Need a tool, Make a tool

If you're gonna drill work hardening materials it's important to take advice from a pro:

 

No Petee I won't touch a budweiser. Stuart on youtube was recommending cleveland and precision twist drill. I need to price them out. The purchases under the magical c note kinda go unnoticed around here. It's when things approach 2 bills I start to get the stink eye. Must be shoe price related. Actually, I'm fortunate, while she may have a couple hundred pairs of shoes, I don't think they cost me too too much. I hope!

Might check into those cobalts at the hazard fart. I've got about 5sets of the ones that ya get on sale for 10bucks. Titanitum I think... Great for woodworking, just so so on mild steel. IMPOSSIBLE on this hard stuff and I even had a pilot hole already!

 

The main advantage of high speed steel over high carbon steel is the ability to withstand high temps without losing the heat treatment, some tool steels can even glow a dull red and still be hard like cobalt steels. That said, cheaper drills have their place especially in the larger morse taper sizes, so long as you drill slow and use the right lubricant to reduce heat and eliminate galling/friction welding of the drill to the metal. I have a set of cheap morse taper drills that I keep as placeholders until I get some better ones: they will drill steel with good lubricant and are big enough to hand sharpen as needed....they are better than no drill at all. Just as an example, at the 12:28 minute mark, I'm drilling 316 stainless steel with a cheap 1/8" black finish cheap high speed steel drill without snapping it the drill from friction welding. The sulphurized oil chemically reacts with the freshly exposed metal to form sulphides that are extreme pressure lubricants. If I tried to drill 316 stainless dry it would get hot and make horrible jerky motions as the drill tip friction welds to the iron, chrome and nickel and then snaps the drill.

 

I seriously hope you are joking! That guy barely has a clue. First off even the lowest speed on that drill press is still way too fast. Watching him abuse the drill press changing the belt without using the motor release on the side is cringe worthy. Then he’s drilling the hole over the overhang of the vise so gets no pressure because it tilts.

Because the secret to drilling stainless is to push hard enough to make a thick chip. Stop making a chip and the stainless work hardens and you are done. That’s why hand drilling stainless is hard, you simply can’t apply enough pressure. The oil or WD40 isn’t coolant, its lubricant to keep the chip from welding to the tool.

 

Yeah he's rather special, I can't watch the entire video without shouting at the screen.

 

Special as in special needs maybe! He was at least mildly entertaining to watch, but his info was rubbish.

So I jumped back on the lathe tonight and tried to make magic strike twice. NOPE! Seems everything I learned last night went right out the window! I couldn't turn a decent finish to save my ass.
Seems there is an issue with carbide. It doesn't really like light cuts. (maybe it's me or my machine) Perhaps 1000rpm wasn't enough. I understand as a part gets smaller, speeds and feeds get wonky. hmmm.. SO then I found this guy. It was like watching what I was doing. If ya don't hit your dimension and need to skim off say 10-20 thou, is it time to pull out the hss?



The amp draw thing was interesting.




I thought avia was worth subbing to... The kid with the junk drill press, not so much.

 

There are diamond honed carbide inserts that are more expensive than the moulded inserts but have more of a shearing action when machining. Also there are "finishing" inserts for specific metals that are good for light cuts.

 

Shearing action sounds good. I've had 5foot long coils whipping to beat the band! Gets a bit hairy when you feel them on your hand on the handle!

 

Some folks use those foot long long-nose pliers and some have a long hook with a handle to pull the swarf off. I haven't used either so I don't know if they are doing this while under power or not....(probably not)

 

For those of you in North A merica, Click this link and get yourself a FREE feed/speed calculator courtesy of Niagara Cutters!
http://www.niagaracutter.com/speed-feed-slide

 

I use the cheap as dirt insert parting tool from Aliexpress. I think I got this one in 10mm shank and 2mm wide, as I also use an AXA tool post. Works surprisingly well, although I haven't tried parting anything as thick as you have there yet.
https://de.aliexpress.com/item/3303...earchweb0_0,searchweb201602_,searchweb201603_
Mark

 

Glad you got some steel at the right price.

A note on Stress Proof. I first used it in 1972. Very forgiving. Very good for some uses.

You can use a dowel rod to safely fish long hips away from the work. Wear gloves.

 

I second the diamond hones, frequently used in my shop.

 

The tool is gone. Mailed it out this morning. I hit the business end with the torch until red hot and quenched it in water. (it's what I had) After the wire wheel, I hit it again in the middle and walked the color up to the teeth. When they hit blue, I went back in the bucket. Brushed it clean, and see ya later! I didn't have the stones to beat the piss outta of it. I did take a file to it and it skated across the teeth and didn't leave a mark. Found out my local steel yard carries 4140 in a few different sizes at reasonable prices and I don't have to buy 20ft long sticks either. So what this thing was hardened to is a wild ass guess. Let me take a try.... I think it's around 35-40...?? Am I close? I'm just farting in the breeze here. I know if I would have stopped it at straw, it would have been harder, but holy shit did the heat travel FAST! Then I had something inside that said if this thing was too hard, the teeth could be brittle. Didn't want that either.

Oh, I almost forgot, I found in my endmill stack a dark color cutter. It had cobalt markings on it. I used it turning around 150rpms and took really light cuts with oil. It worked, but man was it
S L O W ! Will need to get some carbide cutters if I mill this stuff again.

 

Jason, 4140 and 01 heat treat very similar. Quenching with water freeze is the Grain structure too fast. The ferrite & pearlite make miniature crystals inside the steel. Grey cast iron usually has a long grain structure. Martensite structure is the crystallized form. This can be altered by tempering so long as cracking or fracturing hasn't occurred.

Freezing too fast (quenching) on larger blocks creates surface cracks. On thinner material the surface tension could migrate right to the other side.

I'd like to try to explain this like glass. Tempered glass when it breaks it holds its tightest crystal form. But when non-tempered glass breaks it has long shards.

Edit; hopefully you did not have it to red hot for the first quench in water.

 

Here is an 01 quench from 1500°F

 

F it! I got other stuff to do. I'll let you guys know if it breaks. lol