3.5 hp is this too strong?

[alabama_lowlife]

i stumbled across a 3.5 hp 220 motor that a friend of mine had, so i've got it now. i've got it wired up and mounted on a bench and i was going to use a bench mandrel, but it is just too insanely fast. the pulley on the motor is about 6 inches and the pulley on the mandrel is about 2 inches. the motor is 3450 rpm, so that works out to 10350 rpm at the mandrel right? anybody have any recommendations? i'd really like to have a really strong buffer, but this thing is scary as it is.

[ERService]

That is turning entirely too fast.You need to change the motor pulley to a 2 inch to bring your spindle speed down to 3450.You don't say what kind of polishing you're doing.Do you want 3450 or 1760 RPM?

[alabama_lowlife]

i'm polishing mostly aluminum, although i may do some stainless now. i guess i'm going for 3450. i looked at some 2" pulleys on ebay, i'll order one if i can't find one around here, thanks......why didn't i think of that? i must have been trying too hard lol

[ERService]

You may find 3450 too fast at first.A 1760 rpm may be a better speed to start with.I've used 5-10 hp Hammonds for 25 years and could slow some of those down because they were belt driven.I was on a 7.5 Baldor for awhile and that I couldn't slow down as it was direct drive.On the 3450 your buffs will stand out pretty good, but with the 1760 you'll be able to make them bend and give easier without having to turn off the machine to get the buffs into tight spots.Maybe other people will give their opinions for what would be best and use whatever would work best for you.

[mpierich]

Originally Posted by ERService

You may find 3450 too fast at first.A 1760 rpm may be a better speed to start with.I've used 5-10 hp Hammonds for 25 years and could slow some of those down because they were belt driven.I was on a 7.5 Baldor for awhile and that I couldn't slow down as it was direct drive.On the 3450 your buffs will stand out pretty good, but with the 1760 you'll be able to make them bend and give easier without having to turn off the machine to get the buffs into tight spots.Maybe other people will give their opinions for what would be best and use whatever would work best for you.

Ditto...plus if you're using it for final buffing I believe slower speeds leave fewer swirl marks, probably also because of the lower "centrifugal force" - less slapping on the material.