Scorp Rehab
Now,
this may sound misleading. It is not the rehabilitation and
recovery of an old and treasured piece of history, It is the
attempt to take a cheaply made German inshave and make it useable,
because brother.... it sure isn’t straight from the
factory. This partly to help others who may have the same
question I couldn’t find answers to on the web - what is the
proper angle to sharpen an inshave/scorp at?
The shave in question is an Oxhead, made in Germany. I immediately had problems right out of the box. Not only is it terribly dull, but the bevels ground on it are completely wrong. After trying to make it work as is with no success, I began to talk to some more knowledgeable people about it - one a Lee Valley employee, the other a graduate of the Windsor Chair Institute.
The problem is the geometry of the bevels is completely wrong. From the factory, the inshave looks like this:
This is completely wrong for what you need the tool to do - it is in fact nearly impossible to get the cutting edge to even contact the work.
I took my original purchase back, and found one on the clearance table that had the bevel "misground" - it had only be ground on one side. Hoping this would be a lot less work to correct, I picked this up instead.
Information I received about the geometry explains it thusly:
NOTE: Due to a major change in my life, this project has stalled exactly where you see it. I have not had time to take it any farther. That being said, I personally would now buy the Lee Valley pullshave.
However - I seem to regularly get requests for additional information (some more polite than others), so I am posting this below.
I received 2 similar opinions, so here are both of them.
Short Version:
Sharpening:
Outside: File for coarse work. Stones (oil or water) or Scary Sharp (sandpaperon glass) will work. I believe Leonard Lee (founder of Lee Valley) in his book on sharpening recommends a 1" belt sander (the type used for knife making, etc) as it has some flex where there is a gap between the backing plate and pulley enabling you to sort of match the curve. Personally, I find they remove a lot of material and I need to practice before I get there.
I was planning on using an Axe file on the outside to remove most of the metal, and then use a sanding cylinder in a hand drill to carefully reshape the inside. I figured since the top of mine was untouched, I'd be insane to try a bevel, and then remove it (see geometry/shaping notes below)
On the inside, you can use a block of wood with sandpaper for the straights and a large dowel wrapped in sandpaper for the curves, or a round sharpening stone chucked in a hand drill (carefully). Water stones, slips etc can be used as well.
As for shaping, geometry, etc.....
Bad shaves have 2 bevels, at about 45 degrees, and are short and stubby bevels - look like an obelisk. I took mine back, and lucked out paying half price for one that had only a bevel on the bottom (a mis-sharpen). If you see below, you'll understand why I picked it up (will be less work).
I used someone's 2 cherries inshave, and I believe they did little to no work on theirs - cut very nicely.
Here is the information I gathered in regards to this project:
From a friend who worked at Lee Valley: You want a nice long bevel on the bottom (like a French Chef's knife - see next section), and maybe a 1-3 degree back bevel on the top. Which means doing some serious work on the Oxhead ones LV sells.
From Esther on the list:
The short version: It should be beveled like a good french knife - nice slow, long bevel (top AND bottom) - basically the bevel it comes with is way too steep.
The quote:
"This sounds like your first problem, you shouldn't have bevels. A major Dunbar hot button on lousy design for ease of manufacture and impossible use ;-) (and the reason he pushes his recommended suppliers!)
A cross section of the blade should look like a french chef's knife, ie a long skinny triangle, not some variation on the cross section of an obelisk. If you have a lot of visible bevel you are facing a lot of awkward metal removal. On the outside you could attack with files or your choice of grinders, on the inside I sharpen with sandpaper
on fat dowels but you might want to think of apprentices with names like Dremel or some such.
If you have/have access to Dunbar's chairmaking or tool tuning books, this is what he calls a scorp, for further research." (end quote)
The Windsor Institute (founded by Michael Dunbar) would likely be a good place to contact about purchasing a scorp that works properly.
Update: I have contacted most of the people who had originally requested this information. All of them have taken their original inshaves back for a refund, and are seeking a better inshave.
Alternates to an Inshave for shaping a seat are and adze, or a large shallow gouge. These both remove stock quickly. The Lee Valley pull shave is another alternative, although feedback from one of the respondants who returned his inshave for the new pull shave commented he found it did not remove stock quickly, but was more of a finishing tool. I had a chance to try the pull shave at a demo and found it to remove stock at a good rate (similar to the inshave I used previously), and not as tiring to use. With a 3 month return policy, what do you have to lose?
The shave in question is an Oxhead, made in Germany. I immediately had problems right out of the box. Not only is it terribly dull, but the bevels ground on it are completely wrong. After trying to make it work as is with no success, I began to talk to some more knowledgeable people about it - one a Lee Valley employee, the other a graduate of the Windsor Chair Institute.
The problem is the geometry of the bevels is completely wrong. From the factory, the inshave looks like this:
This is completely wrong for what you need the tool to do - it is in fact nearly impossible to get the cutting edge to even contact the work.
I took my original purchase back, and found one on the clearance table that had the bevel "misground" - it had only be ground on one side. Hoping this would be a lot less work to correct, I picked this up instead.
Information I received about the geometry explains it thusly:
NOTE: Due to a major change in my life, this project has stalled exactly where you see it. I have not had time to take it any farther. That being said, I personally would now buy the Lee Valley pullshave.
However - I seem to regularly get requests for additional information (some more polite than others), so I am posting this below.
I received 2 similar opinions, so here are both of them.
Short Version:
- Sharpen it like a good kitchen knife. The bevel should be a long & gentle taper.
- Chef knife bevel on the lower, 1-3 degree on the upper (inside) face.
Sharpening:
Outside: File for coarse work. Stones (oil or water) or Scary Sharp (sandpaperon glass) will work. I believe Leonard Lee (founder of Lee Valley) in his book on sharpening recommends a 1" belt sander (the type used for knife making, etc) as it has some flex where there is a gap between the backing plate and pulley enabling you to sort of match the curve. Personally, I find they remove a lot of material and I need to practice before I get there.
I was planning on using an Axe file on the outside to remove most of the metal, and then use a sanding cylinder in a hand drill to carefully reshape the inside. I figured since the top of mine was untouched, I'd be insane to try a bevel, and then remove it (see geometry/shaping notes below)
On the inside, you can use a block of wood with sandpaper for the straights and a large dowel wrapped in sandpaper for the curves, or a round sharpening stone chucked in a hand drill (carefully). Water stones, slips etc can be used as well.
As for shaping, geometry, etc.....
Bad shaves have 2 bevels, at about 45 degrees, and are short and stubby bevels - look like an obelisk. I took mine back, and lucked out paying half price for one that had only a bevel on the bottom (a mis-sharpen). If you see below, you'll understand why I picked it up (will be less work).
I used someone's 2 cherries inshave, and I believe they did little to no work on theirs - cut very nicely.
Here is the information I gathered in regards to this project:
From a friend who worked at Lee Valley: You want a nice long bevel on the bottom (like a French Chef's knife - see next section), and maybe a 1-3 degree back bevel on the top. Which means doing some serious work on the Oxhead ones LV sells.
From Esther on the list:
The short version: It should be beveled like a good french knife - nice slow, long bevel (top AND bottom) - basically the bevel it comes with is way too steep.
The quote:
"This sounds like your first problem, you shouldn't have bevels. A major Dunbar hot button on lousy design for ease of manufacture and impossible use ;-) (and the reason he pushes his recommended suppliers!)
A cross section of the blade should look like a french chef's knife, ie a long skinny triangle, not some variation on the cross section of an obelisk. If you have a lot of visible bevel you are facing a lot of awkward metal removal. On the outside you could attack with files or your choice of grinders, on the inside I sharpen with sandpaper
on fat dowels but you might want to think of apprentices with names like Dremel or some such.
If you have/have access to Dunbar's chairmaking or tool tuning books, this is what he calls a scorp, for further research." (end quote)
The Windsor Institute (founded by Michael Dunbar) would likely be a good place to contact about purchasing a scorp that works properly.
Update: I have contacted most of the people who had originally requested this information. All of them have taken their original inshaves back for a refund, and are seeking a better inshave.
Alternates to an Inshave for shaping a seat are and adze, or a large shallow gouge. These both remove stock quickly. The Lee Valley pull shave is another alternative, although feedback from one of the respondants who returned his inshave for the new pull shave commented he found it did not remove stock quickly, but was more of a finishing tool. I had a chance to try the pull shave at a demo and found it to remove stock at a good rate (similar to the inshave I used previously), and not as tiring to use. With a 3 month return policy, what do you have to lose?
All Materials not credited to other authors is (c)2003 - 2008 Paul R. Morin.