Whittling/chip carving knife geometry

[Scott H]

I am thinking of making a few little carving knives for fun or gifts. I don't actually do much carving so I am wondering if someone can help give me a little direction.

I'm looking to do something in this genre to start:

pfeil Swiss made #1 Knife Chip Carving | Woodcraft

Buy the #1 Knife Chip Carving for sale online from Woodcraft. Visit us to order online or find your local Woodcraft store today!

www.woodcraft.com

https://www.amazon.com/Flexcut-Cutting-Carbon-Handle-KN12/dp/B000ZRZQ1G/

https://www.amazon.com/Cutting-knife-carving-general-purpose/dp/B071WCH6T4/

I have some 1/16" O1 stock and thinking of aiming for a scandi grind (one primary bevel, no secondary bevel, part of the blade remains flat above the bevel) with about a 15 degree included bevel angle for softer woods like basswood, maybe will make one with a higher angle for utility use in hardwoods.

Does that sounds reasonable or would you do something else if you were making this sort of carving knife?

 

[Scott H]

Just realized we have a woodcarving forum. If that is a better place I am OK with thread being moved.

 

[bob vaughan]

I cheated and used HSS saber saw blades. I was faced with getting a carving set for Boy Scout camp. Something our troop could use to carve neckerchief slides during down time. These were crude but effective. I set the blades with epoxy mixed with sawdust and never had a failure. This is an old photo. Once there were many more that filled the rack. I gave up Boy Scouts when my son graduated out and sent the whole batch to camp with others.

 

[Scott H]

Those look like a nice set of knives @bob vaughan! I was debating whether to pin the blades or just use epoxy by itself and sounds like epoxy alone will work nicely, which simplifies things a fair bit.

It looks like they are basically set in a saw kerf in a solid handle?

 

[bob vaughan]

It looks like they are basically set in a saw kerf in a solid handle?

Exactly, set in a kerf from a band saw.
The trick with epoxy is the sawdust mix as a fortifier. I think epoxy alone wouldn't be as durable or as strong.

 

[Mike Davis]

I made these for my wife last year. I bought the blades from Hock. I figured he can do a better job of hardening and tempering than I can.

 

[Scott H]

Progress so far, one 1-1/4" blade and one 1-3/4" blade. Blades are hardened, still need tempering and final sharpening, one handle is done and one is roughed out. Probably will make some more blade shapes after this. I am finding that doing a saw kerf slot is much easier than trying to shape a 1/16"x1/2"x1-1/2" mortise accurately so I will probably be doing more of that style in the future.

 

[Rwe2156]

What you're making there are whittling knives.

If you want to make a chip carving knife I would copy the profile of the Barton knife, which is identical to Pfeil. Its a fairly thin blade.

The Hock knife I have which looks like the one on the right posted above, is too thick for chip carving.

 

[Scott H]

What you're making there are whittling knives.

If you want to make a chip carving knife I would copy the profile of the Barton knife, which is identical to Pfeil. Its a fairly thin blade.

Yup, I'm starting with the whittling ones, probably gonna do chip carving ones next if these turn out alright. I do not know a lot about chip carving though so I really appreciate hearing peoples' preferences on blade design.

You don't happen to have a number for the thickness at the spine of the blade and how it is ground/beveled do you?

EDIT: Looking online it looks like the Wayne Barton chip carving knives are shaped like this in cross section?

I am also finding this video

that suggests you turn it into a convex grind by rounding out the transition from the flat grind area to the actual cutting bevel.

 

[pop-pop]

Yup, I'm starting with the whittling ones, probably gonna do chip carving ones next if these turn out alright. I do not know a lot about chip carving though so I really appreciate hearing peoples' preferences on blade design.

You don't happen to have a number for the thickness at the spine of the blade and how it is ground/beveled do you?

EDIT: Looking online it looks like the Wayne Barton chip carving knives are shaped like this in cross section?

Scott, I have the Wayne Barton knives that you are welcome to borrow for reference or practice.

 

[Scott H]

Scott, I have the Wayne Barton knives that you are welcome to borrow for reference or practice.

Thank you, maybe I will stop by at some point, I will let you know! Once again I am building tools without an original in hand to copy, you'd think I'd learn my lesson at some point.

 

[Rwe2156]

You don't happen to have a number for the thickness at the spine of the blade and how it is ground/beveled do you?

The Barton is a better knife, blade geometry and handle. Barton knife geometry may off a little due to numerous sharpenings.

 

[Scott H]

@Rwe2156 This is extremely helpful, thank you!

 

[Scott H]

After doing some research, I am going to aim for these cross sections given the 1/16 stock I have.

I will be continuing finishing the whittling knives with a "scandi grind" (flat until it hits the primary bevel, no secondary bevel) and then an approximately 15-20* inclusive primary bevel. These are already hardened and the 15* bevel is already mostly established.

The chip carving knives, based off of the examples seen above which have a clearly visible plunge line, will have a flat grind similar to most "general purpose" knives, where there is a shallow bevel (say about 5* inclusive) the entire face of the blade and then a blunter 15-20* inclusive primary bevel at the tip. In practice with sharpening and stropping the bevels will probably begin to round into each other gently, making a slightly convex shape.

It is definitely clear that blades that are thinner overall perform better but there is a point where they get very bendy, for example the folding pocket marking knife I have that is similar to what Paul Sellers uses is a scandi grind with a 15-17* angle on it and it cuts great, but it is 0.020-0.025" thick and feels too bendy for how long it is.

It is less clear to me how much the scandi vs flat grind matters but once this is done I will be in a position to compare them, apples to apples.

I am aiming for basswood for these and probably a thicker bevel would be needed for harder woods.

EDIT: I also have no idea what bevels the stab knives aka "secondary"/"#2" knives used in chip carving are, it seems like they are double beveled but a much more blunt angle? Will have to research more.

 

[Scott H]

I got the longer whittling knife sharpened, the bevels got away from me a little so they ended up uneven and way too acute (13* inclusive angle) -- edge was failing way too easily in normal use. I put a very light secondary bevel on it and now the edge holds up and stays very sharp.

I continue to be impressed by what you can do with O1 with just a blowtorch and vegetable oil and your eyeballs. It may not have a perfect industrial heat treat but it is still hardened and tempered tool steel and I am very pleased with it.

The pure scandi grind was also not great for gently scalloped cuts, you cannot "scoop" out of a cut at all since the bevel is in full contact with the wood. The very small secondary bevel helps in that regard.

Still need to epoxy the blade in the handle and also sharpen and finish the handle for the smaller knife. Then on to chip carving knives using what I have learned.

 

[Scott H]

The larger knife is done. Glad I finished this one before doing the smaller one, learning a lot.

 

[Scott H]

Interesting day troubleshooting. I hand sanded the final 25-30% of the bevels myself again using a jig, but since last time the bevels got away from me I paid much closer attention this time. It turns out that last time, my jig that used a 1-2-3 block as a height reference and a white pine stick registered against it, the metal block ate a huge hollow in the stick(!!) - which is why the angle got thrown off. And worse, the more I sanded, the shallower the angle got, explaining why I couldn't get rid of the flat on the edge with the jig. No wonder I got so frustrated last time.

For the smaller blade I made, I made a new jig using a hard maple square dowel, started with 40 grit instead of 80 grit, and put UHMW tape I had sitting around on the part of the square dowel that rubs on the 1-2-3 blocks. Worked perfectly. I also used a digital angle finder to try to keep track of the target angle, I ended up having to adjust to counter-act the bend in the blade as it thinned out by going up to 8.5 degrees a side. So it should be the 15-17 degree range for the primary bevel. I put a small convex secondary bevel on the blade and it cuts super well.

Now I just have to work on a handle and also sand off the black scale from heat treating and take the rest of the blade to a polish. I am also going to round the spine on this one gently because your thumb rubs against it a lot in use.

Eventually I'm going to learn to put bevels on with a belt sander or a grinder but I am nervous about messing them up cosmetically or overheating them since they are so small.

 

[Scott H]

The smaller detail knife is done. I made this second handle in a 2-part construction which worked fairly well and was easier to cut an accurate mortise for the blade tang. You can see a glue line from the epoxy but because the halves are book matched otherwise it is not that bad.

The other handle has darkened significantly, not sure if it is just graphite/ink/sharpening steel dust transferring from my fingers, the cherry darkening from sunlight, or what. I tried seeing if rubbing it with wax would clean it but it does not seem to have done a ton although the rag did get visibly dirty. They only have danish oil on them and they are cherry, any thoughts on what I could do to clean the first one (short of a ton of sanding) or at least protect the second one better?

My main concern is with dirt and probably a little alcohol/light solvent resistance, since sometimes I will use sharpie to make sure I am hitting the right angle and then use DNA to take that off, use window cleaner for sharpening lubricant, etc.

Maybe just a light coat of poly?

 

[Scott H]

Got to use the whittling knives I made to carve a prototype handles for the chip carving knives! Already useful.

@Rwe2156 @pop-pop Could I possibly trouble one of you for the side-to-side thickness of the wayne barton handle? I am gathering from the photos that the sides have parallel flats on them.

 

[pop-pop]

Got to use the whittling knives I made to carve a prototype handles for the chip carving knives! Already useful.

@Rwe2156 @pop-pop Could I possibly trouble one of you for the side-to-side thickness of the wayne barton handle? I am gathering from the photos that the sides have parallel flats on them.

As soon as I can find them.