are also unsafe for spindle turning. I have broken two, and my staff have broken two P&N roughing gouges which have much stronger tangs. I conclude that most roughing gouges are not fit for purpose, and that changing the name merely accepts that we should be grateful for being sold unsafe tools.

Another factor is that roughing gouges are expensive. If excessively stressed, it should be the handle (which can be readily replaced) which breaks, not the tang.
 
The problem is usually cutting with the tool rest too far away from the cut and improper technique. Use safety drives keep the rest close keep the tool sharp “rub” the bevel.
 
The problem I see when using the SRG to turn bowls or faceplate is that the student tends to let it take too big of a bite and it rotates the tool to that unsupported part of the U and then they get a really big catch. Long time turners know how to keep the tool in a position that the cut is supported and consequently don't get the same catches.
 
I can see roughing the outside of a bowl with a conventional ground SRG but never ever use it on the inside of a bowl as the wings of the SRG will cause a massive catch. I use a Thompson SRG and I would find it hard to believe that you could break it at the tang. I call it my hundred year tool as I could not use up all of this SRG in a hundred years as it stays sharp for so long.
 
As a person who was away from turning for almost 40 years, I wonder about all these new "super tools" We had gouges back then. No special bowl gouges or roughing gouges.. Amazing that we made anything back in the day, the way some talk. . All these new configured tools and their limitations are a little bewildering. I see spindle roughing gouges big as snow board half pipes and wonder if they are any more efficient than the old tools.
 
A highly experienced turner can use a sharp spoon or a sharp axe head to turn successfully.

Major problem with SRGs is that catches will often be catastrophic.
With regard to face grain turning a side ground bowl gouge is both a more efficient and safer tool to use.
A bad catch is certainly achievable with a bowl gouge - however the comparatively narrow flute makes the catch much less severe that the wider flute of the spindle roughing gouge.

If one follows two concepts
1 Crosscut the fibers and 2 Never let the wood drive down onto the cutting edge.
You will never get a catch.

There is no reason to use an SRG on bowls
It is extremely dangerous for any beginner or intermediate and impractical for most experts.
 
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Most of the roughing gouges made by forging a flat piece of HSS are rendered unsafe for bowl turning by having a narrow and shallow tang. They are also unsafe for spindle turning. I have broken two, and my staff have broken two P&N roughing gouges which have much stronger tangs. I conclude that most roughing gouges are not fit for purpose,

The problem here is not with the SRG. The problem is improper use of the SRG. It is not my intention to be mean or nasty. This is simply a case of operator error.
 
Mike Darlow said:
Another factor is that roughing gouges are expensive. If excessively stressed, it should be the handle (which can be readily replaced) which breaks, not the tang.
Click to expand...

Most woodturners are frugal, but in the wrong hands there can be an indistinct line between frugal and foolish. I remember a discussion on another forum several years ago in which the person had a catch with his SRG and bent the tang roughly 45°. I was among the few who suggested tossing the tool. The person decided to go with the majority opinion and hammered the tang straight ... using the rationale that the worst that might happen would be for the tang to completely break. I agree, but the story doesn't necessarily end there. I would be concerned that the business end of the now unconstrained tool might become a sharp unguided missile headed in my direction. If I were lucky enough I would get to find out how the story ends.
 
Mike, What are the details behind each one of the SRG's breaking? For instance, what position were the SRGs to the wood when it caught (i.e. bevel rubbing mode at an slicing angle or being used more like a scraper)? Also, what makes an SRG inherently more dangerous than other sharp angled turning tools like a skew (made from flat stock the same thickness as an SRGs)?

The SRG from Carter&Sons appears to be slightly better design (shoulder support) than P&N, and it comes with a lifetime guarantee. Most any turning tool can be dangerous if it's used in a wrong manner, but I suspect you have to be doing something seriously wrong to break this one from C&S.
​
 
Timothy White said:
The problem here is not with the SRG. The problem is improper use of the SRG. It is not my intention to be mean or nasty. This is simply a case of operator error.
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I absolutely agree with you.

It is important for intermediate and beginners to never use an SRG on bowls because at that skill level they have a high percentage of getting a catastrophic catch.

Experts will rarely use an SRG on bowls because they know a side ground bowl gouge will out perform the SRG.

Safety should be number 1 in our practices and recommendations to those workin up to advanced levels of skills.
 
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This is the famous, or maybe infamous video by Ian "Robbo" Robertson of Australia, some 8 or so years ago. Notice when he is turning from the side/line of fire, he has the tool rolled onto the side, which prevents a catastrophic catch. If it was in standard 'peeling cut' orientation, flutes straight up, it would have been a major catch, which is obvious to most. When he goes to normal bowl presentation, he is using a standard 'peeling' cut, which is fine on spindles, which are usually smaller diameter. With the peeling cut, the bevel is rubbing, which is a controlled cut. He does make the comment near the end of the clip that he spent some hours in the shop the night before trying to get the catch but didn't. He does get the catch at about 2:45. If you look closely at it, you will see that he extends out too far off of the tool rest, and biggest mistake is that he raises the handle, coming off the bevel, and since the cut is no longer supported, the edge digs in. Some think nothing of doing a peeling cut with a SRG on bowls, but would never try that bevel rubbing cut with a scraper because we all know that you always point a scraper down. Rolled onto the side, you can get a high angle shear cut on the outsides of bowls. Pointing up into the spinning wood and rubbing the bevel, well it does work, but if you come off the bevel the edge digs in instantly and you have a huge problem.... Robbo also does the best 'how to take your chucks apart for cleaning and putting them back together' video I have ever seen, for Vicmarc and Nova chucks... There are some who use a similar peeling cut with more standard bowl gouges on the inside of a bowl where they are cutting with the up hill wing. Again, this is fine as long as you don't come off of the wing. That potential for the huge catch is why I don't use that cut or teach it.

View: https://www.youtube.com/watch?v=IOhHeyoZLaY


robo hippy
 
Karl Loeblein said:
what makes an SRG inherently more dangerous than other sharp angled turning tools like a skew (made from flat stock the same thickness as an SRGs)?
Click to expand...

A skew should not be used on face grain work either.

What makes an SRG so dangerous is the wide U flute. When wood drives over the cutting-edge the cutting edge is prone to bury itself to the full width of the flute. Tearing a 1.25 “ or a 3/4” width of wood free when the gouge is deeply imbedded creates forces that break the tool, bend the tool break the tool rest, break the banjo instead of breaking the wood free.

A catch with skew most of the time pushes the cutting edge along the turning making a spiral gash on the turning but not trapping the tool edge in the wood. Damage is nearly always confined to the turning.

A bowl gouge catch - the narrower flute, thicker steel walls, and often a steeper bevel takes much narrower and less deep bite out of the wood. Typically a 1/4” to 3/8” bite of wood which will usually tear loose damaging only the turning.
 
Thank you to those who have responded. Although I sometimes use a 25-mm P&N roughing gouge (which has a 10-mm-diameter tang) for fine finishing cuts on the outsides of bowls, the thrust of my originating post is that most brands of roughing gouge have tangs which are too weak for roughing spindles. The tangs of the two I broke shattered when I was turning pine with hard knots. The other two tangs broke when my staff were turning hardwood (about 60 lbs per cubic foot) columns about 15 feet long. Certainly we turn with longer overhangs than many, and if you're turning large diameters with pommels, this can be unavoidable, but my point is that the tools should be designed to suit turners, turners shouldn't have to compromise and turn timidly because manufacturers can't be bothered to produce properly stiff tools.The raison d'etre for woodturning is speed of production (anything we can turn can be carved). This requires heavy cuts. Therefore I reject the safety drives which Timothy White advocates because they produce turners who are frightened to take proper, deep cuts.

Another point is that tangs on most wide tools are unnecessarily narrow. Resulting skews may not may fail, but don't feel stiff. Turn with a 6-mm-thick 25-mm-wide skew, and one with the same width but 8-mm-thick, and you'll feel the difference. And why are tangs weak? Because manufacturers cut too much metal away, not because they would have to add metal in the tang region, to suit the overly small-diameter hole they persist in boring into handles.

We should be more critical of suppliers. Let's not forget that HSS was fully developed by 1905 (by Taylor and White in Philadelphia), yet wasn't introduced into commercially-manufactured hand woodturning tools until the 1970s.
 
Mike Darlow said:
We should be more critical of suppliers. Let's not forget that HSS was fully developed by 1905 (by Taylor and White in Philadelphia), yet wasn't introduced into commercially-manufactured hand woodturning tools until the 1970s.
Click to expand...

Although Bethlehem Steel was the first to use the name high speed steel, its origin actually began many decades earlier as mentioned in this brief timeline of HSS. HSS is a subset of tool steel which was used to make turning tools in the earlier part of the twentieth century. Various forms of tool steel have been around for several centuries. I could hazard some thoughts as to why it took so long for HSS to be introduced into woodturning.
  • First I wouldn't be surprised if resistance against change didn't have a lot to do with it. It seems like especially in Europe that woodturning was still stuck in the guild mindset with rigid rules of only one way to do things.
  • Until recently, woodturning was essentially production work of utilitarian pieces and architectural turning. And automation was rapidly turning production woodturners into dinosaurs.
  • The market for woodturning tools was so small and dwindling that there was no incentive to come up to speed with the way that the rest of the world was operating.
Almost serendipitously it seemed like the renaissance in woodturning came about because of its emergence as an art form and as a very attractive hobby which in turn led to opportunities for someone to build a better mousetrap ... and turning tools. This seems to be a particularly good time for many craft hobbies, not just woodturning.
 
"automation was rapidly turning production woodturners into dinosaurs."
Can I be a T. rex?
FWIW, resistance to change is a factor, IMHO, that creates a comfort zone. My father was an ME in the appliance industry. It used to raise his blood pressure when someone would say, "We've always done it that way." Even when shown another way, there was the negative attitude about the new way.
 
I think Bill has it right. I would posit that hss was used for woodturning early in the 20th century, but as tool bits in more automated lathes vs a person holding them. It probably took 2 things to happen for hss to come to handled lathe tools:

1) After decades of development hss production methods got prices down for larger pieces (vs bits)

2) The growth of the middle class after WWll and increasing leisure time and discretionary $, allowing more people to have hobbies, of which turning was one
 
Mike, Someday I'd like to replace my old SRG (from flat stock) with a safer design so thanks for starting this topic because. No doubt SRGs designed from flat stock with thin tangs can be dangerous in beginners hands, but I'm not ready to toss the baby out with the bath water just yet. Maybe what needs to happen is for AAW members to push manufactures toward a safer design.

In this regard, does anyone have experience using the Carter&Son SRG that I previously mentioned?

Here's what I notice when visually comparing the C&S SRG with other designs like P&N:



    • Second, the shoulder where the gouge joins the tang hasn't been cut down. This adds extra support where it's most needed.
    • Third, the C&S sides don't look as tall/steep. This lower profile might prevent the wings from catching on wood as much.
P&N
P&N_SRG.png

C&S
C&S_SRG.png

C&S gouges are expensive, but maybe they might be worth saving up some funds if it's safer.
 
Dont forget the Thompson SRG. Tang is full thickness on that one. Couple that with the edge holding of that metal and you have a tool that will last a lifetime.
 
FWIW, I was at the Louisville Slugger plant in KY a few weeks ago. There was a demo on turning a bat on a lathe as in the olden days. The fellow told me he used Sorby tools. Had a C&S he was trying but said it was prone to catches, unlike his Sorby tools. Have a one minute video- h e used a roughing gouge to turn the bat. Will try to download it. BTW, interesting place. Used to take over 30 minutes to turn a bat. Now it is less than a minute- all automated machinery. Can't take photos in the plant for the privacy of the employees. I wouldn't think the machinery would be a secret as any company worth their salt could design the machinery.
 
Bill Blasic said:
I believe I said that about 15 posts ago. I personally would never buy a c&s tool of any sort.
Click to expand...

Does you concern with C&S tools anything to do with the design aspects that I'm wanting to discuss?

I intended to also bring up the Thompson SRG that John mentioned above, but Thompson's website lacks any detail information to post. Still I've heard nothing but great things about Thompson tools so let's discuss the safety aspects of his SRG design if desired.
 
I finally found the Louisville Slugger video. If you look under the end of the model bat, you will see the silver handle of the C&S gouge. I still can't find the video! I can find it on my phone and pinpoint the two photos one either side of it but it's not in my Picture folders.
Finally found it but states it's too large. Thumbnail w ill have to do.
 

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Karl Loeblein said:
Does you concern with C&S tools anything to do with the design aspects that I'm wanting to discuss?

I intended to also bring up the Thompson SRG that John mentioned above, but Thompson's website lacks any detail information to post. Still I've heard nothing but great things about Thompson tools so let's discuss the safety aspects of his SRG design if desired.
Click to expand...
FWIW: Tangs are flat Shanks are round. C&S both have shanks the Thompson has a 3/4” shank not sure what size the C&S shank is.
No matter how strong the tool is, hag it too far over the tool rest and a catch is inevitable. The momentum created by the spinning of the post is significant get a catch something is going to give.In my opinion an SRG (Tang or Shank) should not be extended over the tool rest more than 1/3 the length of the bevel.
C&S makes good tools sharpened properly and asked properly the SRG you pictured will last a lifetime.

I am a Thompson tool guy. But he isn’t the only one that makes good tools
 
Timothy White is wrong on two counts.
1. A catch occurs when the forces on a tool tip aren't in equilibrium. The main force the hand turner needs to apply is axial thrust. If you apply the appropriate amount, the forces on the tool tip are, ignoring rotational forces, in equilibrium, and theoretically you can turn at any overhang. Thus I can readily turn beads with an overhang of 6 inches. What is correct is that as the overhang increases the effect of a loss of equilibrium is more obvious and serious, and the likelihood of not maintaining equilibrium increases.
2. When I teach a class spindle turning we use 3 inches x 3 inches square stock. After roughing for the first time someone always moves the toolrest forward to minimise overhang. I then insist the toolrest is returned to its original position. I explain that continuously moving the toolrest forwards slows production, is unnecessary if you apply an appropriate axial thrust, prevents one seeing the top and bottom of the workpiece and thus makes it more difficult to monitor the diameters and forms you're attempting to turn, prevents one using the tied-underhand grip for turning details, and means that when you're forced to turn at longer overhangs (say by the presence of pommels) your unused to applying sufficient thrust and instead undesirably rely on leverage.

A clarification regarding HSS. Taylor and White's breakthrough was not in improving the alloying composition of tool steels (that had basically been achieved by Mushet and Koller), but in discovering the beneficial effects of an extreme form of heat treatment which it had previously been assumed would render the steel useless.

A roughing gouge can be an excellent finishing tool, especially if honed. Some brands of blades look very short which prematurely makes honing difficult.
 
A large number of wood turners are what you would consider amateur and they are taught the safest way to work on a lathe. As their skills increase over time and other techniques are learned from more skilled professionals the wood turner will usually identify there limitations compared to a total novice that does not have any experience or knowledge to identify a safe or unsafe turning method. We live in a very litigious society these days and teaching someone a higher risk technique opens up the concern of liability when an amateur has an accident. Another problem with a large number of wood turners is the time they devote to wood turning on a regular basis, if you do not spend time with the tools on a daily or weekly basis your skills become questionable and it takes time to regain muscle memory and skills mastered by repetition with handling the different tools on a regular basis. There are plenty of turners that do not have the mental focus required to employ a turning tool with a large overhang on the tool rest without running the risk of a tool catch. Even an experienced wood turner having a bad day working for too many hours can lose mental focus easily and have a bad tool catch.
 
John Torchick said:
I finally found the Louisville Slugger video. If you look under the end of the model bat, you will see the silver handle of the C&S gouge. I still can't find the video! I can find it on my phone and pinpoint the two photos one either side of it but it's not in my Picture folders.
Finally found it but states it's too large. Thumbnail w ill have to do.
Click to expand...

I've been working to disable loading videos directly to this site, but I am not completely there yet. The reason is that videos use a lot of server disk space. It would be much better to upload the video to YouTube or Vimeo and then just link to it in your post.
 
Mike Johnson correctly describes one of woodturning's dilemmas: people want the gain without the pain of having to devote about 40 hours to the disciplined learning and practice which will give them the basic skills. There is then the second dilemma that much of teaching and information on basic techniques is suboptimal.
 
Bill, as some one who posts videos here on occasion, I can understand how they take up a lot of room. So, rather than have the whole video up, can it be done with just the link? Over at Woodturner's Resource, they have one section just for videos, but it has been rather dead lately. I hope to have a bunch of new videos coming out later this year. Still trying to get the new shop some what organized...

robo hippy
 
robo hippy said:
Bill, as some one who posts videos here on occasion, I can understand how they take up a lot of room. So, rather than have the whole video up, can it be done with just the link? Over at Woodturner's Resource, they have one section just for videos, but it has been rather dead lately. I hope to have a bunch of new videos coming out later this year. Still trying to get the new shop some what organized...

robo hippy
Click to expand...

Since you upload your videos to YouTube, they basically don't take up any space here other than a few bytes for the link.

I'm still trying to get the old shop organized ... but I'm losing ground.
 
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