I have those hunting knives heat treated (that's BOTH the Hardening and the Tempering). You can see the heat treat colors here. The colors have a direct relationship to the steel hardness (once you have hardened the steel first).



Here's one of the great grinders I built about circa 76-80. Note the flat "platen" behind the vertical section of belt. It's hardened tool steel. From pushing the work against the belt, the fabric back of belt rubs against the hard steel. Decades of me standing using this grinder, and that rubbing of the belt back wears the hard tool steel. Amazing - huh? It gets all washboard. Once before, I "milled" it flat again. But it was all washboard again, and I wanted to shape the bolsters for the hunting knife. So, this time I surface ground the platen.



Here it is in a vise on the magnetic Chuck of the Surface Grinder. That section that almost looks like you can see "through it" is a low spot. I have to grind everything else down to that level. Didn't think of a pic earlier. There were several spots and much deeper. I'd already done 70% of the grinding before I thought to take this pic. But, now it's ground flat and all assembled again. Ready for more decades of grinding.

Since I put things into motion down here at BPS, sooo many of my tools have shown themselves to need "Refreshing". Thankfully, I can do it. But it interrupts and takes up time. Has to be done though, to produce good work.

Gary

Wow that's a heavy duty thick platen . I've seen guys use ceramic on them but often wondered how that hastalloy metal would wear . I'll bet if Matt was to throw some stellite on there fer ya , you'd never have to do it again .

Anyways I'll have to make mine thicker now that I see yours . How many hp is your Moter ? I have a 1-1/2 hp and a 1 hp I was hoping would be good enough for a hobby guy like myself .
Thanks

Thanks
Kurt

Hi Kurt,

That Platen is probably 3/8" and it's made from 90 degree angle steel. The part was an accessory on a commercial grinder I bought and never liked. China I suspect. You know they make everything from God Awful Hard too steel. Stuff must grow on trees there and they seem to always have it about Rockwell C-70.

Yeah, well, grinding this platen every 20 years isn't THAT much of a problem. I'll do it another 4 or 5 times and I'm good.

The motor on this grinder is only 3/4 hp. Plenty. The motor on my main grinder is 1 hp. The motor on my floor unit is 2 hp, but that's turning 24" wheels.

You can't do anything with dull abrasive belts except make heat. So; sharp belts do not need brute power. . Now, there are jobs for new belts and then jobs for mildly worn belts. Then older belts deburr mild steel and drill burrs. You cycle them through. I hate to see a good belt die. Only thing worse is tearing a new belt. That's a crime.

Remember. Run jackshafts and get down. I think commercial grinders run about 4,000 surface feet per min. I don't like that. I honestly either forget it never knew mine, but it's half that at least. Commercial grinders just scream. Anything that happens happens way too fast. You don't want to brush the edge of a belt any time, but those things will mess ya up.

Gary

Very cool that you built so many of your own tools decades ago. I doubt commercial built would have lasted that long without major repairs!

Thanks for sharing,

Pedro

Gary,

That grinder is nicely made! looks good and sturdy, not surprised it has lasted so long! Love too see these shop made items....interesting how there are so many different ways to build something! I like the knife also does look nicely balanced.... I was wondering if you've ever flame colored a finished blade or would it mess up the heat treatment?

Kurt,
I'll bet that hastalloy would work good... Not sure if that stuff is easy to drill tho , I've got some ar-400 and ar-500 left over from a job, the stuff is vary tough but extremely hard to drill! Those abrasion resistent meteIs can be a pain to work with...can you weld hastalloy? Was at the scrap yard the other day returning some turnings... Seen a big pile of motors, made me think of your belt sander you plan to build, I was gonna say if you got a scrapyard around your place sometimes they have some good useable motors if there kept out of the weather! Might be worth checking out.

Matt

Matt
That AR plate is hard stuff but welds easy. The Hastalloy we had to cut parent steel left over from same job and TIG weld . ( filler rod ) It weld fine with any nickle rod or wire but but looses its property I guess . Special certs like stellite too.
They both work harden so yes , drilling is tuff . Even punch and shearing and sawing will reck tools . Cutting wheel and grinder is best . Or lazer jet: water jet

The belt sander is great and I got plenty of moters . I usually bring more home from scrap yards than I take in . For me it's s big time saver to convert or recycle things into other things . I have an old skate board with great wheels on it I've been looking at . So who knows . I've even been thinking forge too ! I found this pipe laying around and it would never burn out or need insulation ! Stainless would be good too but just got to-many choices

Gary don't you wish your steel room had this many choices ? Haha

Thanks
Kurt

Now you are just bragging Kurt! Ha.

You do need the insulation to hold your heat. It's not to protect the pipe.

You have some great ones there. 'Bout 18" long is probably enough.

Now - I never do this ..... But everybody has always suggested I start slow. If you just want to bang out a couple of hunting knives, then firebrick and a propane weed burner will get you going. You don't need that forge unless you are gonna forge weld.

Eating dinner in the shop.

Gary

Guys.

Late 70s thru the early 90s, I frequented a scrap yard in Frederick, Md. It was called "Reliable Junk Co."

I could go, and just look around. They let me just go, unattended; and find stuff and set out in a group or pile. I'd even crawl up on a mountain of steel, to roll down an item I dug out.

Yep. That's when I bought truckloads of stuff. Then .... You guessed it .....

Got so you couldn't see anything. Couldn't go anywhere. It morphed into a clinical shrink wrapped sterile, safety zone.

Gary

Gary
You don't think 1" thick wall pipe would insulate better than mortar ? I would have to think it would be close enough if not better for heat retention. I definitely don't want to have to make it again for forge welding later . I do have a 5 gal bucket of roller chain that's good size links . I saw a great knife made from the same stuff . It had a great design to the pattern .

Thanks

Thanks
Kurt

Hi Kurt,

You made a nice looking little knife there. Good job!

Here's my thought train..... Choo-choooo

1). Steel is an excellent conductor of heat. Thus - steel wood stoves. You don't want to "conduct" heat. You want to insulate and preserve the heat. To keep wood stoves from burning out (even at the mild heat of a wood fire - wood burns at 451 degrees F) they line them with fire brick.

2). If you wanted to weld up a billet of Damascus - it would start close to three inches thick, and you need to heat it to about 2,300 F.

3). It's the oxidation that kills steel. Heat it high, cool it - it blisters and flakes. At very high heat, it turns to corn flakes.

4). You'd use all your fuel - getting the one inch pipe to welding heat before the billet did.

5). If utube kids can source refractory cement - my Bud Kurt can.

See, that's the problem with HAVING a Ford Transmission .... you want to put it in your General Motors Truck.

Hehe.

Gary



Edited 1 time(s). Last edit at 05/28/2016 03:14PM by barnespneumatic.

Another think Kurt (don't you hate the old men insisting there's right and wrong ways - haha)

THE enemy of clean welds is oxidation flakes producing "cold shuts". Can you imagine putting your pristine clean billet of Damascus into a scaling, flaking, forge - where flakes of oxidized steel are blistering, popping off, and sticking to the outside of your heating billet?

Just say'n

Gary

Gary
All very good points and there's nothing like getting it right the first time . I'm sure I can source all the products needed for a good forge , but I'm always looking at shortcuts . I believe that the building of the forge is probably the easy part of hammering / steel process . There's sooooo much that I'm sure I will have to experience to get it right . I was telling a buddy of mine about my plans on identifying the proper temps for each stage of the process and the more I think about it the more I'm sure it will be a trial and error thing . All fun stuff in my garage / shop .
Thanks a bunch

Thanks
Kurt

Kurt,
That's good you like to use old stuff around the shop and bring em new life! If you can weld that hastalloy would prolly work well! Those old polyurethane skate board wheels would work well..that skate board may be a collectable tho haha... You've got some good options for your forge you plan to make also! Was watching a guy forge weld on tv, some neat stuff. Btw I here you on the scrap yards defiantly can find some hidden treasures!

Matt

The lesson I learned the last time I was beating on hot metal was a nice demonstration of the physics property called "elastic rebound". You too can demonstrate this by leaning down just a little bit too far when hammering cold steel against an anvil (Gary probably knows where I'm going with this).

When the piece you're working on is red-hot, the hammer deforms it quite nicely against the anvils surface. If, however, you keep hammering after the piece you're working on has cooled enough to become dull and grey, the steel gets quite a bit "springier". It's pretty amazing how quickly a four-pound hammer can bounce right up and kiss you on the forehead. It makes quite an impression, in more than once sense.