Triangular machinist scraper AKA Burr knive.

[Charlotte]

I just happened to be paging through a jewlery supply catalogue and noticed my old friend the burr knife.

I know than anyone here that has worked in a machine shop or handled sheared, or punched sheet metal on a daily basis has used one.

However since many some new smiths may not have the same back ground I thought someone might take a picture of his/hers and post it. Some anecodotes relating to use and abuse would be nice also.

The first one I had was a taper ground triangular file. I was given the scraper and three pallets of machined and drilled castings to "clean up" :D

[meinhoutexas]

have one at the job that started out 6" long now roughly 2.5" but i keep it razor sharp.

[pkrankow]

Lately I have used the backside of disposable razor knife blades. Just flip the knife over and push the burr off. Since they are stamped, one side has a nice corner that removes aluminum and mild steel burs nicely. Then again, I've only been messing with sheet metal lately, and burnishing is sometimes as effective as stripping the burr away.

I've used a variety of purpose built deburring tools that have swivel heads for cleaning holes, and a double carbide wheel job for cleaning sheet metal edges, but these were provided, either in class or by my employer (or a machinist I was helping). I wouldn't buy one of these unless I was repeating the same type of cleaning frequently, they are too specialized.

I've use a file, but never thought of sharpening any part of it differently for use deburring metal.

I find the shoulder between the tang and file of a file without handle to work excellent for deburring pipe after cutting. Yes this involves holding the business end of the file, but most of my files are very old and near worn out to start with.

I've also used a larger drill bit for cleaning the edge of small holes and small metal tubing. A half turn plus a bit and you are done.

Phil

[Fe-Wood]

Another twist on the de-burring tool- As a wood worker, I use one to PUT a burr on tool steel scrapers I make from old saw blades. With the scraper mounted in a vice, file the edge sharp at 90 deg. and then holding the de-burring tool at a slight angle with the leading edge slightly raised, push a burr onto the scraper. THIS IS A VERY SIMPLIFIED explanation. I have seen MANY people do this and wind up with NASTY gashes on there fingers, wrists and arms. Be Carefull!!!

[mcraigl]

I must have about a dozen of these things made from triangle files. A lot of the old millwrights are dieing and my wife is an estate sale junkie. She figures if she brings me some bobble home I won't complain about her habit. Mostly she's right. Anyway, I've yet to use one for anything. I have one of the swivelly deburring tools from MSC that I use a lot, are the situations where the little triangle file sharpened up thingy would work better?

Fe.. I'd like to talk to you some time about the wood scrapers. I have a friend who does incredible hand joinery work and uses scrapers. I've thought about making some for him, but am not sure on the particulars... I had planned on making them out of 1095 and grinding the edges to 90 then hardening, but from the sounds of your post they should be left annealed, or tempered wayyy back? Also, maybe he'd rather have one of the little triangle thingys for putting a new burr on his scrapers??? I'll ask him how he sharpens them and offer him one.

[Dick L.]

Here are three I've had for a good while. Used to de-burr everything from drilled holes to machined slots and corners in all types of material. When I apprenticed in the paper industry as a millwright the guys pouring the line shaft bearings in place had a special favorite that they only used for the babbitt bearings. You seldom see a newcomer to the trade with one. They all have the fancy specialized swiveling types you can get in all the tool supply catalogs.

Dick

[John B]

I use a small half round scraper for deburring holes, its also good for cleaning the spatter from the nozzle on the MiG welder, spent many an hour using flat scrapers to bed in mating surfaces.

You can use a polished hardened steel bar for putting the edge on cabinet makers scrapers (Silver steel O1 is ideal)

[thingmaker3]

I've used mine on knife bevels in lieu a sen tool. Works great.

[JNewman]

I have used various shaped scrapers for cleaning up aluminum matchplates, cast aluminum patterns, cast aluminum vaccum tools and cast aluminum styrofoam moulds. Die grinders with flap wheels and Socat disks work a lot faster where you can get them in but there are still lots of places you cannot get the rotary tools. The shapes I have used the most are a woodworking chisel sharpened almost square and a round file with a bit of a bevel ground on the end. both of thes are pushed and basically used like a single tooth file.

[Will. K.]

I've acquired a couple of similar looking scrapers at auction this last year in mixed lots of tools. I'm not sure if they're burr knives or are meant for some other task. the larger one is made from a triangular file. The smaller one is 4-sided. The faces on both are ground slightly concave.

[Charlotte]

Generally slightly concave means that they are burr knives. You can touch up and edge garden tools. Carve a chamfer on cast iron. Slick off sheared sheet metal etc.
I always carry one in my tool boxes.
Generally convex and polished are burnishers. They are used to, well, burnish ( polish metal ). Burnsishers work by molding the metal smooth by pressure. Today we mostly think of them as John B mentioned to edge cabinet scarpers.

[pkrankow]

Another twist on the de-burring tool- As a wood worker, I use one to PUT a burr on tool steel scrapers I make from old saw blades. With the scraper mounted in a vice, file the edge sharp at 90 deg. and then holding the de-burring tool at a slight angle with the leading edge slightly raised, push a burr onto the scraper. THIS IS A VERY SIMPLIFIED explanation. I have seen MANY people do this and wind up with NASTY gashes on there fingers, wrists and arms. Be Carefull!!!

Funny, I use the back of a hacksaw blade as my scraper for wood and the shank of a 1/4 inch or so drill to put my burr on. I've also used broken glass, no need to put a burr on that, but wear good leather gloves, and tape the edges you are not using.

For scraping wood with glass, take a piece of window glass (I like double strength) nick the edge near a corner or short edge with your glass cutter and use a padded pair of pliers to "twist" off a useful shape for your project (concave or convex) between 1/2 and 1 inch wide, as long as you need. Voila! you have a double edged scraper that will last for the day and cost near nothing. Takes practice to use these, more tricky than metal scrapers.

But this is somewhat off topic now:o

Phil

[bigfootnampa]

Phil; The thing that you miss when scraping with glass is the geometry of the properly turned scraper edge. A card scraper with a proper and sharp burr cuts very quickly and with miniscule dig-in problems. The curve of the burr creates a limiter that prevents the scraper from digging into the wood too deeply. This is the real beauty of such a tool... I've scraped large tabletops removing impressive amounts of material in rather short order. It helps to wear gloves and to have several good scrapers sharp and ready... heat builds extremely quickly when scraping oak tabletops! I rotate my scrapers to allow cooling time and the gloves save my fingers as even a single pass with a newly sharpened burr can burn your fingertips.

Mcraigl; The old timers used to make their scrapers from handsaw blades which had become too bent or been sharpened too many times to be good saws anymore. This steel was fairly springy and still works well though the younger guys seem to like pricy factory stuff of which some is much more hardened. You might try some variations and see what your guy likes best. Personally I kind of like the old way but when I have heavy scraping to do I will use thicker scraper stock so that it resists chattering... it must still bend a little in my hands though, that keeps the corners off the work and allows a super shallow gouging effect as I scrape.

When the steel is left in a harder state it is less malleable making the burr harder to form. At the extreme here we approach the same sort of performance as glass (the edges are sharp and durable but the proper burr geometry is compromised or eliminated). Steel scrapers that are heat treated to finish very hard will also require harder burnishers to turn their burrs at all (some guys are using solid carbide rod for this).

IMO they work best with a temper more like a saber blade than like a razor blade. I'd say spring temper or just a wee bit harder.

[mcraigl]

Thanks for that Bigfoot! rusted out old handsaws are a pretty easy garage sale scrounge item, so that's just about as easy to source as new steel. Just leave the saw's original heat treat then? I know just from watching Brian work that the bend is crucial, kind of the built in, on the fly, adjustment. So a burnisher made out of o-1 would be a good gift for him too then? See, I want him to make me a real nice hand dovetailed box, that I want to build all the hardware for. Seems like a couple of nice hand made tools would be a good start at talking him into it....

[bigfootnampa]

mcraigl;
Rusted out is not so good as you want nice smooth flat sides on your scrapers. Saws with busted handles and messed up teeth are fine though. There is a movement away from handsaws alltogether so they are fairly easy to find on the used market now. Burnishers should be file hard and polished quite smoothly. I have made them from old file steel. They work very nicely but it takes a lot of time to get a smooth and polished surface on steel that hard. They are not cheap at the woodworker's stores either so they would make a nice gift. Straight round is my favorite shape but I love ovals too (they are much harder to make).
Original heat treat on old handsaws should be about right as is. Better saws have better steel of course... Atkins was famed for their quality steels, but it's a shame to cut one up if it seems salvageable.

[mcraigl]

a little rust don't scare me. that's what abrasives are made for ain't it? I can always run them down to 15 microns or so if I need to...

[pkrankow]

Bigfoot, I've never scraped a table top. I seem to end up doing detail work like cleaning pinrails for refinishing, or molding with several funny curves. Larger scrapers make a mess on small stuff like this. On this small scale, dig in is not a problem (for me).

I do want a good set of scrapers, and picked up some worn industrial hacksaw blades, thick and about 2 inches across. I haven't needed anything larger than broken glass though, so I haven't bothered making the scrapers yet.
Phil

[bigfootnampa]

mcraigl You are right about a little rust... I pictured deeply pitted stuff when you said rusted out.

Phil those hacksaw blades ought to work well if they are not too thick to flex in your hands. I have some small versions that are air hardening. They are too small for scrapers but make excellent carving knives. I have to be very careful forging the tangs though, they will crumble if I overwork them. They are especially useful as spiky little detail knives. No worries about drawing too much temper on these... as soft as I can get them is about right (just this side of too brittle).

[Bentiron1946]

I got two scrapers at an estate sale awhile back, one was a jewelers tool, very nice rosewood handle, highly polished blade, but definitely a scraper not a burnisher. The second was a Heller brand and was new with a few flecks of rust. It had never been sharpened, nice tool. Both were three sided and both a dollar each. I also got two nice jewelers burnishers.:cool: