Burr removal NOT with a stone, but with a burr file..?

I (non-professional as far as scraping, although I have sold reconditioned machines) used to use a fairly fine india stone for de-burring. Probably not the exact one Mr King recommends in another thread, although it was somewhat similar in description.

I found that I had to clean the stone so much that I started using a burr file, a file that is intentionally dulled by rubbing on a flat oilstone until the teeth all have flats on them. The flats should all be in a single plane...

The theory, which seems to work, is that the teeth will slide on a flat surface, and cut anything that sticks above it. So unlike a stone, it *should* not cut anything but the burrs, even if one were to be a bit heavy-handed with it (which I am usually not). it can be felt cutting, and then starts to slide free when the bumps are cut down.

It seems to work well. But, as with many things that look good, there may be a catch that I have not discovered.

Is there any particularly bad feature of this tool in place of a stone?

bump....

This is indeed a question..... if anyone has an opinion.......

Well if it works for you then I find nothing wrong with it. Never tried a file like you described, perhaps you have come across something new?

Charles

I prefer a cleaned India stone dulled with a DMT diamond stone to a very slight convexity for de-burring over the burr file but that's my preference.

A properly prepared contoured India stone requires daily maintenence and are fragile but they have the advantage of predictable action and, if kept clean, zero sratches.

Burr files (segments of files deliberately dulled with a stone) work equally well for all but the final few cuts on reference tools and they require less maintenance (no cleaning, de-pinning, contouring). They seldom scratch and they remove the burrs and shreds of raised metal more efficiently than a stone - and a burr file does not load or pin.

The Biax people pack a versatile scraper tip radius gage in every power scraper box. This gage not only features several radii for gaging scraper tips but a one square inch window for point counting and a blunted scraper edge for deburring. Many prefer this scraper edge for de-burring over the stone or the burr file.

However a burr file is hard to employ as a developer of final bearing where the "cusps" (the crests between the troughs cut by the scraper) are flattened to perfect the bearing. The object is to acheive about 20% of the scraped surface to flat bearing areas that are not "points," strictly speaking, but flat miniature bearing surfaces. The advantage of the stone is that it has a predictable cutting action that may be used selectively to acheive final bearing distribution - not as a crutch where areas are abraded down to blend with the scraping troughs in one place to get blue points in another but as the final touch to the scraped surface.

This final touch is intended for use for reference tooling (surface plates, straight edges, scraped prisms, gages, etc) where a 4x greater degree of refinement is necessary for printing the working surfaces to be scraped from them.

I'd suggest the stone, Biax gage, or burr file as the choice of the scraper hand but when the final cuts on reference tooling are in progress where the reference tool is allowed to rest for hours between cuts, use the dulled slightly convex India stone to not only de-burr but refine the bearing points.

JST said:

I (non-professional as far as scraping, although I have sold reconditioned machines) used to use a fairly fine india stone for de-burring. Probably not the exact one Mr King recommends in another thread, although it was somewhat similar in description.

I found that I had to clean the stone so much that I started using a burr file, a file that is intentionally dulled by rubbing on a flat oilstone until the teeth all have flats on them. The flats should all be in a single plane...

The theory, which seems to work, is that the teeth will slide on a flat surface, and cut anything that sticks above it. So unlike a stone, it *should* not cut anything but the burrs, even if one were to be a bit heavy-handed with it (which I am usually not). it can be felt cutting, and then starts to slide free when the bumps are cut down.

It seems to work well. But, as with many things that look good, there may be a catch that I have not discovered.

Is there any particularly bad feature of this tool in place of a stone?

Click to expand...

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i use alcohol to clean coolant off parts then a fine stone to remove and you can feel if burr sticking up. i have to get large parts to sit on support pads within .0001" (.0002" max)
......... the reason we use a stone is it is for the most part impossible to remove too much material cleaning and deburring a part. i would be concerned a file might remove too much in some situations. the stone works and i have never felt the need for anything better. it is part deburring but also part feeling if somewhere has a localized resistance to stone going across because something is sticking up.

My thoughts are if you take your printed part and rub it a little on a clean area of the stone it cleans off the highest points to bright. If there is a burr left then its going to be immediately obvious, right at the end of a scrape mark and usually holding the part high with few other polished points.

The orange india stones I have (Nortons IIRC) are a lot finer than the scraping stone. Which may be the reason it loads quickly. I've had great luck unloading stones with Windex for the water based canode, and with CRC natural degreaser (orange smelling solvent) for general purpose/oil-based debris.

As far as the file, if its working then I'd stay with it.

we just use mineral spirits to clean stones and to use as a lubricant when stoning. usually stoning with mineral spirits and wiping with a rag cleans the stone most times within seconds

Here in my amateur, non-profit, home shed, I use an Oregon 6" flat chainsaw file (single cut fine file) that I took the edges off in the surface grinder. It doesn't have a handle or a tang, just the file. It won't cut flat metal but does knock burs off. You can feel the difference between burred and smooth quite quickly.

For tiny work and many points per inch (top slide dovetails for example) a flat square polished carbide insert works very well to knock burs off. The hard Arkansas stone does a similar job on larger flat areas until I drop it and it breaks.

I find that more abrasive stones broaden the tops of the bearing points. I don't always want this.

Forrest Addy said:

However a burr file is hard to employ as a developer of final bearing where the "cusps" (the crests between the troughs cut by the scraper) are flattened to perfect the bearing. The object is to acheive about 20% of the scraped surface to flat bearing areas that are not "points," strictly speaking, but flat miniature bearing surfaces. The advantage of the stone is that it has a predictable cutting action that may be used selectively to acheive final bearing distribution - not as a crutch where areas are abraded down to blend with the scraping troughs in one place to get blue points in another but as the final touch to the scraped surface.

This final touch is intended for use for reference tooling (surface plates, straight edges, scraped prisms, gages, etc) where a 4x greater degree of refinement is necessary for printing the working surfaces to be scraped from them.

Click to expand...

Thanks, Forrest.

It seemed a bit too good to be true, so I thought I'd ask.

Your point on the contact refinement is well taken. In the few cases I have worked on reference stuff (some R.A. references, and a couple of straightedges), I sort-of by knee-jerk response got gun shy of the file and stoned the last couple passes.... sounds like I did some of the right thing despite doing it almost out of "superstition", and not for a good thought-out reason.

i use 3M Stikit abrasive that comes in rolls
Stikit Abrasive :3M US
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i get a piece of precision ground flat stock and use between 100 to 600 grit on it. i use to remove minor fuzz and burrs and have used to lap 0.00005" , yes thats 1/2 a .0001"
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when sand paper get old remove and put another on. every so often check for glue residue which comes off with citrus based degreasers easily.
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the metal block can be machined in any shape then abrasive applied. we had some complicated abrasive stone holders which we replaced with simple ones because we used stikit rolls now. it has been around for decades and is technology that was not around 120 years ago

For unloading a stone, I typically rub it on a flat surface covered in coolant, seems to work great. Flat surfaces and coolant are always readily available.

DMF_TomB said:

i use 3M Stikit abrasive that comes in rolls
Stikit Abrasive :3M US
.
i get a piece of precision ground flat stock and use between 100 to 600 grit on it. i use to remove minor fuzz and burrs and have used to lap 0.00005" , yes thats 1/2 a .0001"
.
when sand paper get old remove and put another on. every so often check for glue residue which comes off with citrus based degreasers easily.
.
the metal block can be machined in any shape then abrasive applied. we had some complicated abrasive stone holders which we replaced with simple ones because we used stikit rolls now. it has been around for decades and is technology that was not around 120 years ago

Click to expand...

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you could apply stikit to the bottom of a carpenters plane and with 100 grit rub and mark high spots fairly quickly. easy to take concave out but you have to watch doing ends enough or to much or surface will become convex. obviously the longer the better.
...... with a dovetail or angle shape a precision ground metal block with stikit paper applied can show small errors in surface fairly quickly. both internal and external angle surfaces. we used to have a hopper with a sharp lip pouring 8 layers of chemicals on to paper moving at 1500 feet per minute. the hopper lip needed touching up to maintain liquid pouring smoothly so the chemical layers were even within millions of an inch and not mixed. this was done with abrasive stones and abrasive paper. we used to take rubber impressions of hopper lip and photograph and put on computer to measure shape within .001" and angle 0.1 degree. Final lip geometry was always done with abrasive stones or paper by hand

While I have only a general knowledge of scarping, the file you are describing sounds like a body or vixen file in action. It will only cut the high spots while burnishing the rest of the surface. The problems I have encountered with them is mostly in holding them, any uneven pressure can cause the file to flex and want to dig in or washboard. I usually use them bolted to a frame to support them evenly along their length. Not sure how that translates to the micro scale of scraping, but I imagine you need to find a balance between a large enough file to give you even bearing between the points and not so large that it is digging in at the corners or middle.

Most of mine are about 0.75 x 2.5, and 0.25 inch thick. I don't press hard....