What size dovetail cutter? Mitutoyo test indicator

[dkemppai]

Vegetable oil, hugh. Never thought of it. Works ok?

It's pretty slow, and messy. But it's worked for stuff I've when I've needed it to.
Quench speed needed is usually related to alloy content. Plain carbon needs to cool fast. 440C can air cool and will harden. O1, being oil cooled is in the middle of the road. A2, should be an air cooled steel. (A2 has about 5% more Chrome, and some Moly. i.e. more alloy = slower quench needed).

The trouble you're running into is the thick cross section. As the outside cools, is shrinks faster than the inside, which is building up wicked internal stresses. Thinking about this last night, for the base you could try an alumimum plate quench. That is, use two big chunks of alumimum fly cut flat, and drop the samples between them, push them together, and let it all cool. It works wonders on thin knife blades and other parts you don't want to warp.

The 416 is lower carbon, but is martensitic. At 14% chrome it's going to be more 'stainless' than the A2. Although, it's not 'stainless' like 304 or other austenitic steels. It won't get super hard, maybe 35HRC.

Dan

 

[Janderso]

Maybe already talked about? I didn't read every thread. I buy clamps from these guys. Probably cheaper to buy one then making one.

Dove Tail Swivel Clamps | Gem Instrument Company

Gem Instrument Company manufacturers a range of Dove Tail Swivel Clamps in different materials & sizes. Learn more here.

gem-instrument.com

Thanks Richard.
I hope you and yours are well.
Jeff Anderson

 

[pontiac428]

Just a note on the cyanide stuff, in case you are interested- it's not so bad as it sounds. Well, it's a lot safer than lawn darts, that's for sure. You're only putting a few grams of cyanide (from the case salts product) in the bag. Only a portion of the salts is cyanide proper, and only a portion of that becomes gas to be absorbed by the steel. What gas escapes is over the course of the treatment is spread over that time frame, into the open air of your back porch or whatever. The hot gases coming from your heat source go straight up like a helium balloon, cyanide with it. HCN is extremely reactive stuff, carbon and nitrogen hogging all the electrons like greedy kids, furiously heated... the cyanide won't make it 20 feet from the source, it'll react out with anything it bumps into on the way up into the atmosphere. So not only are you only releasing only a few grams of gas, it's stretched out over time and does not make it very far in the air. Don't do it in the basement, and call a ventilation engineer if you ramp up to industrial scale, but it is not a scary process. No scarier than pouring a cup of bleach into the washing machine's dispenser or using ammonia to clean a window, all highly toxic substances but in miniscule quantities. I experienced the sensation of cyanide gas a couple of times in the lab, believe me, your body will tell you to move the heck out. It's like smelling salts and fuming acid, it'll wake the dead. That means your human aversion response will alert you. I always warn about chemicals, unless it amounts to nothing.

It's just beautiful as a finish for precision tools, guns, anything that deserves a machine turned finish but has too many nonflat surfaces to turn. I know you didn't ask, but it just seems right...

 

[Richard King 2]

Thanks Richard.
I hope you and yours are well.
Jeff Anderson

I'm Ok. a few issues..one big hassle is Neuropathy on my from Diabetes. I just order some "Red Light" slippers that are suppose to heal the blood vessels...sounds like BS but if it helps I'll try it. My feet are numb. My wife and I were lucky, No Covid. I leave to teach 2 weeks in PA in 3 weeks then I have another week in March. Hope my feet are better by then.

 

[Larry$]

I'm Ok. a few issues..one big hassle is Neuropathy on my from Diabetes. I just order some "Red Light" slippers

Diabetes can control your life. It has mine. I've been found twice, passed out from low glucose, on the concrete. Had it not been from pure chance that someone stopped in after hours & found me, I'd be dead. I've got a continuous glucose monitor & pump now and it has been better. "Red Light Slippers" sounds like one of those places of ill-repute right outside the Navy docks.

 

[Janderso]

Just a note on the cyanide stuff, in case you are interested- it's not so bad as it sounds. Well, it's a lot safer than lawn darts, that's for sure. You're only putting a few grams of cyanide (from the case salts product) in the bag. Only a portion of the salts is cyanide proper, and only a portion of that becomes gas to be absorbed by the steel. What gas escapes is over the course of the treatment is spread over that time frame, into the open air of your back porch or whatever. The hot gases coming from your heat source go straight up like a helium balloon, cyanide with it. HCN is extremely reactive stuff, carbon and nitrogen hogging all the electrons like greedy kids, furiously heated... the cyanide won't make it 20 feet from the source, it'll react out with anything it bumps into on the way up into the atmosphere. So not only are you only releasing only a few grams of gas, it's stretched out over time and does not make it very far in the air. Don't do it in the basement, and call a ventilation engineer if you ramp up to industrial scale, but it is not a scary process. No scarier than pouring a cup of bleach into the washing machine's dispenser or using ammonia to clean a window, all highly toxic substances but in miniscule quantities. I experienced the sensation of cyanide gas a couple of times in the lab, believe me, your body will tell you to move the heck out. It's like smelling salts and fuming acid, it'll wake the dead. That means your human aversion response will alert you. I always warn about chemicals, unless it amounts to nothing.

It's just beautiful as a finish for precision tools, guns, anything that deserves a machine turned finish but has too many nonflat surfaces to turn. I know you didn't ask, but it just seems right...

View attachment 434835

Well shoot.
You can't buy Kasenit anymore.
Any idea what I could use to create the colors with a surface hardening affect.

 

[jwmelvin]

Well shoot.
You can't buy Kasenit anymore.
Any idea what I could use to create the colors with a surface hardening affect.

I don’t know about colors; I haven’t really gotten any with Kasenit. I believe this is the current substitute: https://www.brownells.com/gunsmith-...ing/surface-hardening-compound-prod27119.aspx

 

[mattthemuppet2]

For a simple black you can try salt blueing with ammonium nitrate. Worked really for my qctp holders and it retains some oil to prevent rust. No idea what it does for wear resistance though

 

[pontiac428]

There are a few substitutes. Potassium ferrocyanate is the safer replacement for binary cyanide salts. It's not just cyanide that contributes, you get carbonate and nitride out of the salts too. The gases precipitate in the metal matrix leaving a grain that is many times harder than the base material. A lot of what I have read on color case is backyard chemistry with readily available materials. The workshop practice series has a chapter on it, as do other books on metal finishing. Gas hardening an important topic in metallurgy, so every shop manual has something on the subject. Since it can be done without tight control over processes, its' a backyard treatment, just as it was in 1860.

 

[pontiac428]

Okay, "Cherry Red" is the salt mix that is available today for your searches. It's on eBay and Amazon, there are reviews with pictures, and there are project logs on the web using it. People who report mixed results are probably mixing their methods, as there are many ways to skin the cat, including following the directions on the label.