Buffing Standard

[FreeCitizen]

Hi, I tried searching this forum and couldn't find what I was looking for. I would be much obliged if someone could enlighten me to what is meant by buff to #300 or #400. What does it mean in terms of surface texture? What would be the roughness height in microinch or micrometre? Many thanks.

FC

[sswee]

Without seeing the post I take it as the grit of sand paper used.
SS

[FreeCitizen]

Originally Posted by sswee

Without seeing the post I take it as the grit of sand paper used.
SS

Thanks SS,

Assuming it is the number corresponding to grit size and I hope this is right, what sort of finish can we expect from buffing stainless steel to say #300. What would be the Roughness Height Rating in microinch or micrometre?

[pickleboy]

Originally Posted by FreeCitizen

Thanks SS,

Assuming it is the number corresponding to grit size and I hope this is right, what sort of finish can we expect from buffing stainless steel to say #300. What would be the Roughness Height Rating in microinch or micrometre?

not to step on sswee's toes but it might be better to ask what finish you are looking for. say 16-32 micro or ?

[sswee]

Go for it pickle. Your as able as I to answer, maybe more so.
SS

[FreeCitizen]

Originally Posted by pickleboy

not to step on sswee's toes but it might be better to ask what finish you are looking for. say 16-32 micro or ?

Thank you for chipping in. Of course it would be ideal if we can look from the desired finish point of view. But as it is, we can't. The specification says; internal steel surface to Buff #300. If we use a tracer-point analyzer, what sort of roughness value should we be getting from Buff #300?

[sswee]

I've never seen a surface call out like that. If it is a grit call out, #300 should give between a 32 to 63 micro inch finish. Without seeing a print or knowing the fit and function of the part it is only an assumption as to what is wanted. The only way to know for sure would be to check with the engineer that drew it. If he's like some I've dealt with, he may not even know.
SS

[FreeCitizen]

Originally Posted by sswee

I've never seen a surface call out like that. If it is a grit call out, #300 should give between a 32 to 63 micro inch finish. Without seeing a print or knowing the fit and function of the part it is only an assumption as to what is wanted. The only way to know for sure would be to check with the engineer that drew it. If he's like some I've dealt with, he may not even know.
SS

Actually, this sort of finish is called for in the manufacture of vessels for pharmaceutical or processes where contamination is an issue. In this case, BUFF #300 is called for to reduce the likelyhood of the material sticking to the surface causing what is known as 'snakeskin'. In such applications, tons of polishing compounds is used to finish off the very large areas. The biggest we have done is 4.5 metres diameter. The reason why I pose this question here is to try and establish what is the standard that is used to gauge a particular buffing number. I don't have the standard and previous jobs were done with reference to a sample finish. But now when we have quality checks in the form of a profile stylus, we are at a lost for what the standard should be. Even the sample finish that served as our reference gave variable readings. So, anyone knowledgeable here can help?

[sswee]

Learn something new every day. I checked my machinist handbook and could find no reference to that sort of call out. The reflector plates I used to make were polished to mirror finish but I never saw any surface call out other than a 32 micro inch off the machine. Sorry I couldn't be more help.
SS