What what? an Ra of 3!?!?!?!?

[4U2QUIK]

I thinks this speaks for itself.


next is the profilometer.

 

[tbcmorris]

Nice video!!

 

[IJ.]

Try the meter on some glass.

 

[iMike_G.]

dam it you dont hear my commentary

 

[IJ.]

dam it you dont hear my commentary

pardon?

 

[iMike_G.]

pardon?

i was there when he did that and i was talking about it in the back ground. but you couldn't hear me.

 

[gaboonviper85]

add a 0 to that and thats your ra....30-40 ra.....a glass mirror is ruffly 4ra....that head is not hear as smooth as glass

 

[Rennat]

i think this is funny... because the head was as smooth as glass.
how you can say its not smooth as glass if you werent there?

and i was the other person who was there today.

 

[Doward]

The smoothness of the surface is evident in the amount of optical clarity.

That looks closer to 30-35 RA to me.

If that were truly 4 RA, it would be a mirror reflection. From the pictures, that does not seem to be the case.

Not busting on you, just doubting the accuracy of that profilometer.

 

[gaboonviper85]

i think this is funny... because the head was as smooth as glass.
how you can say its not smooth as glass if you werent there?

and i was the other person who was there today.

because i do this shit for a living.....isnt that good enough?

i know what "smooth as glass" is....and i can tell by the pics thats not "smooth as glass"....you can see the tool lines and marks where the chips rolled over on the aluminum...its a great finish...its a perfect finish...but its not "smooth as glass"

that is how i can say that

 

[Poodles]

Also, if you've ever seen glass cut/polished it done MUCH slower...

 

[3p141592654]

You guys don't know what flat is! :icon_bigg

 

[iMike_G.]

because i do this shit for a living.....isnt that good enough?

i know what "smooth as glass" is....and i can tell by the pics thats not "smooth as glass"....you can see the tool lines and marks where the chips rolled over on the aluminum...its a great finish...its a perfect finish...but its not "smooth as glass"

that is how i can say that

Brandon the guy who's head it is. dose that shit for a living to. so i would think he knos wat smooth as glass is too...:icon_surp

 

[Doward]

You guys don't know what flat is! :icon_bigg

Is anything truly flat in the universe? Considering the space time curvature and all

Seriously, put that profilometer on a sheet of glass and see what comes up.

 

[iMike_G.]

LOL we put the profilometer on the back of my iPod and that got a ra of 1

 

[4U2QUIK]

the profilometer was just calibrated and is tracable to NIST.
I also checked it on the roughness standard that we have.
the head is as smooth as glass.
and the cutter is a special cutter meant to put glass like finishes on aluminum at high speeds. Plus the video was of the rough cut. not the finishing cut.



also just for shits and gigles I just walked over and tried it on a sheet of glass. and guess what?
it had an ra of 3. So soory if you guys can't tell from the pic. but it is what it is.

btw I'm a inspector at a machine shop that does work for places like lawerence livermoor labs, berkely physics and space labs, san dia labs, and nasa.
So think twice before second guessing my work.

 

[IJ.]

If you can consistantly provide an ra3 finish ALL 7M heads should go to that shop.

All I asked for was the meter to be checked on a sheet of glass and Mike started shooting his mouth off about his commentary....... (tone deaf from years of engines and machinery so no I couldn't hear shit on that vid)

Got some details on the cutter used?
(I'll buy one and do my own surfacing in house as I have trouble getting a shop to do an acceptable job)

 

[4U2QUIK]

lol yeah, I know mike got a little overexcited, but he's young so just take it with a grain of salt. he's a good kid.

I haven't gotten a consistent ra of 3, but I can keep it under ra10 without an issue, it averages around 5-7 ra.

as far as the cutter goes IJ, I'll pm you the details, but I've seen the pics of your machine and I have some questions as to rigidity. (not trying to talk bad about it. I'm actually very impressed with it.) Also you need to run it between 4-6000 Rpm and it requires a 40 taper spindle or better.

 

[IJ.]

Damn that's just over the limits of my machine in all ways....
(30int/3800 rpm)

I think people need to keep in mind the meter only samples a small area at a time so it very well could be 3 in that area just not across the entire surface.

10 is damn good though!

 

[4U2QUIK]

Also, if you've ever seen glass cut/polished it done MUCH slower...

That's because glass is incrediably harder material.

add a 0 to that and thats your ra....30-40 ra.....a glass mirror is ruffly 4ra....that head is not hear as smooth as glass

just because something isn't reflective dosen't mean that it dosen't have a low ra. I proved that to rennat and mike by taking a piece of stainless that started with a ra of 12 then bead blasted it with ultra fine grit (175+beads). Then I tested it again and got a 15ra, and the part had a totally flat, non-reflective surface. This is why you CANNOT determine an ra just by looking. just because a surface is reflective DOES NOT mean that it has a low Ra number.

Is anything truly flat in the universe? Considering the space time curvature and all

Seriously, put that profilometer on a sheet of glass and see what comes up.

flatness and roughness are two totally seperate things.
But yeah, nothing is perfectly flat.