The last person to post in this thread don’t get nothing.

[Justsomedude]

Love it.

[rberg]

I really do like the looks of that knife!

[breamfisher]

That looks sweet!

[CPJ 2.0]

I REALLY wish I was using ground flat stock. It’s what the name implies.
Ground and flat.
Has a pretty much perfect finish out of the package, and it’s flat.
What I used has light mill scale from the manufacturing process. Id wager 98% of people making knives use the same. Ground stock is more expensive. Probably 2-3 times for the same variety of steel as opposed to mill finish. But……it’s almost perfect with no extra work.


I’ll find out tonight if the scale will blast and tumble its way into oblivion. If so, then it’s not a concern.

[CPJ 2.0]

The other annoying part of mill finish stock is it’s a bit warped. Not much, but enough to see. So I bought something one needed for a LONG time. An arbor press. After using it, I realized just how much I could have been using one over the years. Works awesome for tweaking the blades flat.

[Chiro1989]

That is a good project, how will you create the bevel, if I am saying that correctly?

[CPJ 2.0]

That is a good project, how will you create the bevel, if I am saying that correctly?

The machine makes the main bevel, (as shown in the pics) as far as how it gets sharpened….get back to me. Thats still in process. Most likely done free hand-ish on the belt grinder, then on to the diamond stone.

[Justsomedude]

Is it worth it to get a cup wheel, cover the mill and use it to grind your stock flat?

[CPJ 2.0]

Is it worth it to get a cup wheel, cover the mill and use it to grind your stock flat?

No.
It’s flat enough flat wise if that makes sense. The wonky gets pressed out with the arbor press. The grinding would just be nice to make the surface finish of the unmachined areas better. And I really don’t want to take off any thickness. Like me the blade could be fine with a little less girth, but consistent stock size makes a consistent product.

A roll-loc type scotchbrite disk however may get ran across when I do stock prep.

But….if it all blasts and tumbles out, the point is moot anyway.

Which I wager it will be. And I’ll find out later today.

[CPJ 2.0]

Tell me which one was sanded before bead blasting.

[Diver43]

Tell me which one was sanded before bead blasting.

One on the left

[GrapeApe]

One on the right. Looking at the pic full sized can see more machining marks on the bevel on the one on the left.

[CPJ 2.0]

After bead blasting they go into the RATT.
Rotary Action Turbo Tumbler.
Made from a wiper motor off a new-ish VW Beetle, PWM speed control, laptop power supply, buckets and casters. Kinda hacky, but it does the thing. And I can swap buckets at will, I have one with stainless pins for tumbling brass. Works stupidly good.
Here’s a video…The sound is even more pleasing in person…..


https://youtube.com/shorts/ja4pAj5gTM4? ... LEqkMBi4wo

[CPJ 2.0]

One on the right. Looking at the pic full sized can see more machining marks on the bevel on the one on the left.

The bevels weren’t sanded on either.

[CPJ 2.0]

One on the right. Looking at the pic full sized can see more machining marks on the bevel on the one on the left.

The bevels weren’t sanded on either.

But you’re correct. It’s the one on the right. Just not for the right reasons.

[CPJ 2.0]

So. Problems.
Tip isn’t suited for spinny rock buckets.
Neither is the jimping.
(Blades are still in the annealed state)

[sakodude]

I'd file the jimping after the sand blast and tumble. Give you a nice shiny contrast.

[CPJ 2.0]

“Stonewashed” finish.
Which if you see that term advertised for knives, now you know how they do it.

Isn’t worth poop testing on soft steel. I’ll harden tomorrow.

[CPJ 2.0]

I'd file the jimping after the sand blast and tumble. Give you a nice shiny contrast.

After hardening it shouldn’t be an issue when tumbling. Which if I powder coat I won’t be tumbling anyway. That requires a bead blasted surface.

[Justsomedude]

They're looking good. And maybe a smaller media in your deafening bucket?

[CPJ 2.0]

They're looking good. And maybe a smaller media in your deafening bucket?

Yeah, for sure.
But this was free ninety nine. Thought Id try it. Probably will be fine with the knife heat treated.

[Japhy]

Heat treat questions:How long does it take for HC steel to heat so the interior is the same temp as the outside. How does one determine it is uniformly heated? Same for the quench how long must it be immersed to insure the temperature is uniform?
Is steel machineable after heat treating?

[CPJ 2.0]

Heat treat questions:How long does it take for HC steel to heat so the interior is the same temp as the outside. How does one determine it is uniformly heated? Same for the quench how long must it be immersed to insure the temperature is uniform?
Is steel machineable after heat treating?

1. Till it’s done. I dont have an exact time. But the way you know it’s ready is to stick a magnet to it. When it reaches the correct temp, it becomes non-magnetic. Once at that point, I’ll hold it there for a bit longer. I’ve never had an issue heat treating, with it not being uniform where it needs to be.
2. The quench….good question. But it doesn’t take long to be “right”. Oil and especially water hardening steels are super forgiving. But if you try and run a file across the metal and it skates across rather than digs in, you know it’s hard enough.
3. Yes. With carbide tools it is machinable. Referred to as “hard milling”, because….you’re milling hardened metal. It’s a slow process, but typically gives amazing surface finishes. Far better than softer metals. And of course it can be ground with belts or wheels, there's not many things can’t be ground with the right abrasive.

[CPJ 2.0]

Here’s the exact process for the steel I’m using.




8670
Hardening

Austenizing temperature - 1,550
Hold/Soak Time - 3-10 minutes
Expected Rc (as quenched) - 63-65

Oil Quench - Parks 50

Tempering

Temper twice for 2hrs.

300°F - 325°F - 62-63
375°F - 400°F - 61-62

[CPJ 2.0]

This is number 2 of a two part video by one of the best teachers of blade making on the you tubes. Number one was listed yesterday, easy to find if you wish.

But this one specifically shows why I’m commanding my robot to make knives for me, more specifically why I’m building a process that requires no sanding. Sanding blows.

https://youtu.be/nugAPzYLrjg?si=LJ0aT3BOWqFITsqd