125-250 Surface Finish, Valve-Flange

[implmex]

Hi bcurtis:
Can you have the front face of the trepan tool etched or laser cut to put in the microgroove pattern?
It might be an expensive tool, but it would give you a very specific outcome and allow you to just plunge in the pattern.
Just about any etching house should be able to do this for you.
Here's one picked at random:

Micro Laser Services

VACCO’s Precision Etched Parts group offers Micro Laser Services for precision laser cutting, welding, marking or other machining & matl selection assistance.

vacco-etch.com

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[guythatbrews]

Another way may be to polish the groove face with a 60 grit stone shaped to get in the groove. Chart says 85 Ra for 60 grit.

it's yet another case of a generic surface finish callout with not enough surface to properly make the measurement.

I run into this frequently. Usually it's for 32 max, often in similar type/size of groove you are making bcurtis. Working with the customer they realize they have no practical way to measure the surface either. Basically stuck with making a very smooth groove so we are reasonably sure it's 32 max. The customer makes their own parts and this is the method they use. Would be another thing if they required a range say 16 to 32. Interested to hear how others handle small features.

Bcurtis you can qualify your finish by duplicating cutting parameters on the face of a sample part similar size but with enough width to accommodate proper surface tester parameters for 125-250. Conrad is correct it will take a good bit of travel.

Here is a tool that will work .023R, which is a kinda big radius. .0083 ipr yields 95 Ra

Oops I had 63-125 in my head so this feedrate is incorrect. My bad. Tool will still work if you can use R.023.

 

[eKretz]

I am used to valve manufacturers spec'ing a little coarser finish for a specific and picky gasket seat. If this is for something else maybe it doesn't even matter.

 

[gbent]

Make a HSS plunge tool. Hand grind the end with a 24 grit wheel to get appropriate roughness, or put a very rough dress on a surface grinder wheel. How fast can you traverse a sharp diamond?