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Rounding Plane / Dowel Maker attempt #2: The blade

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Blog entry by llwynog posted 925 days ago 8033 reads 0 times favorited 12 comments Add to Favorites Watch
« Part 1: Wooden body Part 2 of Rounding Plane / Dowel Maker attempt series Part 3: Tool making gone fractal + finishing the blade holder »

I am back with a new update which brings us to the current state of the project.
First of all, thanks to everyone who shared their interest on this experiment.
As I basically make it up as I go along, any advice, past experience or actual tool description is very welcome.

I did not have a spare blade lying around so I bought a cheap (still it is high carbon steel and appears to hold an edge decently) block plane blade. I chose a block plane blade as the metal is thicker than many bevel down bench plane blades and the width matched the dimensions of the tool.

Here is the blade straight out of the parcel, with a mark on it to show the desired angle :

As you can imagine from the above picture, shaping the blade to the correct angle, flattening the back and then honing the bevel took a little while (about 1 hour) It would have been much quicker if I had owned a coarse dry grinder instead of my relatively smooth and slow wet grinder.

Here is the result :

Obviously it does not show on the picture but I managed to get the edge really sharp. Bevel angle came out about 30 degree which looks kind of right.

The next step will be to recess the blade holder (or the actual body itself, I do not know yet) so that it can be screwed back onto the body and its height comes back to what it used to be before I kerfed it with my saw. (does anyone even understand this sentence ?).
In other words, if I screw the blade holder back on like it is now and without the blade, it will come 1 kerf short of the top of the body. The goal is to recess the blade of its thickness minus the original saw kerf which should garantee that the top of the blade holder ends up flush with the top of the body (which is required for the bored hole and cone to keep their proper shapes).

I could not resist a quick test with a 22mm dowel and the blade clamped on the body alone :

The blade on the picture appears almost square accross but it was really the same angle as penciled above.

This quick try was rather disappointing as you may see on the picture that there was very heavy tear out when I gave the dowel a few turns.

So far the various explanations I am considering for the tear out are :
  • The blade geometry within the tool might be bad. Right now, the blade is almost radial to the cone and I am considering wheter the finish might be smoother with a lower angle, so that the blade gets more tangential to the cone.
  • The blade might be sticking out too much from the surface of the cone, creating chatter. If I could take a smaller shaving out of the dowel, there might be less tear out. This is probably linked to the irregular shape of the cone, a straighter cone (especially near the transition bewteen the cone and the bored hole) might enable a thinner shaving.

From there, my next course of action will be to continue with the current iteration of the tool (recessing the blade holder or the body to accomodate for the blade) and see the results. If I still get heavy tear out, I will try to correct the shape of the cone by hand with gouges or rasps and then if it still does not work, I will probably try to find another blank of wood to experiment with different blade angles and locations.

If anyone owns a wooden or metal rounding plane, I would be very interested in some information regarding its geometry. I am particularly interested in rounding planes by Ray Iles (http://www.toolsforworkingwood.com//Merchant/merchant.mvc?Screen=PROD&Store_Code=toolshop&Product_Code=MS-IROUND.XX&Category_Code=CRI) if anyone owns one.

Until next time,

-- Fabrice - "On est bien bête mais on sent bien quand on se fait mal" - my grandfather



12 comments so far

View Sodabowski's profile

Sodabowski

2002 posts in 1467 days


#1 posted 925 days ago

Ah, je vois, ta lame doit être tangente au barreau, pas perpendiculaire!

Intl version: the blade must be tangent to the dowel, not perpendicular.

-- Holy scrap Barkman!

View llwynog's profile

llwynog

283 posts in 1213 days


#2 posted 925 days ago

Thomas,
That would be my gut feeling indeed (this is also how a pencil sharpener is made).
The article I followed (as far as I remember/understood it) used this geometry however so I thought I would give it a try like this first.
I will probably need to make another blank but I don’t have any more wood of the appropriate size under hand…

-- Fabrice - "On est bien bête mais on sent bien quand on se fait mal" - my grandfather

View stefang's profile

stefang

12950 posts in 1968 days


#3 posted 925 days ago

Good going! This is sure to be a winner.

-- Mike, an American living in Norway.

View canadianchips's profile

canadianchips

1831 posts in 1631 days


#4 posted 925 days ago

You might be able to salvage this prototype by makeing a steeper cone shape. This would make LESS blade doing the cutting, more skew ! I posted pictures on your forum . My cone is a 60 degree angle. (Unfortunately the flash blocked the numbers on my protractor)

-- "My mission in life - make everyone smile !"

View canadianchips's profile

canadianchips

1831 posts in 1631 days


#5 posted 925 days ago

Another plan.

-- "My mission in life - make everyone smile !"

View Will Mego's profile

Will Mego

307 posts in 2346 days


#6 posted 925 days ago

oh, I know in “olden” days in england they used a small plane in a scratch stock sort of way to make arrow shafts, is that sort of what you’re trying to get to, but perhaps bigger? If I can find a link to one, I’ll post it.

-- "That which has in itself the greatest use, possesses the greatest beauty." - http://www.willmego.com/

View llwynog's profile

llwynog

283 posts in 1213 days


#7 posted 925 days ago

Once again, Canadianchips, this is very interesting information and the pictures you posted on the forum thread also shows that the blade is pretty much radial to the cone so all hope is not lost with this first prototype.

@Will Mego : Yes I think we are talking about the same thing, all pictures welcome.

-- Fabrice - "On est bien bête mais on sent bien quand on se fait mal" - my grandfather

View mafe's profile

mafe

9492 posts in 1723 days


#8 posted 925 days ago

I follow closely, but have no advice.
Thank you.
Best thoughts,
Mads

-- Mad F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

View Sylvain's profile (online now)

Sylvain

543 posts in 1133 days


#9 posted 924 days ago

Instead of cutting the blade at an angle, why not secure it at an angle; you would not loss “precious” metal.

I wouldn’t cut the blade just to experiment the best angle.

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

View Will Mego's profile

Will Mego

307 posts in 2346 days


#10 posted 924 days ago

no, actually, we’re not talking about the same thing, this is a very small handplane where after securing a length of straight grained wood (remember, arrows, pretty narrow) to a bench, the plane is dragged along it’s length and essentially cuts/scratches the stock half round. The process is repeated on the other side. Clearly, the english made, lets say, SEVERAL arrows, so it must have worked at least alright. Only found pictures which show how small it is, not the cutter itself so far…but I SAW this thing being used someplace weird, like 30 seconds related to some movie…driving me nuts, so I NEED to find it now.

-- "That which has in itself the greatest use, possesses the greatest beauty." - http://www.willmego.com/

View Will Mego's profile

Will Mego

307 posts in 2346 days


#11 posted 924 days ago

Arrow Shaft Plane http://www.3riversarchery.com/images/large/5600.jpg

-- "That which has in itself the greatest use, possesses the greatest beauty." - http://www.willmego.com/

View llwynog's profile

llwynog

283 posts in 1213 days


#12 posted 924 days ago

@WillMego : I see, this is indeed another beast altogether.
@Sylvain : I can’t contradict you on this. My only excuse is that I need to have the blade angle not too far off the target as my adjustment is limited on each side by the 4 screws which will hold the blade holder and fasten the blade.

-- Fabrice - "On est bien bête mais on sent bien quand on se fait mal" - my grandfather

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