HELP! Chipbreaker bending blade

[Peter Pedisich]

Hi, any help with my problem described below is greatly appreciated!

I have a Craftsman No. 6 sized plane by Sargent that I've tuned up, but still have a few issues...

1) The chipbreaker bends the blade so much (fig. C) that even when the lever cap is engaged and clamped down I can still see light between the blade and the frog face about mid-way. The blade and chipbreaker are stock, and I flattened the face of the frog with a Diamond plate and checked it with a straightedge. The blade is about 0.085" thk.

2) The rear edge of the mouth is not ground 45 degrees to the sole, so it does not match the angle of the frog (fig. A), is this normal?

3) Due to the frog having to move forward to allow the blade to clear the rear edge of the mouth the blade is unsupported (fig. B), and I get chatter in red oak, although its fine in white pine.

Thanks in advance!

Pete

https://lh5.googleusercontent.com/-xx3p1l0L414/UGIcqmxADsI/AAAAAAAABIk/kQS5M4CHx30/s800/Chipbreaker%2520problem.jpg

https://lh5.googleusercontent.com/-nXuZuU-wfX8/UF-o48M6xBI/AAAAAAAABG4/4AaXGooNrkc/s800/IMG_7229.JPG

[Jim Matthews]

I wonder if you're over tensioning this? If the lever is over exerting force, there may be distortion of the casting in the middle.
How does everything line up, without the lever body installed?

If the chipbreaker exerts this much pressure, it's probably bent into the curve you have described.

I would have a look at it, disassembled, to see if it's flat.
The only purpose of a chip breaker is to keep the blade from chattering, so far as I can tell.

This should be a stock size part - if it's not up to snuff, a Hock blade replacement may be in order.

The mouth of the plane should not touch the iron, when the frog is properly bedded.
A couple strokes with a heavy mill bastard file should knock that back.

[Peter Pedisich]

Jim, thanks for the reply! see my answers in red.

I wonder if you're over tensioning this? If the lever is over exerting force, there may be distortion of the casting in the middle. The casting stays flat, the blade/chipbreaker combo are flexing, and the lever cap straighten it out a little but not perfectly flat against the frog.
How does everything line up, without the lever body installed? The chipbreaker bows the blade even more without the lever cap.

If the chipbreaker exerts this much pressure, it's probably bent into the curve you have described. I'll have to take a look at this tonight

I would have a look at it, disassembled, to see if it's flat. The blade/chipbreaker combo are like a banana, laid flat on bench there is an easy 3/16" under the middle.
The only purpose of a chip breaker is to keep the blade from chattering, so far as I can tell.

This should be a stock size part - if it's not up to snuff, a Hock blade replacement may be in order. I did try a Hock O1, but the slot was a hair too tight for the lateral adjuster tab, but even the Hock iron bends with this chipbreaker.

The mouth of the plane should not touch the iron, when the frog is properly bedded.
A couple strokes with a heavy mill bastard file should knock that back.Thanks, I'll try to file it tonight.

[David Weaver]

If the frog leaves a long length of unsupported iron, I would set the plane up so that the iron is resting on the casting and the frog is directly in line.

If the iron is completely straight without the cap iron applied, it's interesting it'd bend that much. BUT, it only matters that the iron touches the casting on both sides (left and right) close to the mouth and then one single point on the cap iron, and is snug. An iron never actually beds uniformly on a frog, it touches in various places.

If you really don't like the iron flexing (mine all flex some under the chipbreaker tension), then you can reduce the tension of the cap iron set some by putting the cap iron hump in a vise with soft jaws (your bench vise would be fine) and making it so that it is closer to touching the iron both at the front and the back of the hump, with the bias obviously toward the front.

Bed the iron as close to where it cuts, though (and if that's the casting, that's the casting), and rely on the cap iron to combat tearout, there's no need for closing the mouth in a fore plane, even if you're going to use it to smooth.

If the iron can't bed evenly across the back of the mouth when the frog is set just so it's doing that, then a tiny bit of careful filework on the casting to remove high spots should be in order.

It's been a while since we had this discussion, but it still remains true that my $11 millers falls smoother will easily hang with a tight-mouthed 55 degree infill smoother that cost me $300 in materials to make. Properly set, the bailey pattern plane is a genius design.

[george wilson]

The blade has a big groove in it that makes the blade weaker to bend than the iron. If all else fails,just get e thicker blade to compensate for the chip breaker having no groove.

[James Taglienti]

Often times -even in a properly machined bailey type plane- the cutter doesnt contact the plane body at all, even when the frog is in line with the back of the mouth. It depends on what bevel you put on the cutter. An acute angle with a normal secondary bevel typicaly will not touch. A single bevel has a better chance of hitting the back of the mouth.

I see this a lot when dismantling a plane to find the area under the frog packed with shavings.

I am not sure just how much better a plane will work with the cutter ground at an angle that will surely touch the body.

[Peter Pedisich]

Thanks for all your replies guys, it was helpful.
I worked on it a little more tonight, and I see that even with my Record 04 the blade is not perfectly flat against the frog face, but the chip breaker/cap iron on this Craftsman was putting too much pressure on the blade, so I worked on it a little, and its working well with white pine.

Doing this work gives me a newfound appreciation for Lie-Nielsen and Lee Valley planes. It also makes a compelling argument for a low angle plane without a chip breaker.

Thanks,

Pete

[David Weaver]

At least in some planes, Lee Valley aims for three key points of contact. The frog surface might be jeweled, but they know that making a plane work well and making it have a nice smooth even adjustment feel is dependent on consistency of contact.

If I make a plane that has a lever cap, I always bias the bed (undercut in the middle) so that the iron is contacting on the left and right at the mouth for sure and right in the middle at the top of the bed. It makes for a great performing plane and one that is predictable with its adjustment.

[Peter Pedisich]

At least in some planes, Lee Valley aims for three key points of contact. The frog surface might be jeweled, but they know that making a plane work well and making it have a nice smooth even adjustment feel is dependent on consistency of contact.

If I make a plane that has a lever cap, I always bias the bed (undercut in the middle) so that the iron is contacting on the left and right at the mouth for sure and right in the middle at the top of the bed. It makes for a great performing plane and one that is predictable with its adjustment.

David, thanks... I can see what you're saying and it makes sense, it's just funny that the way the frog face was cast on this plane, and another plane I fettled was the exact opposite of what you describe - high in the middle - but that's Murphy's Law #243.

[David Weaver]

Yeah, high in the middle is bad if it's high-centering the iron. The lever cap should press down enough even on a plane like that so that there is contact at the end of the iron on the bevel side close to where the cut is being made.