What is Zero Torque? A Putter Torque Analysis. LAB, Axis1... A Call to Engineers

[joostin]

Update 3/2/24.  Linking post from another thread:

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Update: For putter torque analysis diagrams, see the post linked from down in this thread:

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I posted this in @Nels55's thread, and figured it could make for its own.

 

It's all about the putter head's CG location and where the shaft axis is in relation to it.

 

Zero torque (or low torque) means the shaft axis crosses directly with the CG.  It's that simple.  Zero torque as far as rotation around the shaft axis.  There's no moment arm from the shaft axis to the CG.  If you simply get that axis inline with the CG (yellow dot below on the 1st Mezz pic), then you can balance it toe up, face up, any toe hang angle, or even spin it like LAB in does this video .

 

Technically "Lie Angle Balance" can mean the same or also if the CG of the putter head is directly below (green dot on the 2nd pic) or even directly above (purple dot) where the shaft axis intersects with the head, when you hold the putter toe up and face square to target.  Then you can balance it like @SeeMore Putters does in their video.

 

Zero torque CG location:

 

CGs below are still "lie angle balanced", toe up, or 90° toe hang:

 

You can manipulate any putter like this by modifying where the main shaft axis crosses in relation to the CG.  It doesn't have to be a funky shaped putter.  As for normal "face balanced" putters, simply move the shaft axis directly to the left (or right) of the CG.  Whether the shaft is straight in, double bend, rear mounted, whatever... it's all about the relationship of the main shaft axis and CG location.

 

LAB does a great job of catering to this.  Making smart unique designs that stand out definitely put them on the map.  Adjusting for lie angle (and adjusting for weighting accordingly); broomstick; and even having different grips to allow for forward press of different angles, or making up for the shaft lean from a rearward CG while wanting to keep hands at a preferred ball position, while keeping the grip vertical.  But make no mistake... there's no magic dust in what they or others do, or in the catch phrases.  It's this. 

 

Bullseye putters are lie angle balance... and if you can spin it on your hand, like some mini golf puters, it's zero or low torque also!  They would just have relatively low MOI.

 

 

Axis1 goes a step further in getting CG forward and on with the face, which IMO is the most technically advanced CG location.  Center impact is directly on the CG, and there's zero gear effect on off-center hits when CG is directly on the face, only when it's behind or away from the face.  So there would be no induced gear spin on an Axis1 putter, however little is actually there.

Edited March 2 by joostin
Add updated link

[5hort5tuff]

If you are saying Bullseys are the perfect lie angle Balanced putters but have low MOI...seems like Sacks P has tried to address this. I would love to try that bad boy. 

 

https://sacksparente.com/configure/series-39-true-blade-putter-2

Edited November 3, 2023 by 5hort5tuff

[dmeeksDC]

Tried ‘em all. IMO the Axis1 putters are patented for a reason and they work. They also are not like the others in one area: Ease of use. 
 

You can use any putting style or grip you want, any lie angle you want. On short putts these putters are so balanced it is very easy to knock them in. It almost putts by itself if you line it up and swing it but don’t death grip it. I put the Axis1 Rose in the bag and it has been a big boost to my game. 

[5hort5tuff]

4 hours ago, dmeeksDC said:

Tried ‘em all. IMO the Axis1 putters are patented for a reason and they work. They also are not like the others in one area: Ease of use. 
 

You can use any putting style or grip you want, any lie angle you want. On short putts these putters are so balanced it is very easy to knock them in. It almost putts by itself if you line it up and swing it but don’t death grip it. I put the Axis1 Rose in the bag and it has been a big boost to my game. 

 

Correct me if I'm wrong but they have never made the rose style in Left? 

[MattM97]

40 minutes ago, 5hort5tuff said:

 

Correct me if I'm wrong but they have never made the rose style in Left? 

 

They made 1 for a tour player to try, that's all I've seen but no chance we'll see lefty options from them anytime soon. Sadly. 

[jblough99]

Axis 1 is the only company that has this completely figured out.  May not be the prettiest to look at, but they flat out perform.  Putting has always been the weakest part of my game, switched to the Tour-B last year and haven’t looked back.

 

Edited November 4, 2023 by jblough99

[dmeeksDC]

58 minutes ago, jblough99 said:

Axis 1 is the only company that has this completely figured out.  May not be the prettiest to look at, but they flat out perform.  Putting has always been the weakest part of my game, switched to the Tour-B last year and haven’t looked back.

 

You are exactly right. Takes no time til you don’t even notice the hosel design. But if that design is what it makes it seem like the putts are rolling on rails and on target, I love it. 
 

I had this putter in my stable, had sampled it but was not gaming it. It does take some getting used to because the putts seem to come off faster. They’re not, I’ve measured it, it is just that I was hitting them in the middle of the face at a high rate. The roll is excellent. 

 

I put it in the bag, figured try it a few rounds. My son was with me. It was him who told me I should not take it out because I started making lots of putts. Now the Axis1 Rose is solidly in the bag. Make rate went up and 3 putting has become a rarity for me because even if I leave myself a 4-5 footer, this thing is money on those. Just line it up and let it roll it in. 

[joostin]

Some more thoughts.  I don't have a zero torque, torque balanced, etc. putter, but probably will eventually.  From an engineering view I do agree with their reasoning.  Getting rid of CG to shaft axis torque is something that scientifically makes sense, as our game is so feel based, and that feel can differ day to day.  @labgolf puts it well:

 

 

Regarding how much torque makes a difference, I think that's something very personal to how someone reacts to that torque.  It's just like all the other clubs which have torque (and MOI) from the shaft axis because they are all off-center masses from the shaft.  E.g. you'll get completely opposite answers from people saying with large headed high MOI drivers, or with lead tape toe weighted irons, whether they feel it affects their ability to close the face.  Same with grip size.  Some say things helps slow their closure; others say there's no difference.  Some say lighter shafts help them swing faster.  Others say they need more weight to feel the club and swing faster.

 

In that web page, it's really cool for the LAB CEO to give props to other zero/low torque putters, though of course he's rightly a bit biased!  It's like Santa Claus in Macy's sending customers to Gimbels in Miracle on 34th Street 😄🎅 .

 

In the videos of him testing the other companies' putters on the LAB "Revealer" they're not as steady as the LABs.  By design they should also not flop around, and really should be zero torque (not just low).  However I think it may be because the other putters use bent shafts.  They're prone to some more manufacturing tolerances (bend height, angle, orientation) vs. the straight shafts of LAB, and especially installation that's just a little off with bent shafts.  A little sabotage was also possible in the vids, but we don't have to assume they went there!  I think LAB is smart to go straight in as they eliminate variation there.  LAB also may have higher MOI designs.  Higher MOI around the shaft axis gives more resistance to having it rotate.

 

If Axis1 can introduce something straight shafted with higher MOI, IMO they'd have the most technical advantage over others.  They already benefit with all the claims of forward CG putters that have been trending.  However, getting the CG on the face limits their designs more than other companies due to the ability to distribute mass.  In one of their vids, Axis1 showed the CG and shaft axis behind the face, centered on the topline.  Not sure if that's true or just the graphics, but that wouldn't be CG truly on the face:

 

Anyway great stuff coming out from these companies, and IMO worth giving a spot in everyone's putter collections as a way to reduce variables and maybe a different feeling or visual when things aren't working with more "normal" putters that only report a toe hang or face balance.  Even if just a Bullseye 🎯 🙂. 

Edited November 4, 2023 by joostin

[ThinkingPlus]

24 minutes ago, joostin said:

Some more thoughts.  I don't have a zero torque, torque balanced, etc. putter, but probably will eventually.  From an engineering view I do agree with their reasoning.  Getting rid of CG to shaft axis torque is something that scientifically makes sense, as our game is so feel based, and that feel can differ day to day.  @labgolf puts it well:

 

 

Regarding how much torque makes a difference, I think that's something very personal to how someone reacts to that torque.  It's just like all the other clubs which have torque (and MOI) from the shaft axis because they are all off-center masses from the shaft.  E.g. you'll get completely opposite answers from people saying with large headed high MOI drivers, or with lead tape toe weighted irons, whether they feel it affects their ability to close the face.  Same with grip size.  Some say things helps slow their closure; others say there's no difference.  Some say lighter shafts help them swing faster.  Others say they need more weight to feel the club and swing faster.

 

In that web page, it's really cool for the LAB CEO to give props to other zero/low torque putters, though of course he's rightly a bit biased!  It's like Santa Claus in Macy's sending customers to Gimbels in Miracle on 34th Street 😄🎅 .

 

In the videos of him testing the other companies' putters on the LAB "Revealer" they're not as steady as the LABs.  By design they should also not flop around, and really should be zero torque (not just low).  However I think it may be because the other putters use bent shafts.  They're prone to some more manufacturing tolerances (bend height, angle, orientation) vs. the straight shafts of LAB, and especially installation that's just a little off with bent shafts.  A little sabotage was also possible in the vids, but we don't have to assume they went there!  I think LAB is smart to go straight in as they eliminate variation there.  LAB also may have higher MOI designs.  Higher MOI around the shaft axis gives more resistance to having it rotate.

 

If Axis1 can introduce something straight shafted with higher MOI, IMO they'd have the most technical advantage over others.  They already benefit with all the claims of forward CG putters that have been trending.  However, getting the CG on the face limits their designs more than other companies due to the ability to distribute mass.  In one of their vids, Axis1 showed the CG and shaft axis behind the face, centered on the topline.  Not sure if that's true or just the graphics, but that wouldn't be CG truly on the face:

 

Anyway great stuff coming out from these companies, and IMO worth giving a spot in everyone's putter collections as a way to reduce variables and maybe a different feeling or visual when things aren't working with more "normal" putters that only report a toe hang or face balance.  Even if just a Bullseye 🎯 🙂. 

The other zero torque designs are zero torque about the gravity or vertical axis. L.A.B. torque balances (zero torque) about the lie angle axis. It is a subtle difference, but is illustrated by the slightly different behavior in their Revealer.

[Lasorcier]

As to the question on the Sacks Parente model 39.  It is an excellent putter.   I have had about a year and a half.   In the bag 80% of the time.   Queen Bee 6 the other 20% just for a change. 

[03trdblack]

15 hours ago, jblough99 said:

Axis 1 is the only company that has this completely figured out.  May not be the prettiest to look at, but they flat out perform.  Putting has always been the weakest part of my game, switched to the Tour-B last year and haven’t looked back.

 

 

Can't fully agree with that IMO. Axis puts so much weight in the heel that the toe strike is super penalizing. I had the Rose and loved the balance but any toe hits seemed to get halfway to the hole at best. 

 

I equate it to a toe strike with a pure blade iron head. The toe miss is much more penal than the heel. 

 

At least with the LAB putters, toe and heel hits get the same amount of mass behind them and are much more consistent. 

 

 

Edited November 5, 2023 by 03trdblack

[joostin]

6 hours ago, ThinkingPlus said:

The other zero torque designs are zero torque about the gravity or vertical axis. L.A.B. torque balances (zero torque) about the lie angle axis. It is a subtle difference, but is illustrated by the slightly different behavior in their Revealer.

I'm not sure on the term gravity/vertical axis.  Could you clarify?  Not trying to sound condescending, just want to understand before seeing if it's a sound explanation.

 

Only because if they're both referring to the same shaft axis - one on the lie angle plane and the other one horizontally like on a table with the putter head hanging off of it (heard toe hang as "gravity angle") - it really is the same axis and same torque or zero torque around it regardless of what tilted angle or plane the axis is oriented on.

[ThinkingPlus]

2 minutes ago, joostin said:

I'm not sure on the term gravity/vertical axis.  Could you clarify?  Not trying to sound condescending, just want to understand before seeing if it's a sound explanation.

 

Only because if they're both referring to the same shaft axis - one on the lie angle plane and the other one horizontally like on a table with the putter head hanging off of it (heard toe hang as "gravity angle") - it really is the same axis and same torque or zero torque around it regardless of what tilted angle or plane the axis is oriented on.

Gravity axis is the axis coincident with the gravity vector. If the lie angle was 90°,  it would be the same axis as the gravity axis or purely vertical. Not sure how else to define it.

[joostin]

8 minutes ago, ThinkingPlus said:

Gravity axis is the axis coincident with the gravity vector. If the lie angle was 90°,  it would be the same axis as the gravity axis or purely vertical. Not sure how else to define it.

Got it.  They're all still supposed to be zero torque about the shaft axis (by intent, maybe not always in reality because of tolerances or build precision), whether they're hanging straight down with the gravity vector or inclined on the lie angle.  All that matters is if the CG is directly on that axis (zero torque because of zero moment arm) or eccentric to it (some torque because of a little moment arm).  LAB would be zero torque hanging vertically, at lie angle, or horizontal, and that should apply to the others as well.

 

There were definitely some eccentric CGs in the Revealer test videos of the other brands.

[ThinkingPlus]

7 hours ago, joostin said:

Got it.  They're all still supposed to be zero torque about the shaft axis (by intent, maybe not always in reality because of tolerances or build precision), whether they're hanging straight down with the gravity vector or inclined on the lie angle.  All that matters is if the CG is directly on that axis (zero torque because of zero moment arm) or eccentric to it (some torque because of a little moment arm).  LAB would be zero torque hanging vertically, at lie angle, or horizontal, and that should apply to the others as well.

 

There were definitely some eccentric CGs in the Revealer test videos of the other brands.

Actually, I don't believe that is correct. Orientation of the shaft in the putter head matters. You can check with @labgolf or @Stuart_G to verify for sure.

[Stuart_G]

Personally, I think the concept of a head (or even a full club) having torque is a bit contrived.   A body - alone by itself - doesn't have torque or able to a produce any kind of force in isolation.  It can respond to forces in different ways (resist them) or it can be oriented and held in certain ways such that gravity might result in a certain natural orientation (e.g. face balance) - but the head itself doesn't have any torque.

 

I don't doubt they have some meaning behind it but calling it "zero torque" is not a good way to describe it and the actual meaning is not clear from anything I've read in this thread - so I can't say how accurate @joostin interpretation might be or not.

 

Even so, I don't really see the relevance as it might apply to an actual stroke.   Of course, I never did fully buy into the importance of face balance as a fitting criteria in an objective sense (other than how it might effect the feel of the stroke).

Edited November 5, 2023 by Stuart_G

[joostin]

@ThinkingPlus and @Stuart_G I'll make up some diagrams.  There's only torque because of gravity and because we're applying forces.  The zero torque is only in relation to the shaft axis.  And that's simply Torque = Whatever Force is seen around that axis × distance or moment arm of that force from the axis.  Doesn’t matter what lie angle the head is at.

 

Now there are other torques involved with the stroke that at are definitely not zero, and one is definitely associated with lie angle, but that's not something any putter can zero out, and not the torque they're talking about.

[joostin]

Ok here we go.  To look at the torques involved let's first look at a couple macro views, then we'll look at around the shaft axis.  I'm only looking at the start of the putting stroke because it gets complicated, and this is already an involved analysis. 

 

Torques due to weight

 

Here's Tiger face on.  Right now I'm only analyzing at the effects of weight in relation to torques, as if the putter is lifted from the ground at address.  Later we will analyze the effects of the starting motion.

There's torque at the hands in this view (center of rotation at the hands face on) because the putter head CG is normally back vs the grip, and also due to any forward shaft lean.  Reduction of torque here would require forward CG and minimal forward shaft lean.  Torque = Weight of head * moment arm d.

 

Here's Tiger down the line.

There's torque at the hands in this view (center of rotation at the hands DTL) because the putter head CG, and shaft CG, are outward of the hands.  Tiger has upward force countering the weight, and also torque equal to the sum of the weights times their moment arm distances.  It's impossible to get rid of this torque unless you have the hands directly above the club's total CG.  Broomstick putters with the most upright lies would reduce this torque the most, or maybe side saddle.

 

Let's focus on the putter head.  Because of the lie angle, the weight of the head can be broken into an axial force along the shaft and what I'll call an eccentric force perpendicular to the shaft (bending force).  It's just trigonometry to figure this out:

 

That leads us to another view - looking down the shaft axis (get to use my CAD model 🙂), into the hosel.  In this view we can take that force applied to the clubhead CG.  Because the CG's position is eccentric to the shaft axis, there's another torque that the hands have to counteract when lifting the putter:

 

Again, T=F*d.  The farther away the CG from the shaft axis, the greater the torque. 

 

- Putters with toe hang have this torque (mallets would normally have more than blades)

- Face balanced putters also have this torque 

- "Zero torque" and toe-up putters will not have this torque because there's no moment arm.  Zero torque in this view can be CG above or below the shaft axis (see my first post) or better yet directly on the shaft axis - like LAB and Axis1.

 

Torques due to applied forces

 

Ok that's just weight.  How about in the takeaway of the stroke?  Let's look at the macro view again, face on, just focusing on the putter head, not shaft.  To get the head moving from a static start he has to apply torque, T, to get the head of mass m to accelerate, α.  From there the dynamic rotation will be applied by a torque, τ, which is τ = I*α (total club MOI * angular acceleration).  The hands will move in an arc not just rotation, but these are the torques involved at takeaway. 

 

How about the putter head?  Here's the CAD model again from the view we had before to look at torques around the grip at takeaway.  Same thing... there's a torque, T, to start the linear motion of the CG, and then a torque, τ, to rotate the putter head.

 

Torque T would vary depending how fast or abrupt your takeaway is.

 

- Putters with any kind of toe hang, like above, will have this starting torque.

- Face balanced putters will not have this torque because there will be no moment arm between the shaft axis and the CG.

- Toe up putters will have this torque if the CG is above or below the shaft axis

- "Zero torque" putters like LAB and Axis1 will not have this torque either because of no moment arm.

 

The τ torque would be relatively small, as it's rotation around the shaft axis which is dependent in the MOI around that axis and the angular acceleration, and I don't know if anyone rotates the putter all that fast.  Even "zero torque" putters will still have this torque.

 

So in summary the "zero torque" putters are only zero torque in a couple aspects, but there are other torques that will always be involved in the putting stroke.  The zero torque aspects will definitely be a feel thing and up to each person to feel if it makes a difference for them or not.

 

All right, tired.  I did my best to explain things for now.  It's simple but its not!  Anyone with fresh physics, statics, and dynamics in their head, feel free to chime in.  @ThinkingPlus I don't know about the balance on lie angle axis vs gravity axis, but would dig in more if there's truly something there.  I know its coming from the respected LAB, but just not sure as the golf world tends to say scientific sounding things without really being able to show exactly what's behind them!

[ThinkingPlus]

22 minutes ago, joostin said:

Ok here we go.  To look at the torques involved let's first look at a couple macro views, then we'll look at around the shaft axis.  I'm only looking at the start of the putting stroke because it gets complicated, and this is already an involved analysis. 

 

Torques due to weight

 

Here's Tiger face on.  Right now I'm only analyzing at the effects of weight in relation to torques, as if the putter is lifted from the ground at address.  Later we will analyze the effects of the starting motion.

There's torque at the hands in this view (center of rotation at the hands face on) because the putter head CG is normally back vs the grip, and also due to any forward shaft lean.  Reduction of torque here would require forward CG and minimal forward shaft lean.  Torque = Weight of head * moment arm d.

 

Here's Tiger down the line.

There's torque at the hands in this view (center of rotation at the hands DTL) because the putter head CG, and shaft CG, are outward of the hands.  Tiger has upward force countering the weight, and also torque equal to the sum of the weights times their moment arm distances.  It's impossible to get rid of this torque unless you have the hands directly above the club's total CG.  Broomstick putters with the most upright lies would reduce this torque the most, or maybe side saddle.

 

Let's focus on the putter head.  Because of the lie angle, the weight of the head can be broken into an axial force along the shaft and what I'll call an eccentric force perpendicular to the shaft (bending force).  It's just trigonometry to figure this out:

 

That leads us to another view - looking down the shaft axis (get to use my CAD model 🙂), into the hosel.  In this view we can take that force applied to the clubhead CG.  Because the CG's position is eccentric to the shaft axis, there's another torque that the hands have to counteract when lifting the putter:

 

Again, T=F*d.  The farther away the CG from the shaft axis, the greater the torque. 

 

- Putters with toe hang have this torque (mallets would normally have more than blades)

- Face balanced putters also have this torque 

- "Zero torque" and toe-up putters will not have this torque because there's no moment arm.  Zero torque in this view can be CG above or below the shaft axis (see my first post) or better yet directly on the shaft axis - like LAB and Axis1.

 

Torques due to applied forces

 

Ok that's just weight.  How about in the takeaway of the stroke?  Let's look at the macro view again, face on, just focusing on the putter head, not shaft.  To get the head moving from a static start he has to apply torque, T, to get the head of mass m to accelerate, α.  From there the dynamic rotation will be applied by a torque, τ, which is τ = I*α (total club MOI * angular acceleration).  The hands will move in an arc not just rotation, but these are the torques involved at takeaway. 

 

How about the putter head?  Here's the CAD model again from the view we had before to look at torques around the grip at takeaway.  Same thing... there's a torque, T, to start the linear motion of the CG, and then a torque, τ, to rotate the putter head.

 

Torque T would vary depending how fast or abrupt your takeaway is.

 

- Putters with any kind of toe hang, like above, will have this starting torque.

- Face balanced putters will not have this torque because there will be no moment arm between the shaft axis and the CG.

- Toe up putters will have this torque if the CG is above or below the shaft axis

- "Zero torque" putters like LAB and Axis1 will not have this torque either because of no moment arm.

 

The τ torque would be relatively small, as it's rotation around the shaft axis which is dependent in the MOI around that axis and the angular acceleration, and I don't know if anyone rotates the putter all that fast.  Even "zero torque" putters will still have this torque.

 

So in summary the "zero torque" putters are only zero torque in a couple aspects, but there are other torques that will always be involved in the putting stroke.  The zero torque aspects will definitely be a feel thing and up to each person to feel if it makes a difference for them or not.

 

All right, tired.  I did my best to explain things for now.  It's simple but its not!  Anyone with fresh physics, statics, and dynamics in their head, feel free to chime in.  @ThinkingPlus I don't know about the balance on lie angle axis vs gravity axis, but would dig in more if there's truly something there.  I know its coming from the respected LAB, but just not sure as the golf world tends to say scientific sounding things without really being able to show exactly what's behind them!

Very nice write-up. It is the tau torque that the L.A.B. folks mostly eliminate. Essentially they adjust the mass distribution of the head so that the linear force of swinging the putter on the lie angle plane results in no induced tau torque.

 

It isn't perfect, but better than zero torque about the gravity axis and much better than putters with varying amounts of toe hang. The amount an Axis 1 (for example) rotates in the Revealer vs. any of the L.A.B. putters illustrates the difference. The Revealer allows linear force to be applied without the hands rotating the putter shaft, while still allowing the putter to freely rotate due to the residual un-balanced torque about the lie axis.

[joostin]

6 hours ago, ThinkingPlus said:

Very nice write-up. It is the tau torque that the L.A.B. folks mostly eliminate. Essentially they adjust the mass distribution of the head so that the linear force of swinging the putter on the lie angle plane results in no induced tau torque.

 

It isn't perfect, but better than zero torque about the gravity axis and much better than putters with varying amounts of toe hang. The amount an Axis 1 (for example) rotates in the Revealer vs. any of the L.A.B. putters illustrates the difference. The Revealer allows linear force to be applied without the hands rotating the putter shaft, while still allowing the putter to freely rotate due to the residual un-balanced torque about the lie axis.

Thanks, but look again, the tau torque will always be there.  They can't eliminate it because it's MOI related.  The torques they can eliminate are:

 

(1) the gravity and lie affected torque

And

(2) the circled torque from linear force

Which is what the Revealer can "reveal".

 

I assume a "gravity axis" balance means passing the Revealer at 90° vertical?

 

Thing is, torques (1) and (2) for any "zero torque" putter, Axis1 included, should be non-existent for any lie angle because of zero moment arms.  That includes if they were "revealed" vertically.  As long as CG is directly on the shaft axis, (1) and (2) are gone, and the putter is balanced on any lie angle axis including 90°.

 

My only explanation as mentioned before is a lack of build precision throwing the CG a little eccentric.  Very easy to happen if a single or double bend shaft is installed a little off.  LAB should be pretty much perfect every time with their straight shafts.

[ThinkingPlus]

1 hour ago, joostin said:

Thanks, but look again, the tau torque will always be there.  They can't eliminate it because it's MOI related.  The torques they can eliminate are:

 

(1) the gravity and lie affected torque

And

(2) the circled torque from linear force

Which is what the Revealer can "reveal".

 

I assume a "gravity axis" balance means passing the Revealer at 90° vertical?

 

Thing is, torques (1) and (2) for any "zero torque" putter, Axis1 included, should be non-existent for any lie angle because of zero moment arms.  That includes if they were "revealed" vertically.  As long as CG is directly on the shaft axis, (1) and (2) are gone, and the putter is balanced on any lie angle axis including 90°.

 

My only explanation as mentioned before is a lack of build precision throwing the CG a little eccentric.  Very easy to happen if a single or double bend shaft is installed a little off.  LAB should be pretty much perfect every time with their straight shafts.

The tau torque can be eliminated by distributing the mass appropriately. Remember that MOI is a 3x3 matrix. The off-axis elements in the MOI matrix give rise to the induced torques. Changing the mass distribution of the putter head (all those weight screws on the L.A.B. putters) minimizes the off-axis values in the MOI matrix for the given lie angle. Thus, the induced torques are minimized as well.

[Cwing]

Wow, great thread.

[joostin]

12 hours ago, ThinkingPlus said:

The tau torque can be eliminated by distributing the mass appropriately. Remember that MOI is a 3x3 matrix. The off-axis elements in the MOI matrix give rise to the induced torques. Changing the mass distribution of the putter head (all those weight screws on the L.A.B. putters) minimizes the off-axis values in the MOI matrix for the given lie angle. Thus, the induced torques are minimized as well.

Thanks for engaging btw.  I just wanted to put the torque analysis together because there seems to be absolutely no one online, other than Tutelman, short of research papers, who tries to make sense of things like these using free body diagrams, equations and such (mechanical engineer here) in a way that's visual and easy-ish to understand without getting into calculus.  The golf world like I said seems to love lingo that's mostly unexplained, and most have no clue or care what's really behind it.  But for those of us that do, the math and physics is hard to come by without doing it yourself.  So I'm just trying to decrypt things for myself and anyone interested. 

 

Yes MOI exists about any axis, the principal 3 axes, and classically represented in the matrix.  CAD makes it easy to evaluate how any MOI is affected with mass distribution changes.  LAB seems to be second to none about adjustability while maintaining "zero torque" aspects. 

 

As far as the tau torque above, it's simple math.  τ = Iα.  It cannot be zero unless α is zero.  The I in my case is MOI about the shaft axis, a singular MOI, and α is any applied angular acceleration.  Either MOI is zero or α is, and MOI can't physically be zero.  That's all.

 

It's the other torques, T = Fd, that can be zero because they can, and do, get d to be zero.  That's where LAB is adjusting masses to zero out d, during lie angle adjustments, preventing the CG from being off axis.

 

For a τ = Iα example take a perfectly balanced 40lb Peleton flywheel, CG perfectly balanced with the center axis, nothing off axis, and start to rotate it.  τ will never be zero torque no matter what mass you try to manipulate unless there's no angular acceleration.  Now take a 4,000 lb flywheel, perfectly balanced again, and try to start rotation.  τ will be much greater because it has a much higher MOI.  That's the tau I'm talking about.  T = Fd, yes they can zero that out.

[joostin]

Just wanted to post a “call for engineering analysis" on golf technical things.
Occasionally I feel the need to decrypt golf understandings or terminology with some math and physics.  Whether supporting or not supporting something, try to put some backing to it, and present it here.  “Show your work" and encourage other technical-oriented people to fact check me and fact check the terminology. “What really is zero torque?" for example in this thread.

The reason Dave Tutelman is such a great resource is because he shows the math and physics to a level that no other does.  With all the engineers out there like myself, it’s pretty disappointing that other than him, maybe research papers, and some biomechanics people like Dr. Kwon, there’s almost no online golf presence putting engineering analysis into golf's question marks, claims, and terminology, especially equipment-wise.  Seems not many really care.  Testing things out, like LAB's Revealer is great, but one-off sampling by a biased source isn’t exactly a controlled experiment (though I do believe their results based on the possibility of build inconsistencies with the other companies).  However, concepts can be broken down pretty straightforwardly with engineering analysis - Free Body Diagrams, basic physics equations, use of CAD - things I attempt sometimes on golfwrx.

 

The golf world puts out science-y terminology, and if from a trusted source it’s normally accepted even if not many really show any math or physics to technically back things up.  It's mostly experimental.  So for the engineering and technical people out there:  Come show the math; fact check mine; fact check Tutelman’s; fact check others; come up with your own; come out of the woodwork!

 

It’ll do the golf world some good, especially in a forum setting, for more engineering type analysis.  Rather than just science-y lingo and evidence, or simply accepting something because a trusted source said so (even from the revered Wishon, Maltby, Solheim, …), let the unbiased math and physics speak.  Then we can de-mystify things and determine what’s really behind them like I attempted above with “zero torque”.

[MattUtah]

Because LAB’s whole thing is ZERO torque, they’ve kind of designed themselves into a corner. When you have to have absolutely zero torque, it limits what you can do and what your designs can be. I keep seeing people post things like, “I can’t wait until LAB makes a Link.1 that’s heel shafted - then I’ll buy it!”  Well, that’s never, ever going to happen because of their insistence on zero torque. 
 

I look at something like the Axis1 as a better model because while it may not be exactly zero torque, it’s ultra low and still sets up and looks somewhat normal. On most putts within 20 ft, it doesn’t torque noticeably more than a LAB. If you watch the LAB demo of the Axis1 in their revealer, when the Axis was used at a normal tempo on a medium long stroke, it held up fine. Getting the CG forward to the face on the Axis1 is an achievement too that can’t be understated. 
 

All that said, I still don’t think normal putters with torque require that much hand pressure to control them. The torque can even can help with tempo and pace when you’ve gotten used to it. 
 

 

 

[pjl1959]

I appreciate the technical explanations as I’m interested in an Axis or Lab putter. That said, how much difference does a low torque putter really make if your grip prevents twisting? Is it minuscule?

[ThinkingPlus]

11 minutes ago, pjl1959 said:

I appreciate the technical explanations as I’m interested in an Axis or Lab putter. That said, how much difference does a low torque putter really make if your grip prevents twisting? Is it minuscule?

My experience is that I could feel regular putters try to twist during my putting stroke.  The bigger the stroke, the more twisting. I had to actively compensate that twist during the stroke to keep the face square. Since it varied with how hard I swung the putter, it was a constant issue chasing the exact right amount of compensation.

 

With a L.A.B. putter there is no twist. If I pull or push a putt, it's all on me. The putter cannot be blamed. No more fighting with a putter rotating in a way I don’t want it to.

[pjl1959]

I hope to try a L.A.B. this coming Thursday. I’m looking forward to it! 

[joostin]

13 hours ago, MattUtah said:

Because LAB’s whole thing is ZERO torque, they’ve kind of designed themselves into a corner. When you have to have absolutely zero torque, it limits what you can do and what your designs can be. I keep seeing people post things like, “I can’t wait until LAB makes a Link.1 that’s heel shafted - then I’ll buy it!”  Well, that’s never, ever going to happen because of their insistence on zero torque. 
 

I look at something like the Axis1 as a better model because while it may not be exactly zero torque, it’s ultra low and still sets up and looks somewhat normal. On most putts within 20 ft, it doesn’t torque noticeably more than a LAB. If you watch the LAB demo of the Axis1 in their revealer, when the Axis was used at a normal tempo on a medium long stroke, it held up fine. Getting the CG forward to the face on the Axis1 is an achievement too that can’t be understated. 
 

All that said, I still don’t think normal putters with torque require that much hand pressure to control them. The torque can even can help with tempo and pace when you’ve gotten used to it. 
 

 

 

Well torque is definitely a feel thing which is very subjective, but also varies by amount based on the forces you apply.  So from a scientific view why not get rid of it (certain aspects) as a variable?  Yes, in reality it's not a whole lot.  We swing with induced and applied torques because every other club has the shaft axis on the heel (even Cleveland VAS is still very heel side)..  We've all putted with a belly wedge and normal non-zero-torque putters somewhat successfully.  However little, these torques are there, and everything has some relation to what we feel and react to.  So while zero torque putters may not feel or look right to everyone, it's the one club that they can physically / legally design the shaft aligned with the CG and remove the little but subjective torques mentioned.

 

As far as cornering themselves, yeah but they found and named the company to fill a niche and differentiate themselves.  The CEO is a smart guy.  If they wanted to make non-zero putters, they could start another brand/line, and attach shafts heelward.  IMO there's a lot to explore design-wise with "zero torque".  They're probably doing pretty well with plenty of market share to grab.  Also it's more interesting than making more of the same that most love to do (e.g. a special-er Anser than everyone else's Anser because of a welded hosel, milling, stamping, handcrafter reputation, and cool factor).

[Soloman1]

More shaft offset can increase head MOI by as much as 4X, if you’re interested in strike torque and geometry.

 

If you’re interested in dynamic torque during the stroke, that’s more “it depends” on the person and their stroke, visual clues during it, intent, grip, hand, arm and shoulder movements, proximity to the ball, daily horoscope… 😉