Almost thought this is Michael Caine's secret workshop haha! Love the auto-punch method for mostly repeatable and quantifiable results, suppose the tip or spring barely wear out over time. Nice little joke at the end! Thanks again for this wonderful video sir!
Thanks Rob. Over the years I kept hearing references to the hammer hammer and spark test. Your video was exactly what I needed a clear simple and concise method.. Re the ball bearing test a clear piece of tubing might allow the bounce height to be observed but it will be the ball-peen hammer method for me. I lose enought things on the floor as it is. Regards Owen
The two idea's I like the most are the hammer, and the center punch. Thanks for the video Rob. Hello from the Pacific Northwest, part of the United States, Washington State. 50 miles (80.5 kilometers) north of Seattle.
Thanks for the heads up mate. The ball peen hammer seems the way to go. I had only ever seen the file method shown but it certainly doesn't cut the mustard.
Thx for sharing Rob. Sorry I haven't had much time to watch many creators channels lately, but hope as soon as the Bride's cancer fight is hopefully over. My ole friend of 65+ has a Rockwell B-29 he mite sell me one day, but till then I use the the ole hammer and punch method as well,,no space shuttles planned here :)>. Have a great year, and like Harold says,,Keep on Keeping on! Bear in Tx.
NIce ways to test the hardness. I just drop it on the vice and the higher the tone the harder it is. But mostly I label steel when I buy it. Not always possible when you get bits and pieces from arround.
With files, I can get some quick approximate reading by listening to the sound. The higher the frequency, the harder the material. It’s just a quick test. Your hammer does about the same thing. The hardness file set you can buy is pretty useful, and I find pretty reliable within about 5 RC. The set costs around $100. Not bad if you need some fairly close, reliable, but not critical tests. My Rockwell bench tester is pretty accurate and consistent to within about 0.2 RC. But you need to carefully calibrate these units, and check the calibration every so often. They also cost, new, for the HR-150A Chinese model sold by many vendors, for over $1,000 to $1,500. Buy from a known vendor, not online from some unknown source. That model is the most used by small shops and amateur knife makers and machinists. It’s quite good! If you do critical work, you really do need one of these. Be very careful about deciding to save some money and buying a used one off eBay, or some other source, no matter who may have made the model. You really don’t know the condition of these. When they’re shipped from the factory, there are a number of wood or plastic blocks inside you need to remove that prevent damage to the delicate mechanism. Used models don’t have that, so it can get damaged in shipment. Not worth it. What’s being done here is relative testing. Is this harder than that? Useful to get some vague idea of what you’re using. But it won’t tell you anything about the composition for hardening, wear, tensile or shear strength, etc.
Useful practical stuff. I have always struggled with the file test & usually end up trying to use what ever I have & if I can't it's too hard! Course, as you say, having struggled to make some thing & then find it breaks a tap is a real downer that brings on ferocious cussing!
Yes, the steel can be too hard. I have a four foot length of 100 mm round stock I bought from a scrap yard (old new) that machines beautifully with carbide to a mirror finish, but is so hard you can't tap a thread in it. It's only good for certain work. Easy to get caught out. Cheers Rob
While the spark test may not be very good for hardness - the heat treatment and tempering can result in greatly varying hardness for the same steel - it is very good for determining what *type* of steel you have. Especially if you have a known sample to compare it to. That can be very important if you plan on heat treating it for hardness or annealing it for working.
Good point. I touched on this with my comment about high carbon steel, but I think it takes considerable experience to know what you're looking at regarding spark density and colour. Cheers Rob
One way to test hardness is to use a hacksaw. Hardened coil springs may be subject to scuffing by hacksaws. True high carbon steel will cause the blade of a hacksaw to skate. Medium carbon or CrMo will be scuffed, even in it's hardened state. So yeah! You can use a hacksaw if are afraid of wasting an expensive file.
Please don't take this as me trying to be smartypants but I wanted to point out something about the use of files in general. Please avoid filing backwards. Files are designed to remove material only in the forward strokes. Backward strokes can dull and render almost any file useless in a couple of minutes depending on how hard the base material is. The technique is to either release pressure on the backward stroke or better yet, lift and bring it back to the starting position. Lost many files during my childhood without this knowledge so I thought I should help others to save time, money and effort.
Almost thought this is Michael Caine's secret workshop haha! Love the auto-punch method for mostly repeatable and quantifiable results, suppose the tip or spring barely wear out over time. Nice little joke at the end! Thanks again for this wonderful video sir!
Thanks Rob. Over the years I kept hearing references to the hammer hammer and spark test. Your video was exactly what I needed a clear simple and concise method..
Re the ball bearing test a clear piece of tubing might allow the bounce height to be observed but it will be the ball-peen hammer method for me. I lose enought things on the floor as it is.
Regards
Owen
The two idea's I like the most are the hammer, and the center punch. Thanks for the video Rob. Hello from the Pacific Northwest, part of the United States, Washington State. 50 miles (80.5 kilometers) north of Seattle.
The Auto punch was a great idea.. portable and after a bit of use easy to get know when something is hard or soft. Thanks for the video!
This helped me immensely, thank you for making it.
You're very welcome!
That automatic punch idea is good, thank you!
Yes, that's the most reliable and uniform way to do it. The one to do first. Cheers Rob
Some nice tips there Rob. Thanks for sharing. regards from the UK
Thank you. I liked the automatic center punch idea. Just ordered one :)
Good choice!
Thanks for the heads up mate. The ball peen hammer seems the way to go. I had only ever seen the file method shown but it certainly doesn't cut the mustard.
G'day mate. Very nice demo there. Certainly makes sense to me. Keep on keeping on.
Thx for sharing Rob. Sorry I haven't had much time to watch many creators channels lately, but hope as soon as the Bride's cancer fight is hopefully over. My ole friend of 65+ has a Rockwell B-29 he mite sell me one day, but till then I use the the ole hammer and punch method as well,,no space shuttles planned here :)>. Have a great year, and like Harold says,,Keep on Keeping on! Bear in Tx.
Thanks for dropping by. Cheers Rob
This was very interesting, i learned allot from this, thanks! now im gonna run around the house looking for hardness LOL
Very useful ideas Rob, thanks mate.
NIce ways to test the hardness. I just drop it on the vice and the higher the tone the harder it is. But mostly I label steel when I buy it. Not always possible when you get bits and pieces from arround.
Great stuff. Thanks for sharing your experience.
Assalamalikum I am trained by Pak swiss training center. It is really wonderful technics. Easy and quick. Canada
With files, I can get some quick approximate reading by listening to the sound. The higher the frequency, the harder the material. It’s just a quick test. Your hammer does about the same thing.
The hardness file set you can buy is pretty useful, and I find pretty reliable within about 5 RC. The set costs around $100. Not bad if you need some fairly close, reliable, but not critical tests. My Rockwell bench tester is pretty accurate and consistent to within about 0.2 RC. But you need to carefully calibrate these units, and check the calibration every so often. They also cost, new, for the HR-150A Chinese model sold by many vendors, for over $1,000 to $1,500. Buy from a known vendor, not online from some unknown source. That model is the most used by small shops and amateur knife makers and machinists. It’s quite good!
If you do critical work, you really do need one of these.
Be very careful about deciding to save some money and buying a used one off eBay, or some other source, no matter who may have made the model. You really don’t know the condition of these. When they’re shipped from the factory, there are a number of wood or plastic blocks inside you need to remove that prevent damage to the delicate mechanism. Used models don’t have that, so it can get damaged in shipment. Not worth it.
What’s being done here is relative testing. Is this harder than that? Useful to get some vague idea of what you’re using. But it won’t tell you anything about the composition for hardening, wear, tensile or shear strength, etc.
Useful practical stuff. I have always struggled with the file test & usually end up trying to use what ever I have & if I can't it's too hard! Course, as you say, having struggled to make some thing & then find it breaks a tap is a real downer that brings on ferocious cussing!
Yes, the steel can be too hard.
I have a four foot length of 100 mm round stock I bought from a scrap yard (old new) that machines beautifully with carbide to a mirror finish, but is so hard you can't tap a thread in it. It's only good for certain work.
Easy to get caught out.
Cheers Rob
My method so far has been to see whether I've ruined my favorite endmill on it. If so, it's hard stuff.
Ha Ha. That's a good one.
Cheers Rob
While the spark test may not be very good for hardness - the heat treatment and tempering can result in greatly varying hardness for the same steel - it is very good for determining what *type* of steel you have. Especially if you have a known sample to compare it to. That can be very important if you plan on heat treating it for hardness or annealing it for working.
Good point.
I touched on this with my comment about high carbon steel, but I think it takes considerable experience to know what you're looking at regarding spark density and colour.
Cheers Rob
It is very difficult, agreed, but if you have known samples it's not that hard to compare. Collecting the known samples is the hardest part.
good video. thanks for taking the time.
I use the blade of an x-act that has between 56-60hrc, works quite well.
One way to test hardness is to use a hacksaw. Hardened coil springs may be subject to scuffing by hacksaws.
True high carbon steel will cause the blade of a hacksaw to skate. Medium carbon or CrMo will be scuffed, even in it's hardened state.
So yeah! You can use a hacksaw if are afraid of wasting an expensive file.
Great vid many thanks.
Im wondering if dropping a normal center punch thru a pipe would also work, atleast until i get one like that.
Not really. How would you line it up ?
that is experienced persons tak ,,,,, thanks a lot
Good video. The ball bounce seemed terrible as did the grinder. I'll try the hammer next time.
Please don't take this as me trying to be smartypants but I wanted to point out something about the use of files in general. Please avoid filing backwards. Files are designed to remove material only in the forward strokes. Backward strokes can dull and render almost any file useless in a couple of minutes depending on how hard the base material is. The technique is to either release pressure on the backward stroke or better yet, lift and bring it back to the starting position. Lost many files during my childhood without this knowledge so I thought I should help others to save time, money and effort.
Thanks Brian. Good tip. Makes sense when you look at the file cutting edges/pattern profile.
Cheers Rob
Thank you. You probly just saved me many files
good work bro
Excellent video as usual.
you just need to get a good sound system.
I do believe all those were hardened… Using a known piece of mild steel as a baseline would be helpful.
The hammer method has almost always worked even for those guys not paying attention by at least the third or fourth whack around here. LOL
I like it nice and easy
i didnt see any differance in the sparks either.
POV: your design technology homework
your saw, err.. file must be dull!