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jefferson
26th August 2008, 07:22 PM
I received some square scrapers from Jim Carroll yesterday - P & N in 32mm and 18mm.

Both are in need of a grind, existing bevel set at around 80 degrees.

The Hamlet scrapers that I have are ground to around 70 degrees on the Tormek, with no discernable burr. These tools are very sharp and work extremely well on redgum platters (as Ern might attest to).

I know Ern is comparing bevels and burrs as a pet project but I was wondering what everyone else does. The bevels on Richard Raffan DVDs seem to be a lot less that 70 degrees, maybe even 60.

What is the consensus out there?

For the moment, I'm sticking with 70 degrees but will go with the flow.

Jeff

Cliff Rogers
26th August 2008, 07:49 PM
Depends....

on the steel...

on the application....

on what colour undies you like to wear.... :D

I have a mixture of angles & I find that the angle that it is presented to the timber while in use makes a greater difference than the angle it is sharpened at.

As a general rule, my thinner scrapers are sharpened at a more acute angle than my thicker ones, I don't know why, they just are. :shrug:

Jim Carroll
26th August 2008, 08:11 PM
I prefer less angle so there is more support under the cutting edge.75-80 for me

I also have the toolrest above centre height with the tool tip just above or on centre height .

Skew ChiDAMN!!
26th August 2008, 10:08 PM
A scraper, when used as a scraper cuts best with the burr. Like Jim, I like to have a steep bevel as it provides extra support and also more mass to act as a heat sink. (Heat kills burrs as quickly as hard timber does.) Mine are typically sharpened at around 75-85° but I'm not anal about it 'cos I sharpen freehand.

A scraper, when used as a bedan (as many people do, although they still call it scraping. :rolleyes:) uses the edge to cut and needs to be sharpened at a shallower angle and the burr removed. I've seen these sharpened at everything from something like 30° up to probably 70° My bedans are around 45-55°

I also have a couple of "mule" scrapers that are neither this nor that but get used as both bedan and scraper. They do neither particularly well, but are good enough that if I can only take a few tools one of these will be thrown into the box. These, I sharpen at around 60°

Mind you, the above angles are what work for me. To complicate things, sometimes you need to temporarily sharpen at a different angle for some more cantankerous woods.

Oh joy, oh fun.

So, all in all, the "right" angle is the one that works for you. :U

Grumpy John
26th August 2008, 10:37 PM
......... To complicate things, sometimes you need to temporarily sharpen at a different angle for some more cantankerous woods.

Oh joy, oh fun.

So, all in all, the "right" angle is the one that works for you. :U

Thanks Skew, you've been a great help to me :p now that I'll be receiving 10 P&N chisels shortly.

Cheers
GJ

Skew ChiDAMN!!
26th August 2008, 10:44 PM
Thanks Skew, you've been a great help to me :p now that I'll be receiving 10 P&N chisels shortly.

:U

Somewhere around here I have a notice I printed up and had stuck over my grinder. It listed the "traditional" bevel angles for the different chisel types, the ones which I was taught and are generally mentioned in most books.

But it didn't take me long to notice that very few of the professional turners used those angles... only the people who were buying those books! :rolleyes:

Still, I can always see if I can find it if you want a list of "recommended" angles...

TTIT
26th August 2008, 11:16 PM
........ It listed the "traditional" bevel angles for the different chisel types, the ones which I was taught and are generally mentioned in most books.. ..........I bought one of those cast-alloy centre-finders from Carbatec that have those 'traditional' angles notched into the edge - checked all my angles straight away and found they were all so different that I'd wear out a white wheel just 'correcting' them - hid angley checker thing away in cupboard :B:;

RETIRED
27th August 2008, 09:01 AM
I prefer less angle so there is more support under the cutting edge.75-80 for me

I also have the toolrest above centre height with the tool tip just above or on centre height .


A scraper, when used as a scraper cuts best with the burr. Like Jim, I like to have a steep bevel as it provides extra support and also more mass to act as a heat sink. (Heat kills burrs as quickly as hard timber does.) Mine are typically sharpened at around 75-85° but I'm not anal about it 'cos I sharpen freehand.

A scraper, when used as a bedan (as many people do, although they still call it scraping. :rolleyes:) uses the edge to cut and needs to be sharpened at a shallower angle and the burr removed. I've seen these sharpened at everything from something like 30° up to probably 70° My bedans are around 45-55°

I also have a couple of "mule" scrapers that are neither this nor that but get used as both bedan and scraper. They do neither particularly well, but are good enough that if I can only take a few tools one of these will be thrown into the box. These, I sharpen at around 60°

Mind you, the above angles are what work for me. To complicate things, sometimes you need to temporarily sharpen at a different angle for some more cantankerous woods.

Oh joy, oh fun.

So, all in all, the "right" angle is the one that works for you. :USame here.

Cliff Rogers
27th August 2008, 09:32 AM
I haven't checked mine but I know that there is one that is sharpened at 90°.
It is a special case as the tip is ground across at an angle to match my chuck jaw dovetails & I can flip it over & use the other side to cut inside or outside dovetails lips.

Skew ChiDAMN!!
27th August 2008, 06:21 PM
That's just a very blunt skew, Cliff. :U

Sawdust Maker
27th August 2008, 08:32 PM
That's just a very blunt skew, Cliff. :U

:roflmao:

Cliff Rogers
27th August 2008, 10:08 PM
That's just a very blunt skew, Cliff. :U
Hollow ground tip. :D

jefferson
27th August 2008, 10:26 PM
You got them Cliff.

Depending on your grind wheel, the angle has got to be a few degrees less than 90.

Sharp or not, the scraper is no replacement for good gouge technique! Tell me about it, I spent a good hour fixing with the scraper what a good turner would have done in a minute with the gouge.

Jeff

rodent
28th August 2008, 11:51 PM
And let's not get into shear scraping will we.ie sorby multi tip tools. ( ern ).Don't forget it's all about tool presentation to the timber ,handle lift ( ie height above horizontal ) and last but not least how you hold your toung .:doh:

woodwork wally
30th August 2008, 06:05 PM
same here but if I find one differant and it is working o.k. Then I am not pedantic a case of what works well on that tool with that handle and what day . but like JC & more support under cutting edge and a heat sink

mpax356
2nd September 2008, 02:08 AM
Here is what I took away from a recent two day class from Stuart Batty as it relates to scraper angle:

Soft to Medium dense wood - 70-80 deg with burr
Medium to dense wood, 70-80 deg with no burr

Course grit wheel like 60 grit provides a better burr than a finer grit wheel.