Scraper plane vs. Card Scraper
#11
I've been learning to use a Lie Neilsen scraper plane. I was having some light tearout on quilted maple and was able to solve that by sharpening extra sharp with an 8000 grit water stone and then about 20 swipes with green compound on leather. Prior to this I tried a card scraper, new out of the box from Woodcraft, and had no tearout at all on the same piece of maple. The LN scraper tilts to a maximum 25 degrees or so which is where I used it with good results after sharpening; I had no hook on the blade. When I used the card scraper I held it at about 45 degrees, and of course it had a hook rolled on it. Card scrapers are only sharpened with a file, then a hook is rolled with a burnisher. And the card scraper easily removed the tearout left by the scraper plane.

Seems to me the scraper plane has all the advantages except the tilt angle is limited to 25 degrees. I am not understanding why a scraper plane must be so carefully sharpened and the card scraper does not.
Reply
#12
A card scraper will only get your wood to the finish of the last grit of sharpening agent you use to sharpen it.  The burr you turn will represent that last grit used.  The higher the grit used, the finer the burr will cut.  You can get a card scraper to work using only a file and burnisher.  It will work at that point, but if you stop sharpening there, when you use it, it is as if you used that file to scrape your work.

Many years ago when I first learned to use a scraper, I made a small piece as a gift for my aunt.  I hated sanding, which is why I got into hand tools in the first place, and used a card scraper that I had prepared using only a file and burnisher.  The marks that were left on the piece after scraping made it look as if I had used 80 grit sandpaper as a final prep.  Now that I know better and sharpen my scrapers to a much higher grit, that finish is as good as I get with any other hand plane, including a scraper plane sharpened as you did yours.  Interestingly enough, that aunt passed away several years back and her family wanted me to have that piece back.  It's sitting on the table next to where I am sitting right now.

As with any edged hand tool, the finer grit with which you finish your sharpening, the finer will be your finish after using that tool.

Blaine
Reply
#13
Quote:I am not understanding why a scraper plane must be so carefully sharpened and the card scraper does not.
Homer, I do not know where you got this from. 

Think of a coarse sharpened edge as akin to a jack plane - takes off a lot quickly but without finesse. One example of this is a scraper with an edge off a 80 grit CBN wheel ...

[Image: Sharpening-blade-scrapera_zpslgrvfjha.jpg]

[Image: 1_zpspr2v0uh1.jpg]

But that will not leave a finish that one can get from a polished edge (finished on green compound after 10K ceramic stone). In the example below, the scraper is following a 400 grit sanded finish ...

[Image: FinishingTheDrawers_html_7f541cdc.jpg]

Regards from Perth

Derek
Articles on furniture building, shop made tools and tool reviews at www.inthewoodshop.com
Reply
#14
Hey Blaine, good to see you in here again!
Ya'll take care;
Skip


Reply
#15
Thanks Skip.  I lurk and contribute when I think I might add something that another member might not.  Hopefully, that's the case here.

The forum has gone so much more toward saws and that's just not my thing.

Blaine
Reply
#16
Sounds like you are rolling the burr too far around on the scrapers.  The burr only needs to be just a little bit "forward", maybe a maximum of 5-7 degrees of hook. 

A polished edge does indeed make a finer burr.  But even more important to me, the burr lasts longer.  My theory being that the scratches left by the last polishing medium are where the fractures begin.  Larger and more scratches, larger and more (quickly) the burr fractures and falls away.

Also, taking time to consolidate the edge (a bit of work hardening) with the burnisher before rolling the burr helps me.

A filed burr is great for quickly removing old finish.  Quick and efficient.


Side note: Just the other day when I was acting as the hall monitor (foreman) in the KCWG shop (we keep at least one person who knows how to do basic maintenance on all the equipment in the shop when it is open) there was a member trying to clean up the inside curves of some funky little bud vases he had made.  Scroll saw work with lots of internal cut-outs.  Think "insideout turning" but with out the lathe.  Anyway, he had used a small rat-tail rasp to blend some of the curves but was not getting annoyed with the followup sanding.  I showed him how to snap off a bit of old hacksaw blade and roll a burr on the back edge.  A small and flexible scraper let him skip right from a coarse rasped surface on a mix of edge and endgrain right to a 220 grit paper so he could apply his finish.  In this case, we did just use a file and burnisher. By drawfiling with a fine, single-cut file, one gets a more refined surface.

Moral of the story, scrapers are GREAT and can save one a lot of grief once you get the hang of them.
Don't sweat the petty things and don't pet the sweaty things. -- G. Carlin
Reply
#17
(12-16-2016, 10:03 AM)Blaine Wrote: Thanks Skip.  I lurk and contribute when I think I might add something that another member might not.  Hopefully, that's the case here.

The forum has gone so much more toward saws and that's just not my thing.

Blaine

Put a burr on the back edge of all your saws then if that makes you more comfortable with them... 
Big Grin
Don't sweat the petty things and don't pet the sweaty things. -- G. Carlin
Reply
#18
Thanks for all the shared expertise. Day before Christmas I turn 77 and hope the Lord lets me stick around a while and learn some more (if I can get beyond the bladder cancer I've been battling for over two years - keeps coming back).

Anyway I'm always amazed at the collective knowledge here and the spirit with which it is shared!

Homer
Reply
#19
Of all the scraper maintenance directions, answers, blurbs, and tips I have seen over the years, I do not recall Blaine's pointer about creating an edge for a corresponding coarse or finer finish when scraping. Yet it makes total sense. I blunter along and probably moved to a finer abrasive grit just to save my flesh from uglier cuts a coarse-toothed burr causes.

Thanks, Blaine; and Derek, and Rob. Your lurk-and-pounce stance is greatly appreciated, Blaine. And Homer, for the OP. Finding nuggets of new information is a treat.
Reply
#20
(12-16-2016, 10:16 AM)Rob Young Wrote: Put a burr on the back edge of all your saws then if that makes you more comfortable with them... 
Big Grin

Excellent comeback Rob.... and thanks Blaine for the explanation, it really helps to understand what's going on at the edge.

Sorry to hear about your health Homer, best wishes from all of us this holiday season!
Skip


Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)

Product Recommendations

Here are some supplies and tools we find essential in our everyday work around the shop. We may receive a commission from sales referred by our links; however, we have carefully selected these products for their usefulness and quality.