plane blade question

[joshua giles]

I just picked up a sargent 3412 hand plane that was missing the cap iron and blade. I was considering making the new blades but was wondering if I could just make a .25" blade and eliminate the cap iron. I know that some people do this on Krenov style planes but was wondering if it could be done on this one.

[David Weaver]

If you have machining capability and can hollow out the middle and make a moveable insert that would engage the depth adjuster, you could probably do it.

You will still need a slot in the middle of the blade for the lever cap screw to fit through, and for the lateral adjuster to engage.

You could, of course, make at adjustable only by hammer, and bust out the adjuster and lateral adjuster, and then you would only have to slot the blade for the frog screw.

[joshua giles]

I work at a machine shop, so I will have no problem with the machining of the blade. However, I am new to handplanes and somewhat unsure as to how the moveable insert would need to ingage the adjuster. Would it just need to be a block that would ride along the slot?

[David Weaver]

I work at a machine shop, so I will have no problem with the machining of the blade. However, I am new to handplanes and somewhat unsure as to how the moveable insert would need to ingage the adjuster. Would it just need to be a block that would ride along the slot?

Yes. When you wear the iron of a bench plane, you inevitably move the chipbreaker further toward the non-business end of the iron. You need something that mimics that, which would be like a moving dog that fits in the slot in the middle of the iron, but that can lock down. You could also adjust depth with a brass hammer, though, and avoid the depth adjuster completely, and just make a slot wide enough that the lateral adjuster fits in it.

[Dale Sautter]

I don't know if you have seen A Galoot’s Infill Smoother at Derek's site... I just did a quick google search for a pic of your 3412 and it looks like a transitional plane, yes? Don't know if that might make things easier or not worthwhile, but it's another option.

[joshua giles]

Thanks for the help guys. I am leaning towards just creating a slot for the lateral adjuster and eliminating the depth adjuster, but I do have a couple of ideas as how to machine the blade and retain the depth adjuster. Will I lose any performance of the plane by eliminating the chip breaker and going with a thicker blade?

[David Weaver]

Only in wood where you would gain by setting the chipbreaker right up at the edge of the plane iron.

I don't think most people use their chipbreakers properly to eliminate tearout in reasonably thin shavings, anyway - they have to be tuned properly to do it and setting a chipbreaker a thousandth away from the plane edge is tedious.

At the price of a transitional, you could just get another sort of junky one and see which performs better.

The more easily noticed difference will probably be that the chips don't come out of the plane quite as nice and easy like they do with a chipbreaker pushing them pretty much straight up and out.

[Jim Koepke]

Thanks for the help guys. I am leaning towards just creating a slot for the lateral adjuster and eliminating the depth adjuster, but I do have a couple of ideas as how to machine the blade and retain the depth adjuster. Will I lose any performance of the plane by eliminating the chip breaker and going with a thicker blade?

You may find the lever cap will not hold the blade in place. The "bubble" on the chip breaker is part of the set up that helps the lever cap hold the blade.

jim

[joshua giles]

I was going to make the blade thicker in hopes that this would allow the lever cap to fit properly, but I am also considering just making the cap iron too instead of just a thicker blade. However I am unsure of a good way to put the correct bend on the end of the cap iron. I was considering machine a small die and with a radiused groove to allow the forming of the cap iron.

[Ron Hock]

It is my opinion that a thicker blade adds little to the performance of a plane. If I were designing a plane, I'd spec a thick (3/16"?) blade because thicker blades have the advantage of being (much) easier to hand hone with a hollow ground bevel. But simply adding thickness does not add stiffness at the cutting edge where it's most needed. The cap iron however does add rigidity right down at the cutting edge by pre-loading the cantilevered edge thus reducing its tendency to vibrate.

I wrote this up recently here: http://hocktools.wordpress.com/2010/...hick-and-thin/ (with a diagram, even.)

I think you'd be much better off making the blade only as much thicker as the plane can handle easily while making the cap iron as much thicker as you can get away with given the plane's mechanical constraints. A sharp blade with a proper cap iron and a tight mouth and your plane work as well as any.

[James Taglienti]

the stanley #25 low angle transitional plane has no chipbreaker per se- just a small disc of steel with the necessary cutouts to register on the planes adjusters. it is secured to the blade in the normal fashion. you could just copy that, or cut and grind a regular chipbreaker to match. then you'd have your cake and eat it too.

i just resoled a #35 with a 50* angle and as a result the throat is a little crowded... i might have to do that myself just so i can get the shavings to escape.

[joshua giles]

thanks for all the help with the situation. Im not sure exactly what I will do but I will post pictures with what ever solution I utilize.