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View Full Version : Best wheel size for general wire brushing vs grinding



davefr
07-23-2012, 06:50 PM
I have 2 pedestal grinders.

Grinder A is a Baldor 7" 1/2HP, 3.4 amp, 3600 RPM
Grinder B is a Jet 8" 1 HP, 8 amp, 3600 RPM

I want to dedicate one to general shop grinding and one to wire wheel brushing. Does anyone have an opinion on which machine should do the grinding vs brushing?

I'm leaning towards making the Jet the brushing machine since brushing seems to require more power then grinding.

Any opinions?

Duffy
07-23-2012, 07:54 PM
Hi, I think that you answered your own question. The (slight) added benefit of using the Baldor fpr grinding is that wheels are generally priced by size. One additional thought is that buffing is even MORE power hungry.

sasquatch
07-23-2012, 09:54 PM
Wondering,, Why is the amperage ratings on your'e motors so low?

Or are these on 220?

!/2 HP should be about 8amps, and the 1Hp should be 13-15 amps?? No???

lazlo
07-23-2012, 09:59 PM
Wondering,, Why is the amperage ratings on your'e motors so low?

1/2 HP should be about 8 amps, and the 1Hp should be 13-15 amps?? No???

1 Horsepower is 736 watts. So 1/2 HP = 373 watts. @ 120V nominal that's 3.11 A, or around 3.4 A at 91% efficiency.

oldtiffie
07-23-2012, 10:12 PM
There are a whole range of "brushes" that will require diferent power requirments for the same diameter and speed - check them out.

I listen for the motor "under load" as that is a good measure of how the motor is performing - pedestal grinders and angle grinders alike.

davefr
07-24-2012, 12:00 AM
Wondering,, Why is the amperage ratings on your'e motors so low?

Or are these on 220?

!/2 HP should be about 8amps, and the 1Hp should be 13-15 amps?? No???

We can thank our friends at Sears and their deceptive marketing tactics for making HP ratings irrelevant. (and others have followed Sears lead). I don't believe any HP ratings anymore. The only correlation to true power is amperage. However I've noticed that many products omit amperage ratings in their specs these days.

It's becoming a guessing game in evaluating machinery power.

sasquatch
07-24-2012, 10:00 AM
For over 1/2 a century Amperage ratings on electric motors were just what i posted above.

It was a set standard everyone used and many still do.

Boucher
07-24-2012, 10:28 AM
I have a 1 hp 1725 rpm Baldor Buffer with a 10" soft wire brush on one end and a Scotch-brite deburing wheel on the other. This is probably the most used tool in my shop. I have had an old 7" grinder similarly outfitted with a harder wire brush and Scotch-brite wheel that is also excellent but just not as conveniently located.
A good quality soft brush is expensive but well worth its cost.

oldtiffie
07-24-2012, 10:42 AM
I don't have brushes on my pedestal grinder - but I do use my belt sander and my disk sander occassionally.

All my wirre brushes are on angle grinders.

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander/Belt_sander1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander/Belt_sander2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander/Belt_sander3.jpg

Bill736
07-24-2012, 09:41 PM
My 7 inch diameter grinder/wire wheel unit runs from a 1/3 hp. washing machine motor to the head unit, via a belt. Over the past 38 years, it's been enough power for my home shop uses. The pulleys are sized to overdrive the 1725 rpm motor to about 2000 rpm at the wheel. I also have a direct drive, 3/4 hp. 3450 rpm grinder, but I prefer the slower machine.
Besides, when wire wheels get a bit tired, they start throwing wires out. At 2000 rpm, they are less of a hazzard ( but I always wear a face shield.) Abrasive flap wheels work well, but they throw fragments all over , and make a mess.

BadDog
07-25-2012, 03:33 AM
My 7" Baldor runs a 7" surface grinder wheel designed for efficiently cutting tool steels. 1.250 adapter lets you run the SG wheels, which gives you the best prices on the widest variety of wheels. The other wheel is a general purpose "gray" wheel used for softer "mild" steel. Love that grinder...

I've also got 2 typical chinese import 6" bench grinders. You know the ones where they seem to think a large hollow bulge in the middle (gets in the way of everything) with a tinny motor suspended in a huge void is what we want. It could actually be said to have some redeeming points if not for the bulge making it the worst of all worlds, but I digress. Those work well enough for wire brushing most of the time, but yes they do stall too easily. I've got a relatively narrow soft(ish) crimped wheel along with a brutal knotted wheel on one. The other has a very dense 1" wide crimped wire wheel on one side with a Scotch Brite debur wheel on the other.

Eventually I need to finish my "super grinder" which will use a 2hp remote Baldor TEFC motor with a quick change arbor (belt driven with ER32 collets for swapping wheel mounts) combined with VFD for flexibility. I've got all the stuff except time. Also need to finish my G8 5hp monster, but again, time...

aboard_epsilon
07-25-2012, 07:38 AM
the sticking point is this

when you go hunting down a replacement wire brush wheel ...you'll find that the most common and cheapest are 6 inch ones ..

when you go looking for anything bigger.....they have to bought from the specialists ..

so have a good stock of 8 inches ready ..and don't get caught out .

and you better make darned well sure you are wearing safety goggles with the wire brush wheels ..oner of those strands will pearce your eye ball.

they shed them .

all the best.markj