Sharpening Scrapers

[bluenoser]

Moderators, I considered placing this in Tutorials rather than Gun Building but thought this section a better fit.  Please move it if you think otherwise.

There is an excellent article on sharpening scrapers in the August 2012 issue of Fine Woodworking magazine.  To view the video, go to Finewoodworking.com/extras.  Go to issue # 227 and click on the video.  Alternatively, this link should take you directly to the video.
http://www.finewoodworking.com/tool-guide/video/how-to-sharpen-a-card-scraper.aspx

When there, you will have access to the article as well as a companion article and videos.  The videos are free, but you need an online subscription, which I don’t have, in order to read the articles.

If you are not familiar with the magazine, you might want to take a look at it.  It is quite pricey, but I think it is, hands down, the best woodworking magazine on the market.

Laurie

[Acer Saccharum]

Woodcraft also has handouts on various techniques, probably sharpening scrapers among them.

[WadePatton]

http://www.finewoodworking.com/how-to/video/tune-up-a-card-scraper.aspx

very nice.  I've scraped a bunch, but ne'er with a "proper" scraper.  this changes that.

[smart dog]

Hi Laurie,
Thank you for the link.  There are many ways to sharpen scrapers and his is as good a way as I've ever seen.  Something to point out is that he is using scrapers to clean up flat surfaces.  Hence, he works very hard to flatten and even up the edges.  In gun making, we mostly work on curved surfaces and almost never broad flat areas.  Consequently, at least in my experience, it is not as critical that the edge be perfectly straight and even.  That makes it a little easier and less time consuming to sharpen scrapers.  Again thanks for the link.

dave

[Kermit]

Straightening the edge makes it easier to sharpen, IMO. Doesn't much matter for "flat surfaces," because in use you spring a curve into it with your thumbs on the back. The whole edge seldom, if ever, gets used scraping a flat surface. I'm a scraper cheerleader. Once you get a good piece of steel and can keep it sharp and get a good technique, there's no turning back.

[bluenoser]

Dave

You make some good points.  I have been making and using scrapers in cabinetmaking and gun building for over 40 years and certainly agree with you with regard to the curved surfaces on a longrifle – both convex and concave.  In my opinion, the universal truth here is the faces should be smooth and flat and the edge (before rolling the hook) should be square with the faces and also smooth and flat, but not necessarily straight. I consider that to be true for straight, convex and concave scrapers. I find concave scrapers to be the greatest challenge to sharpen and frequently use a straight scraper where a concave tool would do better - just so I don’t have to mess with sharpening it.  If the faces and/or edges are not smooth, the hook will have a saw-tooth appearance and the wood surface will suffer accordingly.  If they are not square with one another, it will likely be difficult to turn a good hook.

I make my scrapers both with and without a hook.  Those without a hook are less aggressive and I tend to use them where a light touch is desired.  I think smooth faces and edges that are square with each other are even more critical here.   Prior to reading the article, I had always created my hook by just running the burnishing tool at a slight angle across the edge of the scraper.  The eye-opener for me was the recommendation to first pass the burnisher across the face of the scraper. I found that method to be quite superior to mine.

Being a backward kind of guy - some might say contrary - I tend to use a scraper on the pull stroke, rather than the customary push stroke.  It seems to feel more natural and I feel I have better visual control.

I think the lowly scraper is a much under-utilized tool.  It is inexpensive, easy to make, use and maintain and pretty difficult to get into trouble with compared to other cutting tools.  If you are working wild grain, it can truly be your best friend.  I think most folks who have tried one and set it aside did so because it was not properly set up and they did not know how to properly sharpen and use it.

OK, I’m going to get off my soapbox now 
Laurie

[Mark Elliott]

I have a bunch of scrapers, but I mainly use two.  The first is one from a Kit Ravenshear pattern out of one of his little booklets that TOW carries.   It has all the complex curves you are likely to need in building a longrifle.    The other scraper which I use the most was introduced to me by  Allen Martin.   It is the lowely utility knife blade that has had its edge flattened on a stone.   I keep a 1200 grit continuous diamond stone on my bench.   A couple of pulls across this stone gives you 20 minutes of the best scraping you have ever seen.   That little blade will get in just about everywhere and can really move some wood.    I event use it to scrape brass and iron.    Try finishing up your brass trigger guard with one of these.   You are guaranteed to keep those flats nice and sharp.    I have even used it on iron mounts and lock plates.   A box of the things is a couple of dollars and I have yet to throw one away because it was too damaged or used up.

[WadePatton]

suitable alloys? i don't see that at a glance and i'll bet you somebuddy knows without looking. 

thanks

[Dr. Tim-Boone]

"It is the lowely utility knife blade that has had its edge flattened on a stone."

Mark, would you post a picture of this scraper..?  I think I know the blade you mean but I am not sure.

[SuperCracker]

 It is the lowely utility knife blade that has had its edge flattened on a stone. 

I tried that as well and it worked good. If you can get ahold of a worn out, quality, metal cutting band saw blade to cut into sections they make excellent scrapers and stay sharp even better. Especially for Brass and soft iron.

[rich pierce]

I've been over-aggressive turning the edge according to the video.  Will see how the gentle approach works.

[bluenoser]

Rich,
We appear to be in the same boat.

Regarding suitable alloys - I cut most of my scrapers out of old hand saws.  I avoid those with tapered blades, ie thinner at the back than at the teeth.  I find it difficult to cut scrapers of uniform and  what I consider appropriate thickness out of the tapered stock.  Those tend to be higher quality saws and better choices for refurbishment.  I have also used metal banding, hacksaw blades and power hacksaw blades but prefer hand saws.

Mark,
Kit's scraper pattern sounds interesting.  Could you post a photo?

Laurie

[WadePatton]

junk saws... no prob.  and yes, i refurb the good stuff.

[Meteorman]

It is the lowely utility knife blade that has had its edge flattened on a stone.   I keep a 1200 grit continuous diamond stone on my bench.   A couple of pulls across this stone gives you 20 minutes of the best scraping you have ever seen.

+1.
I learned this from Mark Wheland and I use them more than any other scraper now.
The carpet knife blades give you twice the edge - just makes handling a little more exciting.
The scalpel blades also give you a handy little convex radius for those difficult little concave surfaces.

[Mark Elliott]

Here is a picture of the scrapers I mentioned previously for those who asked.

[bluenoser]

Thanks Mark.

I see what you mean about the profile.  Would that scraper measure about 6" across the straight edge?

Laurie

[Kermit]

Don't forget glass. A lot of years ago I was introduced to microscope slides. Then I used a piece of broken window glass. Masking tape on the non-working edges helps keep the red stuff on the inside of your fingers. 

[Mark Elliott]

Yea,  5-6" is about right on the scraper length.  I made it from a standard Sandvik cabinet scraper blank.

[SuperCracker]

Don't forget glass. A lot of years ago I was introduced to microscope slides. Then I used a piece of broken window glass. Masking tape on the non-working edges helps keep the red stuff on the inside of your fingers. 

Don't pieces of glass for scraping show up in the estate inventories of gunsmiths and other woodworkers from time to time?

[Dr. Tim-Boone]

In about 1956 my Father gave me an old .22 bolt action and said I could have it if I smoothed and refinished the stock. He taught me to steam dents and to break one of Mom's Mason Jars to use the broken glass as a scraper.. worked like the dickens!!!

[bluenoser]

Bet mom was impressed

[Dale Campbell]

Probably not. Dad didn't explain to young Dr. Tim that you empty the jar first.

[Dr. Tim-Boone]

     

[heinz]

I think two different kinds of scraping techniques are being confused here.  One uses a scraper with a "hook" or burr turned on the edge of the metal and is essentially a microplane producing a very smooth surface.   The other uses an edge, more or less square, without a hook and scrapes off material rather than planing it off.  The cabinet scraper produces very fine curls of wood like a very sharp plane, the right angle scraper produces sawdust of very small short curls. Both work but the hook produces a finer surface in my opinion. 

[Kermit]

Heinz is right. If you are looking to produce a fine finish ready for French polishing, a steel cabinet scraper, properly sharpened, is the tool you want. Since I usually see guns hyped as having a scraped finish, meaning some tool marks are acceptable, I'd say breaking Mom's mason jar will do quite nicely.