Frog seating

[Tom Bussey]

I received a question about the frog needing to be in place when flattening a plane.

And my answer is there are lots of fairy tails out there. If someone wants to sound knowledgeable, they throw in the frog needs to be attached. My question is do you really think you can move a cast iron plane body into registration with 2 (12-24 ) screws and a screw driver?


In industry, the piece to be machined is set up so that the largest surface can be machined In its free state. This establishes the parts datum surface. And a datum is a plain, line, surface, or feature assumed to be perfect.The rest of the diffination deals with tolerancing. Dimensions comes from a datum but in itself a datum has no tolerance.The last part paraphrased


Once the largest surface is machined ( bottom of the plane body) then one has control of all plains of motion, of which there are twelve, and the sides and then the frog seats can be machined by locating on the bottom. Not the other way around.


If there is a problem with the bottom not being flat then is is because of the person who took the milling marks out when finishing the job, Which would not effect the relation of the planes bottom and the planes seats. Or casting stress being relieved over a 100 years. And the seating area being the thickest eare would be least effected.


The idea probably came from a person who wanted to sound knowledgeable and to embellish an article to sell a book or magazine. And it continues to get parretted.


The world is not flat even though every one knew that it was at one time so my questions remains. Do you really think you can move a cast iron plane body into registration with 2 (12-24 ) screws and a screw driver?

[Frederick Skelly]

Thanks for the lesson Tom, and for sharing your years of experience as a tool and die man. I hadn't thought about it your way before, but it makes sense to me.

Best regards,
Fred

[Joshua Lucas]

I'd bet that the origin of this myth comes from confusion between wooden and metal planes. When flattening the sole of a wooden plane, the wedge and iron absolutely need to be installed because the body of the plane does flex when the wedge is set. Probably the good advice that your (wooden) plane needs to be fully assembled when flattening was accidentally transferred to metal planes, where it's not necessary at all.

[Jim Koepke]

This is an interesting topic.

Another question might be, is there a problem caused by having the frog installed when lapping the sole?

This may be the case with a milling machine set up. For hand lapping the biggest problem might be the need to disassemble and clean after lapping.

For me when hand lapping a plane's sole, it is just as easy to do with the frog in place. If this doesn't cause a problem, it will likely be continued.

With Stanley/Bailey planes before type 9 the frog was seated on a single platform. Type 9 and later made contact not only in the area where the screws were securing it but also behind the mouth. Could a slight variation in the machining of the frog or the sole cause extra pressure at the back of the mouth?

More than one of my block planes have had varying degrees of a concave sole. The weight from my hand would cause the plane to cut. At the end of the cut as the weight from my hand diminished, the blade would lift out of the cut. This was corrected with some careful use of abrasive paper on a flat surface.

A block plane has the blade resting on an area behind the mouth and a pedestal closer to the back of the blade. This is all held securely in place by a screw in the middle. There have been a few in the past who have said over tightening of this screw may cause damage to a block plane.

By my best estimation the distortion from the weight of my hand is likely not any more than what of a couple of #12 screws are able to bring to bear.

As always, 420346

jtk

[Tom Bussey]

No, having the frog in place when hand lapping doesn't cause a problem. The problem with hand lapping is 100 year old cast iron doesn't lap very well. And the closey one get to flat the more of the entire surface one need to take off. So one can spend months and still not get it flat.I have fixed enough planes others have tried to hand lap to know it is not worth the effort. One can do as much good by taking a random orbital sander with 180 paper and shining the bottom and then waxing it.

Having to flatten planes is like having to rebuild a car engine every time one trades vehicles

Yes, every one knows how to flatten a plane but then everyone also knew if you sailed to far you would fall off the world. And every one also said if man was supposed to fly then God would have given him wings. Flatten planes,, falling off the world and God giving man wings is all a myth. Just because one believes something is true doesn't make it so

[Pat Barry]

12 planes of motion? Care to elaborate? I understand X, Y, Z. What are the other 9? Thanks

[Jim Koepke]

Tom, we can agree that lapping the sole of a plane is not a simple operation.

We can also likely agree that it involves more than just pushing a plane back and forth on an abrasive surface.

We likely agree using a flat surface with abrasive sheets isn't going to produce a surface flat to some precise measurement. My contention, from experience, is it is possible to use care and make a plane's sole flat enough to do its job quite well.

If one wants the sole to be flat to a couple thousands over the full length and width it will require a machine shop or buying from LN or LV.

My position on lapping the sole of a plane is to not do it unless there is a problem that can be demonstrated as being caused by the sole being out of flat. Then my first suggestion would be for a person to find a machinist such as yourself to do the job. Failing that, they should find someone with some experience. Finally if that is not available in their locality they should approach lapping very carefully and have a plan to accomplish their goal.

Of all my planes, only a very few had problems that were fixed by lapping with abrasive sheets on a flat surface.

One thing many do not realize is without much effort it is very easy to make the sole of a plane much worse than it was with a few minutes of running a plane back and forth on abrasive paper.

jtk

[steven c newman]

Back to the frog seats:

About the only thing I usually do when rehabbing a plane....a wire cup brush is run on the seats....mainly to remove all that thick paint....I take the seat down to bare metal ( along with the underside of the frog) then try the frog on the cleaned up seats....IF anything needs corrected ( RARE...) then a flat file that spans the entire seat area, is used a couple times, until the base and the frog sit nicely. Same with the face of the frog...more to remove all that paint...and sometimes a bit of rust. I usually just go for clean, bare metal on the face. A quick check with a straightedge...all the way down and out the mouth.

[Doug Dawson]

I received a question about the frog needing to be in place when flattening a plane.

And my answer is there are lots of fairy tails out there. If someone wants to sound knowledgeable, they throw in the frog needs to be attached. My question is do you really think you can move a cast iron plane body into registration with 2 (12-24 ) screws and a screw driver?


In industry, the piece to be machined is set up so that the largest surface can be machined In its free state.

And there lies a potential flaw in the logic, as it applies to hand planes. Because their "flatness" (whatever that means) is only of value when the plane is actually _used_, in its working configuration. Perhaps this is what is throwing people off.

Think about it.

(And no, I've never had to lap a plane sole.)

[Jim Koepke]

(And no, I've never had to lap a plane sole.)

My suspicion on some of the planes that came through my shop needing work on their sole is they were previously "lapped" by someone with no idea of what they were doing.

jtk

[Doug Dawson]

My suspicion on some of the planes that came through my shop needing work on their sole is they were previously "lapped" by someone with no idea of what they were doing.



You can talk about your suspicion all you want, and I will counter that with my conviction that you are probably right.

[Jim Koepke]

LOL!

jtk

[Mike Cornwall]

And there lies a potential flaw in the logic, as it applies to hand planes. Because their "flatness" (whatever that means) is only of value when the plane is actually _used_, in its working configuration. Perhaps this is what is throwing people off.

Think about it.

(And no, I've never had to lap a plane sole.)

I’m thinking about it, and the wording of your statement. I very much want to understand, having a personal interest in the subject. When you say “used in its working configuration,” do you mean under the tension of the lever cap? Something has been throwing me off with my jointer plane and I’m very interested to understand your point of view.

[Doug Dawson]

I’m thinking about it, and the wording of your statement. I very much want to understand, having a personal interest in the subject. When you say “used in its working configuration,” do you mean under the tension of the lever cap? Something has been throwing me off with my jointer plane and I’m very interested to understand your point of view.

What I mean is, in full trim as used to plane a surface, or to joint an edge (over some non-trivial length.) It doesn't need to be more complex than that.

[steven c newman]

Ya think?
420385420386

[Jim Koepke]

I’m thinking about it, and the wording of your statement. I very much want to understand, having a personal interest in the subject. When you say “used in its working configuration,” do you mean under the tension of the lever cap? Something has been throwing me off with my jointer plane and I’m very interested to understand your point of view.

Mike, It may be more helpful to try to describe what has been 'throwing you off with your jointer plane'. You would be surprised at how many odd behaviors a plane can commit.

It might even be good to start a new post.

It also helps to have your location known. Heck, if you are in the are of the Pacific Northwest you would be welcome to help. If you live in another area there are also other members who have always been willing to help others at getting their plane in working order.

jtk

[Doug Dawson]

Ya think?
420385420386

So, what's your point?

[Michael Bulatowicz]

Do you really think you can move a cast iron plane body into registration with 2 (12-24 ) screws and a screw driver?

According to some rough calculations (I was curious) the type 11 Stanley frog with its two seating surfaces and #12 screws is likely to make the sole of my type 11 #5 more concave by about half a thousandth of an inch or so directly under the frog and depending on the torque you use when tightening the screws. At the extreme ends, you’re talking about a thou or two of deflection, which is probably easily counteracted during use if you push down on the plane at all (as evidenced by Jim’s hand pressure anecdote). Not going to make any noticeable difference in how the plane performs, and not going to make a difference in any flattening efforts.

So, I agree with you, backed up with calculations and not just opinion or guessing, that it’s not necessary to have the frog installed while flattening.

Best regards,
Michael Bulatowicz

[Robert Hazelwood]

I've always suspected this was overblown. Also they will tell you to make sure the blade is installed and the lever cap tightened- for this to matter it would have to bend the frog casting and then in turn bend the plane body where the frog seats. I'm sure this happens to some tiny extent but it's got to be below the level of accuracy you can get from lapping anyways. That said, for hand lapping there's no reason to take any of it off, so why not leave it on.

I will defend lapping plane soles. The detractors start by declaring that soles don't need even need to be flat and none of the old timers cared about flatness, then in the next breath protest that how you'll ruin the sole by improper lapping, which is so hard as to be all but impossible.

Planes can work well with an out of flat sole...sometimes, and sometimes not. If I had a choice, I'd never choose a plane with an out of flat sole over one with a flat sole, and I don't think any sane person would.

So how hard is lapping, actually? I think it is more tedious than hard. It doesn't take months, but mere hours (or even minutes for smoothing planes). Sure it is possible to do a hack job of it, but we've all seen hack jobs done to things that are even simpler than lapping. The basic rules I'd give are:

- Use a lap that is at least twice as long as the plane (helps speed and accuracy)

-Check the sole carefully before beginning. Measure how out of flat it is, record your findings. This will help you know what the lapping is accomplishing.

-Use a coarse PSA sandpaper, decent quality aluminium oxide. 80 grit is good. Get a long roll (say 4" wide), because you need to...

-Change the paper extremely often. 80 grit will be cutting like fresh 320 grit after a couple of minutes. Seriously, you need to change the paper after no more than 5 minutes of lapping, probably sooner. Complaints about extremely long lapping sessions are related to not doing this, I suspect.

-Hold the plane just like you are going to take a shaving off a piece of wood, and push the plane in a straight line with normal planing pressure. Don't bear down and don't vary pressure front and back, keep it consistent. Only push the plane, lift it up on the back stroke. Don't go back and forth, don't do circular motions or figure 8s. Just a straight push. This helps minimize any rocking, which would produce a convex sole. In truth, off of a flat lap you are going to get a slightly convex sole anyways , but that's fine (even preferable IMO) if kept within reason. You don't want it getting out of hand though.

-Check your work periodically, compare with the beginning measurements. You should be improving things. If that's not happening you need to stop and think for a bit.


The larger planes like a #6 through 8 benefit from augmenting the lapping with spot removal of high spots, using a file, small sanding block, or machinists scraper. Use the lap to identify the high spots, and to smooth everything out at the end, but do most of the material removal with the spot removal tool. There is too much surface area on these planes to get much bite on the sandpaper. The paper on the lap needs to be changed even more often for larger planes.

[steven c newman]

Would you prefer the same plane looking like this?
420408
420409
420410
Different plane, same results, same amount of time to do..
420411
the before..and...
420412
After.
420413
(with the OEM iron and chipbreaker..)

Been rehabbing planes since the late 1980s....might have learned a thing or two....as to what works...and what is "hype"....

[Mike Cornwall]

Mike, It may be more helpful to try to describe what has been 'throwing you off with your jointer plane'. You would be surprised at how many odd behaviors a plane can commit.

It might even be good to start a new post.

It also helps to have your location known. Heck, if you are in the are of the Pacific Northwest you would be welcome to help. If you live in another area there are also other members who have always been willing to help others at getting their plane in working order.

jtk


Thanks Jim, it is out of gratitude and consideration for the people who have shared their valuable expertise with me, and whose kind instruction I am trying to take, that I wasn’t inclined to ask questions on the forum.
Mike siemsen told me to get the plane flat, and though I’ve heard others say it’s not necessary, I proceeded on his generous advice. Why ask if I’m not going to take his word for it?
I get asked for advice on my own field, and when I have shared my point of view, which has cost me plenty to cultivate, and then seen the asker keep asking elsewhere, it’s very discouraging with regard to humanity.

FWIW This thread is in response to my well-intentioned question to OP regarding disassembly of a plane for machining.

[Jim Koepke]

Mike siemsen told me to get the plane flat, and though I’ve heard others say it’s not necessary, I proceeded on his generous advice.

The sole of a plane needs to be flat enough to do its job properly. This is only my opinion and nothing more. In my experience if one wants to take super thin shavings with a smoother, having the sole flat enough to allow the blade to take a shaving without downward pressure on the plane's body is an important factor.

If a plane's sole is slightly concave, it might require the blade to be extended out of the mouth before it engages the wood. Once it does engage, the principles of physics will cause the blade to dig in an pull a much thicker shaving.

A convex sole will cause a different problem depending on how the arc aligns in relationship to the mouth. A little wear at the toe or heel is not going to be as big a problem.


FWIW This thread is in response to my well-intentioned question to OP regarding disassembly of a plane for machining.

There are differences between lapping at home and using machinery to true the sole of a plane. For machine work it may be necessary to disassemble the plane to mount it on a mill or surface grinder. Having never worked with either of these machines my knowledge is zilch.

For me, it is just as easy to lap a plane's sole with the frog in place if there isn't a need to remove it.

If it doesn't make a difference with the frog off, then likewise it won't make a difference with the frog in place.

My expectation about what Tom Bussey is stating in the first post of this thread is that it comes from his years of experience. He has worked on planes for years and has developed a respectable reputation for his work at restoring planes. His results speak for them self.

jtk

[Tom Trees]

Lapping a plane is easy, using an abrasive held down tight onto a surface plate that is longer than the plane's sole will make the plane have a convex profile.
A regular strip of sandpaper cut down halfway that is no wider than the plane, will stay put resting on another self adhesive strip stuck to the surface
plate and will last much longer because the loose grit gets pushed off the paper, so doesn't abrade the rest of the grit off.
Much quicker and cleaner to boot.
Don't trust anyone's advice on YouTube that doesn't get the feelers out in the end.
Shavings are no proof of success unless they're cap iron shavings adjusted to show a narrower shaving still under infulence.I
Tom

[Stewie Simpson]

When flattening the sole it’s important to have the blade in place (but retracted!) and under normal-use compression. This is especially the case with wedged wooden planes but applies to metal planes as well. The pressure applied by the lever cap presses the front of the frog against the sole, creating a slight, but real, bulge. If you flatten without the blade in place, this bulge will appear when you re-install the blade and all bets are off.

My own experience backs that being offered by the Ron Hock.

[Jim Koepke]

[edited]
Shavings are no proof of success unless they're cap iron shavings adjusted to show a narrower shaving still under infulence.
Tom

The meaning of the statement above eludes me. Can it be stated in a different way?

On a recent lapping of a #3 for another SMC member the final test shavings were made by pushing on the bottom of the tote without applying downward pressure on the plane. My recollection is it took a shaving under 0.001". Before the lapping the plane profile was convex from heel to toe. Before working on the sole it was almost impossible to take a controlled shaving with this plane.

In my opinion a plane should be able to take a controlled shaving through a full range of what the plane is used to do. It may be impressive for a jointer to take a sub thou shaving, but it isn't a requirement for its intended purpose. If a jointer had troubles taking 2 or 3 thousandths of an inch shavings, then my advice might be to find the cause and to see what could correct the situation.

jtk

[steven c newman]

Have done a hundred or so planes each way.....can't tell a bit of difference, either way.....

[Tom Trees]

I have noticed a heavier cut on the start of the work using a plane that is convex, leading to inaccuracy.
It becomes a lot more noticeable working on shorter stock with gnarly grain, whilst starting the cut with an iron that's needing a hone.
What should be a narrow shaving might not be if using a close set cap iron.
If one isn't used to using the cap fully, then my comment won't make sense, as its easy to take consistent narrow shavings with a convex sole,
if the cap iron is set further back than a 32", but try getting the same consistency with the cap iron's influence on some dense timbers and it becomes a problem.

I think the cap iron effect is useful and near essential for all my planes apart from a rough no.4.
Tom

[Jim Koepke]

What should be a narrow shaving might not be if using a close set cap iron.

Tom, by narrow do you mean what most people would call thin?

To me the descriptor 'narrow' is used in relation to the width of a shaving.


its easy to take consistent narrow shavings with a convex sole

This would be dependent on the geometry of the sole. With a hump in front of the mouth, it could be a bit tricky.

jtk

[Tom Trees]

Tom, by narrow do you mean what most people would call thin?

To me the descriptor 'narrow' is used in relation to the width of a shaving.



This would be dependent on the geometry of the sole. With a hump in front of the mouth, it could be a bit tricky.

jtk

Narrow, as in the width and thin, near fully influenced shavings, that can take a consistent shaving up through the middle of a
perfectly planed up piece.

Much different ballgame than an uninfluenced tearout prone setting on its lightest cut.
as there is not really any room atall for deciding cambers and its the depth adjustment that dictates the width of shaving.
Important if you want the slightest hollow for gluing up.

And regards to a convex plane in length, I wouldn't jump to mention a hump in front of the mouth as the problem I have noticed, no doubt that is another issue that one might have in relation to excessive blade projection, which might bring a plane to a halt or come close to it.
We could be describing the same thing though.
More of a matter of the plane not registering on the work until the cut is established.
Upon resharpening and advancing the cutter, I can see the back of the mouth somewhat, which probably shouldn't be visible.
These things only become more apparent when the cap iron's involved.
I would have never noticed that as being an issue before I used it to its potential.


Tom

[Anuj Prateek]

The meaning of the statement above eludes me. Can it be stated in a different way?

On a recent lapping of a #3 for another SMC member the final test shavings were made by pushing on the bottom of the tote without applying downward pressure on the plane. My recollection is it took a shaving under 0.001". Before the lapping the plane profile was convex from heel to toe. Before working on the sole it was almost impossible to take a controlled shaving with this plane.

In my opinion a plane should be able to take a controlled shaving through a full range of what the plane is used to do. It may be impressive for a jointer to take a sub thou shaving, but it isn't a requirement for its intended purpose. If a jointer had troubles taking 2 or 3 thousandths of an inch shavings, then my advice might be to find the cause and to see what could correct the situation.

jtk

This was probably my plane that you fixed.

Yup, micrometer showed < 0.001" shaving after you lapped the plane, sharpened the blade and fixed cap iron (which I had spoiled).

It still takes ~0.001" shavings and leaves surface glassy. Variance due to operator :)

After seeing you lap, I bought a cheap block plane from eBay I tried lapping it. Turned out okayish. I use it for rough flushing now.

I think, one should lap their nice planes themselves if and only if they are experienced and know what they are doing. Rest should practice on $10 planes or seek help.

[Jim Koepke]

This was probably my plane that you fixed.

Yep, since then another #3 size plane, a Dunlap #9 for my grandson, and an old #60-1/2 block plane have also been improved in the same way.

jtk