Picture of a lock. How is the finish obtained?

[Stefflus]

This is a picture of a "Stabburslås". A "Stabbur" is an outhouse set on stumps (stabbur) that are carved so that mice cannot climb them, where food and fine clothing was stored.

It is made as an apprentice exam by locksmith Kjell Foldvik, in 1955. The key is typically around 5-6 inches long, so it is a rather large lock.

 

What I'm wondering is how the near perfect finish is obtained? I do not think any sanding is used, power or not. and the baseplate is rather large to file, no? I've heard something about scraping. Is this somewhat like scraping wood? Or how does it work? Other possibilities?

 

[postleg]

It looks like unpolished stainless steel from the pic?

[Frozenforge]

Appears to have been blasted with glass beads. This will leave a slightly smoother matt finish than sand.

[Alan Evans]

I also thought bead blast at first but if you zoom in you can see some longitudinal marks on the back plate, running in the same direction as the wood grain.

 

So I would think probably just fine wet and dry or similar (crocus paper, rouge paper), wrapped around a stick or block. May even have been Water of Ayre stone. Then either oiled or waxed.

 

Does the book give any clues as to what it is made from?

 

Of course it might have been made out of brass and been chemically patinated....it looks very similar to a silvered clock face, treated with silver nitrate.

[HWooldridge]

As a journeyman "masterpiece", I doubt he would have been allowed to use a labor saver like bead blasting. To my eyes, it appears to be a gorgeous example of whitesmithing, especially the key. Whitesmithing was the end product of blacksmithing after filing and polishing with rottenstone or a similar abrasive to remove all forge scale. Don Streeter's book "Professional Smithing" shows similar work.

[Stefflus]

The book doesn't say anything useful about it other than praising it. But yes, it is somewhat read between the lines (being a blacksmiths book) that it is made in a very traditional manner with non-alloyed steel.

I was trying to keep the picture size down, but I sort of wish I didn't. The reason I was puzzled is these longitudal lines that run much more true, smooth and unbroken than I have ever seen with grinding.

I'll post a full size one, but it's still a photo from a book, so it won't be great.

[Stefflus]

http://i754.photobucket.com/albums/xx189/Stefflus2/P40500022_zpse30c33f0.jpg:original

[the branch]

Du kan jo ringe Håvard Bergland og spør. Han liker at folk er nyskjerrige =) 

[Stefflus]

Hi, haven't seen you around before :)

Yes didn't cross my mind to call him.. is he still attending at Seljord every year?

[the branch]

Doing a lot of lurking in my down time :P I don´t know if he is still attending (since he isn´t smithing prof. anymore afaik.) But could be. seems like a chap who can´t stop beeing involved with dyrsku´n. :F

[HWooldridge]

Note the screwdriver slots are all oriented.

[Stephen Olivo]

Might be draw-filing with a fine file.  I have done some white work that way and the finish is pretty similar.  Scraping is a possibility though it is much like draw filing only with one blade instead of many.

[Stefflus]

Is this the sort of thing that one uses for scraping?

 

[Chinobi]

am i the only one that is seeing concentric rings on the two circular studs that retain the backwards C shaped bracket, and possibly on the circular knob/studs on the left too?  that keeps jumping out at me as machining tell-tales, but i probably wouldnt know any better :)

beautiful piece though, love the work on the key!

[Frank Turley]

Sanding blocks date way back. Crocus cloth is still being made. A strip can be torn to size, wrapped, and fixed around a block of wood and used with "elbow grease."

[John B]

Is this the sort of thing that one uses for scraping?

 

 

That looks more like a woodworking plane,

 

Metal scraping is done with a flat, semi round or triangular shaped blade, easily forged from an old file.

 

Flat scrapers (forged like a shallow fishtail) are used normally on cast iron machine beds/sliding surfaces, or surface plates, to achieve flatness, and the results of using them appear as a frosted finish which helps retain oils when lubrication is used.

 

Semi round scrapers are used to bed in bearings ((bronze) or remove sharp edges on steels and other metals, or to remove sharp edges on holes.

 

Triangular scrapers are commonly used for deburring holes, and other suitable applications, ie oil grooves

 

Burnishing using a smooth faced hardened steel tool of suitable profile can also be used after draw filing to give a polished look.

[Frosty]

If you look at a draw knife you'll have a good idea what a scraper looks like. They vary widely depending on maker, use and which way the maker was holding his/er tongue at the time.

 

Have you taken a magnet to it to see if it's iron/steel? SS is usually only weakly magnetic if at all, brass not at all. Don't use the chemical methods to identify the metal, you do NOT want rust stains on that work of art.

 

I'd put my money on it being block sanded or stoned after draw filing. Draw filing leaves some distinctive marks even when done to a near mirror finish, it's still distinctive. Stoning or block sanding on the other hand can be done in such a way so as to obscure if not remove long marks. One method if memory serves is jittering the stone. This is simply making very short strokes up and back with a very slight side move between. Same can be done block sanding. I imagine there was a reason we weren't allowed to use side strokes or circular strokes but nobody told us.

 

Oh for a return of Jr. high and high school shop classes. <sigh>

 

Frosty the Lucky.