LV Jack Blade Opinons

Re: LV Jack Blade Opinons

Frank Mutchler in Colorado Springs

>Jim, I'd vote for the xtra blade(s) simply bcause of the time savings. Funny, I had read all the posts about using a high angle blade in a low angle plane and just forgot completely about them when I was working some crazy grained mahogany with my #164. These senior moments are becomming a little too frequent for comfort. Spare blade runs about $35.00.

Re: LV Jack Blade Opinons

Greg Sloop

>Going up angle is easy. However going back isn't as easy. I don't like changing the base angle often, so I've decided one dedicated to each angle I want to have is the way to go. Plus it only takes seconds to switch to a new iron if that's what you find you need. If you have to regrind - well, that's a grind.

Cheers,

Greg

Re: LV Jack Blade Opinons

Lyn J. Mangiameli

>It is definitely desirable to have multiple blades for the multiple angles. As has been said, it is easy to go up in angle, but requires more grinding to go back down. Having two or more blades will make changing angle quick and easy, and thus encourages you to change to the optimal angle.

As for whether or not to get the LV high angle version of the blade, I'd say it really doesn't make the least bit of difference. Before the HA blade ever existed, I reground a fairly wide microbevel on a LA blade to 64 degrees and achieves simply astounding results. I have since used the HA ground blade at its factory delivered setting and it works well too, but I've never felt the need to supplant my original 64 degree blade. LV just saves you some grinding time if you want the angle they provide, or even one higher.

As for the steeper primary bevel of the HA blade, I just don't see how it makes any significant difference in this sort of low bedding angle blade. Certainly in my use, it hasn't.

Frog Opinons

Derek Cohen (in Perth, Australia)

>Yes Lyn, I can see the advantage of a cutting angle greater than the 50 degrees of the HA LV factory-cut blade. Many of us use cutting angles of 60 degrees on gnarly woods.

My question for you and others has to do with the perceived advantage of the "bevel up" frog set up of the #62/62 1/2/164 LA planes verses that of a "bevel down" frog of the standard bench planes.

My perception is that the bevel up frog offers greater support for the blade, which should translate to reduced chatter and, hence, better control on tricky grain direction. It is a simple matter to have a selection of blades with a range of bevel angles.

If this is so, then the direction of plane design ideally should be planes with bevel up frogs.

The other point of enormous attraction of these planes is their adjustable mouths. It is a simple matter to increase/decrease mouth size for the occasion. The potential for versatility combined with superior performance is very exciting.

Comments?

Regards from Perth

Derek

Re: LV Jack Blade Opinons

Chad Boehlke

>As a collector and maker of planes I offten use a toothin plane for hard grain wood. It cut very fine lines and after a few passes, I can sand it off and start over. But if you don't want to buy another plane I would go ahead a buy another blade and see if it would work, however that frog is made for a lower angle.

Re: Frog Opinons

Frank Mutchler in Colorado Springs

>Derek, can you explain how a bevel up frog differs from standard frogs? (Boy, not there's a straight line for someone!)

Seriously, I've never encountered the term before and don't mind asking stupid questions. ;>)

Re: Frogs Opinon

Frank D.

>Hi Derek,

You bevel-up guys are turning into a real horde! :)

I just have another variable that I want to throw in that Lyn can discuss if he thinks it's relevant.

OK for the frog advantage (Frank: a bevel-up plane has no real frog to speak of: it's just a bed that is included in the main casting; it doesn't move and as Derek said it extends all the way down to the back of the mouth). But in my limited experience chatter is not the biggest problem. The wood I work with the most is hard figured maple; it's a bear to plane. Chatter can be a problem but the catastrophic tearout that can happen in a single stroke is not caused by chatter. A sharp blade, thin cuts and a high angle all help, but what I was wondering is if the included angle (same thing as the primary bevel angle on a bevel-up plane blade) also has something to do with the quality of the cut. A bevel-up plane with a blade set for a high angle has a much higher primary bevel angle than a bevel-down plane. This must affect the quality of the cut, is what I'm trying to say.

Frank

(the bevel-down guy who's going to get a 164 to try one out himself)

It's about the wood, not the plane...

Rob Lee

>Hi Frank -

Below is a post I made awhile ago on an Australian forum (Derek's familiar with it).

It may give some additional insight into this discussion. We have several major "pure" research projects under way right now (which we don't want to disclose until the research is done) but it involves hundreds of thousands of strokes ....will take awhile to finish yet.

Anyway - post follows:

Cheers -

Rob

Hi -

It's not about the planes - it's about the wood, and how the wood fails.

A plane is a carrier for a blade used to induce controlled wood failure.

Much of the confusion over which plane is best, or which angle is best really comes down to which wood are you using... tougher, more "failure resistant" woods can be well worked with a low angle plane....

Y'all have have a bunch of tough, failure resistent woods down there - which may run contrary to the experiences N Americans and Europeans have with their common domestics.

Wood failure generally falls into two types - Type 1 and Type 2 chip formation (creative naming, eh?). Type 1 is typical at lower bevel angles (angle between the bevel and the wood), and involves having the wood "splinter" ahead of the blade...usually evidenced by tear-out... For a really tough wood - this may not happen!

Type 2 chip formation is where the wood fails right at the cutting edge - essentially, the wood fibres are severed by the blade before they fracture. Type II chip formation (or behavior) is what we strive for, for a clean surface..

Now, there will be some exception woods to all of this...

Really soft/fragile woods can be difficult to get Type 2 failure .... so now we have to discuss Type 3. This is where the blade actually pushes the wood fibres ahead of the blade, inducing a compression failure - often leaving a fuzzy or furry surface. It looks a lot like the way a snow plow pushing sticky snow does....you can picture that, eh? :D (couldn't resist!)

This is why softer pines don't scrape well.... there's compression failure....

So - now we come to plane geometry...

Standard angle planes have a 45 degrees effective cutting angle, and are generally bevel down - a generic "best" angle for NA and European domestic woods...Keep in mind too, that planes were developed a century ago, when the quality of wood used was far better (more plentiful, old growth woods, and lots of mahogany) - today we work generally more "demanding" woods....

Low angle planes are generally below 45 degrees, and are typically bevel up...

High angle planes are generally 45 degrees plus, and bevel down...

So why bevel up/bevel down? Well - there are engineering constraints imposed by each method of construction... If you want an adjustable mouth - then there's a limit to how small an included bed angle you can have. Using a frog � it�s larger. Using an adjustable sliding plate ahead the blade � it�s smaller. With a low bed angle � a bevel up configuration gives a cut angle of �bed angle + bevel angle� � with modern blade steels � this can effectively be as low as 12+20 , or as high as 12+ 78� (a 58 degree range)

A higher bed angle � with a bevel down blade � is fixed at 45 degrees (or whatever the bed angle is). In order to increase the effective cut angle � we have to introduce the concept of a �back-bevel��. Using back-bevels � the effective cutting angles can range from � bed angle� to 90 degrees � (a 45 degree range for standard planes). Additionally � using a back bevel has the advantage of strengthening the edge on the blade � as the included angle on the blade tip is greater.

So for bed angles � there are also performance differences. Lower bed angles make the plane sole more susceptible to distortion � as tightening the lever cap can exert enough force to cause sole deflection. This is commonly observed in LA shoulder, rabbet (rebate) block planes etc., and is a technique often used purposefully to �adjust� blade projection.

Low bed angles do have the advantage that the blade is held in an orientation more in-line with the force applied � with should resist chatter more effectively than a higher bed angle plane made to the same tolerances.

A list of �truisms� (not really rules) I�d put forth would be:

1 - A back bevel works at least as well as a change in bed angle - and possibly better if the blade is not perfectly bedded, as a blade more in-line with the applied force can resist chatter better. (note - an adjustable mouth is usually necessary if using back bevels)

2 - A bevel up plane will work at least as well as a bevel down plane with the same effective cut angle - same reason as above...

3 � a low bed angle (bevel up) plane gives you the widest range of cut angle choices (rapidly changeable, if you have extra blades!)

4 � A narrow mouth with a light blade feed may allow a plane to �emulate� type 2 chip formation by reducing the possibility of the wood tearing-out (the sole ahead of the blade reduces the magnitude of, or stops the type 1 chip)

5 � how the wood you�re using fails is really the most important factor in determining which cut angle is best�

All of these factors (and there are more - like skewing a plane to reduce the effective cut angle) can make for a real witches brew when it comes down to interpreting why one configuration works, and another doesn't...but it's really about the wood...

Cheers -

Rob

Re: It's about the wood, not the plane...

Greg Sloop

>Thanks Rob!

Excellent information! I appreciate it.

Greg

HIJACK - kind of...

Greg Sloop

>I have wondered something about this for a while...

Here's my theory, which may just be ramblings of a loony, but I'd like some feedback.

Ideally, one shoots for a type II chip. Type I is tear out, and type III is a compression fracture.

So, here's my theory

Select the lowest total angle possible that doesn't present Type I chips. This may still allow for a wide range of acceptable angles however. The point being, that higher angles are NOT always better. In short, pick the angle that presents the most Type II chip formation. Too low and Type I chips are the result, too high and Type III chips are the result. (Perhaps we should call this the Goldilocks conjecture.)

This will give the best surface appearance, and prevent the progression into Type III chips and the damage to the fiber structure that occurs from compression.

Thus, one can't say - well, just grind a blade to 85 deg total angle and it will do anything - because it may do some things well, but others not so well. In some woods 85 deg may the the sweet spot between Type 1 and Type III chips, but for others it will be well into the Type III chip formation.

Ok, does this make sense? Or should I take my lithium and go away?

Cheers,

Greg

Re: HIJACK - kind of...

Rob Lee

>Hi Greg -

Yes it makes sense...but I would add:

"Select the lowest total angle possible that doesn't present Type I chips - consistent with desired edge retention"

Cheers -

Rob

Re: It's about the wood, not the plane...

Jim in Burlington Ontario

>Rob Thanks that's alot of good info. I'm going to try the back bevel and pop over and buy the high angle blade. Entertain myself for a few hours making my scrap pile into shavings. While using the Jack it occoured to me a 22" - 24" with the same features wider blade would be so sweet.

Re: HIJACK - kind of...

Jim in Burlington Ontario

>Greg I see the pics in the LV website for distingusing the different kind of chips but how do you tell them apart at home? Do you look at them thru a maganifing glass or is there a specific wood that show's them better. This might be part of the answer when trying to tailor planes to specific woods.

Rob has just saved me a lot.....

Lyn J. Mangiameli

>of typing, and his discussion largely matches my empirical findings (and apparently, his own experimental findings).

I'll expand on his discussion slightly to add some of my own thoughts and findings.

First, only with a bevel up plane is the blade fully bedded right up to the cuttng edge minus the actual extension beyond the sole for cutting. With a bevel down plane, one looses bedding at the point where the bevel begins. The thicker the blade, and the shallower the bevel, the longer the unsupported distance will be for a given blade extension. (Though carefully note Rob's comments about how a back bevel changes the included angle, and thus-I would add --depending on its width, can change the amount of unsupported bevel,)

Back bevels to the side, the above suggests that thick "chipbreakers" may be a better way to create a more massive blade assembly, than just thickening the blade itself on bevel down planes. It also suggests that chip breakers set close to the edge of the blade my help stabilize that unsupported--by the bed--blade edge in the area of the bevel, which of course says that such chip breakers are indeed best set close to the blade edge. The bevel up plane avoids all this compensation and usually also offers a superior damping surface--i.e., cast iron--closest to the cutting edge.

Second, and this builds on the above but is more speculative on my part, I don't think the influence of effective cutting angle can be divorced from blade width. Higher effective cutting angles result in greater resistance to cutting, and increase the perceived force required to push the plane through the wood for a given width. The muscular forces required to drive the plane through the wood, obviously increase as a wider cut is made. Wider blades (say those over 2 inches) are more difficult to push than planes with blades that are narrower (2 inches or less), this was clearly discernable in my last planing study. But I think another factor related to blade width comes into play. To throw away another finding from my last study, certain plane types actually DECREASED in performance at very highest effectively cutting angles, namely those with 2.25 inch and wider blades (namely both infill and cast iron bevel down planes). I think this is because their larger unsupported blade edge begins to flex slightly along their width under the greater resistive forces encountered in planing hard dense woods with a very high effective cutting angle.

Rob and others have noted that a plane is not just a blade carrier, but also can function to control wood failure ahead of the blade edge (the Type 1 chip). No where does the latter become more apparent than in a chisel plane that offers outstanding blade bedding (take the L-N chisel plane with its thick bevel up blade fully bedded to the edge). Yet as anyone who has used a chisel plane is all but too aware, Type 1 failure is totally uncontrolled, and in certain woods cut with the grain can result in wood failure far ahead of and much deeper than the blade edge.

In a plane with mouth that can be set close to the blade edge, the plane sole not only locates the blade with respect to the wood, but it also controls against foward failure. It does this by providing compression on the wood fibers. So I want to emphasize that a plane is a wood compression device as well as a blade carrier. Now I am going to go on to speculate that compression is significant not only for Type I failure woods, but also Type III failure woods. That is, the plane sole before the mouth not only can provide pressure to prevent cleavage well ahead of the blade, but it can also "pre-compress" softer fibers (i.e, less dense woods) and diminish the effect of high angle blades "pushing a raised wall of wood cells" ahead of the blade resulting in more ragged intermittent shearing as the compressed wall fails. The overall density, cellular structure, and dryness of the wood involved, will influence how much downward force is required to achieve functional compression. Functional compression will be achieve by a combination of downward pressure and how closely the compression occurs to the cutting edg---not always will the tightest, closest mouth result in the optimal cleavage of wood fibers.

Anyway, I don't want to get too far afield from the original questions, so I will stop here, but to say that there are many individual variables that influence the quality of surface finish one will achieve by planing. Overal there is much greater range of variance in wood than in the tools we use. Many woods will be quite insensitive to the type of plane, or its adjustment. Others will be excruciatingly demanding. What the bevel up, movable toepiece, low bedding angle, plane style offers is a great combination of good inherent design and easy adjustability (including blade sustitution) that allows it to adapt to a wide range of wood characteristics.

Ditto!

Frank Mutchler in Colorado Springs

>

Re: HIJACK - kind of...

Greg Sloop

>Oh, I can't say I've done anything scientific as Lyn and Rob and Rob's dad have done, but here's how I generally see it occur.

This is on the QS Sycamore I've talked about before. The wood is fairly soft, IMHO and with the most pronounced grain stuff I've had it moves quite easily from Type I (I assume) to Type III failures.

On a very sharp blade at ~65 deg it cuts very well.

If you drop below 60 deg it's very easy to have Type I failures - you can see these with the naked eye in a raking light. Small pits between the rays, if I have my terminology right. I may have some pictures that show this, so I'll dig around some. If the iron is very sharp, then you can get away with lower and lower angles.

(I need to *finally* get the samples of QS Syc off to Joel - I haven't forgotten - so he can compare with his standard 45 deg stanley. [I did warn him however, that my follow-through was less than timely often!])

I find the failures showing up at anything below ~55 deg no matter how sharp, how small the mouth, and almost taking "dust" for a cut.

I have found that lightly spraying/misting the surface of the wood with water and letting sit for 10 minutes makes quite a bit of difference. The angle still has to be high, but it's less sensitive to iron sharpness. ie. you can plane longer between sharpenings.

What I do notice at ~60-65 deg is that I don't get Type I failures initially. Here's the progression. All of this is observed with the naked eye.

Newly sharp iron - perfect surface, as long as your cut is not too thick. Mouth opening doesn't seem very important.

After some planing and the iron is dulling a bit, I see more "fuzzing" of the surface. It's harder to push and more sensitive to mouth opening. You may start to see a few Type I failures. (It's hard to tell the way I've done it - as I don't start with a perfect surface- if you've created new pits/tearout or just haven't removed the ones already there - but I'm pretty sure you see some new pits. Smaller mouth and lighter cuts will control it.

Some time later, and the iron is clearly pretty dull you start to see more Type I failures. The fuzz is still there.

What I wonder about in all this is getting farther and farther afield and more pure speculation... but as the "sharpness" of the edge decreases, you get higher effective angle cutting - thus more Type III failures. Eventually the iron isn't really cleanly cutting anything and simply does more and more ripping of the fibers - thus the Type I failures appearance.

Note that I'm speculating almost entirely on some batches of QS Sycamore I have. This may or may not apply to other tricky woods. Lacewood seems to have similar issues, but somewhat different.

I'm not sure why the water misting makes a difference. Any thoughts? Clearly, at least anecdotally, moisture content makes a big difference though.

Thanks for the thread all, I've enjoyed it. (If I'm taking this thread too far afield, let me know and we can start a new one if anyone is interested.)

Greg

Great analyses so far

Derek Cohen (in Perth, Australia)

>Lyn and Rob

My thanks for your usual carefully thought out and worded analyses.

Your observations are very much in line with my own thoughts, although I do not have your user time with the bevel up planes to offer anything more than casual speculations. I have only very recently begun using bevel up bench planes but already I can see their potential. Here in Oz I work largely in hard timbers such as Jarrah, sometime in Karri, and these can be frustratingly difficult to finish without tearout. I see the potential of the bevel up bench plane as a carrier for high cutting angle blades, not just low angle for which they were originally designed, since the "frog" design is inherently better. Logic says that there will be less blade deflection when the blade is supported better and projects less from the plane body (than in the traditional bevel down design). I am sure that there is more to it than that, and I am going to watch this space with much interest.

Regards from Perth

Derek

Re: Great analyses so far

Lyn J. Mangiameli

>In the last plane test I included a couple of Australian woods that Mick Doherty was kind enough to send me. One of the findings is that the 60-63 degree woodies (Gordon, Mujingfang, a Knight Coffin) were just outstanding on the difficult woods (irrespective of continent). Equally surprising was that the bevel up planes, when used in the 62-65 degree range were right up in the mix, with the LV LA Jack at 64 degrees being just astoundingly good (not part of the study, but in later comparison to the study planes). It is the empirical evidence from this last study, and my experience with the LV LA Jack at super high angles, that has caused me to develop an enthusiasm for bevel up planes that I simply never had previously when I had only used them as delivered with a low effective cutting angle.