Iron bedding problem

[Cody Cantrell]

I have two lanes that have iron bedding issues. There is a gap between the iron and the frog. The frog is flat, but when I put the chip breaker on the iron it bows the iron creating a gap. Can this be adjusted out of the chipbreaker? The planes are a Stanley #4 type 7 and an Ohio No 07. Thanks for any help.

[Maurice Ungaro]

Do you have any pictures? Also, are these the original irons? They seem to be rather thin if the chip breaker is bowing them. Could be your technique if it happens the same way on two different planes.

[Jessica Pierce-LaRose]

The chipbreaker bows the iron before you even get it in the plane? Might just be too much curve in the front of the breaker.

[David Posey]

How is this affecting the performance of the plane? It could be the case that the lever cap is holding everything in place well enough that you don't need to do anything.

[Jim Koepke]

Cody,

Here is a post of mine on chip breaker tuning:

http://www.sawmillcreek.org/showthread.php?114373-Fettling-A-Plane-from-Junker-to-Jointer&p=1158886#post1158886

Your profile doesn't list your location. There may be a member close to you who is willing to spend some time to help you tune your planes.

jtk

[Cody Cantrell]

They ars recent purchases from the bay. They are both restoration projects that arent quite done yet so I am not sure if the bow affects performance. The Stanley has the original iron and the Ohio plane has a Millers Falls iron in it not sure what flavor the chipbreaker is. I will have to try and edit my profile but I am located in Knob Noster MO. Jim I will give your article a try and see if I can correct it. There is a good possibility it could be user error.

[David Weaver]

The iron in a bench plane never actually touches the frog all over. It might even be a bit advantageous to have this bow.

I would use the plane and not worry about it, few vintage irons are actually that straight, especially with the cap iron tensioned properly. It's not the straightness of the iron or the maximizing the touching on the frog that makes a plane work well, it's the tension the lever cap exerts on the cap iron, which in turn exerts pressure right at the edge of the iron and slightly back from the edge (pushing the very edge tight against the bottom of the frog), combined with the tension of at a single point further up on the frog under the lever cap cam, or whatever you'd call it.

You want the frog to be clean in the middle so the iron doesn't high center on anything or be kept from contacting at the top. that's generally not a problem. Lapping frogs and such things usually isn't necessary, and a file just across the surface lightly removing no metal, but only checking for something sticking up is probably a better idea. Lapping a frog hard may even be a little detrimental.

[Jim Koepke]

The iron in a bench plane never actually touches the frog all over. It might even be a bit advantageous to have this bow.

Interesting comment. I am not sure if my blades touch the frog all over, but I try to tune my planes to not being able to pass light between the blade and the frog.

Wouldn't this be the same concept as making the bed on a wooden plane to get full contact?

My curiosity is piqued as to how it might be advantageous.

jtk

[Sean Richards]

Interesting comment. I am not sure if my blades touch the frog all over, but I try to tune my planes to not being able to pass light between the blade and the frog.

Wouldn't this be the same concept as making the bed on a wooden plane to get full contact?

My curiosity is piqued as to how it might be advantageous.

jtk

Pretty sure most of my older Stanley and Record irons would show a slight curve along their length with the cap-iron screwed up tight. Mr. Weaver has pretty much already covered as to why this might be an advantage.

[Kees Heiden]

On some wooden planes you also see a slightly concave bedding. That's a lot better then convex!

[Chris Vandiver]

As David and others have said, it's only really important that the blade has good and full contact at the bottom of the frog or blade ramp(in the case of wooden planes). This is where all the business takes place.

[Jim Koepke]

Mr. Weaver has pretty much already covered as to why this might be an advantage.

After reading Mr. Weaver's post a few times I am still missing why there is an advantage to having the blade slightly off the frog.

My reasoning is that having full blade contact against the frog helps to dampen any resonance that could occur in an unsupported blade.

I am also trying to understand why full contact between the blade and the frog could lessen the performance of my planes. If my planes can be made to perform better by a little adjustment to my chip breakers, then I have a boat load of chip breakers to adjust.

If there is a better way, I not only want to know about it, but I like to understand why it is better.

jtk