Teknatool chucks not suitable to woodturning.

[Lennart Delin]

I looked at the manual for Teknatools jaws. https://www.teknatool.com/wp-content/uploads/2018/04/Accessory-Jaw-Manual_June08.pdf

Very few jaw sets have a maximum speed above 684 rpm, so obviously they cannot be recommended for woodturning. Any comments?

 

[Richard Coers]

Lawyers recommendations and woodturners recommendations are evidently not close to each other.

 

[Mark Jundanian]

I agree with @Richard Coers.
It's as if a swimming pool had a warning label: "do not get wet".
The same company makes lathes that turn 3000 RPM.

 

[Jon Rista]

Yeah, legal vs. in practice conflict here? These probably greatly limit Nova's exposure to legal issues, even though its highly doubtful that any chuck's jaws would fly apart at 1500, 2000 rpm?



FWIW, is expansion the primary use case? When I first started turning, I used mortises, I guess because that was how many of the videos I learned by did things.

I learned a lot from Kent Weakly's site and videos, and he explained the nature of expand into a mortise vs. contract onto a tenon, and when I have the option, I will usually choose tenon and that compressive force. Sometimes, depending on the design of a platter, I'll mortise, just because the design of the foot necessitates it....however, I often turn those at 1500rpm or thereabouts... I am usually using 75mm or 100mm Nova jaws...

Also FWIW, I tend to keep the tail stock in play until I plain and simply cannot anymore, and if necessary a steady rest, so its not that often that I'm spinning anything at high RPM without additional support.

 

[John Whitley]

I'll also note that a minor irritation of mine with otherwise excellent Nova drill presses and lathes are the startup "lawyer screens" which waste the user's time with mostly pointless safety admonishments, etc. As if adding a screen to a thing immediately obligates the maker to add this text, as compared to every other piece of equipment in history. It was such a dumb relief on my Nova Galaxi when I decided to turn off electric braking, which made the related startup warning go away. I'd be more sanguine about it if I could at least go into the device settings and turn off those screens.

No, I think that Teknatool just got bad legal advice.

 

[John K Jordan]

I'll also note that a minor irritation of mine with otherwise excellent Nova drill presses and lathes are the startup "lawyer screens" which waste the user's time with mostly pointless safety admonishments, etc.

And that can’t be turned off? Note to self: never acquire such a machine.

 

[Doug Freeman]

I'll also note that a minor irritation of mine with otherwise excellent Nova drill presses and lathes are the startup "lawyer screens" which waste the user's time with mostly pointless safety admonishments, etc. As if adding a screen to a thing immediately obligates the maker to add this text, as compared to every other piece of equipment in history. It was such a dumb relief on my Nova Galaxi when I decided to turn off electric braking, which made the related startup warning go away. I'd be more sanguine about it if I could at least go into the device settings and turn off those screens.

No, I think that Teknatool just got bad legal advice.

And that can’t be turned off? Note to self: never acquire such a machine.

The Galaxi “plays a little tune” as the system boots when main power is applied, and during this time a few screens scroll by. Don’t know if the screens extend the system boot time or not. I love the e-brake on the lathe, so never investigated what happened with it off. Not a big deal to me, turn the main power on, go do other things that have to be done before turning, push one button, and the lathe is ready.

 

[John Whitley]

And that can’t be turned off? Note to self: never acquire such a machine.

It bugged me more on the lathe, fwiw. but was still just a nit. Not even close to stopping me from (trying) to get a Nebula before that all went haywire w/ the Teknatool USA issues. Hilariously, my new Harvey T-60S clearly also has a measure of electronic braking... but no screen for a dumb warning!

The drill press also has some dumb warnings, but those are less irritating. They only happen once when the main power switch goes on, i.e. just once a day (less if I forget to turn it off! ), and are both ignored and done by the time I'm ready to get a bit in the machine. I forgive the drill press that because it's otherwise by far the best I've ever used. I happily accept that nit e.g. over the big Powermatic variable speed's fussy as heck CVT system and belts any time. (Talk about time wasted....)

 

[John Whitley]

Not a big deal to me, turn the main power on, go do other things that have to be done before turning, push one button, and the lathe is ready.

This ^. I don't want to overstate this issue... just pointing it out to illustrate that Teknatool has had some IMO poor legal advice that relates to OP's observation about ridiculous chuck speed limits.

 

[hughie]

I looked at the manual for Teknatools jaws. https://www.teknatool.com/wp-content/uploads/2018/04/Accessory-Jaw-Manual_June08.pdf

Very few jaw sets have a maximum speed above 684 rpm, so obviously they cannot be recommended for woodturning. Any comments?

View attachment 74903

Well as the owner of several Nova SN2 chucks I have never had an issue with any of them. I might point out the 684rpm is in expanding mode, something I rarely do and when I do I have a specific chuck designed for expansion gripping. I read the spec on the chucks when I started out and promptly threw it out, recognizing what it was saying and where it was coming from.

In this fast past world of the internet and impossible amounts of information, where it seems taking responsibility for ones actions is rare, we have also lost the value of common sense. The end result is we have to give warnings on everything for the fear of successful litigation that would break anyone of us let alone a business venture.

Basically its catering to the lowest common denominator, for many years I managed a engineering workshop where safety was paramount and we had courses, signs and all manner procedures. We in fact adopted the DuPont system PSM which proved to be highly successful. But there were some who thought more was needed, so I suggested locking the workshop door indicating this was the only sure fire way of success.
The bottom line is adequate training on the job by confident qualified instructors will alleviate these issues, but personal responsibility never goes way, you can lead a horse to water but you cant make it drink.

 

[William Rogers]

Everyone seem to jump to “lawyers”. I no longer own any Nova chucks, but when I did I saw the speed chart. As an engineer it made me suspect their design may be at risk at higher speeds. Also as an engineer it seemed very unlikely those speeds were really correct except for maybe some of the speciality jaws. Most of the manufactures of Cole jaws have a 600 rpm limit. I find it somewhat odd their Titan power grip jaws are limited to 400 rpm. My take is they are taking into account for poor tendon or irregular shapes since they don’t control how we use them.

 

[Doug Freeman]

Very few jaw sets have a maximum speed above 684 rpm, so obviously they cannot be recommended for woodturning. Any comments?

Yep, liability cya. I use the g3 and several different jaw sets up to 1500rpm all the time. A couple of the smaller jaw sets I use up to 2500rpm (small dia spindle stuff).

 

[Mike Selser]

And that can’t be turned off? Note to self: never acquire such a machine.

Can you even buy a car or truck these days that don’t have such warnings?

 

[Jon Rista]

Can you even buy a car or truck these days that don’t have such warnings?

They are just as ludicrous in cars and trucks. The single most annoying thing my Acura does, is show its darn warnings EVERY SINGLE TIME I turn on the car. It doesn't just show me the map, it shows me a warning, and it doesn't just flash, it sits there until I acknowledge it. Its a symptom...this country is so deeply steeped in ridiculous laws, legal issues, loopholes, and CYA...because we've made this a litigation heavy society... There is common sense, then there is lawyer sense, and the latter is generally designed to CREATE PROBLEMS, not solve them, IME.

 

[Richard Coers]

Everyone seem to jump to “lawyers”. I no longer own any Nova chucks, but when I did I saw the speed chart. As an engineer it made me suspect their design may be at risk at higher speeds. Also as an engineer it seemed very unlikely those speeds were really correct except for maybe some of the speciality jaws. Most of the manufactures of Cole jaws have a 600 rpm limit. I find it somewhat odd their Titan power grip jaws are limited to 400 rpm. My take is they are taking into account for poor tendon or irregular shapes since they don’t control how we use them.

What makes you jump on the engineers? You really think that chuck is so bad you have to spin it slowly? Also it totally ignores the species of wood. A gross negligence to think red cedar and white oak have to spin the same speed when you use the chuck in expanding mode. No engineer would ignore that variable in the design.

 

[Lennart Delin]

I have for a long time got the impression that Nova chucks were considered very good chucks.

Is the quality so extremely poor, in which case there should also be a warning to only tighten the jaws very lightly, otherwise they may crack. The other possibly is that the manufacturer has no understanding of his own product. Neither seems likely to me. In their product catalog there is no mention of these speed limitations. https://www.teknatool.com/wp-content/uploads/2024/08/2024-Nova-Product-Catalog.8.1.24.pdf

My conclusion is that the company has badly injured itself by misleading jurists, trying to protect it from the American suing lunacy. May be that also contributes to the Ch 11 bankruptcy discussed in another thread.

In either case my conclusion is that I cannot recommend others to buy these jaws as long as these speed recommendations are not withdrawn.

May be someone from AAW should contact Teknatool to sort this out?

 

[William Rogers]

What makes you jump on the engineers? You really think that chuck is so bad you have to spin it slowly? Also it totally ignores the species of wood. A gross negligence to think red cedar and white oak have to spin the same speed when you use the chuck in expanding mode. No engineer would ignore that variable in the design.

You didnt read my post correctly. I did not jump on engineers, I am an engineer. Also I said it didn't make sense to me in so many words why the speeds are low like their power grip jaws having a lower speed than Cole jaws. That doesn’t make sense. I am not sure what you think you read, but no where did I say anything about ignoring anything.

 

[Bill Blasic]

Sometime I just wonder why? Number 1 I have never heard anywhere of jaws flying off of any of the big named chucks except once on a Oneway chuck where the person pulled that safety pin out. Number 2 I generally never turn slower than 2000 RPM and usually faster as long as the piece is reasonably round and the last of my worries in turning is the chucks and that is with any of the brands I have. I remember my first Cincy symposium in 2005 where I first saw Jimmy Clewes turning with very high speeds (Like a airplane propeller) where he did the same thing in my shop and at my club. Number 3 I'll bet that those numbers associated with those chucks jaws are in conjunction with the thought of whoever wrote them about having pieces in them while turning because with the chuck all alone (no wood on them) on your lathe with any speed (fastest) those jaws are not going anywhere even if that lathe was spinning at 4000 RPM for 50 years. All you have to do is use common sense in your turning and turn at a speed you (not me or anyone else), yes you feel safe and not worry about numbers on a page that may have been written by someone who has never turned on a lathe. Now just as an aside I turn a lot of small hollow forms and it was not unusual for me to be hollowing them at the fastest speed the lathe has. Now if I went for very thin at those speeds certain woods will flex and it would not be unusual to have a piece that is 50 thou thick in one place and 90° it is only 15 thou thick. Again common sense, I have never had one explode but wood doing that can. Now as I use my Hunter carbides more and more I don't turn that fast as with the scrapers which worked better at high speeds.

 

[Bryan Field]

I use Teknatool Nova chucks exclusively. I use Kent Weakley's speed chart , so often run the chucks at greater than Teknatool's recommended speeds and have never had an issue with bowls flying off. As always, use common sense. I turn pens too, and often run the lathe (a Nova Nebula) at over 2,000 RPM. As a teacher I stress to my students the importance of a well made tenon.

 

[John K Jordan]

I looked at the manual for Teknatools jaws. https://www.teknatool.com/wp-content/uploads/2018/04/Accessory-Jaw-Manual_June08.pdf

Very few jaw sets have a maximum speed above 684 rpm, so obviously they cannot be recommended for woodturning. Any comments?

As someone noted, most of the slower speeds in the Accessory Jaw Manual are for expanding into recesses. But even the compression grip speeds don't make sense for some work.

One thing the Supernova 2 manual points out is "Speed will vary with wood blank size... Consult your lathe manual ... for speed guidelines."

For several reasons I almost exclusively expand jaws into recesses for face turning (bowls, etc). Off the top of my head, here are some factors I consider when judging how well a given jaw set will hold at a given speed:

• the type of wood (e.g., basswood vs persimmon)
• the integrity of the blank (punky, cracks?)
• dry wood or green?
• the grain orientation of the blank (I almost never use a recess for end grain turning)
• the the amount and shape of the solid wood outside the recess
• the size of the blank, both diameter and height
• the balance of the spinning blank, and
• whether the blank is also supported by the tailstock
• shape of the recess and the outside of the jaws (!!)
• the diameter of the recess relative to the diameter of the jaws (nearly closed holds far better in recesses then nearly open)
• the type of and size of the tool (i.e., small/narrow cutting edge contact vs large/wide)
• the type of cut - hollowing end grain, outside of a tall vase? (again, supported by tailstock or not)
• the skill of the turner (prone to catches?)

Under some circumstances and with some wood, I think a recess can hold better than a tenon (again, for face turning).

If I decide the conditions are right, I turn a fairly high speeds. I will often turn balanced 8-12" bowl/platter blanks, 6/4-10/4 at far over the speed numbers in Telnatool's chart. (For face turning, I like to start with a blank cut round on the bandsaw rather than a large, unbalanced chunk.) And I can't forget what the other John Jordan said: "Life's too short to turn crappy wood." No disrespect intended for those who enjoy turning big wood with questionable integrity, but for me some wood is better cut into smaller pieces or split and fed to the fireplace.

I also turn at relatively high speeds for compression grip on a tenon on a balanced blank of good wood.

For compression grip on spindles, up to 3" or so, gripping a tenon or the square blank directly (depending on length. with tailstock support or not), and depending on the tool and type of cut I often turn wide open after the blank is round - over 3000 rpm on my lathe - it's easier to get a clean cut and minimize sanding. If the wood and technique are good there is no reasonable chance of the piece coming out of the jaws or even breaking. My personal guideline is "turn fast, sand slow".

For those beginning, I recommend:

• Turn at slower speeds and with smaller wood while developing expertise. (proceed with patience)
• Support with the tailstock when possible and practical.
• Stand out of the "line of fire" when turning the lathe on and increasing the speed.
• Back off the speed if getting significant vibration.
• Learn techniques to balance a blank when mounting and turning.
• Learn methods of using tools that don't put excessive forces on the wood at the mounting point.
• and of course, join a club and watch demos, take classes, find a mentor, and read good books!

And regardless of the speed or type of turning, always use the appropriate face/eye protection!

JKJ

 

[Alan Weinberg]

where I first saw Jimmy Clewes turning with very high speeds

When I think of Jimmy—after two classes with him—I always think of him saying, “faster, faster, faster.”

 

[Russell Nugent]

I have for a long time got the impression that Nova chucks were considered very good chucks.

Is the quality so extremely poor, in which case there should also be a warning to only tighten the jaws very lightly, otherwise they may crack. The other possibly is that the manufacturer has no understanding of his own product. Neither seems likely to me. In their product catalog there is no mention of these speed limitations. https://www.teknatool.com/wp-content/uploads/2024/08/2024-Nova-Product-Catalog.8.1.24.pdf

My conclusion is that the company has badly injured itself by misleading jurists, trying to protect it from the American suing lunacy. May be that also contributes to the Ch 11 bankruptcy discussed in another thread.

In either case my conclusion is that I cannot recommend others to buy these jaws as long as these speed recommendations are not withdrawn.

May be someone from AAW should contact Teknatool to sort this out?

Personally I don't spend too much time worrying about these types of things. They are in there to protect themselves from stupid people(we've all seen pictures and heard stories, like the guy who had an itchy nose, stuck the power drill up with a bit and pulled the trigger). The stupidity of humans knows no bounds so I don't judge companies to much when they put in things like that.

 

[robo hippy]

Comedy spot for this morning.... I have only had lathes with speed read outs in the last few years, they were never standard in my earlier years. This means I NEVER check my rpm. Some times I do for videos though since that is some thing people always seem to ask. I find the "compression" and "expansion" to be confusing, at least to me. The wood is under compression no matter what you do with the chuck. One is pushing in, the other is pushing out, which to me is the same difference. Both recess and tenon hold equally as long as they are made properly, and I have torn bowls off my lathes in both methods. I would say that I don't use a recess on end grain vessels though. I mean, how many actually read all the "legal" stuff that comes with your products?

robo hippy

 

[Lennart Delin]

The more I think about it, the more ridiculous or rather idiotic, I find the chart. I choose the speed that seems comfortable to me. As an example, let´s say I have a 25 cm bowl for which I may go up to 1000 rpm. I like small feet so I could choose 50 mm jaws, which would the be OK according to the chart. However, if I wanted a big foot I might go for the 130 mm jaws , which I suppose everybody here would agree will be much safer, the chart says max 400 rpm.

 

[Bryan Field]

THe trick about the chart is that it assumes the blank will come out of the chuck. If it does, the RPM dictate whether the blank will fly towards you, or away from you. I'd prefer that it flies away from me, so that's why I use the chart.

 

[Bill Blasic]

THe trick about the chart is that it assumes the blank will come out of the chuck. If it does, the RPM dictate whether the blank will fly towards you, or away from you. I'd prefer that it flies away from me, so that's why I use the chart.

Bryan that's all well and good until the predicted results don't end up like the real results Stay safe.

 

[William Rogers]

Most of us are familiar with the 9000/6000 guidelines where 9000/diameter indicates the maximum safe turning speed. (Not sure where that guideline originated, but has been around for many years.) Also in the Technatool manual they list the maximum diameter of the for bowls, spigots, and platters for their jaws. Looking at the contracting mode, the 75mm bowl jaws it list a diameter of 14” Applying the 9000 rule that would be 9000/14” = 642.857” rpm that is less than the 1020 rpm listed for that jaw set. Their 100mm jaws (not labeled as bowl jaws) list the same 14” max diameter are rated at 684 rpm, still more than the 9000/6000 guideline. Looking at their Power Grip jaws the max diameter is listed at 16”. Using the guideline 9000/16 =562.5 rpm, again lower than their rated 684 rpm. Now I would likely use the 75mm jaws on a smaller diameter bowl say 10” allowing 900 rpm and their 684 rpm would seem way low for that size bowl. Doc Green’s speed chart below is in line with the 9000/6000 rule and shows the speeds in relation to the size. My conclusion is Technatool gives the maximum speed for the maximum diameter work piece for those two jaw sets in line with the 9000/6000 guideline. II didn’t check any of the other jaws.

https://www.teknatool.com/wp-content/uploads/2018/04/Accessory-Jaw-Manual_June08.pdf

Lathe Speed

Doc Green's woodturning tips.

www.docgreenwoodturner.com

 

[robo hippy]

The problem with it flying towards you or away from you makes no sense to me. I do make a point to stand out of the line of fire, at ALL times. The bowl is going to fly in which ever direction it wants to...

robo hippy

 

[Randy Heinemann]

Because I started out with a Nova lathe, I accumulated Nova chucks and jaws for my Nova midi lathe. When I moved to the Powermatic full-size lathe, I just kept using the Nova chucks because I had various sets of jaws for them, and even bought a larger Nova chuck. This kept all my jawsets compatible with my chucks. These chucks and jaws have never given me any problems. While they might not be the best on the market (although I'm not sure which ones are), they are ahigh quality and I have never had any complaints about them. The only time a blank loosened while turning was because I didn't get the face where the jaws sit against the blank flat. That is me and not the jaws or chucks.

 

[Lennart Delin]

The problem with it flying towards you or away from you makes no sense to me. I do make a point to stand out of the line of fire, at ALL times. The bowl is going to fly in which ever direction it wants to...

robo hippy

To summarize this. There is almost nothing in this thread that makes sense. I started with questioning speed vs jaw size in Teknatools descriptions, which is absolute rubbish in their documentations. The thread has later come to be a discussion of rpm vs diameter of turning, where my point is to use what you are comfortable with. Back to my original question. Teknatool publish a table of speeds that are absolutely rubbish. Should we dump Teknatool down the drain, or should we disregard this and still accept Teknatool as a serious manufacturer?

 

[Randy Heinemann]

Seems like an ultimatum...all or nothing. Continuing to use what you have or spending a lot of money replacing what you have is a personal decision. Why would I quit using them and spend upwards of a $1,000 to replace all my chucks and my jaw sets when I have never had any issues with these Nova chucks. Nothing has ever flown off the lathe unless I didn't get the tenon right. Other companies must also have listed max speeds. Now I certainly don't have as much experience as some others on this site do, but I'm not dumping what works for me and the Nova chucks/jaws I have work for me.

 

[John K Jordan]

Should we dump Teknatool down the drain, or should we disregard this and still accept Teknatool as a serious manufacturer?

Easier solution. I just trade their speed chart for common sense and carry on.

I keep 20 Nova chucks and I think have all their jaws. Couldn't be happier. (I recently bought two more but only because I gave two away.)

Anyone want a set of their 50mm jaws? I have extras since every chuck came with another set. Maybe I'll weld some together and make me some art.

 

[Jon Rista]

Most of us are familiar with the 9000/6000 guidelines where 9000/diameter indicates the maximum safe turning speed. (Not sure where that guideline originated, but has been around for many years.) Also in the Technatool manual they list the maximum diameter of the for bowls, spigots, and platters for their jaws. Looking at the contracting mode, the 75mm bowl jaws it list a diameter of 14” Applying the 9000 rule that would be 9000/14” = 642.857” rpm that is less than the 1020 rpm listed for that jaw set. Their 100mm jaws (not labeled as bowl jaws) list the same 14” max diameter are rated at 684 rpm, still more than the 9000/6000 guideline. Looking at their Power Grip jaws the max diameter is listed at 16”. Using the guideline 9000/16 =562.5 rpm, again lower than their rated 684 rpm. Now I would likely use the 75mm jaws on a smaller diameter bowl say 10” allowing 900 rpm and their 684 rpm would seem way low for that size bowl. Doc Green’s speed chart below is in line with the 9000/6000 rule and shows the speeds in relation to the size. My conclusion is Technatool gives the maximum speed for the maximum diameter work piece for those two jaw sets in line with the 9000/6000 guideline. II didn’t check any of the other jaws.

https://www.teknatool.com/wp-content/uploads/2018/04/Accessory-Jaw-Manual_June08.pdf

Lathe Speed

Doc Green's woodturning tips.

www.docgreenwoodturner.com

View attachment 74978

Hmm... I've seen a number of very well respected turners, including Jimmy Clewes and Stuart Batty, two that I probably learned the most from, turning at much higher speeds than this for large diameter items. The very first Batty video I watched, it was Batty on his 40/40 grind and turning with it. He made a number of comments about lathe speed. The first one, IIRC, was about the ~1000rpm "drop vs. fly" threshold. For "unsafe" things, such as rounding a bowl blank just between centers, he kept it below 1000, and his comment was it'll just drop if he pulled the tailstock off while it was running, but if he upped the speed to 1200rpm it would start to fly if he did that. Later on, he talked more about "road speed" of the blank at the outer edge of the radius. He started turning the blank, which is rather large, at the maximum speed for the given pulley, which was around 1200rpm, and described the road speed at the outer edge of the blank being "45 miles per hour" (like a tire on the road.) His comment in general was that you don't really care what the RPM is...you care what the "road speed" is for any given blank...the smaller the blank, the higher the RPM for a given road speed. Jimmy Clewes also usually turns his platters at around 1200rpm or so (sometimes even faster than that). Clewes ALSO talks about that outer radius speed. Another guy I learned from early on was Kent Weakly, and he also talked about never really being concerned about RPM, and instead paying attention to the speed of the outer edge of the blank, and that its a "feel thing." Batty and Clewes both talk about safety, and about always wearing a face shield, using a chuck and using it properly (i.e. not between centers...I've never turned a bowl blank between centers...I either use a woodworm screw or a face place), knowing the structural soundness of your blank (i.e. are there any cracks and where), etc.

Anyway, when I first started turning, I'd been watching videos for about a year or so, and most people started (and often fully turned) at pretty slow speeds...400, 600 rpm, maybe 800-900 for the "brave" ones. But then I got into platters, and started watching Clewes a lot....and that guy turns fast. I had also seen the Batty video, where he also turned at 1200rpm. One video in particular with Clewes, he was turning a square platter, and he ran at an rpm of (IIRC) 1600. I started upping the RPM as a result of all their videos, and learning their techniques, and turning became a lot simpler. The heavy "chunking" you get with the tool against an irregularly shaped piece of wood at low RPMs of 400-600, just vanished. The "air gap" became short, it was easier to maintain stability of the tool, and turning became a much faster operation overall...

How is it that some of the great powerhouse turners of the last couple decades, consistently and religiously turn at much higher RPMs than would be offered by the 9000/6000 rules? And their work is top notch, they both have turned 1000x more than I have for sure, they probably turn more than most turners in general (Batty at least, since he turned since he was 10 and it was his fathers then his business)...and if the risk was particularly high to turn a bowl at 1200+ RPM...statistically speaking, both of them should have been injured many times by now and one of them statistically should be dead....right?

Yet....

 

[hughie]

To summarize this. There is almost nothing in this thread that makes sense. I started with questioning speed vs jaw size in Teknatools descriptions, which is absolute rubbish in their documentations. The thread has later come to be a discussion of rpm vs diameter of turning, where my point is to use what you are comfortable with. Back to my original question. Teknatool publish a table of speeds that are absolutely rubbish. Should we dump Teknatool down the drain, or should we disregard this and still accept Teknatool as a serious manufacturer?

well part of your question is about dumping and most have indicated they like the Nova chuck, so that I would think is good enough answer, perhaps not the definitive answer you wanted. As to speed, yeah 684 is all they are good for according to Teknatool. I read that and thought yeah nah, and so I have ignored that advice for years. I think John kinda summed it up, well for me anyway " I just trade their speed chart for common sense and carry on."
For example many of the blanks I turn some folk think I'm crazy, but me, I'm happy in my crazy
Definitive answers in wood turning with regard to opinions, I reckon you have wade through them and make your own decision based your abilities and experience, well thats what I do. Its a bit like asking what the best grinding angle.

 

[William Rogers]

@Jon Rista It is a guideline, not a rule. It has been around for a very long time. When I first started I was aware of it and likely used those speed guidelines. I'm sure I now turn faster than the guideline most of the time, but not as fast as Jimmy or Stuart. The late John Jordan did a demo at our club and he said he never needed to go above 900 rpm. However I don’t have any Nova chucks. Mostly Axminster and one Hurricane 125, and a OneWay Talon. And as far as I know, they don’t have any published speeds. Technatool published specs, but didn’t explain anything. I can understand their numbers if it is related to the maximum diameter of the work. So I take their numbers in that regard and don’t consider their specs rubbish. Diameter vs. rpm does matter to me as I would turn a 6” bowl a lot faster than a 16” bowl. Nova chucks and spec have been around for a very long time and work well for wood turning.

 

[Jon Rista]

@Jon Rista It is a guideline, not a rule. It has been around for a very long time. When I first started I was aware of it and likely used those speed guidelines. tI’m sure I now turn faster than the guideline most of the time, but not as fast as Jimmy or Stuart. The late John Jordan did a demo at our club and he said he never needed to go above 900 rpm. However I don’t have any Nova chucks. Mostly Axminster and one Hurricane 125, and a OneWay Talon. And as far as I know, they don’t have any published speeds. Technatool published specs, but didn’t explain anything. I can understand their numbers if it is related to the maximum diameter of the work. So I take their numbers in that regard and don’t consider them rubbish. Diameter vs. rpm does matter to me as I would turn a 6” bowl a lot faster than a 16” bowl.

Yeah, I heard about the guidelines when I started as well. Granted, that was only five years ago...

Regarding "speed"...I think that is exactly what Batty gets to in his video (I'll find the link)...RPM is technically not speed! Thats' where the "road speed" comes into play, which would be the rotational velocity of the surface of the blank. A 6" bowl would require a higher RPM, for its surface to move the same speed as a 16" blank at a lower RPM. I think that's why Kent Weakly frequently discusses the "feel" of the speed of the blank, and IIRC his lathe's RPM readout is broken (or maybe he manually disconnected it), because he prefers to dial in the feel of the right speed, rather than be concerned with RPM.

I also don't know enough about the ~1000rpm "drop vs. fly" cutoff...I am not sure if that is purely an RPM thing, and at that RPM a blank of ANY size would fly? Or if it depends on the radius of the blank... In any case, I tend to turn at around 1200rpm for bowls or platters in the range of 10-14" (I don't have many much larger than that, TBPH).

Something else, too...I used to have a Laguna lathe. I was quite enamored with their PWM technology at first, however...in practice, the nature of their PWM drive left me feeling LESS SAFE at any RPM, than any other lathe I've used. The Powermatic uses a VFD, and while a VFD internally relies on a PWM as well, the actual output signal is smoothed into a more natural sine wave. My experience has been, I feel FAR more comfortable and safer turning at 1200-1300rpm or so, with a 10-14" blank, than I ever did turning anything on the Laguna even at 900-1000. The PWM on the laguna had no smoothing, so the stepped nature of the PWM was directly applied to the spindle and thus the blank. When you touched the tool to the wood, that changes the load, and the RPM would adjust. With the Laguna, you would feel a sudden slowdown, then a rampup in speed, then a small ramp down in speed, as the lathe adjusted its PWM to try and update the power to continue delivering the same RPM. With the Powermatic, I've NEVER felt that same kind of jolting RPM change. I can momentarily hear a change in the motor, but the response is far more natural and I have never had any issues turning at higher RPM. The Laguna, I eventually just stopped turning bigger items on it...just never "felt" safe given its unnatural response to changing load.

Anecdotal, I know...but, I wonder, if maybe that might play into who considers what speeds to be safe and reliable?

 

[Jon Rista]

FWIW, here is that Stuart Batty video. I thought it was quite good, and had some great info on lathe speeds:

View: https://youtu.be/N7BjRcSDurM?t=1043


I've linked it around the time he starts talking about turning speeds. He mentioned he began turning at 10, and due to the "pay situation" he decided to try something new and learn a way to turn more bowls faster, since his father paid him on a per bowl basis. The rest is quite interesting. I'm sure many of you know all of this already, but since this thread is pretty much about turning speeds, what's safe, etc. Batty has some really interesting comments on the subject.

 

[Rusty Nesmith]

I would be willing to bet Jimmy Clewes has never read that.

 

[Russell Nugent]

To summarize this. There is almost nothing in this thread that makes sense. I started with questioning speed vs jaw size in Teknatools descriptions, which is absolute rubbish in their documentations. The thread has later come to be a discussion of rpm vs diameter of turning, where my point is to use what you are comfortable with. Back to my original question. Teknatool publish a table of speeds that are absolutely rubbish. Should we dump Teknatool down the drain, or should we disregard this and still accept Teknatool as a serious manufacturer?

Many of us have nova chucks. Many of us looked at the speed guide once(let's be honest, the entire manual) and never thought of it again. If you want to start a campaign against Teknatool I guess feel free but the number of people who have and are happy with nova chucks sort of says they are and will be a serious tool manufacturer.

 

[Doug Freeman]

Teknatool publish a table of speeds that are absolutely rubbish. Should we dump Teknatool down the drain, or should we disregard this and still accept Teknatool as a serious manufacturer?

Do what you want. I’ll keep using my Nova chucks and jaws without regard to the Nova docs for rpm. As an engineer I knew exactly what the Nova speed charts were the moment I saw them, liability coverage, not limits of the product.

As for speed, I’ve always turned with regard to surface speed, a fundamental principle in any machining (we are machining wood, or plastic, etc.). A line graph/chart hangs behind my lathe, dia vertical axis, rpm horizontal axis. There are 4 lines plotted - the 6000 rule, the 9000 rule, Batty’s “40 mph” limit, and Batty’s “45 mph never exceed” limit. I insist on knowing what rpm I’m turning at, so that I know where I am in relation to the 4 lines plotted on the chart.