Need a tool, Make a tool

Awesome! Looking forward to it. Ya had me scared there. Here is my joke of a tool for parting. I think I'm screwed, this blade is only 12mm tall. Looks like I got a little hot last time I jammed it's ass into that steel. lol

 

Thanks!

 

OH lookie what I found. Should fit my little girl tool holder.

https://www.shars.com/products/inde...-retrofit-gtn-cut-off-and-grooving-blades-axa

 

Jason, that looks like some dodgy no-name, movie prop, mild steel posing as a parting off blade. You'll need constant lubrication for parting off steel with a high speed steel tool, run it at a low speed and drown it with cutting oil from a sauce bottle or coolant if you have that set up and running. The tool should be bang on centre height and I have a small oilstone to touch up the tool edge. If you can score some Fagersta WKE45 vintage parting blades they are hard to beat and even come in a rare blade that tapers lengthwise (front to back) as well as from top to bottom so it's very tolerant of alignment errors.

 

High speed steel has its advantages and disadvantages. Carbide insert tooling also has its advantages and disadvantages. I use both.

I use 1/8"x 5/8' (0.125") high-speed steel and
3 mm x 25mm(0.118") carbide inserts in my insert tooling.

My high-speed steel blades are slowly getting replaced with 16 mm tall.

Nice thing about high speed steel is you can put a sharp edge on the blade in one minute.

The nice thing about insert tooling is, (although they need more horsepower and cross-feed tork) they give a better finish, last longer and work better with stainless steel or almost all tool steals.

Most often I try not to par turning off. Usually work needs to be done on the other side and I need to face. I will normally take the stock to the bandsaw. Par-ing has its benefits when under cutting or cutting through to a hollow.

 

Mark, carbide or ceramic tooling work best with no coolant or flooding. One thing they don't like is intermitting. By design they put the heat or most of the heat into the chip.

Sometimes what is not explained on YouTube with carbide or ceramic is intermitting thermal shock. In 10 seconds a carbide insert tip temperature could easily exceed 1000°C. dabbing it with oil from a brush or a squirt bottle shocks it. Slowing down the RPM and increasing the feed rate keep a constant chip reducing material heat and insert heat and increasing chip heat.

Speeds and feeds become really important. Tool extension is the primary culprit fort chatter. Most industrial insert par tooling is limited (loosely) to less than 1 inch wall thickness.

 

yeah adam said in that video, if you run dry, stay that way.

 

I think Adam and I would bump heads now and then, but 99% of the time he is dead on.

From what I know of him, he has generally worked big parts, and I've run small parts with finer finishes. his channel, is one of the ones, I would say has good content. He is exceptionally good at what he does.

 

A few comments from a casual observer.

I broke the Shars tool holder crowding it. Not a happy moment but I still have the other end. You obviously didn't have your HSS cutter sharp with proper relief for parting. You need to practice, they work well.

Mystery metal. Try heat treating it. You have a sample tip. Heat it red to non-magnetic then quench it in oil or what I always do is use water. Then reheat to 600F and quench again. Try filing it. If the file skates it's hard. Then put it in a vise and pound one ear over. If it breaks off, you know it's too brittle. If it bends easily, you've learned something else. If it's hard as crap and won't bend but does not break when it finally does bend you have a suitable tool material. Lots of found materials will work quite well Sucker rod heat treats very nicely. I usually make a 1/8"x1/4" coupon and water quench from bright red. If it will bend 30 degrees in a vise before breaking and the surface is covered in microcracks you have a good piece for a knife or tool.

For the tool you're making I suggest proving it with a torque wrench to failure on the bench then make another one and limit your torque in the engine to 75% of failure. You can do the same test with an impact.

The tools probably cost $100 plus $1,000 for the insurance policy.

 

Here's a little fun video on Rockwell A testing, this is using a diamond and not a 1/16 ball bearing.

Initial heat treat.

 

If I paid the big money for one of these tools and it broke inside an engine case, I can bet the company selling or making it would tell me TOUGH SHIT! Guarantees are USELESS these days and no one will take that kind of beating. I know, I've paid dearly through the years at someone else's fault. Take them to court and you lose on a technicality. Was your torque wrench calibrated in the last 30days? Who the hell uses a torque wrench to REMOVE anything? It's not done, period. We do our homework the best we can and take our chances. Anything else falls in the shit happens category.

Trashing a sample is cheap insurance, but with the 4130, I'm not too worried. Let's see if I can even drill the stuff first.

 

Keep a sharp drill. The stuff cuts like butter with coolant.

 

Not seeing annealed. Lots of normalized stuff. ?????

 

Mild steal is = 8-10ish Rc. Annealed 4130/40 = 18-25ish Rc. SS = 22-28Rc. Non-annealed 4130/40 is hard! 28-38Rc.

 

gotcha... so no normalized! duly noted.

 

Normalizing is usually a dubble draw, maintaining Rc. value. It is a usually a stress relief. Annealing is a process of high heating with a really slow cooling period.

 

Hi Matt, my comments were regarding high speed steel parting off which is what Jason has at the moment.

 

Yeah, until I get some proper stuff, I'll stick to my machinist dewalt angle grinder for hacking off crap. no I wont do it in the chuck. lol.

When I used my HSS, I had oil on it constantly, but I do need to learn how to sharpen the stuff. I'm pretty sure it was dull and I know now it's like a spoon.

 

Your parting off blade was overheated which would have some effect on the hardness, if you're grinding the blade to sharpen it you have to avoid getting it hot enough to turn blue: https://www.engineeringtoolbox.com/tempering-colors-steel-d_1530.html


Parting off is one of those things, there's no easy way to describe it, you just have to try it with easy stuff first and work your way up to harder stuff: brass with no lube > aluminium with lube > mild steel with lube > stainless steel with lots of lube (work hardens easily). Having an older lathe causes issues too: My smaller lathe needed the base of the compound re machined flat as it had uneven wear from dirt getting under it over 40 years or so which caused it to rock and chatter. The saddle casting had less than 30% contact when blued, again from wear. Once these two things were fixed up it was like a new machine and parting off was easy.