Thread: A question on Letter/Number puches suitable for hardened steel

There is another solution Bret wear glasses or use a white paint pen or fluro to backfill the stamped area.

I don't see any difference with the two links kits same factory make them Asia.

A good hit and they may shatter, break or even weaken

Hi Brett,

No letter punches that I know of would be suitable.. ... files are generally pretty hard. The diamond engraver is the best bet. Or laser marking, I know some laser cutting places will do laser engraving.

I suppose you could always anneal the files, punch the marks and re-harden...

Regards
Ray

Originally Posted by FenceFurniture

The rasps are about 63-4 Rc as I recall.

Brett. Don't even entertain the thought of a number / letter punch doing anything on some thing as hard as a file. Even the very best ones will start to struggle once you get into the 50's R.c. That kind of punching is an deformation process. The material has to be soft enough to indent and extrude the indentation. Most letter punching leaves a high spot where the material is moved too.

You could try one of those Mister Minute, shoe cobblers, watch battery sellers that proliferate the walking space in any shopping centre. They are set up for engraving. They might not charge a lot, for some thing like that, given its not a trophy or a booze flask. Mind you the hardness might tax them.

Regards Phil.

Thank you chaps - perzackly the answers I thought I'd get. I'll get the Dremel repaired and go to Engraver's School (anyway, it only has to legible to me).

Actually the diamond tip Engraving thows up a new challenge - it'll be fine for the files, but the Rasps have the "Sapphire" coating which is 3800 Vickers hardness. This wouldn't have posed a problem if a punch had been suitable because it's only a few microns thick, but grinding it off will be a different kettle of fish altogether.

I know this because when I sent the prototype Floats around the test circuit I sharpened up a normal milled file that had been coated, to use as a float on softwood (the angled teeth give a far superior result on Douglas Fir). In the process of sharpening just one side of this file I went through 2.5 slim taper files! Diamond is a different story of course but I reckon it'll dull up the bit quick smart (and they ain't cheap).

Hmmmm.....

A carbide burr in a small air die (pencil) grinder would easily handle a file. The Dremel should do it.

This topic is interesting as it brings to mind an article I read many many years ago in Popular Mechanics Magazine where they impressed the image of a coin into mild steel (numerous times).

The coin was your plain old soft metal coin and they did it using ultrasonic vibration of the coin.

Quite amazing at the time (1960's).

To see soft metal do that to harder stuff seemed to defy the laws of physics.

Rob

The other possibility is electro etching

Michael

Originally Posted by nearnexus

To see soft metal do that to harder stuff seemed to defy the laws of physics.

Rob

I've seen numerous plastic covers on various cars wear holes into aluminium and steel components they've been vibrating against, and with barely a mark on the plastic... As you say, seems to defy the laws of physics!

Originally Posted by Jekyll and Hyde

I've seen numerous plastic covers on various cars wear holes into aluminium and steel components they've been vibrating against, and with barely a mark on the plastic... As you say, seems to defy the laws of physics!

I've got a whole pile of those old 1950s - late 60's Popular Mechanics and Popular Science magazines that I haven't the heart to throw out.

Some of the technical stuff in them is just amazing. They were so anti Commy and so pro American at the time. Amazing stuff. Our machine gun is better than theirs sort of stuff

You can look at them on line : “Popular Science� Magazine – 91 Years Worth of Back Issues In The Public Domain

Lurve those front page headings. Awesome.

I looked up the silent engine issue.

Popular Science - Google Books

Interesting little project.

Rob

What about making a little wax dam and placing some acid inside the dam to dissolve away the sapphire coat?

Good idea Bob, but they are pretty much acid proof as well (as I recall, anyway)!

Maybe I should just get my eyes lasered

Originally Posted by FenceFurniture

Good idea Bob, but they are pretty much acid proof as well (as I recall, anyway)!

I looked up the solubility of sapphire in various things.
It will dissolve in very hot (110ºC) phosphoric acid and warm (50ºC) caustic soda.

"Sapphire" is a trade name only I believe, because of the colour. The composition is some big commercial secret. The only publicly known facts are that it is applied under vacuum, and it's a really pretty blue. Oh, yeah, and hard as.

But thanks for the extra yards there Bob - appreciated.

Have you thought of marking the handles of each file and rasp? They can be marked with the metal stamps. If your tools don't have handles (kind of dangerous ) you could paint the tangs to differentiate them. Could paint the handles too for that mater.

Pete