Burnishing a 112 scraper plane blade

[PaulO]

I can confirm that flattening the back of an A2 112 scraper blade is a long and boring task.

Having done this and having sharpened the blade, can anybody recommend a burnishing technique? I have read the gospel according to St.David, chapter II verse 110, but unfortunately I possess neither an ejector pin, nor an LV burnishing steel. I am thinking of using the polished shank of a large(ish) milling cutter, am I mad?

 

[Paul Chapman]

Clifton do a very nice burnisher link

Cheers :wink:

Paul

 

[CHJ]

Do you know anyone working in a machine shop that uses cobalt endmill cutters, it is not unknown for the cutting edge on these to shatter when a small lapse in concentration occurs.

The shanks make good burnishers when mounted in a suitable holder.

 

[dchenard]

Anything HSS should be able to putt a burr on that blade. Anything harder than the blade should do it...

BTW, Chris Schwartz uses the Charlesworth ruler trick on scraper blades, saves a lot of time compared to flattening the whole thing, with no lost performance. Something to think about...

DC

 

[David C]

Paul,

Ron Hock, Clifton, gudgeon pins out of old deisel engines, smooth solid carbide router cutter shanks, Nice carbide burnishers in handles from France

Beware most people use far far too much force on the burnisher, very very gentle is what does the job for me.

We need far less pressure to turn the hook on a 45 degree sharp edge than on a square edged card scraper, and the best hooks seem to be very small indeed.

Hope you get wonderful results, and so pleased to have been sanctified before death......

David Charlesworth

 

[bugbear]

I can confirm that flattening the back of an A2 112 scraper blade is a long and boring task.

Having done this and having sharpened the blade, can anybody recommend a burnishing technique? I have read the gospel according to St.David, chapter II verse 110, but unfortunately I possess neither an ejector pin, nor an LV burnishing steel. I am thinking of using the polished shank of a large(ish) milling cutter, am I mad?

Perhaps someone can confirm/deny that

a) scraper PLANE blades can be used without a burr

and that

b) A2 steel may have different burring properties to O1?

BugBear (with no scraper planes and only one A2 blade)

 

[Racers]

Hi, Bugbear

My home made scraper plane has a O1 steel blade that I heat treated my self is a little to hard as when I last tried to turn a hook I could hear it cracking so I just re-ground it and used it with out a hook, works o/k.

I did manage to turn a hook at first so that must have been in the de-carburised steel at the edge of the blade.

I did the ruler trick (thanks Dave C) to flatten it saves hours. I have been meaning to pop it back in the oven and re-temper it.

 

[Frank D.]

Perhaps someone can confirm/deny that

a) scraper PLANE blades can be used without a burr

and that

b) A2 steel may have different burring properties to O1?

BugBear (with no scraper planes and only one A2 blade)

I get very good results (IMHO) with no burr. The Lie-Nielsen site also says you get very good results without it, and they recommend sharpening at 45° without a hook.
A2 steel is VERY hard to give a hook to at plane blade hardnesses (RC 60-62). Lie-Nielsen 112 blades are not as hard as their plane blades (RC 50-55).

 

[dchenard]

We need far less pressure to turn the hook on a 45 degree sharp edge than on a square edged card scraper, and the best hooks seem to be very small indeed.

David Charlesworth

Very true, it's easy to go overboard and turn the scraper into a snowplow :roll: :lol:

Another DC

 

[dunbarhamlin]

A pointer which I found useful (can't remember if it was Mr C?) was to use the same pressure as when buttering toast. (So regardless of how cold the butter, toast mangling force is too much)

* Edit: The tip was from Chris Schwarz (thanks the proper attribution David)

 

[Paul Kierstead]

I'd very strongly suspect that A2 would be inclined to chip before you could turn a hook. Turning a hook wants a little give. Might work with a burr left from grinding, though, ala scrapers in turning as some do it. Mind you, I still suspect the burr would break off.

I find my LV 112-like works ok without a hook.

 

[dchenard]

I'd very strongly suspect that A2 would be inclined to chip before you could turn a hook. Turning a hook wants a little give. Might work with a burr left from grinding, though, ala scrapers in turning as some do it. Mind you, I still suspect the burr would break off.

I find my LV 112-like works ok without a hook.

I think that these blades are soft enough to avoid the chipping problem. LV states that their A2 blade (and the carbon one too) is at Rc 48-51.

I do have the A2 blade, I have yet to install it. Maybe I should

DC

 

[Derek Cohen (Perth Oz)]

I have a Stanley #112 and have used this with a LN "Stanley Replacement" blade for some years.

Actually, it lay on the shelf mostly since it was not needed - I managed to get the performance I required from handplanes and card scrapers. I think that the main reason it was not used much was that I did not get a great performance, full stop.

I have gotten into the habit of honing it sans burr. The edge was sharpened like a plane blade. For extra sharpness, the bevel was at 30 degreesrather than the 45 degrees recommended by LN (originally they had recommended 60 degrees).

Recently I was giving a length of carbide rod for a burnisher. My burnisher has been one sold by Crown, and it has done a decent job on card scrapers for me over the years. This carbide rod was quite a bit thinner in diameter. Out of curiosity, I decided to put a burr on the #112, and used the carbide rod to do so.

It was very easy to add a fine burr - much easier than with the thicker Crown burnisher. Steel on wood, and I was very pleasantly surprised at the fine shavings that the #112 now made. Significantly better than when used without a burr.

I have been discussing scrapers with Paul Hamler on Knots over the past few days, and he made the comment that he viewed a scraper blade as "a plane blade and performs the same cutting action on wood that a conventional plane iron does, the differeaence is the scale or size of the plane blade that we have always called a scraper. Maybe a better name for a scraper might be "Micro Plane"

Paul also went on to say that "because the burr on a properly sharpened scraper actually slices, lifts and curls a continuous shaving from the wood like a plane but on a scale so small that tear-out is practically eliminated."

Now Paul's view does not account for why a burr-less scraper blade working as well as it does, but his comments do give good reason why scrapers should preferably be used with a burr.

Regards from Perth

Derek

 

[engineer one]

some years ago before i had even heard of this kind of place to find out, i re-finished an oak dining table that my folks had had since just after the second war.

since i did not know any better, i just ran a card scraper over it without the bevel. i wonder if it depends upon the finish of the surface that you are scraping?? if it was smooth, i e re-finishing, then maybe a burr is not needed whereas just after planing, or for final finishing it might be more valuable.

i have an LV scraper plane, and although i sharpened it, found getting the burr much more difficult. maybe i was trying too hard :?

will try again

paul :wink:

 

[David C]

I tested the 60 degree scraper plane without hook, with all the students in my workshop at the time. One was particularly able.

Although the no hook blade did work, we infinitely preferred the 45 degree with hook.

My opinion is that a scraper with a hook is a cutting edge with an almost infinitely close set aggressively steep chipbreaker, and it is clearly a cutting tool, like a plane.

I described this to my best ability in an article in F&C July issue 129 page 16.

Scraper planes, double bevel sharpening and raised effective pitch were demonstrated in the dvd which we shot in Maine this May.

Scrapers without hook are described by Hoadley as producing type three shaving/chip. This is an entirely different cutting/scraping action.

A2 blades work just as well as carbon steel with the usual advantage of longer life but possibly greater difficulty of sharpening and grinding. Particularly for those who do not use waterstones or scary sharp.

Burnisher shape is interesting, for the same applied force a larger radius will apply less pressure than a smaller radius.

The spreading butter analogy was Chris Schwarz not me, but the ruler trick time saving method is mine and Chris described its use for card scrapers in an excellent recent article in PW.

best wishes,
David Charlesworth