Calculating Mount Point Speeds

Hi,

I have been given a selection of mount point grinding tools, which I am using in a Die Grinder.

I am happy with the grinding speeds for my Carbide Burrs an Aluminium Oxide Mount Points. However I have some pink vitrified bonded corundum stones and I am struggling to work out the correct speeds for these.

According to the guy who gave me them they come from Suhner and the company lists them with maximum surface speed of 45 m/sec.

I have tried to convert this to RPM using this tool here, and get a speed 66110 min-1 (whatever that means)

I am grinding Cast Iron.

Can anyone help?

45 m/ sec is 45 x 60 metres per minute = 2700 m/min. One revolution of you grinding wheel is the diameter (D) In metres times π. (π is about 3.142 in case you have forgotten it from when you were at school.)

So the surface speed will π x D x RPM (In metres/min)
So rearranging this RPM = surface speed./(π x D)
So RPM =2700/(π x D)

Les.

Same as 66110rpm.

Andrew

Thanks Les - CSE Grade 1 maths, but my brain has suffered a lot of abuse since then

Thanks Andrew - using Les's formula I get 66176 RPM so looks to be about the same.

So the maximum safe speed for the Corundum Vitrified Mount Points is 66110 RPM, I wonder what the minimum effective speed is? My Die Grinder will only go up to 25000.

"4 speed setting air regulator 8300-25000 RPM, Supplied with 1/8", 1/4" and 6mm collets"

So maybe I can't use them in my grinder?

Google grinding pin speed there are plenty of examples out there
giving wheel diameter to rpm and metres /sec

like this one below

http://www.denchong.com/E/body.php?web=14&PNo=2007110150

John

Running at slower speeds makes the wheel appear softer, and therefore it will wear quicker. Practically I expect that running at 25000rpm will be fine.

Andrew

An air powered pencil grinder can run at 60,000 rpm and is a useful tool for small mounted points, buying one specially to run some free points rather negates getting a nice freebie. I would use what you have to run them until you have used them up.

Mike