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Bevels on a draw knife

Lataxe's picture

Recently the draw knife, spokeshave and carving axe have been oft in my hand, as I have added green woodworking to my WW panoply.


The correct profile and sharpening of spokeshave blades, axes, lathe chisels and wood carving chisels does not seem to be in dispute.  However, each green woodworker I talk to has a different opinion on how a draw knife should be bevelled.


Some say that one side should be flat with a 25 degree bevel on the other side.  The flat side cuts deep, for rapid stock removal; the bevel side cuts shallow for finer work.  This is what I currently do, not least since my Ray Iles draw knife came with this profile and honed razor sharp. 


Others say that a different bevel on each side of the draw knife is better.  Degrees are not give - rather they show you their draw knife so-ground.  In essence, one side (the shallower bevel I presume) cuts more aggresively than the other bevel, but both offer more control of the cut than a flat blade.


Some say a straight blade is the best all-rounder.  Others recommend a slight covex curve across the length of the blade. Some say that a shallow curve of the whole blade itself iss a good thing (in the French style).


Are there any experienced draw knife users out there who have wisdom, preferably including a bit of technical detail about bevel angles and whatever other blade configurations they recommend?  Is it a good thing to have more than one draw knife, with different grindings for significantly different tasks?  (I have one variation myself: an inshave, which is a curved-up draw knife for hollowing out chair seats).


Thanks in anticipation.


Lataxe.

JP's picture

(post #103304, reply #1 of 7)

Lataxe,

I am certainly no pro with a drawknife but mine is sharpened with a knife edge. I have a bevel on both sides roughly the same angle. I can take light or heavy cuts depending on how much tilt I put on the blade, plus I think it helps to come out of a cut more easily since you can use the bevel as a fulcrum which I think aids in the overall control of the tool.

I mostly use mine for rough work like removing the bulk of a chamfer or knocking corners off of cabriole legs before going to the rasp.

J.P.

John500's picture

(post #103304, reply #2 of 7)

I have taken two windsor chair classes with Mike Dunbar and so have gone through purchasing a good draw knife and sharpening it. You can see details of how Mike Dunbar does thisin his book Restoring, Tuning & Using Classic Woodworking Tools. This is a great reference.

Anyway, for the draw knife one side is flat and the other has a bezel. In use the bezel side should be up.

John

mike4244's picture

(post #103304, reply #3 of 7)

I have two drawknives,slight convex curve and a straight drawknife. Both have a flat back and a bezel of about 25°. I prefer the curved one.It seems to me if the knife had a back bevel, it would have to be tilted too high to cut comfortable.Never used a drawknife with a back bevel, just a guess though.


mike

Lataxe's picture

(post #103304, reply #4 of 7)

Thanks all for the replies.


Modern drawknives all seem to be sold with one flat side and one bevelled (usually at 25 degrees).  The tutor on my chair course used old drawknives, which had (different angle) bevels on both sides.  These did seem to allow more variance in the aggresiveness of cut, as JP confims.


I use my modern flat back/single bevel drawknife bevel-side down only.  I cannot take a controlled cut with the flat side down; it bites too hard or not at all.


Drew Langster, an American chairmaker, says in his book that a drawknife should have "rolled over or dubbed edges" on both the flat and bevel side.  He says this allows a much better control, especially with the flat side down.  Unfortunately he doesn't explain how much to roll over the edges or anything about the necessary degree of curvature of this dubbing. 


I think he means that the bevel and back of the knife should themselves not be flat but slightly convex.  This was another feature of the old drawknives that my tutor had.


John 500 - I should have thought of Mike Dunbar myself; I've read enough of his articles in FWW to realise he would be the likely source for wisdom relating to drawknives.  Another trip to Amazon.  :-)


Mike 4344 - Drew Langster also says that a straight blade is best and that old blades are only curved "because this suited the blacksmiths making process".  I wonder how he knew that? :-/  My course tutor's old drawknives, as well as having the double bevel, were alo slightly curved, in both planes (along the edge but also perpendicular to the edge).  This too seemed to allow better control.


So, I've learnt quite a bit so far, but haven't got the definitive picture yet.  Here's hoping Mike Dunbar has the answer.


One last question: has anyone had any experience of the Flexcut drawknife, which they say can be bent (presumably as you use it) to accommodate different cutting needs?

agomega's picture

(post #103304, reply #5 of 7)

I don't know if you paid for the fine woodworking network membership, but if you did then you might want to go to the members only section and ask your question to Brian Boggs. I saw him working with a drawknife recently and I believe it had one beveled side and one flat side. He made cuts with both edges and explained when you would use each side. I don't remember all the details and I'm sure he could give you a better explanation than I could.


If you have never talked to Brian he is truly remarkable. He seems to have a well thought out answer for virtually every question, especially questions concerning chairmaking and tools associated with chairmaking. I believe that he recently designed a drawknife that Lie Nielsen will be producing soon. If you have ever tried his spokeshaves then I think you will be excited about the new drawknife.


Hope this helps,


Phil

wdrite's picture

(post #103304, reply #6 of 7)

I have used drawknives on occasion for years  and have always sharpened them flat on one side and bevel on the other.  Last summer I went to a community yard sale and ran across a pair of drawknives for $ 10.00 each in good condition.  Although I already owned one, I couldn't resist the temptation.  Upon getting home and sharpening them I found that all three of my knives were made with the handles at different angles to the blade and that each of these angles worked well for different applications.  Having only used drawknives when necessary, I had not paid close attention to this feature.  Just goes to show, you are never too old to learn.

Lataxe's picture

(post #103304, reply #7 of 7)

Agomega,


Your advice about joining the network and getting Mr Boggs to issue wisdom is a very good one.  I have other questions for him too. :-) 


By the way, you are a bad person to tempt me with tool goodies like that.  I'm already addicted to shiny Veritas things and know that if I buy one Lie-Nielsen object that'll be another expensive addiction I can't fight. (Lady-wife advises, "Just say No" but my cart-filling fingers don't listen|).


As I'm an FWW subscriber and also a bit mean, I want the $15 subscription to the network rather than the non-FWW subscriber $35 one.  But can I find my customer number? Of course not.  Doh!


Wdrite,


I would be interested in learning a bit about your findings on the 3 draw knives you mention, specifically what sort of handle/blade configurations are good for which types of work.  (Sorry to pester).


Lataxe.