Corrosion Resistance

[MichaelMouse]

Been roughing, in this case birch, and noticed that the bevels I was renewing already showed some surface corrosion even after a few minutes working this comparatively low acid wood.

Which makes me think that perhaps my observations that the edge-holding ability of my M2, powdered metal, high-carbon and A2 gouges are pretty much equal when cutting wet wood are valid. The limit is corrosion rather than heat, because I'm roughing wet and pretty well cold-soaked wood at slower speeds.

Anyone else have a suspicion that the true destroyer of edges in this application is corrosive dulling? Owners of other more exotic alloys have different experience? The grind angles on the various gouges are different, but I am normally paring wood under low tool pressure regardless, because I'm hoping to have a good elbow when I eventually reach Dustpan's age.

 

[dkulze]

Actually haven't noticed any significant corrosion when turning wet wood, Mike. I use HSS and powdered metal tools. I do notice abrasion from some woods that have a high silicate content, which I believe includes birch and aspen. Surprising how such a soft wood can dull the tools so quickly because of this.

I don't even notice any corrosion with oak, though it discolors my hands and the lathe in general quite a bit. Always figured that was abraided metal rather than corroded. Was I wrong?

Dietrich

 

[MichaelMouse]

It's not the ferric blue-stain corrosion like you get from woods with heavy tannins. This stuff is a white haze, or at least light haze that dulls the bright surface of the tool. Not the red oxide, though it could progress to it.

Couple weeks ago when I began this batch of blanks I forgot to cover the tablesaw (again) and the stuff left grey corrosion on the iron.

Can't confirm or deny heavy silicate content in yellow birch, though that would certainly be an edge equalizer. Have noticed that not wiping an edge used on wet known corrosive woods guarantees a trip to the grinder next time it's picked up, which is why I figured corrosion. I discount my roughers, because they're fed the bark and grit I don't take away with the bandsaw.

Advertising to the contrary, something out there's making a PM edge dull as fast as the others. Just wondered about other common or uncommon alloys, and couldn't dig up much on the net.

 

[Richard Baker]

Corrosion?

MM,
Is possible. Recall from a few (?) years ago, the reason the "new" stainless steel razor blades lasted so much longer than "blue blades" was mostly their corrosion resistance. The blue blades tended to loose their edge on the shelf overnight due to corrosion.

 

[Bill Boehme]

I can't say that I have seen any corrosion, but I have noticed that it does not take very long for pitch buildup to stop a gouge from cutting on mesquite. If I am diligent about keeping the bevel squeaky clean, I can go much longer before the tool needs sharpening.

Michael, I think that you could carry your observation a step further to try separating corrosion from dulling by having one gouge that you sharpen and then pack a wad of wet shavings around the business end for X number of hours and then see how well it cuts after corrosion has set in. My speculation is that the dulling may be more due to silica in the wood and pitch build up forcing you to change the AOA (angle of attack).

Bill

 

[MichaelMouse]

Does this count, Bill? LOL

 

[Bill Boehme]

It looks like I may be conducting the same experiment.

Bill

 

[dkulze]

Hmph. Amatures. At least you can still see your lathe.

Looks like what I get from turning oak, that black cruddy stuff.

Actually washes off easy if you use dandruff shampoo (the blue kind).

Dietrich

 

[Mike Gould]

Michael,

I have and older Crown 1/2" bowl gouge with the beech handle from about 4 years ago and a newer Crown Pro-PM 1/2" bowl gouge. I find the older one seems to cut better and hold the edge just as long as the PM.

I know the PM gouge is supposed to be better and hold an edge 3-4x longer but that is not what I see.

As a result....I rough turn bowls with my PM gouge and do all my finish cuts with the Older one. It gives me a better surface.

BTW, both gouges are sharpened at the same angle on the same stone with a Wolverine jig. So the tool shape and sharpness are the same.

I asked David Ellsworth about this at a demo a few years ago and he hadn't heard it before.

I wish I could still get the older crown tools but all that the retailers sell now is the newer PM stuff.

Just food for thought.
---Nailer---

 

[John Nicholas]

Older Crown Gouges

Michael,

I have and older Crown 1/2" bowl gouge with the beech handle from about 4 years ago and a newer Crown Pro-PM 1/2" bowl gouge. I find the older one seems to cut better and hold the edge just as long as the PM.

I wish I could still get the older crown tools but all that the retailers sell now is the newer PM stuff.

I find the same with my Crown ?Gouge that I've had for 2 years. Final cuts. Craft Supply carries this line.

John

 

[Gretch Flo]

Michael,

I have and older Crown 1/2" bowl gouge with the beech handle from about 4 years ago and a newer Crown Pro-PM 1/2" bowl gouge. I find the older one seems to cut better and hold the edge just as long as the PM.

I know the PM gouge is supposed to be better and hold an edge 3-4x longer but that is not what I see.


Could this be another example of "marketing" so we'll all go out and buy the latest toy???? or "upgrade"??? for more $$. A retired transmission engineer for Gen Motors goes on and on at our sat am coffee rendevous about the dumb public buying into front wheel drive (he was the engineer that had to design the transmission for the Toronado front wheel drive and has been on a crusade for years to get people/car industry to realize their mistake), antilock brakes (the computer cannot react fast enuf,), heavy duty shocks, rack and pinion steering, disc breaks etc etc. "It's all about making $ for the car industry". He 's talking to a person (me) that hardly knows where the windshield wiper fluid goes or the oil!!!!

Michael-I think you need a shower curtain!!!!Gretch

 

[MichaelMouse]

Michael-I think you need a shower curtain!!!!Gretch

I do, when I remember to use it, have a bag to cover the iron on my tablesaw. The cardboard behind the lathe that looks like Polish underwear keeps me from messing up the stuff on the pegboard behind it.

The real joy of cutting as I do is that cutting outside pretty much drops the shavings right into the horsey bag, while hollowing out flings it into the wall and drops to the table for retrieval without stooping. It's the first part of the hollowing, at shallow depth, that throws forward and into the wall, and only on the push stroke. The pull dumps into the bag. What you see is waste from at least four fairly large diameter bowls, so I'm not necessarily sloppy, just too lazy to clean up while in progress.

Took six more crammed seed/feed sacks up yesterday, and there's still a pallet of roughs waiting. Wood is starting to smell great, with that grand wine-like smell you get as the sugars first begin to ferment.

 

[Steve Worcester]

The cardboard behind the lathe that looks like Polish underwear ....

What is..... nevermind, I don't even want to know.

 

[Bill Boehme]

What is..... nevermind, I don't even want to know.

Aww ... go ahead and ask ... you want to know about the ... uh ... nevermind.

 

[Gretch Flo]

polish underwear

Aww ... go ahead and ask ... you want to know about the ... uh ... nevermind.

Same thing crossed my mind!!!! Gretch

 

[wdspinner]

"The real joy of cutting as I do is that cutting outside pretty much drops the shavings right into the horsey bag, while hollowing out flings it into the wall and drops to the table for retrieval without stooping."

Sounds to me like some good planning for various things in the shop could help in the collection of lathe curlies. :cool2: