why we need variable speed grinder/polisher

[ple02]

I am a beginer and have one question. Why do we need variable speed grinder/polisher to polish granite? Is there any special about MK grinder? Thanks.

[Mark D.]

If you are dry polishing they are necessary because of two reasons:
1) Nobody makes a dry diamond pad that will work correctly above 4500RPM
2) If you run those pads at 10,000 RPM the centrifugal force will want to throw them off of the velcro faced backer pad that is supposed to hold them.

As far as wet polishing, you don't need to go variable speed. In fact. most wet polishers are not variable speed, they are single speed around 3,600 RPM. You still need to polish at a relatively slow speed (relative to a high speed grinder). The reason for this is the physics involved on the bonding agent (resin) surrounding the diamonds will act harder than they are supposed to causing pads to glaze shut or rip or disintegrate.

You ask if there is anything special about the MK grinder, and although I like MK I don't think they are special. They are made well and they perform well plus they have a one year warranty while some of the others carry 3 months.

If you tell me whether you are a fabricator or a DIY person and what your application is (electric or pneumatic and how much use) I will be happy to make a recommendation based on our history with these tools.

Glad to be of service,
Mark

[ple02]

You are amazing. Post two messages & got two answer the next day. Anyway, I just want to learn all these before I start doing my one kitchen counter top. Yes I am a DIY. Thanks.

[ple02]

I forgot one thing Mark. I have so much interest in granite works but I have not found much information until lately. If I am sucessful learning it, I might want to get into this business. Any advice, please let me know in this area.

[ple02]

Mark,

 Today I found a 7" MK variable speed grinder from a friend. Is it going to work for grinding & polishing? or is it too big? Thanks

[Mark D.]

Check the make and model. I don't believe MK makes a 7" grinder.

It will be bulky to use for a start.
What is the RPM range?

You might want to check out our DVD's on fabricating granite here:
http://www.defusco.com/How-To-DVDs-&-Tool-Packages/c654/p2478/Buy-Fabricating-Stone-DVDs-1,2-&-3.--Save-10/product_info.html

Glad to be of service,
Mark