Poor surface finish

[Nutfarmer]

New to me Taiwan copy of a Brown and Sharp surface grinder 6 by 10. Any ideas on how to improve the surface finish? The grinding wheel is a 9A60 J3 VOS 8 inch dia half inch wide. The wheel came with the machine so I dressed it then tried it out. The part is the anvil of a power pruning shear. It’s good steel ,but soft enough to still cut with a file. Down feed about . 0002 and step over about 200 thousand. Running the grinder dry. Never have run a surface grinder before so first off looking at operator errors. Also the grinder is new to me and could need work. The spindle is quiet and seams smooth to me. Any ideas?

 

[Liljoebrshooter]

Practice. I bought an old grinder a couple years ago and had the same problem with the finish of my parts.
I would try another wheel. Get a 46 grit and give it a shot.
Joe

 

[Richard King 2]

Looks like the wheel is dull. Your probably dressing the wheel wrong. When you dress get the wheel round and then take 1 .002" pass and stop. Many move the diamond back and forth until they stop hearing it cutting anything off the wheel. That burnishes the wheel and dulls it. Also what Lil Joe said, use a 46 grit wheel. and if you can afford it, buy a new diamond dresser. They get dull. Take a photo of the diamond if it is in a block , loosen the set screw and rotate the diamond 45 degrees.

 

[Richard King 2]

I used to have a pump plastic bottle that I would squirt some coolant too Not just plain water.

 

[sdelivery]

One of the biggest issues is properly dressing the wheel.
How fast is the wheel traveling over the part?
Try varying this speed and watch the finish change.

 

[benmychree]

Coolant can make a big difference with finish quality, and I agree, a 46 grit wheel is more appropriate, and the dressing method that Rich details is appropriate as well.

 

[Liljoebrshooter]

On my older lower power grinder, I found that a slower speed traversing the part and less stepover helped a lot. This may not be true for a newer 3 hp one but it sure made a difference for me.
Joe

 

[Cadillac]

Decrease your step over.

 

[Nutfarmer]

Thanks to everyone who took the time to make suggestions. This will give me several items to work on. I want to eliminate operator errors before looking for machine problems. First thing is change to a 46 wheel and properly dress the wheel. Next is to try some of the recommendations on operating the grinder. Thanks again

 

[Dabbler]

Any ideas?

+1 to the dressing and the step over.

I think your part is way too soft, and it is pulling the grit out of your fairly soft J wheel. That is why you are seeing those stripes: wheel break down. For very soft parts you need a lot harder wheel, such as a ruby M or N hardness wheel (maybe even harder).