Scraper filing jig

[Ikisumu]

Here is my easy jig for filing a scraper. It can be used to consistently file the edge of the card scraper very square. It is a very simple thing to make, for example with just those three strips of plywood and some screws.

I have used it quite a lot now, and it has been found to be a real user. It is a completely handheld thing, there is no real need to clamp it at all. During storing, it will hang at the file quite nicely.

There is a single-cut metal file in use, ment to be pushed only. It is fitted there so that it does not much move during use. That can be done for example with a layer of paper or with other similar filler layer.

You can make the groove for the file quite deep, too. When the file wears and gets dull, just add some filler in the bottom of the groove to lift the file upwards, to expose a new line of sharp teeth.

The file is set so that when you push the scraper edge along the file, the tilted teeth of the file will draw and press the scraper against the "table" of the jig. Just remember to do pushes only.

Consistently square edge will provide a good starting point for different burnishing angles.

Here is a 0.05 mm thick shaving, a typical for a sapele mahogany (works like a butter with a scraper).

I did not compress the shaving during thickness measurement.

Samu

 

[Sportique]

Thanks Samu, I always find it difficult to sharpen a scaper, this will help

Dave

 

[bugbear]

Here is my easy jig for filing a scraper. It can be used to consistently file the edge of the card scraper very square. It is a very simple thing to make, for example with just those three strips of plywood and some screws.

I have used it quite a lot now, and it has been found to be a real user. It is a completely handheld thing, there is no real need to clamp it at all. During storing, it will hang at the file quite nicely.

It's normal to remove the handle of a file used for this purpose, which allows the whole length of the file to be used.

Since the file is held by the "gadget", no (normal) handle is required, especially if the gadget is comfortable to hold in its own right.

When searching, it's useful to know that "saw jointing jigs" and "scraper filing jigs" are the same object!

BugBear

 

[lurker]

It's normal to remove the handle of a file used for this purpose,
BugBear

And risk stabbing yourself with the tang - no thanks!

I have something almost identical Samu - great minds :lol:

 

[Mike H]

As somebody who did just that 20 odd years ago, went right trough the side of the palm and out of the other side,

I will second that!


Mike

8)

 

[Benchwayze]

That file looks like it has a bonded plastic handle anyhow.

All the rage in my son's trade, (Mechanic).. and now in my shop too!

Unless I am just not strong enough to remove them!

John

 

[bugbear]

As somebody who did just that 20 odd years ago, went right trough the side of the palm and out of the other side,

I will second that!


Mike

8)

If you're talking about "normal" filing, I heartily agree, but in this case you DO have a handle - it's the jig.

So you're NOT pushing the file by its tang-end (which is, as you imply, "rather dangerous").

But if you want to joint a 28" and don't (!!) have a 28" long file, you HAVE to remove the handle, to allow the file to travel fully the length of the saw.

I suppose, if you have a dedicated jointing file, you could saw the tang off for super-safety.

Edit; it appears that Veritas agree:

http://www.leevalley.com/US/wood/page.a ... 43089&ap=1

BugBear

 

[Corneel]

Shouldn't you stone a scraper, to get an acceptable finish?

 

[Ikisumu]

Shouldn't you stone a scraper, to get an acceptable finish?

Yes, I do further polishing of my scrapers sometimes, really depending on the case, and the wood. Sometimes I just only lap them quickly against oil-treated sandpapers, let's say 800, 1500, 2400 and 4000, for example. I have a nice set of actual stones, too. A burnishable scraper-soft steel does not need much of elbow grease.

The file in that position will continuously draw the steel residues in between the file and the "table" part of the jig. The biggest filing burr will also appear on that dark side edge of the scraper. There is some deformation on the visible side too, but it is much cleaner, and sometimes really only filing is needed before burnishing. The scraper will be the single-sided. You will need a straight and sharp fine single cut file for the job.

That one is local Viialan Viila Oy file, from the times before Sandvik bought them and ended their story in the mid 90's. The plastic handle is ment to be perfectly detachable. It will pop off with a quick pull.

Samu

 

[Mike H]

I find that the filing square bit is only the beginning. I use a slot guide cut on the bandsaw.

If I am after a really good fine burr for finish work, rather than scraping off some glue joint, I treat the scraper as if it was a normal blade and hone it all the way to a fine stone. It seems to make it easier to draw and turn a lasting edge.

By the way my anecdote about the file accident was nothing to do with scrapers.


Mike

8)

 

[Ikisumu]

I find that the filing square bit is only the beginning.

It is precisely so in very many cases.

However, one might get pleasently surprised when using a quality file for the task, too. Grobet makes some excellent files for scraper-soft steels. They seem to really "plane" the narrow edge of the scraper, leaving a readily reasonably sharp edge there. Sure, they need some attention in how fast and with how much of pressure the file is worked with. Wiping the file with some kerosene does also good.

Then again, the sharpness of any file is very soon lost if scraper is not worked only against the teeth of the file. If working it backwards, even a scraper steel seems to chip the unsupported edges of the teeth.

If I am after a really good fine burr for finish work, rather than scraping off some glue joint, I treat the scraper as if it was a normal blade and hone it all the way to a fine stone. It seems to make it easier to draw and turn a lasting edge.

Yes... softer tempered steels which are able to take a deliberate burr without chipping seem to need a bit different kind of sharpening gear though. At least in my hands.

I highly prefer fine sandpapers, used with thin oil. They are hard enough and will not round the edge significantly, and give away minimal slurry. (Water seems to be not that adequate wetting agent here, even when treated with surfactants.) There will be thin film of oil left even after wiping, making the burnishing much easier.

Samu

 

[Corneel]

Thanks for the info ikisumu. Sounds reasonable. Now I should replace my cheap Bahco files with some good ones.

 

[Alder]

When I typed in card scraper in the search box this is the site I chose to visit out of the many listed.
My query is in respect of what type of file to use to sharpen a scraper, the file used in this old thread is described as single cut metal file, by this I understand it to mean file in one direction only.
Does 'single cut metal file' have another name?
What type of file to others use for this purpose?
Thank you,
Russell

 

[Wuffles]

I found this helpful when I asked myself the very same question a few weeks ago.

http://tradetools.co.nz/webimages/6020190-10.pdf

 

[rafezetter]

When I typed in card scraper in the search box this is the site I chose to visit out of the many listed.
My query is in respect of what type of file to use to sharpen a scraper, the file used in this old thread is described as single cut metal file, by this I understand it to mean file in one direction only.
Does 'single cut metal file' have another name?
What type of file to others use for this purpose?
Thank you,
Russell

A google with "single cut file" will be sufficient bring up any type fo file you are looking for of this type as the different names are for the shapes rather than type; flat, hand, pillar, square etc.

All metal files are to be used in one direction only, irrespecting of type, single cut or double cut - moving the file over the work towards the handle rather than away.

The single / double cut refers to how the teeth are machined - single is just rows of grooves set at 75deg angle to the direction of the file body, double has a second set of grooves at an opposing angle get a criss-cross pattern. Each type is designed for different work, I think the double is designed for faster removal, and single for finishing.

 

[Derek Cohen (Perth Oz)]

When preparing a card/cabinet scraper, I just eye ball it on a worn 600 grit Eze-lap diamond plate (It is closer to 2000 grit by now).

Being exactly square is not really important. The key to obtaining reliable shavings are first to draw out the steel ...

and then turn the burr twice - first at 5 degrees and again at 10 degrees ..

The results are good enough to finish ...

I made a scraper for roughing out (thick shavings with a decent but not a final finish) from an old 3/16" plane blade. This is ground square on a grinder (until you can feel a fine burr). That's all that is needed.

Regards from Perth

Derek

 

[ED65]

I made a scraper for roughing out (thick shavings with a decent but not a final finish) from an old 3/16" plane blade. This is ground square on a grinder (until you can feel a fine burr). That's all that is needed.

Could you estimate how long you need to go between grindings Derek?

I do something similar using the thick back of a knife, using it straight from the file. Obviously the lifespan of the burr is nothing to write home about.

 

[Derek Cohen (Perth Oz)]

It is difficult to estimate how long the edge holds since the woods I use are very abrasive. Let's say, compared to a card/cabinet scraper, the thick scraper holds an edge about three times as long.

I grind it on a 80 grit CBN wheel (which makes it easier to keep an edge straight), and just enough that there is a flat along a side, and a small burr is raised. I flip the blade and do the same on the other side - in other words, the grind is not perfectly square to the edge.

The thickness of the blade makes it easy to hold and use.

Stewmac make a similar scraper (more expensively!) ...

http://www.stewmac.com/Luthier_Tools/Ty ... raper.html

Regards from Perth

Derek

 

[MIGNAL]

I made one out of those thick Chinese HSS plane blades, ground on a hand crank to raise the burr. I think the Stewmac one is harder steel than your common plane blade. With card scrapers I use exactly the same technique as Derek, except I use a 360 grit diamond, which has probably turned into 600G.

 

[ED65]

Let's say, compared to a card/cabinet scraper, the thick scraper holds an edge about three times as long.

Ta, that makes a perfect starting point for me to go by.