Frog adjustment on a Stanley plane

[Phil Russell]

While replacing a newly sharpened blade on a No.4 plane (about 50 years old and owned by me from new) I noticed that the 'arms' of the frog were unevenly spaced at the blade slot in the sole plate. They were set back maybe 0.5mm but one was more set back than the other by maybe an extra 0.5mm. Thinking the frog must have slipped, I released the two fixing screws and tried to realign the frog. Strangely it was not possible to get the ends of the arms in perfect alignment with the blade slot. Close, maybe within 0.5mm, but not perfect. Now I stress that, to me, the plane was working as it should so maybe the frog issue does not matter; indeed I checked another plane (No.5) and, hey ho, the frog arms were also a little out of alignment by about 0.5mm.
But should the frog be perfectly aligned?
Cheers, Phil

 

[David C]

No. What matters is the ability to set a balanced/ even shaving, when sighting along the sole.

Best wishes, David Charlesworth

 

[Phil Russell]

Well, there you go. Thank you. In all the time I have owned the plane I had never noticed it.. but then I had never looked for it.
Cheers, Phil

 

[Jacob]

While replacing a newly sharpened blade on a No.4 plane (about 50 years old and owned by me from new) I noticed that the 'arms' of the frog were unevenly spaced at the blade slot in the sole plate. They were set back maybe 0.5mm but one was more set back than the other by maybe an extra 0.5mm. Thinking the frog must have slipped, I released the two fixing screws and tried to realign the frog. Strangely it was not possible to get the ends of the arms in perfect alignment with the blade slot. Close, maybe within 0.5mm, but not perfect. Now I stress that, to me, the plane was working as it should so maybe the frog issue does not matter; indeed I checked another plane (No.5) and, hey ho, the frog arms were also a little out of alignment by about 0.5mm.
But should the frog be perfectly aligned?
Cheers, Phil

My theory is that the face of the frog and the back of the mouth should be exactly in line, co planar, to give maximum support for the blade where it most needs it. In fact this is how it is shown in the old drawings, with the last 2 or 3 mm sited on the back of the mouth.
I think the frog was made loose because it was easier to manufacture with a bolt-on frog rather than machining all in one piece.
I expect plane enthusiasts from day one started fiddling with this and the addition of an 'adjusting' screw would suit them. They've been fiddling away to this day!
I reckon this should be the default position and everything else should be adjusted first before this is disturbed, if ever.

 

[D_W]

Planar, jacob. Co planar would be if they were in parallel but separate planes.

I agree with you, though - having the frog in line with the sole directly simplifies things. If there are tearout issues, the cap iron solves them better and there may be some thin irons that get better support by having the frog in line with the sole.

If a plane isn't manufactured perfectly and that's not possible but it works well, anyway, "it ain't broke, so don't fix it, or you might fix it broke".

 

[IWW]

Well I go with David Charlesworth. A frog that doesn't sit square to the sides is a bit of an eyesore to an obsessive type, but as long as all the flats are mating sweetly and it's not so far out of whack it restricts lateral adjustment (there's so much room inside a typical Bailey that's highly unlikely!), I see no problem. I don't think I've seen many post WW2 planes with a perfectly aligned frog, so there are probably many planes out there with slightly off-square frogs & owners blissfully unaware they have a 'problem'.

It's no different in effect from having your blade sharpened slightly off-square (many of mine are off a wee bit). The lateral adjuster easily takes care of both issues. Once the blade extrusion is set evenly, the fact the frog is ever so slightly out of square to the axis of the plane is not going to make an iota of difference to performance - in fact you can claim your (slightly) skewed blade is a performance enhancer.

The fact the discrepancy wasn't noticed for 50 years should tell us something....

Cheers,

 

[IWW]

My theory is that the face of the frog and the back of the mouth should be exactly in line, co planar, to give maximum support for the blade where it most needs it. In fact this is how it is shown in the old drawings, with the last 2 or 3 mm sited on the back of the mouth.
I think the frog was made loose because it was easier to manufacture with a bolt-on frog rather than machining all in one piece.....

You have me confused, Jacob. The original Bailey frog sits on two sets of 'flats' which have varied a bit in extent over time, but the principle that the frog is supported at the toe (behind he mouth) & under the mounting screws remained constant until some point late in the 20thC when some accountant genius decided they could shave a few pence off the cost by dispensing with the the flats behind the mouth. The toe of the frog is then cantilevered and not terribly stable planing anything harder than warm butter. Consequently, such planes are absolute pigs to use - if you ever encounter one, do the woodworking world a favour & drop it in the nearest bin.

Blades are typically supported only by the frog, given the thickness of a typical sole & blade (the propensity for us moderns to fit thicker blades means a longer blade bevel & the last contact point of blade & frog moves even higher up). It sort of has to be that way, so you can move the frog back without the blade bevel fouling the bevel on the sole. Frog & sole bevels are only in alignment with the frog at one point of its potential range of travel.

I reckon that frog adjusting screw is one of the more useless "imrovements" Stanley ever made - owners got by perfectly happily for decades without it. Frog position is a 'close enough is good enough' sort of thing, it certainly doesn't require micro adjustment! And unlike a "Bedrock", on the Bailey frog you have to pull everything out to adjust its position, so the 'convenience' it might add is insignificant. If the little tag on the frog that engages the screw, or the screw itself is missing (not all that uncommon), I say don't worry a bit, you'll never miss them...

Just the opinions of a GOM....

 

[toolsntat]

Yes, in my opinion, the flat of the frog should be parallel and in line with the mouth opening.
You say it will not line up laterally, even when loosening the frog fixing screws. I assume you have a frog adjustment screw.
Sometimes the metal plate on the frog that slots into the adjuster is tightened up a bit off centre. This will allow the rear of the frog to go to one side more than the other.
Loosen the screw that holds the plate and then try to make the adjustment you're speaking of.
Cheers Andy

 

[Jacob]

...Blades are typically supported only by the frog, given the thickness of a typical sole & blade (the propensity for us moderns to fit thicker blades means a longer blade bevel & the last contact point of blade & frog moves even higher up).

Except that the blade in a normal setting position and with a normal bevel extends beyond the frog. If you slide the frog back eventually the back of the blade is up against the back of the mouth (on a normal, not bedrock, design)

........ Frog & sole bevels are only in alignment with the frog at one point of its potential range of travel.

And that's the point where the back of the blade meets the back of the mouth. It's difficult to see but that's how it is with all my very ordinary Records/Stanleys etc.
The whole logic of the Bailey design is to give maximum support and mass (frog+cap+lever cap) to a thin and easily removable/sharpenable blade, to make it perform as well as the thick blade of an old woody. The little extra support given by the back of the mouth is where it is most needed.

 

[IWW]

Except that the blade in a normal setting position and with a normal bevel extends beyond the frog. If you slide the frog back eventually the back of the blade is up against the back of the mouth (on a normal, not bedrock, design)And that's the point where the back of the blade meets the back of the mouth. It's difficult to see but that's how it is with all my very ordinary Records/Stanleys etc.
The whole logic of the Bailey design is to give maximum support and mass (frog+cap+lever cap) to a thin and easily removable/sharpenable blade, to make it perform as well as the thick blade of an old woody. The little extra support given by the back of the mouth is where it is most needed.

Well Jacob, I can only speak for the 3 Bailey type planes I own (2 (English Stanleys and a circa 1918 51/2). The flats machined on the sole behind the mouth on the 1918 model bring the sole thickness to quite a bit less than 3mm, while the two English planes are ~3mm thick at that point (I have no way to get an exact measurement without a lot of faffing about, but they are in that ball park).

The thinnest blade I have at present is 2.76mm thick. So lets do some trig, rounding the blade thickness to 2.5mm. I come up with figures like this:

So both by calculation and such empirical evidence as I'm able to muster (sticking a feeler gauge up under the blade till it stops), the blade bevel extends well above the sole on any of my planes. Given the above figures, I would have to expose the cutting edge of the blade ~2mm before the top of the blade bevel would extend past the bottom of the frog. I'm unlikely ever to need to do that.

Your planes may be different; if the soles are machined a little thicker than mine and you're using thinner 'original' blades, maybe you can get the back of your blades resting on the sole at normal blade esposures. My question is, would that confer any great benefits? It could make adjustment awkward if the frog is pulled back for a large mouth because the blade bevel might foul the sole bevel. If the frog is properly machined and sitting firmly on its receiving flats on the sole, it can be considered a structural part of the sole & will give as much support & damping as required. To my way of thinking it is not necessary & possibly not desirable that the blade rest on the sole.

The old infills with their grossly thick blades needed a 'blade block' to increase the thickness behind the mouth & ensure the blade was resting on metal.


Cheers,

Edit, before anyone else points it out, I should have used the other arm of the blade triangle (5.4mm) in my clculation. This is the crucial dimension as it's parallel to the blade bed, so the blade back will meet the frog 5.4mm from the tip of the sole bevel in this example. Still comfortably above the sole....

 

[D_W]

stock stanley blades are about .08, or about 2mm. a single bevel sharpener may use something like 3
0 degrees (Especially if sharpening on a hollow).

That means the unsupported length (the adjacent side) is about 3.5mm.

I measure my 4 at about .18" past the end of the frog, or about 4.5mm. That's not a world changing difference (1 mm), but it's a little bit of potential non-support.

The non-standard planes with a gap between the frog and sole pose a bigger problem.

 

[Jacob]

Well Jacob, I can only speak for the 3 Bailey type planes I own (2 (English Stanleys and a circa 1918 51/2). The flats machined on the sole behind the mouth on the 1918 model bring the sole thickness to quite a bit less than 3mm, while the two English planes are ~3mm thick at that point (I have no way to get an exact measurement without a lot of faffing about, but they are in that ball park).

The thinnest blade I have at present is 2.76mm thick. So lets do some trig, rounding the blade thickness to 2.5mm. I come up with figures like this: View attachment 99534

So both by calculation and such empirical evidence as I'm able to muster (sticking a feeler gauge up under the blade till it stops), the blade bevel extends well above the sole on any of my planes. Given the above figures, I would have to expose the cutting edge of the blade ~2mm before the top of the blade bevel would extend past the bottom of the frog. I'm unlikely ever to need to do that.

Your planes may be different; if the soles are machined a little thicker than mine and you're using thinner 'original' blades, maybe you can get the back of your blades resting on the sole at normal blade esposures. My question is, would that confer any great benefits? It could make adjustment awkward if the frog is pulled back for a large mouth because the blade bevel might foul the sole bevel. If the frog is properly machined and sitting firmly on its receiving flats on the sole, it can be considered a structural part of the sole & will give as much support & damping as required. To my way of thinking it is not necessary & possibly not desirable that the blade rest on the sole.

The old infills with their grossly thick blades needed a 'blade block' to increase the thickness behind the mouth & ensure the blade was resting on metal.


Cheers,

Edit, before anyone else points it out, I should have used the other arm of the blade triangle (5.4mm) in my clculation. This is the crucial dimension as it's parallel to the blade bed, so the blade back will meet the frog 5.4mm from the tip of the sole bevel in this example. Still comfortably above the sole....

30º is the normal honing angle.
n.b. using the thinner "original" blades is the whole point of the Stanley design; for ease of sharpening - no grinding or primary/secondary bevel nonsense. If you use a thicker one and an unnecessarily shallow honing angle you are throwing away the principle Stanley design feature, though you still have the ease of adjustment/removal/replacement.

 

[IWW]

30º is the normal honing angle.

Yep,and that's about what I hone at, but I grind a bevel somewhat less than 30.

n.b. using the thinner "original" blades is the whole point of the Stanley design; for ease of sharpening - no grinding or primary/secondary bevel nonsense. If you use a thicker one and an unnecessarily shallow honing angle you are throwing away the principle Stanley design feature, though you still have the ease of adjustment/removal/replacement.

Well, to each his own, Jacob. Indeed the thin blades were a selling point back in 1870 when few woodworkers had access to a grinder driven by other than potato power. I'm a hand-tool enthusiast, but I've owned a bench grinder for close to 50 years, & even learned to use it without cooking the tools during the first 20 or so (a CBN wheel now makes it almost idiot-proof). Grinding a lower bevel & honing just the tip doesn't seem like "nonsense" to me - "practical" seems more appropriate.

P'raps it's just the harder woods we work with down here, but the thicker "modern" blades feel much nicer in my Baileys, and all last longer between sharpenings than any original Stanley or Record blade I've struck (fewer than a dozen, so sample size isn't huge). From my perspective, slightly thicker, somewhat tougher blades confer appreciable benefits and the extra effort to maintain them is insignificant.

Your mileage obviously varies.
All good....

Ian

 

[Jacob]

Yep,and that's about what I hone at, but I grind a bevel somewhat less than 30.



Well, to each his own, Jacob. Indeed the thin blades were a selling point back in 1870 when few woodworkers had access to a grinder driven by other than potato power. I'm a hand-tool enthusiast, but I've owned a bench grinder for close to 50 years, & even learned to use it without cooking the tools during the first 20 or so (a CBN wheel now makes it almost silly person-proof). Grinding a lower bevel & honing just the tip doesn't seem like "nonsense" to me - "practical" seems more appropriate.

P'raps it's just the harder woods we work with down here, but the thicker "modern" blades feel much nicer in my Baileys, and all last longer between sharpenings than any original Stanley or Record blade I've struck (fewer than a dozen, so sample size isn't huge). From my perspective, slightly thicker, somewhat tougher blades confer appreciable benefits and the extra effort to maintain them is insignificant.

Your mileage obviously varies.
All good....

Ian

I have various grinders too but I found eventually that just an energetic freehand hone of the whole bevel was actually less trouble, with a thin blade. Even better if laminated with a soft back. A bit like Paul Sellers' method but on oil stones. By "nonsense" I meant the belief that some seem to have, that grind at 25º and hone at 30º was somehow an absolute rule. It isn't, but it is good default advice to somebody new to the thing, especially thicker blades on wide chisels.