Surprised, dissapointed, puzzeled

[David Dalzell]

:confused: I made two dovetailed drawers today. Both have four tails/pins at each corner. The wood was straight grain (quarter sawn) fir. A softwood. I was trying out two new sets of chisels. Actually one chisel from each set. One is the Veritas PM-V11 at 1/2" the other is LN A-2 also at 1/2". Both sets are fairly new. The LNs I have had for about one year and have used frequently to cut dovetails in Walnut, Ash, and Cherry. No problems with the LNs. Normal dulling and touch-up sharpening. The Veritas PM-V11 is new and this is the first actual use, other than doodling around just to see how they behaved. Both chisels have a 30 deg bevel with an additional 2 deg micro-bevel. In other words the cutting edge is 32 deg. Both are sharpened to 8000 grit with a waterstone and then polished with Veritas green compound on a piece of MDF.

When marking for the dovetail baselines (using a wheel gauge) I noted that the Summer wood rings (dark) were noticeably harder than the Spring wood rings (light). Hard enough that my wheel gauge did not want to score them. Basically the wheel edge rode over the dark rings and left little, if any, scoring. I did not pay much attention to this. Just noticed it.

Cutting the dovetails to the marked lines was no problem. Then came the chopping out of the waste. This is when things became surprising. I did the first drawer with the LN A-2 chisel and the second drawer with the Veritas PM-V11 chisel. I just wanted to compare the edge retention of both. What a surprise. Half way through the first drawer the LN A-2 was looking very bad. The edge had failed badly. I could see and fingernail feel the ragged edge. It had notches in the edge, rounded over. Serious enough that I needed to go down to 1000 grit waterstone to clean it up, and thence to the 8000 grit and green rouge polish. When I finished the first drawer I again had the some ragged edge and had to redo the edge with 1000 grit followed by 8000 grit, then the green rouge polish. To say the least I was rather unhappy and puzzled about the poor performance of the LN A-2 chisel.

I then started the second drawer using the Veritas PM-V11 chisel. Lo and behold, I had exactly the same results with the Veritas PM-V11 chisel. Halfway through the drawer and the edge was ragged, in the same way as the LN chisel, and I had to redo the edge. At the end of the second drawer the edge was equally bad as at the halfway point. In other words the edge retention seemed to be the same with both the LN A-2 and the Veritas PM-V11 with this wood.

This was all a great surprise to me. Is the Summer wood (dark/hard) in qtr sawn fir really hard enough to cause this edge failure? Is something else at work here? I really don't know. Has anybody else experienced similar edge failures under similar conditions? Any ideas?

[Brian Holcombe]

I recently chopped mortises in a walnut tabletop, walnut is typically a very easy wood to work. The particular section I was chopping into was heavily interlocked and was hard like stone.

So, not everything is normal, you can hit sections of woods that are truly hellish to cut for what seems to be no reason at all.

I do try to avoid damaging my tools when I hit stuff like this, so I will slow down and take smaller cuts, relieving the cut if need be.

[Andrew Hughes]

Hi David, I also have same problem with Dougfir.Its got to be the hard and soft layers that need two different bevels.Too steep and the soft wood crushes too low and the hard layers break the edge.
I use Japaneese chisels but still need to be careful and take small cuts like Brian suggested.Aj

[Marc Seguin]

Douglas fir is a lot harder and more problematic than most people give it credit for. It's a 'softwood' categorically but as you've discovered the dark rings can be pretty darn hard. Around here it's the predominant tree. As such I get lots of chances to reclaim old growth douglas fir that was used for studs in old buildings. You can't drive nails into it without pilot holes.

[Reinis Kanders]

I am making two benchtops from tight grained Doug fir, it is tough on planes as well. Even pmv steel does not like those knots. I was lucky that I found more or less knot free 2x12s.

One of the benches is Paul Sellers hybrid with apron that has a 8x6 inch 5/8 deep dados for legs and a wedge. Those dados took some effort to chop out, about an hour for first and 30min for the last. In Seller's video it looked easy in the pine he was using, not the case with this fir.

I used Narex 1.25 inch chisel at 35 degrees, but ended up with 1 inch chisel at around 30 degrees because it seemed to work better. I refreshed the edge frequently. Steel was not chipping though. I do have a set of Veritas pmv chisels, but like narex better for banging out the big stuff. Maybe you just need to grind off a bit of steel that is brittle.

[ian maybury]

One of the peculiarites in this game seems to be just how close to the wind most steels run when used in blades, especially when used for chopping on chisels. Even in the fancier chisels. Just paring the wrong material can fairly quickly destroy an edge as i discovered recently when i unthinkingly used a chisel to clean up the routed rebates for some hinges in plywood. (the adhesive was probably the cause) It's only when you try the same job with a well sharpened box store chisel and see the edge fold over on first touch that it becomes clear how much better the good ones are.

I guess the point in the end may be (?) that if a new steel that was twice as chip/folding/wear resistant as anything about now we'd just see bevel angles reduced to bring it right to the brink too - on the basis that the latter delivered an improvement in performance.

Given that pressure = force/area it's actually a big ask that an edge that's probably a fraction of a micron thick is asked to handle being driven through hard wood. Thinking about the likely mechanics the chances are too that the only effect of increasing a bevel angle is to cause a shorter distance back from the edge to suffer damage, and to make it more resistant to folding. A sharp edge is still a sharp edge, the pressure must be enormous. Especially when its likely not cutting across the full worth of the blade, and the force is instead maybe concentrated on a short section resting on a hard growth ring, glue line or something......

[john zulu]

What is the bevel of the chisel? 25 or 30? 30 degrees is recommended as the edge is more durable for A2 and PM-V11.

I have hit knots but not plow through it. Just constant and gentle strokes. The edge for PM-V11 is still good.

[Patrick Harper]

When I first started chopping tails I had the same issue. I found that my mallet blows were simply too hard. I eased up, and things went much more smoothly. Another mistake I made, was prying ever so slightly. I think this might have been doing more damage than the heavy mallet blows. Now, I can usually go through an entire boards worth of tails, and only need a quick touch up on my finish stone.

[Phil Thien]

I was drilling some small holes in DF once and the bit kept skating off the dark (hard) growth and into the lighter softer growth. Overall I guess the wood is of medium hardness, but is comprised of growth that is half soft as marshmallow and half hard as rock.

[Brian Thornock]

I built the stand for my work bench out of DF, and was chopping in the corners of big mortises (like 2"x2"), and the chisels had this happen all the time. I actually found that a cheap set of beater chisels with a convex bevel worked better than my other set of better chisels with a microbevel. It was rather eye opening just how difficult of a wood it can be.

[george wilson]

Soft wood is a term that can be misleading. Douglas fir has rings that are very hard. I would refrain from using it myself,except to build houses.

[Mel Fulks]

What you are reporting about the chisels is close to what others have said, the new steel is marginally better not a miracle
like a Ron Popeil invention. Some woods are harder to cut and were used just because they were available and cheap.In the south a lot of tough pine was used for things that had dovetails.When the softer NE white pine started to be "imported"
from the North many we're glad to pay more for it. It has always seemed to me that alternate soft,hard grain is
worse to cut than all hard grain.

[Richard Line]

I built my bench top from some reclaimed Douglas Fir 3x6 timbers that were approximately 40 years old. My impression was that they had become harder with age. There still was a difference between the rings, but harder even in the 'soft' rings. Does wood, at least Doug Fir, get harder with age.

[John Sanford]

I built my bench top from some reclaimed Douglas Fir 3x6 timbers that were approximately 40 years old. My impression was that they had become harder with age. There still was a difference between the rings, but harder even in the 'soft' rings. Does wood, at least Doug Fir, get harder with age.

Yes, any wood with a high sap content gets harder with age. Southern Yellow Pine and Douglas Fir are especially well known for this.

************************************************** *

For those curious to explore the density differences in DF, simply take a flat sawn piece and sand it with a fairly aggressive grit. You will get peaks and valleys between the growth rings, with the dark portions barely being scratched and the lighter portions being hollowed out. If you don't want to actually explore like that, but still get a sense of what happens, find a piece of DF ply and you can feel the elevation differences in the faces. That's with plywood that's been machine sanded using massive wide belts... The density difference is profound with DF.

[Jim Koepke]

Just my 307992.

My only experience with PM VII is the Preston copy spoke shave Lee Valley offered.

My first experience was that the blade chipped a bit until it was sharpened a few times. Since then, it has held an edge quite well.

On chopping dovetails in "softwoods" my use of a fret saw has improved to the point of not having to chop them out.

The designation of being a softwood or hardwood has more to do with how the species produces flowers and seeds than it does with actual hardness of the wood produced by a particular species.

This may explain it better for anyone who is interested:

http://www.diffen.com/difference/Hardwood_vs_Softwood

Alder is classified as a hard wood. It is softer than many of the woods classified as softwoods that have been used in my shop.

jtk

[Phillip West]

Ive dealt in steel for a long time..Ive learned to take hearsay and advertisement with a skeptical eye..Thats just the way it is..So many things to consider when you see an edge fail..Sharpening,bevel,angle,microbevel and certainly not least the heat treat..Then likely most of all what your attempting to cut..Though Im sure the Pmv-11 is good steel..Honestly Im somewhat surprised at why we have not seem CPM3v used in more woodworking tools..Its amazing at its edge holding and most of all its fine edge stability..Other than possibly price..Its pretty expensive..My wife actually ordered "One" 18" x 1 1/2" x 5/32" bar last night and it was almost $40 just for the raw piece of steel :eek:

[Winton Applegate]

Surprised, dissapointed, puzzeled
Life in general has that effect on me.
You'll get used to it with time.
The only source of sanity if not grace are Douglas Adams books.
Buy an espresso machine, lay in a stock of his books and take it easy. That's my advice.

[Thomas Schneider]

How timely this is for me! I'm in the process of building a split top saw bench out of Douglas fir, and was chopping out the waste on the dovetails for the top with what I thought were sharp chisels. I was having such a hard time I thought I was doing something wrong! I took a chisel off the rack that was freshly sharpened and went at it again. Same result. Turned out the lights and called it a night vowing to re-evaluate my sharpening technique this weekend. So maybe it's the wood after all!

[george wilson]

JUST observe the hard grains in the fir. They are HARD!!!!!!!:) Give me all hard any time. Those hard rings put a lot of strain on pretty small areas of the chisel blades,causing them to fail in those spots.

[Reinis Kanders]

Yeah, I just remembered that my Ray Isles D2 steel 1/4" chisel was also chipping when mortising in Doug Fir, it had about 35 degree secondary bevel.


How timely this is for me! I'm in the process of building a split top saw bench out of Douglas fir, and was chopping out the waste on the dovetails for the top with what I thought were sharp chisels. I was having such a hard time I thought I was doing something wrong! I took a chisel off the rack that was freshly sharpened and went at it again. Same result. Turned out the lights and called it a night vowing to re-evaluate my sharpening technique this weekend. So maybe it's the wood after all!

[David Dalzell]

Well I guess that my chisels are probably ok. Darned "soft" wood. Thinking about it I can see that narrow bands of hard (dark) wood will put a lot of stress on a narrow portion of the chisel edge, causing edge degradation. A different chopping technique might solve this problem. This is the first time I have built anything with Douglas Fir (a saw till with two drawers). I generally build furniture with hardwood. Softwood is normally limited to drawer bottoms, mostly Port Orford Cedar. PO cedar and other aromatic cedars don't seem to have this problem.

Thanks everyone for the input and collective wisdom.

David

[Andrew Hughes]

Mmm,Port Orford cedar is a lovely wood to work.I hardly ever get any down here in so cal.Have you tryd air dried Doug fir I thought about it and kinda remember it not being so tough.One draw back might be the pitch will flow when it gets warm.Almost as if the tree thinks it's still alive.Aj

[Kees Heiden]

..Honestly Im somewhat surprised at why we have not seem CPM3v used in more woodworking tools..Its amazing at its edge holding and most of all its fine edge stability..Other than possibly price..Its pretty expensive..My wife actually ordered "One" 18" x 1 1/2" x 5/32" bar last night and it was almost $40 just for the raw piece of steel :eek:

I think another reason is "sharpebility". We like a steel to be easilly sharpened. For CPM3v you need diamonds at least and not everyone likes to sharpen with diamonds.

[george wilson]

Just get ceramic stones. They will sharpen any steel out there. Use a diamond stone to quickly eliminate nicks though.

[george wilson]

My house was built in 1949 by a man who owned a lumber mill. The beams in my basement are 2 3/4" x 9" of old,hard yellow pine. You have to pre drill a hole in them too,to drive a nail. No plywood in this house,and real plaster walls. The only house I have lived in where I can't tell if the upstairs shower is running.

[Stephen Clement]

Thinking about it I can see that narrow bands of hard (dark) wood will put a lot of stress on a narrow portion of the chisel edge, causing edge degradation.

David

This is spot on. It has nothing to do with the wood being hard or soft, it is that there are both at the same time. The chisel hardly notices the soft wood, cuts quickly and then slams to a stop when it hits the hardwood. Its almost like running into a nail in a piece of cedar. I bet both chisels stay nicely sharp in both maple and cedar, but doug fir tears them to shreds.

[Shawn Pixley]

I'll second Marc's observation. I've unfortunately bent many a nail in hard DF that were the studs in old houses in the Pacific NW.

[Phillip West]

I think another reason is "sharpebility". We like a steel to be easilly sharpened. For CPM3v you need diamonds at least and not everyone likes to sharpen with diamonds.

That's true, 3v is not easy to sharpen on regular materials..Its very abrasion resistant.