Materials Selection question

[whiterussian1974]

Mega props for the info Baffled.
I always wondered why people turning smooth cones use the entire section of barstock and waste so much material.
I'm more familiar w wood lathes, but is there any reason why 1 couldnt spin the stock and slowly feed a cutting tool in at a 60* angle? You would have multiple cones limiting the waste to the width of the cutting tooth at each pass.

[Bendersquint]

What most don't realize is that most manufacturers don't produce their parts in house they sub them out and that mfg anodizes the parts on site.

Wouldn't the subcontractors also have to be FF7/SOT? After all, they are working Suppressor parts.

Yes they have to be 07/02's.

[Baffled]

Mega props for the info Baffled.
I always wondered why people turning smooth cones use the entire section of barstock and waste so much material.
I'm more familiar w wood lathes, but is there any reason why 1 couldnt spin the stock and slowly feed a cutting tool in at a 60* angle? You would have multiple cones limiting the waste to the width of the cutting tooth at each pass.

Thank you, but I'm not quite understanding your question.

I'm thinking you are referring to a form tool. In other words, you grind a tool to look like a female image of what you are trying to cut, then plunge it straight in, creating the shape in one thrust or motion? If that's the case, it doesn't work well on metal unless you have MASSIVE rigidity and HP and the stock itself needs to be able to handle the resulting forces and pressure.

Regardless of the method for stock removal, you are going to have waste exactly equal to the starting bar stock, minus the finished part. No way around that.

Now, spinning is an excellent way to form sheet material into complex cone shapes, but is a bit of an art that is different from normal lathe turning. Think of brass musical instruments, horns and such. The bells on these are spun, not turned. Same with something like an aluminum rocket nose cone.

For new lathe hands - practice and work with 12L14 mild steel, 7075, 2024, and 6061 aluminums. 12L14 is a glorious mild steel that makes you look like a pro, and the aluminums mentioned all cut nicely. Brass and bronze turn very nice, but the tool angles and rakes are a bit different. Regular cold-roll steel like 1018 and hot roll turn OK, but can be frustrating for new guys. It can be challenging to get a nice finish using them.

[whiterussian1974]

Mega props for the info Baffled.
I always wondered why people turning smooth cones use the entire section of barstock and waste so much material.
I'm more familiar w wood lathes, but is there any reason why 1 couldnt spin the stock and slowly feed a cutting tool in at a 60* angle? You would have multiple cones limiting the waste to the width of the cutting tooth at each pass.

Thank you, but I'm not quite understanding your question.

On a wood lathe I made a bowl. Sandwiched several layers or wood toether w glue. When it dried I spun it and used a tool that looks like a dental probe or pencil lead to remove shavings in straight line on Angle.
Looks like this.

[Baffled]

OK... what you have depicted could in theory be done with a skinny parting tool if the tool is not too tall... but in general, is not a process you'd ever do when working with metal. You'd still have to remove plenty of material to get the angle desired.

What most guys will do for a K-baffle angle is set the compound (top slide) at the appropriate angle - say, 50 degrees - and take shaving cuts of maybe 0.010" to 0.050" or more... depth of cut depends upon lathe HP, rigidity, a number of factors... and repeat until the material is gone.

Metal lathe work means your spindle speed is MUCH slower than for wood, and each pass is going to be smaller than anything you'd see in a wood lathe. It's very common for a new lathe hand to have the speed too fast. Consider that you can make nice passes at only a couple hundred RPM, which in wood would leave behind a terrible finish. Metal can be worked at hand-crank speeds, and in fact that's how a lot of guys thread on a lathe... with a hand-turned crank installed in the spindle.

When your ships come off smoking and blue, you are about as fast as you want to go.

[57fairlane]

When your ships come off smoking and blue, you are about as fast as you want to go.

That's how you know you are getting a good surface finish in chromoly!

[whiterussian1974]

OK... what you have depicted could in theory be done with (A) a skinny parting tool if the tool is not too tall... but in general, is not a process you'd ever do when working with metal. You'd still have to remove plenty of material to get the angle desired.

What most guys will do for a K-baffle angle is set the compound (top slide) at the appropriate angle - say, 50 degrees - and take shaving cuts of maybe 0.010" to 0.050" or more... depth of cut depends upon lathe HP, rigidity, a number of factors... and repeat until the material is gone.

Metal lathe work means your spindle speed is MUCH slower than for wood, and each pass is going to be smaller than anything you'd see in a wood lathe. It's very common for a new lathe hand to have the speed too fast. Consider that you can make nice passes at only a couple hundred RPM, which in wood would leave behind a terrible finish. Metal can be worked at hand-crank speeds, and (B) in fact that's how a lot of guys thread on a lathe... with a hand-turned crank installed in the spindle.

(C) When your ships come off smoking and blue, you are about as fast as you want to go.

Great to know.
I inserted lettered-bullet points into your post to which my answers refer.
A: I would image a curved Tungstun-Carbide cutting tooth shaped like a fingernail. (OR Depleted Uranium/Diamond Tip for automated CNC Ha-ha!) The curvature would be determined by the cut diameter. Ultra-specialized tool that home builders would have to rent.
B: I've heard that and always wondered how they get enough torque. Reduction gears?
C: Yeah, the color code of your material's heat is very important to know. It varies by alloy.

[Bendersquint]

A: I would image a curved Tungstun-Carbide cutting tooth shaped like a fingernail. (OR Depleted Uranium/Diamond Tip for automated CNC Ha-ha!) The curvature would be determined by the cut diameter. Ultra-specialized tool that home builders would have to rent.

Face grooving tools are shaped like you are describing.

The problem I see is that they are designed for set diameters and couldn't be entirely used for what you are thinking. Perhaps have 10-25 of them in varying radiuses and depth might do the trick?

I am going to say that metal is not going to let you treat it like you would a wooden bowl. There are some odd tools out there so who knows whats possible.

What is wrong with machining the cones the tried and true way? You are wasting what about .45 cents of metal?

[whiterussian1974]

Face grooving tools are shaped like you are describing.
The problem I see is that they are designed for set diameters and couldn't be entirely used for what you are thinking. Perhaps have 10-25 of them in varying radiuses and depth might do the trick?
What is wrong with machining the cones the tried and true way? You are wasting what about .45 cents of metal?

Time is far more valuable than material. I'm trying to cut machining time.
Even if it's BEST suited to only 1 thin spread of diameter (say .125") then that just cuts a .125" +/- groove into the bar. Still quicker than cutting interior of cone, then milling entire length of outer surface from the outer Dia of the stock 'til you get to the cone surface.
Maybe it takes same or negligable difference ammount of time to mill. ?
My cousins are Mechanical Engineers and I grew up on a farm, so I'm always looking to improve any process by saving time or material.
Mexicans, Central Americans and some Eastern Europeans are GENIUSES at making something work with unconventional materials or methods. I saw a village use a cow stomach as an oil pan filter for their obsolete village car that they couldn't get parts for from any Distributor. (As I recall.)

[whiterussian1974]

A: I would image a curved Tungstun-Carbide cutting tooth shaped like a fingernail. (OR Depleted Uranium/Diamond Tip for automated CNC Ha-ha!) The curvature would be determined by the cut diameter. Ultra-specialized tool that home builders would have to rent.

Face grooving tools are shaped like you are describing.
The problem I see is that they are designed for set diameters and couldn't be entirely used for what you are thinking. Perhaps have 10-25 of them in varying radiuses and depth might do the trick?

Maybe something like this tool rotated 90* so that tip cuts, and steeply-angled bracing structure is curved behind it to follow the cutting radius. Then slowly insert it at 60* to make your cut. The blade profile would need to look like a straight razor blade. Dual-sided Concave-ground blade. Use will even sharpen tip further through surface friction and work hardening.

I saw an Episode of 'How's It Made' today where they showed metal "butterfly safety razors" being machined. The parts for handle and securing nut look just like miniature suppressor tubes. Would probably work great for .22lr-.17HMR. The techniques they used minimized machine time down to the bone!

[Bendersquint]

Face grooving tools are shaped like you are describing.
The problem I see is that they are designed for set diameters and couldn't be entirely used for what you are thinking. Perhaps have 10-25 of them in varying radiuses and depth might do the trick?
What is wrong with machining the cones the tried and true way? You are wasting what about .45 cents of metal?

Time is far more valuable than material. I'm trying to cut machining time.
Even if it's BEST suited to only 1 thin spread of diameter (say .125") then that just cuts a .125" +/- groove into the bar. Still quicker than cutting interior of cone, then milling entire length of outer surface from the outer Dia of the stock 'til you get to the cone surface.
Maybe it takes same or negligable difference ammount of time to mill. ?
My cousins are Mechanical Engineers and I grew up on a farm, so I'm always looking to improve any process by saving time or material.
Mexicans, Central Americans and some Eastern Europeans are GENIUSES at making something work with unconventional materials or methods. I saw a village use a cow stomach as an oil pan filter for their obsolete village car that they couldn't get parts for from any Distributor. (As I recall.)

Thought we were talking about a lathe, what are you milling?

[Dr.K]

I guess I'm not following.

I don't waste any material when cutting a baffle. I measure and mark what I need then cut away what is not baffle.

I think you may be describing the mental image I have......a stack of solo cups chucked up in the lathe, and you are popping them off one by one? Like cutting them out from inside each other?

[whiterussian1974]

Thought we were talking about a lathe, what are you milling?

Misprint, my mind thought machine, my fingers typed Mill.
Sorry.

[whiterussian1974]

I guess I'm not following.
I don't waste any material when cutting a baffle. I measure and mark what I need then cut away what is not baffle.
I think you may be describing the mental image I have......a stack of solo cups chucked up in the lathe, and you are popping them off one by one? Like cutting them out from inside each other?

Yes! Thank You! That's precisely what I meant, but struggled to say.
Thanks for helping me clarify my message. b=thumbs up

[Bendersquint]

If you can figure out how to do it let everyone know.

I am not aware of any tooling available that will do what you think. Looking into the face grooving tool while the shape is there the further you move towards center the smaller the radius and the different radius tool you will need.

Hmmm.

[Dr.K]

Even if it were possible to get into the bottom of the cut......

How would you part it?

One little hung up chip would crash the s--t out of the lathe if you did somehow manage to get that deep with something. Or snap the tool off most likely.

After you spend about 1000 hours at a metal lathe you'll know what im talking about!

[whiterussian1974]

Bender asked, "If you can figure out how to do it let everyone know."

A: I would image a curved Tungstun-Carbide cutting tooth shaped like a fingernail.

Face grooving tools are shaped like you are describing.

Maybe something like this tool rotated 90* so that tip cuts, and steeply-angled bracing structure is curved behind it to follow the cutting radius. Then slowly insert it at 60* to make your cut. The blade profile would need to look like a straight razor blade. Dual-sided Concave-ground blade. Use will even sharpen tip further through surface friction and work hardening.

Even if it were possible to get into the bottom of the cut......
How would you part it?

Since the backside of the bit would be steeply angled it shouldn't get in the way to prevent reaching the center. Just cut until you reach the center and if the spindles are stiff enough to handle the weight, you have two sections, 1 on each spindle. If you are only using 1 spindle and chuck, then the free piece will fall a few inches onto a padded surface. (The little experience I had on a metal lathe was under supervision and about 23-25yrs ago. So I don't recall very well. I have about 5k hrs on a wood lathe. Maybe 20 hrs on metal?)

[Baffled]

Your enthusiasm is genuine, and appreciated. I like all your posts, and I think you are an excellent addition to the guys here who post regularly.

That said... I've been working a lathe for 25 years, but more importantly, the industry itself, as in, the machine tool / machine shop industry, to whom time VERY MUCH equals money, and who investigate tooling and processes like NASA investigates the outer planets, have not figured out a means to do what you are describing. The cutting forces are too high, the angle of the tool is asking for a crash, and most importantly, there isn't a tool made that has both the clearance and the support to be able to make the cut you seek.

A simple 90 degree parting off is challenge enough on a 12" home lathe.

What it boils down to in the end - the cost of the raw material is trivial with respect to the cost of tooling and time. Machine shops regularly trim 93% of a blank to get to their final product, and rack up a nice profit. A 12" bar of 1.5" aluminum just isn't that big of a deal. Cut off everything that doesn't look like a baffle, part off the finished item, and move on.

The only thing that is going to see you forward is time on a metal lathe. I guarantee you'll run it too fast, take off too big a bite, and crash or break the cutter more than once. It's part of the process of learning. After you've broken your third carbide insert at $10 to $30 each, you'll ease off a bit!

Metal, especially stainless and other more treacherous alloys, like each others company, and do not part ways easily.

[whiterussian1974]

Your enthusiasm is genuine, and appreciated. I like all your posts, and I think you are an excellent addition to the guys here who post regularly.

The only thing that is going to see you forward is time on a metal lathe. I guarantee you'll run it too fast, take off too big a bite, and crash or break the cutter more than once. It's part of the process of learning. After you've broken your third carbide insert at $10 to $30 each, you'll ease off a bit!

Metal, especially stainless and other more treacherous alloys, like each others company, and do not part ways easily.

Thanks for sharing your valuable experience. I was just spitballing some ideas.
Sounds like what we need is a Nikolai Tesla of Metalurgy. Maybe a phase change material that softens when electric current is applied, then becomes untestably high Rockwell hardness when voltage or polarity is changed. This would make heat fatigue a non-issue.
Yet I remain hopeful. 1930s Metalurgists would be awestruck to witness today's Superalloys.
Many Thanks and Best Wishes All.