Scraper sharpening.

[whiskywill]

A good demonstration of scraper sharpening, I think. http://www.stewmac.com/tsarchive/ts0203 ... ign=ts0203

 

[bugbear]

A good demonstration of scraper sharpening, I think. http://www.stewmac.com/tsarchive/ts0203 ... ign=ts0203

Luthiers tend to be the master scraper-preparers.

BugBear

 

[MIGNAL]

You can finish the thin edge with a fine file and turn the edge. It works but it's not quite as sharp as finishing with a stone. Finishing with an 8,000G waterstone takes it a touch further but diminishing returns set in. I take it to a medium Oil or medium waterstone and deem it good enough.
BTW never having used a diamond stone. Will a diamond stone groove if you rubbed the narrow edge of a scraper (not skewed) along it?

 

[David C]

A decent quality Diamond stone will not groove.

David

 

[marcus]

A decent quality Diamond stone will not groove.

+1, I've been doing that for five years on my diamond stones, no sign of a problem at all.

 

[Argus]

.

Agreed.

But, as with everything else it depends on what you want it for.
If you need to get to grips with an awkward bit of grain or tear-out, then a good burnished and turned edge will remove a lot of meat if that's what you need.

I bought some new LN scarpers some years ago and noticed that they worked extremely well straight out of the packet - no burnishing - they had an extremely well-machined edge.
For last-stroke finishing, diamond plates work very well with the edge of scrapers and replicate this sort of a straight, smooth edge.

http://handmadeinwood.wordpress.com/201 ... -scrapers/

For the best, finest finish I tend to use the scraper straight from the stone, preserving the honed edge and without turning a lip - you are using the burr produced by honing and generally the finish from a medium plate gives the best finish.

If you go to a fine plate it tends to produce an edge ideal for burnishing an edge, which in my opinion produces a more aggressive cut.
The down-side is that the un-burnished edge may not last as long in use as a burnished edge, but re-honing is no more than a few up-and-down strokes on the plate and you are back to work.

Hope that this helps.

 

[Kalimna]

A quick question re:honing the scraper edge - I imagine that a groove would easily be made in my waterstones, but is that also likely to be the case with oil stones? I can't quite justify the purchase of a diamond plate, but an oilstone is a wee bit cheaper, and drawfiling the edge has never produced a scraper I'm happy with.

Cheers,
Adam

 

[MIGNAL]

A card scraper will groove an oil stone. It might not be immediately obvious but a groove you will get.
The 'trick' is to skew the scraper on the stone. That also works with waterstones.
If you aren't getting good edges it's very likely that the scraper does not have a sharp 90 degree edge, in other words the edge is rounded over. Frequently the extreme outer edges of the scraper will cut but the central portion (the part that is used the most) will just produce dust. If that is the case you will need to go to the second cut file and remove enough metal so that it eliminates any of the rounding over. Even turning the edge straight from the file should produce a scraper that makes shavings. Going to abrasives just makes the scraper cut a little better.
I think someone on here stated that car engine exhaust valves make a good burnisher. Indeed they do, and cheap enough on the well known auction site.

 

[Kalimna]

Thanks Mignal. I can get them to cut, just not particularly smoothly, so I shall try skewing again.

Cheers,
Adam

 

[bugbear]

.
If you go to a fine plate it tends to produce an edge ideal for burnishing an edge, which in my opinion produces a more aggressive cut.

I suspect you're doing a "lot" of burnishing, or at least using a lot of pressure. This isn't wrong, but it produces a large aggressive burr (as you say). A few light strokes is enough to burnish a scraper used for finishing.

BugBear