Hand scrapers - preferred file?

[rafezetter]

I'm interested in starting to use hand scrapers, for several reasons, and would like to know peoples preferred mill file used to joint them before re burring?

What brand and or type of cut have people been using?

 

[MIGNAL]

Any fine file will do. I've even used a flat needle file, although hardly ideal. These days I don't use a file but use a coarse diamond stone. I simply freehand the scraper, trying to keep it absolutely vertical. The diamond stone will give a slightly better edge than just finishing with a file.

 

[sdjp]

Yep, likewise - my scrapers became a lot better when I started using my diamond stones rather than a file.

I actually go the whole hog, and finish with a ceramic stone before burnishing. I reckon that one probably could get just as good a final finish on the wood with fewer stones, but better burnishing technique - but I don't use them often enough to get the practice in for burnishing, so I'm happy with the trade off point.

 

[jimi43]

Diamond stone here too.

You only need a cheap one but flat as possible and wide as you can so that you can keep a straight edge

Jimi

 

[Paul Chapman]

I also use a diamond stone rather than a file.

Cheers :wink:

Paul

 

[Cheshirechappie]

As a direct answer, the same mill file you use for jointing saws when sharpening them will do fine - but that's for shaping the scraper, not sharpening it.

With a card scraper, the best performance comes from having the edges of the metal sheet clean, well defined and as sharp as you can get them. That's done by establishing the shape of scraper you want by filing or grinding, then by refining the finish on the edge and the sides of the scraper right by the edge to the sort of polish you'd put on a plane iron. It's just the very corner that does the work you want so defined; the finish on the sides away from the edge is immaterial. Once you've got that, the scraper will work well enough without a burr, but turning a small burr with a burnisher will often improve cutting ability.

How to get that sharp edge? Polish both sides on a sharpening stone, and polish the edge on the same stone. Just the same principle as sharpening a plane iron. Use a medium stone to get a polish, then refine it with a fine stone. The late Charles Hayward (who knew a thing or two about woodworking) recommended doing the edge by placing the scraper between the top and base of an oilstone case, and working it up and down the side of the stone. The case kept the edge nicely at 90 degrees to the sides. Something similar can be achieved by a block of wood on a sharpening stone, with the scraper held against it and worked edge-on on the surface of the stone. Freehanding works, as long as you can keep the angle at 90 degrees.

Once you have the cutting edges dead sharp and clearly defined, you can turn a small burr if you wish, and re-turn it a few times before reshaping the edge. With a scraper so sharpened, you'll have no problem producing definite shavings. If all you get is dust, the edge is not sharply defined enough, and either edge or sides right by the edge need more work on the sharpening stones.

It's actually not as much palaver as it sounds. Once you've got a nice polish on the sides, you don't need to do much more to them. Just sharpen off the old burr and repolish the edge; the sides will only need a touch-up on the finest stone. Bit like the flat face of a plane iron - once it's in good order, most maintenance of the iron is done on the bevel, with just a quick back-off of the burr on the flat face.

 

[Trafalgar]

Chappie's got it I think.

 

[bridger]

if the edge is bad enough that I need a file, I like a pretty big file, single cut, with fairly fine teeth. but any sharp file will do.

from there it is to the 600 grit diamond stone. both faces and the edge, lapped to make a crisp 90 degree edge.

sometimes I follow that with a natural stone, about washita or lillywhite. sometimes with 3000 grit diamond. usually I just stick with the 600 grit surface.

then the burnisher. draw the burr up, then out.

then use it. when it starts getting dull, go back to the burnisher. up, then out.

after about 3 "maintenance burnishings" it won't turn an edge anymore. then, go back to the 600 grit stone. after a few rounds of the stone, then a few "maintenance burnishings" then the stone, etc. it gets too rounded over for the stone to get me there in a reasonable time. then, I have to go back to the file.

there really is a curve of diminishing returns to increasing the fineness of the stone you use prepping a scraper for the burnisher. the burnisher improves the edge quite a bit all by itself. I guess if you are scraping ebony or something and that is to be the final surface it might make sense to stone it beyond a mid-grit stone. mostly, I want to get a burr quickly and get back to work.

 

[rafezetter]

As a direct answer, the same mill file you use for jointing saws when sharpening them will do fine - but that's for shaping the scraper, not sharpening it.

With a card scraper, the best performance comes from having the edges of the metal sheet clean, well defined and as sharp as you can get them. That's done by establishing the shape of scraper you want by filing or grinding, then by refining the finish on the edge and the sides of the scraper right by the edge to the sort of polish you'd put on a plane iron. It's just the very corner that does the work you want so defined; the finish on the sides away from the edge is immaterial. Once you've got that, the scraper will work well enough without a burr, but turning a small burr with a burnisher will often improve cutting ability.

How to get that sharp edge? Polish both sides on a sharpening stone, and polish the edge on the same stone. Just the same principle as sharpening a plane iron. Use a medium stone to get a polish, then refine it with a fine stone. The late Charles Hayward (who knew a thing or two about woodworking) recommended doing the edge by placing the scraper between the top and base of an oilstone case, and working it up and down the side of the stone. The case kept the edge nicely at 90 degrees to the sides. Something similar can be achieved by a block of wood on a sharpening stone, with the scraper held against it and worked edge-on on the surface of the stone. Freehanding works, as long as you can keep the angle at 90 degrees.

Once you have the cutting edges dead sharp and clearly defined, you can turn a small burr if you wish, and re-turn it a few times before reshaping the edge. With a scraper so sharpened, you'll have no problem producing definite shavings. If all you get is dust, the edge is not sharply defined enough, and either edge or sides right by the edge need more work on the sharpening stones.

It's actually not as much palaver as it sounds. Once you've got a nice polish on the sides, you don't need to do much more to them. Just sharpen off the old burr and repolish the edge; the sides will only need a touch-up on the finest stone. Bit like the flat face of a plane iron - once it's in good order, most maintenance of the iron is done on the bevel, with just a quick back-off of the burr on the flat face.

Hi thanks for the replies,

I should have said I intended to go (maybe) the whole hog - joint, polish edge sides etc as recommended in this blog:

http://www.timberframe-tools.com/tools/sharpening-card-scraper/

I've only ever used a basic file, I didn't even know it was called a mill file let alone what sort of cut it is, but as I've now made the burnisher from 1 of the broken carbide tips donated at Richards meet (I think it might have been Jimi?) I figured I'd better use it

So next stop is a file holder and reference edge for the stone.

 

[MIGNAL]

2 nd Cut file. No way that you should need anything coarser than that. It's just about maintaining the square edge and then filing/grinding past the worn rounded edge. A 2nd cut file does that very quickly. I never bothered with the holder, just used the draw file technique.
The good thing about using the diamond stone is that it won't groove. On other stone types you really need to skew the scraper. I've also found that it's easy to maintain the scraper vertically (without the need for guide blocks) if you don't have to skew the cabinet scraper. It turns it into a pretty simple and fuss free operation. I don't polish the edge. I find that 600G is about as far as I need to go. Like many things, you experience increasingly smaller returns. Even turning the edge straight from the file works, it's just not quite as sharp.

 

[Tony Zaffuto]

Chappie's posting of Hayward's tip of placing the scraper between the top & bottom of an oilstone wooden case shows the simple brilliance of many of our woodworking ancestors. One of those, slap yourself on the forehead moments!

Thanks for your post!

 

[MIGNAL]

Except that it doesn't work very well in the long run. (if I'm understanding the method correctly). If you are using a guide and the edge of an Oil (or Waterstone) it quickly forms a groove in the edge of that stone. Subsequent use will only serve to round or dome the edge of the scraper, not something we are aiming for. Either skew the blade using the usual face of the stone or buy a diamond stone. With the diamond stone it isn't necessary to skew the scraper, which consequently makes it easier to maintain the 90 degrees (freehand). Skewing the scraper with a guide block isn't a very good method either (with both scraper and guide block moving together). Frequently the guide block rides up on the side of the scraper making it's use inaccurate.
You can use a guide block on a diamond stone and keep the guide block stationary. Just moving the scraper to and fro using the stationary block as a vertical guide. I don't bother with the guide block though, I don't find it necessary. Again the trick is to use short forward/backward movements if you are using freehand. Bigger or greater movements = more chance for things to go wrong.

 

[J_SAMa]

If it hasn't been mentioned, really use some elbow grease consolidating and bringing out but don't overdo turning it. Doing 50 strokes with the burnisher angled on that edge isn't going to help. It was the single biggest cause of failure in my early experimentation with a scraper.

 

[MIGNAL]

No. You shouldn't need elbow grease. Clearly the edge is poor if you have to do that. The degree of pressure you exert determines the degree or thickness of the shaving. Even very light pressure should be enough to give you an edge that results in a shaving. One or two strokes with the burnisher, that's it.

 

[bridger]

For stoning the faces I lay the stone flat on the bench with the card flat on it. Apply pressure with fingertips and make circles. For filing, edge stoning and burnishing I put the card in a vise (a saw vise works great) vertically, edge up, and bring the tool to the edge.

 

[Cheshirechappie]

I'd agree that if you ran a scraper edge along the side of a waterstone, you'd quickly form a groove. However, an oilstone is a good bit harder; you'd have to sharpen an awful lot of scrapers to wear a groove in one. (OK - instrument makers tend to use scrapers more than most woodworkers, but even so....)

Another tip is to hold the scraper with a bit of folded cloth or rag whilst sharpening on the oilstone. The edge you hold is sharp, and the corners (unless you round them off a bit with a file) are even sharper. I found that out the hard way....

(PS - Bridger's tip about holding the scraper in a vice and bringing the sharpening tools to the edge sounds a very good plan to me. Keeps your fingers away from sharp edges. Must try that......thanks, Bridger!)

 

[woodfarmer]

I misunderstood this post. I thought you meant making scrapers from files ( to hand scrape cast iron machine tool beds).
Had my answer all thought out to no avail