Proper Default Frog Position

[yan89]

Hi all

Just after some advice on the default position of the frog in jack and smoothing planes. I found a blog post by Paul Sellers which has images of cutaways showing his preferred default alignment here - flush with the back of the throat. Is this the consensus positioning? Both my Quangsheng No. 5 and No. 4 were preset about 4mm back (see picture), and whilst I followed Cosman and John McGrath’s ‘setting up a new plane out of the box’ videos, I didn’t touch the frog’s positioning screw save for getting the grease off them.

I know I may need to reposition the frog to close the throat at some point down the line, depending on the work I’m doing, but to begin with I’m just going to be making Nick Nacks and boxes until I learn the craft some more.

Is there a default position, or does it not really matter unless I intend to close the throat?

Any advice appreciated

 

[D_W]

Even with the bottom of the casting and use the cap iron to control tearout. That's about it. If a plane has a step of unsupported area between the frog and casting because the frog doesn't go all the way to the casting, it's better to not buy it.

I would assume the luban/qs is a copy of the LN plane so it should be fine. LN planes are the only ones I can think of with that look in the frog and WR changed planes in the US (QS tool made) to look less inside like LN after a dispute.

 

[Ttrees]

I've yet to see a real reason to move the frog forward.
Shearing cuts whilst doing decorative beveling on end grain is about the best
excuse, for getting the most polished surface.
The tight mouth is so the corner won't drop into the mouth.

Thanks to D_W, I learned how a double iron plane should be set up. as most gurus don't want their students to know.
I've never altered the wear of a plane to enable a tight mouth, (so the cap iron could be set close without jamming),
Having experienced much effort with a somewhat tight mouth in the past, whilst trying to use the cap iron, and the mouth for absolutely no reason!.

Thankfully tearout still prevailed on some examples, and eventually... I bit the bullet!
(after trying to buy myself out of it with no.80 & no.3 )

That was the final straw, and took going back to the start of what D_W
was actually saying.
(A woodcentral article he made a decade or so, ago)

More influence from the cap iron, and less from someone trying to sell things.
Clear to see if a smoother has enough, and when it doesn't.

It's simply irrefutable, yet most teacher gurus think that they will get away
(as in not loose a lot of their following) with trying to pull the wool over folks eyes, suggesting that it doesn't work.

And for those who think this is only for the folks who plane see through shavings , just as well mentioning even Mr Chickadee, (not a total woodworking based show) has got this.
Easy to figure out if you're only making a living selling TV watch hours
and not other things!

Look at the article and you will have your own opinion afterwards...
That's if you don't try and mix with others/your own opinions.

https://www.vlynx.com/articles/test/articles_935.shtml

 

[CMax]

Excellent article sums it up well.

 

[MikeK]

I checked a few of my LN smoothing planes, and the frogs are about 2mm behind the rear of the throat. There is still a slight gap between the bevel of the iron and the sole of the plane when the iron is extended for normal cutting. I think if I moved the frog back to about 4mm, the bevel of the iron would touch the top of the throat before it extended through the sole and would not be useful.

 

[Ttrees]

I'd imagine it takes a giant leap for many to hone their cap iron's on the premium
tools to such a steep angle.
Good job we have folks like Derek Cohen to give a voice of reason from a premium tool buyers perspective, as he has many nice tools to choose from, and still regards a cap iron to be commissioned.
As many newcomers might go the premium route instead of the old tools,
and try to squeeze as much moneys worth as they can get. attempting to utilize the more solid frog design feature which is adjustable on the fly, but is best left alone for 99% of tasks.

Tom

 

[MikeK]

I'd imagine it takes a giant leap for many to hone their cap iron's on the premium
tools to such a steep angle.
Good job we have folks like Derek Cohen to give a premium tool buyer a voice of reason, as he has many nice tools to choose from, and still regards a cap iron to be commissioned.
As many newcomers might go the premium route instead of the old tools,
and try to squeeze as much moneys worth as they can get. attempting to utilize the more solid frog design feature which is best left alone.

Tom

When I took David Charlesworth's Tool Tuning course, all of my LN planes benefited from some fettling, some more than others, but all received work on the chip breaker (cap iron). None needed any work on the sole, sides, frog base, or frog, but all of these surfaces were checked. The edge of the chip breaker that contacts the plane iron was honed to about a 1.5-degree clearance angle across its width using a diamond stone for contact area and support block for the other end (I had to consult my notes for the angle).

In my limited experience, one difference between the premium tools and inexpensive tools is the level of effort required to bring each to the same standard. Here is a 15-minute video by Matt Estlea where he spends about nine and a half hours to bring a £39 Amazon Basics No. 4 hand plane to a high standard.



If I was in my 20's and on a limited budget, I might go this route because most of the tasks in the video were one time events. However, I'm at a stage in my life where time is the resource I cannot control.

 

[Ttrees]

IIRC I think Charlesworth recommended a lesser, can't remember if it were 35 or 45 degrees, whichever it was, it wasn't enough to work as intended.
Perhaps he decided to go steeper fairly recently, (as in whenever he appeared on that skype conversation with Cosman)
but he was still a believer in having a tight mouth, so still was in the woods at the time.

You'd think Cosman might have even questioned, even for just using a panel plane with slightly more cap iron influence, apparently not.

Tom

 

[MikeK]

IIRC I think Charlesworth recommended a lesser, can't remember if it were 35 or 45 degrees, whichever it was, it wasn't enough to work as intended.

From my 2019 notes, as well as the videos, here are the key angles for any of the bevel down bench planes:

Plane Iron (no camber)
Primary angle with Tormek: 25 degrees
(leave about 0.5mm unfinished at the edge for the secondary and polishing steps)
Secondary angle with 800-grit water stone: 33 degrees
Polish angle with 10000 grit water stone: 35 degrees
Ruler Trick with 10000 grit water stone

Chip Breaker
The primary angle on the top of the LN chip breaker is 25 degrees. This will remain, but a secondary angle of 45 degrees will be honed at the edge.

Clearance angle at contact edge using 600 mesh diamond stone: 1.5 degrees
(work the CB until there is 1mm of fresh steel visible at edge)
Secondary angle on top of CB with 600 mesh diamond stone: 45 degrees
(work the secondary angle until a wire edge forms on contact side)

Repeat the steps above using the 1200 mesh diamond stone and single light alternating strokes until the wire edge is gone. This is time consuming, but only has to be done once.

Camber
When establishing a camber on a plane iron, he used a thin strip of 0.4mm to 0.5mm plastic shim along the length of one side of the 800 grit stone to lift one side of the iron. This is to remove metal from only the first quarter of the edge at 33 degrees. After about 25 strokes on one side, the shim was moved to the other side of the 800 grit stone to repeat the process for the other side. Once the edges were symmetrical, then the shim was removed and work began on the middle section of the iron. This took 3 to 5 strokes with firm finger pressure at each of the newly created apexes until a wire edge could be felt along the plane iron. The camber was then polished with the 10000 grit stone at 35 degrees using four gentle strokes while varying the finger pressure at the sides of the iron to produce a uniform polished edge. Finish with the ruler trick on the back.

The camber created using this method is slight, unlike the camber on a scrub plane. When the edge is viewed with respect to a flat surface, the gap at the edges is about 0.2mm, or a double layer of printer paper. All of the bench planes I brought to the course now have cambered irons.

When I took his Tool Tuning course in 2019, he used the LN honing guide for all chisels, plane irons, and chip breakers. He had several Eclipse honing guides, but his instruction with me was with the LN honing guide, since that is what I brought. In his Plane Sharpening video, David uses the Eclipse honing guide to touch up an existing camber, but uses the LN honing guide to establish a new camber.

 

[Derek Cohen (Perth Oz)]

Hi all

Just after some advice on the default position of the frog in jack and smoothing planes. I found a blog post by Paul Sellers which has images of cutaways showing his preferred default alignment here - flush with the back of the throat. Is this the consensus positioning? Both my Quangsheng No. 5 and No. 4 were preset about 4mm back (see picture), and whilst I followed Cosman and John McGrath’s ‘setting up a new plane out of the box’ videos, I didn’t touch the frog’s positioning screw save for getting the grease off them.

I know I may need to reposition the frog to close the throat at some point down the line, depending on the work I’m doing, but to begin with I’m just going to be making Nick Nacks and boxes until I learn the craft some more.

Is there a default position, or does it not really matter unless I intend to close the throat?

Any advice appreciated

As I understand, Sellers prefers a closed mouth for tearout control when using Stanley or Record a #4. That, and working with straight grained softer woods. This works well since it does not really test the plane or blade that much. Rob Cosman prefers small mouth/ultra sharp/very fine shaving, and he is quite successful on harder woods .. but I do not know how interlocked they are (I have my doubts).

Both these guys reject bevel up planes, mainly because they are selling their schtick, and because (Sellers especially) deliberately sets the BU planes to fail by using an inappropriately low cutting angle. Now BU planes are not the issue in this thread, but the point I make is that Sellers is rather rigid in his approach.

There is a sweet spot for the frog. The frog needs to support the blade, but it cannot do so to its best if pulled back too far. The ideal spot is where the back of the blade can rest on the mouth bevel without being tilted forward.

I predominantly work with hard woods, and many of them have interlocked grain. Or the panels making up a book-matched join force you to plane partially into the grain. Consequently, setting up a closed up chipbreaker is something I live and breathe. For this to work, there needs to be clearance for the shavings. This means that a tight mouth is the enemy of the frog set up. It needs to be kept in mind that a large mouth opening has no impact on the quality of the cut. Still, I aim to close up the mouth as much as possible (while still leaving space for the shaving) as it is easier to position the blade when reference sole edges are closer.

Since blade thickness may vary from the original, especially if one uses an aftermarket blade, this means that the frog may need to be adjusted a little in-or-out. Ultimately, it is a compromise. Once set up, the position does not need to be changed.

Regards from Perth

Derek

 

[yan89]

As always, wonderfully insightful responses. What a great forum.

Sincerely,

Someone with a lot to learn!

 

[Limey Lurker]

In this pic, the plane iron is resting on the frog If the frog is behind the sole, the iron will be supported only at the top edge of the sole, and at the cap screw. This can force the iron and cap iron into a curve, and I once saw a plane where the owner told me that he had moved back the frog to it's maximum. ad had to use so much weight to lock the cap lever that the cap screw had stripped the thread in the frog.

 

[MikeJhn]

stripped the thread in the frog.

Do you mean stripped the rivet in the frog, I will get my coat.

 

[thetyreman]

IIRC I think Charlesworth recommended a lesser, can't remember if it were 35 or 45 degrees, whichever it was, it wasn't enough to work as intended.
Perhaps he decided to go steeper fairly recently, (as in whenever he appeared on that skype conversation with Cosman)
but he was still a believer in having a tight mouth, so still was in the woods at the time.

You'd think Cosman might have even questioned, even for just using a panel plane with slightly more cap iron influence, apparently not.

Tom

he recommended 45 degrees on the cap iron, I found it's perfect, charlesworth knew what he was doing, there is no need to go higher.

 

[Droogs]

I was taught frog position is entirely dependent on what iron is in the plane. The principle of where/how/why the frog should sit never changes just its position. If using traditional tapered irons then the frog will be slightly forward of where it would sit for modern thicker flat irons. This being due to both thickness and the result of the back of the irons having different points at where they will present to the mating face of the frog. The newer type irons start to mate at a slightly higher point a bit further back to the rear of the mouth. Therefore in theory the frog needs to be back slightly in order to get the benefits of the frogs face mating to the iron in order to help prevent chatter. As it was explained to me, the point at which the bevel begins on the back of the iron should fully mate to the top edge of the rear of the mouth and the frog be positioned to support as much of the irons back as possible. Mouth width has no bearing at all in this as has been said above the magic of guiding the shaving is done by the cap iron which should mate to the front of the iron with its front edge and with no caps at all in order to both break the strands of the saving and curl it round and up away from the body of the plane. This compression is the main factor that prevents tearout as it forces the fibres down onto the surface (only for an instant) enough that the sharp edge of the iron can then cut and lift the shaving cleanly.

The only real problems I have encountered when fettling a plane, has been with the cap iron having moved (warped) over time or rust damage to the edge. I have also found that a very highly polished front to the cap iron really doe help it do its job.

 

[MikeK]

View attachment 141656
In this pic, the plane iron is resting on the frog If the frog is behind the sole, the iron will be supported only at the top edge of the sole, and at the cap screw. This can force the iron and cap iron into a curve, and I once saw a plane where the owner told me that he had moved back the frog to it's maximum. ad had to use so much weight to lock the cap lever that the cap screw had stripped the thread in the frog.

On the Lie Nielsen planes (at least the 4, 4-1/2, 5-1/2 and 7), the mating surface on the sole for the frog is milled at a 20-degree angle all the way to the throat. The frog does not slide parallel to the base of the sole, but on a slope. This allows the leading edge of the frog to be back from the opening of the throat without creating any interference problems with the iron and the majority of the iron's bevel side is n direct contact with the frog.

 

[D_W]

he recommended 45 degrees on the cap iron, I found it's perfect, charlesworth knew what he was doing, there is no need to go higher.

This isn't quite right. 50-60 degrees works better, and if one is able to control the very last bit of an iron, steeper at the very tip (just not a big tall wall).

David Charlesworth didn't use the cap iron on planes for anything until at least 2012. He did at least adopt it when he saw that it worked.

David's articles and videos were a good place to learn basic principles, but they would be limiting to someone who wants to do more by hand than to do light fitting and smoothing. Ultimately, heavier work with planes - especially middle work - leads to much greater proficiency fitting and smoothing. Faster, more intuitive work. I think it's also hobby lengthening in terms of the physical aspect. The last couple of days as I (as a fat lug) scraped about 650 or 700SF of floor in two days, the only reason I was able to do it was what i learned about body position and fatigue.

what's good for a beginner can be very limiting just after that, and rigid body positions stooped over with work right at eye level is very fatiguing.

At any rate, back to the cap, rounding the cap over with a very tiny terminus that's steep is the best compromise between resistance and tearout protection.

 

[Ttrees]

he recommended 45 degrees on the cap iron, I found it's perfect, charlesworth knew what he was doing, there is no need to go higher.

If you use the cap iron to it's potential, you won't have to "suck it and see"
as Charlesworth mentioned before.
Irrefutable evidence if you try it for yourself.

All the best
Tom