Thread: Burnishing rod

Don't know why but I can tell you the answer is "no".

I used a screwdriver for ages until I came across a rod at a garage sale.

The steel might not be hard enough.
Valves from a rebuilt motor are good and cheap, ask your engine reconditioner, or truck mechanic.

Would be interested to know why you can't use a butchers steel. Only reason I can think of is that the steel is too soft. Easy way to find out. Take yr sharpest metal file and have a go at filing a bit off. If the file just skates over the surface, then I'd say it's got to be OK.

Will happily stand correction and a damn good thrashing.

OK, well I'd say it has more to do with the ridges in the steel, than in the hardness of the steel itself.

Tell you what, why don't you give it a try and let us know. If it works, then the proof is in the pudding.

Originally Posted by silentC

OK, well I'd say it has more to do with the ridges in the steel, than in the hardness of the steel itself.

Tell you what, why don't you give it a try and let us know. If it works, then the proof is in the pudding.

Correct, In another thread a couple of posts do a pretty good job of explaining how steels work and how they work on meat cutting blades.

A meat cutting knife is sharpened so a small bur remains on the knife. Someone described a butcher's knife as a fine saw rather than an ultra sharp blade. When using the knife on (soft) meat for an extended period the bur folds over against the blade and the knife loses its sawing ability. The Steel straightens out and stands the bur up straight so the knife can continue to cut. Eventually the bur is lost and the knife is taken back to a stone for sharpening.

When using a scraper on a hard (well, harder than meat) material like wood the scraper becomes less effective because the bur actually gets removed and lost from the edge. Using a steel is useless because the bur had gone and you will just wreck your steel.

I have read the same recent thread, I think and my conclusion was that the effect of a sharpening steel was to straighten up a burr that had been folded over and wasn't to file or sharpen anything. If this is right, then it should be possible to draw a burr and then turn the hook using a steel.

However, interests of scientific rigour, I will have a go with a spare steel on a spare scraper and report back.
Cheers
Jeremy

A quick trial should answer the question. Your finger should tell you if you have a burr and a piece of wood should tell you if its a usable burr.
As Silent said, a screwdriver shaft does the job. The plain shank of a large drill bit is another possibility, but I like to use the shank a 1/2 inch solid carbide router bit.

Forget the sharpening steel and get a proper burnisher.

The sharpening steel will leave fine serrations on the edge of the knife blade. This is good if you want to cut something like a tomato, but not if you want to smooth a wooden surface.

Think of a scraper blade as if it were a hand held plane, one with infinate angles of attack. Think of the hook (burr) as if it were the bevel of the blade, and the greater the hook, the deeper the cut. The finer the hook, the finer the shaving.

Continuing the analogy (well, it is not really an analogy, it is an equivalence): what ever shape is on the bevel edge is transfered to the timber surface. If the edge is serrated, then the newly smoothed timber surface is going to become serrated. That is why we hone smoother blades as high as we can (e.g. 8000 waterstone). We prepare scraper blades in EXACTLY the same way - using the smoothest burnisher possible. Whatever is on the burnisher's surface will end up as the scraper's edge.

Regards from Perth

Derek

Originally Posted by derekcohen

Forget the sharpening steel and get a proper burnisher.

The sharpening steel will leave fine serrations on the edge of the knife blade. This is good if you want to cut something like a tomato, but not if you want to smooth a wooden surface.

Think of a scraper blade as if it were a hand held plane, one with infinate angles of attack. Think of the hook (burr) as if it were the bevel of the blade, and the greater the hook, the deeper the cut. The finer the hook, the finer the shaving.

Continuing the analogy (well, it is not really an analogy, it is an equivalence): what ever shape is on the bevel edge is transfered to the timber surface. If the edge is serrated, then the newly smoothed timber surface is going to become serrated. That is why we hone smoother blades as high as we can (e.g. 8000 waterstone). We prepare scraper blades in EXACTLY the same way - using the smoothest burnisher possible. Whatever is on the burnisher's surface will end up as the scraper's edge.

Regards from Perth

Derek

Derek

Until I read the following thread:
http://www.woodworkforums.ubeaut.com...arpening+steel

I would have agreed with you. But this seems to show that the effect of a steel is to set up a burr that has folded over, which is achieved because it is harder than the steel of the knife. In effect there is no filing or cutting involved (so that the best steels are in fact smooth) and so the steel doesn't do anything to the edge except push its burr around to the cforrect angle.

As I understand the matter, a burnishing rod takes the square edge of the scraper and, as the rod is pushed down and rolled along the scraper edge, it:

1. draws it out, and
2. pushes it over to form a hook on that side.

This happens soley because it the burnishing rod is harder than the steel of the scraper . If this is right, there is no question of putting a serration on the hook. It is all a question of relative hardness, like the sharpening steel.

But (as is often the case) maybe I have got the wrong end of the stick.

As I have a spare, smooth sharpening steel and a spare (blunt) scraper, maybe the only thing to do is to give it a go and report back.

Cheers

Jeremy

I have a burnisher (from LV), but I'd still be very keen to know the outcome of this experiment...

It's certainly possible...

If you've got a solid carbide router bit about the place, they make great burnishers fwiw.

Cheers, Alf

Hi Jeremy

Without wading through the 4 pages of the thread (on knife steels), my understanding is that there are two types of steels: one that is fluted and another that is smooth. The fluted version is the one I was referring to in my above post - this has the effect of turning your scraper edge into the profile of a saw. The other is the smooth, and this would be equivalent to a scraper burnisher. Which do you have?

Regards from Perth

Derek

Sorry Derek, but I'm missing the logic re a fluted steel.

One does not 'roll' the burnisher across the scraper, but slides it, often with some oil to ease the journey.

Take an end elevation of a fluted steel, and whilst it is 'corrugated' lengthwise only one part of the surface, or possibly two 'peaks' will touch the sraper edge.

So I don't see how it will impart a jagged result. If the fluting was around the steel, yes, but it is along the steel.

Originally Posted by jmk89

..............why spend money when it can be avoided?

I think you're missing the point here, spending money on tools is not to be avoided, rather it should be enbraced with open arms (and a pocket full of cash and a few credit cards in hand ). Of course if you're saving money by not buying the burnisher in order to spend more money on another tool purchase then that's okay.

Mick