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    A Grinding spark spun off at 2,554.5 sfpm would travel for a short time at 29.02409 MPH or 153,270 feet per hour, if it could maintain that speed it would travel from Dover to Chicago, a distance of 664 miles in 22.8775 hours.

    But add 3.766 hours to eat, fill the tank and go pee the travel time would be 26.661135 hours plus what ever time you got off as the crow flies and stops for red lights, stop signs and picking up pretty blond hitchers and the like.

    I know one can run a stop sign but it is near impossible to pass picking up pretty blond hitchers

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    Ot doug:
    Operating much like a breeder reactor....
    Breeder reactor - Wikipedia

    In the case of dove birds, the female is the breeder, and the male is the breeddo.

    likely they will still do that even with not having electrical wires to sit on.

    For one example dinosaurs did very well with not even having electricity pr wires to sit on.

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    Quote Originally Posted by michiganbuck View Post
    A Grinding spark spun off at 2,554.5 sfpm would travel for a short time at 29.02409 MPH or 153,270 feet per hour,
    No, you are thinking too straight easy.
    29.02409 MPH in respect to what? Your frame of reference is?
    Are you on the part or in front of the stationary machine?
    One can also do this on OD grinding. Is my world the part surface spinning at different speeds to try or the sit at home base of the machine that is easier to hold onto.

    Wonder much the OP's solution but the more responses here the better and as physics was 8 AM I do admit to dozing off a bit or a tad hungover.
    Bob

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    It is a stationary machine only from the position of the operator with him (or her) standing still.
    Actually, that machine along with the Earth is rounding the sun at 67.000 Miles per hour, it is shooting through space at 1.3 million miles per hour. and spinning at about 1000 MPH (so 1000 has to be added or taken away).

    The gravity that holds the machine down is relative to the earth traveling at 1.3 million MPH but modern science has not discovered/relized that yet. I would tell them but they would not believe me as I am just a grinder hand and not a scientist.

    Oh, wait We can't say him or her anymore.. sorry my bad.

    Replace him or her with It ..that does not sound right.... darn, just ignore this post
    Buck

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    Quote Originally Posted by michiganbuck View Post
    I know one can run a stop sign but it is near impossible to
    .. remain lucky, forever.

    Growing issue, right to-home as I am on a corner lot. Side street stop sign is being run with increasing regularity.

    Just this morning some arrogant young "immortal" flashes through the intersection w/o stopping or looking in a foolish little Honda.

    May as well be a wheelbarrow had I tee-boned him with just under three TONS worth of Old Skewl Range Rover.


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    Quote Originally Posted by michiganbuck View Post
    I know one can run a stop sign but it is near impossible to pass picking up pretty blond hitchers
    I picked one up once before, had a whole lotta fun.
    Afterwards my sausage itched for a few days and she stole my car.

    Was it worth it?











    Yes, yes it was.

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    SU(3)xSU(2)xU(1) May not be as important as "everything wants to stay where it was."

    likey China will start something and we will blow up much of the world..first, before science figures that out ..darn.

    China will likely soon claim its Taiwan and that will start a ruckus.

    I could survive at Kelly Road Camp if it is still there. Yes and if I can get there with the military blocking what few roads are left. I just got the final parts for my water filtration device.

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    Quote Originally Posted by Homebrewblob View Post
    I picked one up once before, had a whole lotta fun.
    You realize that females are blonde, eh ?

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    I usually take these questions seriously and, unlike many of the other responders here, I am not suffering the after effects of several or more holiday brews.

    So, as I see it, the chips are being created by the "cutting edges" of the abrasive particles on the wheel and will have the same velocity as those abrasive particles just before they break free and go flying across the room. The speed of advance of that abrasive wheel across the work piece has little or no effect on that velocity. So a simple calculation of the velocity of those abrasive particles is all that can be invoked here.

    The other forces acting on the chips will only take place AFTER those chips break free of the wheel and their interaction with those chips would be difficult to predict, to say the least. Deceleration happens rapidly and before the chips are even one mm from the point of separation they are probably going a LOT slower. So I can only address that initial velocity at the actual point of separation from the abrasive particle. If you can address it further than that, other than by actual measurement of their velocity, then you are a better man than I.

    Oh, and you do not specify just where those abrasive particles are located on that abrasive wheel, I am forced to assume that they are at the outer diameter and not on a face that would be traveling at different speeds depending on how far they are from the center where the velocity would be zero. In any case, you can determine the velocity at any point on the face of a wheel via a simple calculation by simply multiplying my result below by the percentage of their location from the center. In other words, if a chip is created by a abrasive particle that is only 50% of the full radius of the wheel, then just multiply my result by 0.5 (50%).

    Simple calculation:

    Wheel diameter = 3.25"

    Rotational speed = 3000 RPM

    Time for one rotation = 1/3000 minutes

    Wheel circumference = pi x d = 10.21"

    Velocity at outer diameter = 10.21" / (1/3000) = 10.21 x 3000 in/minute

    Velocity at outer diameter =30630.53 in/minute

    Inches per minute are not a normally used unit combination. That can be converted to any units you wish.

    510.5 in/second
    or
    2552.54 feet/minute
    or
    42.54 feet/second
    or
    29.006 miles/hour

    Convert it where you will, it is still the same velocity.



    Quote Originally Posted by M. Roberts View Post
    Good morning, people...how was the Holiday?
    I am not sure if this is the proper place to post this question, my apologies if it isn't.
    Ok, if a 3.25" diameter tool (in this case, the tool is a diamond plated grinding wheel), rotating at 3000RPM,( in a HAAS VF-3), and traversing thru the work piece at 30 IPM, how fast is the swarf/chips moving as it leaves the tool? Make sense?

    Thanks,
    Mark

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    I believe he is thinking about how a car tire speed varies. Say the car is moving at 60mph. The tire in contact with the road is not moving at all. The top of the tire must be moving at 120 mph so it averages out to 60 mph. The entire wheel and tire unit is attached to a car whose parts are all moving at 60mph.
    Bill D

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    Quote Originally Posted by EPAIII View Post
    Simple calculation:


    Convert it where you will, it is still the same velocity.
    same speed, not velocity (velocity has direction). Not a simple calculation, the chips made near the point of entry likely will be going roughly 29 mph. These pieces of metal got cut and burnished to smaller than the wheel grit depth and have minimized friction with parent material. The chips in the middle will be exiting slower because they are still being and are burnishing the parent material. The chips formed near the point of grinder exiting will have impact acceleration from a relatively massive object - so they are going to be going faster than 29 mph.

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    the chips in the austenitic state initially go faster and then, as they gain volume by transformation, they slow down.

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    EPA III,

    Thank you for the logical, detailed reply. Yes, I was referring to face milling with the 3.25" diameter tool. On one of my first posts in the "Abrasive Machining" section, I posted a picture and some questions about a down draft dust collection system that I was tinkering with on my HAAS VF-3. I was trying to calculate/figure out how much downward force (draw) that I would need to overcome the velocity/kinetic energy of the dust/swarf coming off of the work piece. Again, thank you for all of the help. My apologies if the title to my post wasn't descriptive enough and for wasting some members valuable time as they are obviously much smarter than me.
    Mark

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    In fact the mass to surface area of the small particles is so disadvantageous,initial velocity is unimportant.Air drag will reduce velocity to zero in a few inches.This is the principle of dust in air,air drag exceeds the force of gravity on the particle,and so it remains airborne until it gets into the stillnesss of your spare bedroom, the dust settles out.

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    On an actual grinder, I'd suppose there would be a coolant bath, and that would probably prevent the ejaculate from ever reaching the fabled 29MPH anyway. Or if it did, it would be for .0000001 seconds. The velocity of any ejaculate will be greater when moving through air, and will rapidly decrease upon contact with any object (liquid or solid) that has a higher density. That's a lesson I still remember from my old Physics teacher, Ms. Luchisnki. She had the whitest teeth I've ever come across.

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    dd-top.jpg

    Attached are a few pictures of my setup. The top view; the larger funnels are 1.125" x 60 degree to a 0.3125" thru hole; all the rest are nominal 1/2" holes with a 0.3125" thru hole. The intention was to match the area of the collective holes to that of the two-6" ducts supplying the vacuum. The side picture shows the sub-plate being spaced off of the bed of the machine by 2", with an angled sheet metal tray in between. The tray slopes down from the back to the front; 1/2" gap at the back, to a 2" gap at the front. The previous version, I had the chutes bolted to the ends of the table, but they were in the way, and took up space; besides, the collection was very poor at the center of the table. Also shown in the photo are a few of the diamond tools that I use.

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    dd-side.jpgdd-side.jpg

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    dd-front.jpg Sorry for the screw up

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    M. Roberts, do you run the Od with the larger wheel and finish with the small, or is one wheel just for the corner? How close can you hold the diameter?
    Buck

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    Buck,

    I am using the 3.25" diameter wheel only to face the part; the tool in the picture is nominally 0.5" in diameter. Generally, we "green machine" parts to +/- 0.005", but can achieve tighter tolerances if needed.

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