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jaybird
11-05-2004, 01:19 AM
This may sound like a real novice question but I just gotta ask.

I purchased a HF tool grinder a few days ago and the wheels are covered with paint. I also had bought a diamond wheel dresser and I have never used one before. My idea was to knock off the paint with the diamond dresser.

This is my neophyte question. When the diamond touches the wheel, is the diamond supposed to light up like ET's finger?

I was just amazed and dumb struck.

J http://bbs.homeshopmachinist.net//smile.gif

tattoomike68
11-05-2004, 01:48 AM
painted wheels?(is it just dirty and some overspray)

oh man that cant be right, you can dress them if they dont fly apart and you need to machine them like a wild man on a junk grinder outside.

and yes the diamond will light right up.(wont hurt it bit)

I have run some ceramic tooling in the lathe and its like the 4th of july big time, realy fun

after you dress a wheel you dont want it fine take .002- to .005 on the last dressing and crank it fast and course dress it it will run cooler much longer.

man buy some new wheels if they are painted for safty first and then health reasons.
grinding wheels are made of evil stuff and so is tooling, not what you want to be smelling.

my big ? is what the solvents in the paint have done and the out of balence of the said wheels.

you can "Ring test" a wheel but the paint might ruin that plan.

I would not trust the wheel.

I used to joke to rookie surface grinders that broken wheels have a built in cooling cycle.(every dent in the wall had a story)

be safe, thats #1. http://bbs.homeshopmachinist.net//smile.gif

[This message has been edited by tattoomike68 (edited 11-05-2004).]

jaybird
11-05-2004, 01:58 AM
I plan to trash the wheels. I have HF to replace them and have just bought a diamond wheel.

It looks like the paint has soaked into the A/O wheels and the wheels are not salvageable.

J



[This message has been edited by jaybird (edited 11-05-2004).]

Evan
11-05-2004, 04:16 AM
Yep, they do light up. Diamond burns at around 1800 degrees F. The reason the stone on the tip of a dresser doesn't combust to nothing in use is that diamond conducts heat 4 to 6 times better than copper. Do let the dresser cool while using.

Note: The term "Ice" when refering to diamonds is because a large one feels like ice when touched since it conducts heat so well. Most especially so for natural blue diamonds like the Hope which conducts heat much better than white diamonds.

Forrest Addy
11-05-2004, 04:42 AM
Paint won't seriously hurt a vitrified grinding wheel (that is if it doesn't have a plastic center bushing. Nor will the paint penetrate very far into the wheel's interior. Soak it overnight in laquer thinner and scrub the worst of the paint off with a wire brush. Thereafter it might be ugly but it's usable once it's dressed.

Resin and rubber bonded wheels are far less permeable and so the paint won't penetrate very far. The organic bonds are susceptable to powerful solvents like laquer thinner so don't use them.

Regardless, HF should replace your painted wheels. You should get usable grinding wheels right out of the box.

jaybird
11-05-2004, 05:03 AM
Looks like the night owls are up, I'm "working" you guys should be in bed http://bbs.homeshopmachinist.net//tongue.gif

the wheels are metal backed.

thanks for the info

J

[This message has been edited by jaybird (edited 11-05-2004).]

JRouche
11-05-2004, 11:50 AM
<font face="Verdana, Arial" size="2">Originally posted by Evan:
Note: The term "Ice" when refering to diamonds is because a large one feels like ice when touched since it conducts heat so well. .</font>

Hey, where you getting yer hands on them BIG diamonds? Are you holding out, mining the "good stuff" outta your back forty? Saving up for the "over-the-hill" years. Naw, you gotta already be there. http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif JRouche

billr
11-05-2004, 03:19 PM
good afternoon.

is this a harbor freight 'carbide grinder'? the kind with tables on each end?

as it happens, i recently bought one of them too and mine came with *green* silicone carbide wheels. they are about the same color as the grinder itself. it was my understanding that it came with *white* aluminum oxide wheels. apparently i was mistaken.

so. i ordered a diamond wheel and a *white* aluminum oxide wheel, both of which arrived yesterday. i went to the shop this morning with the idea of putting the new wheels on the grinder. should have taken 15 minutes if i stopped to smoke and drink coffee while i was doing it.

so far it has taken 4 hours. the reason is that a harbor freight 6" wheel is about 3/8" smaller than an american made triumph brand 6" wheel and the new wheels wouldn't fit inside the housing without rubbing it.

the solution: i chucked the end housings up in my lathe and bored them out so the wheels would fit. i am pretty glad i did this because i found 2 loose screws that hold the motor part of it together and also had a chance to deburr some sharp edges. the only problem i have now is that none of the spray paint i have will spray and i want to paint these housings before i put the grinder back together. so it may be another day or two before i am done. town is far enough that i don't go every day.

that being said, i am sort of impressed by the grinder. it is solid and heavy. more so than i expected it to be. i think it will make a pretty good machine as long as the smoke stays in it.

if you have the same machine as me, you might want to check to make sure all the fasteners are tight. also that your wheels fit and are the right kind. if they are green wheels, you might not be able to take that off by dressing it.

that's my story and i am sticking to it.

good luck.

peace.
bill

JRouche
11-05-2004, 04:04 PM
The green wheels are for grinding carbide and should not be used for steel. The white wheels are for HSS and steel products. JRouche

Evan
11-05-2004, 04:11 PM
You can't go by color. The color of a wheel is whatever the manufacturer wants it to be. The color for most wheels is determined by what dye the manufacturer uses and there are no standards. In a few cases the color is actually determined by the wheel material but don't count on it. You need to know what the manufacturer intended the wheel be used on.

Joel
11-05-2004, 05:16 PM
For those of us with HF grinders, accidentally switching the motor from forward to reverse is an undesirable possibility. Rather than take the time to install an extra switch, I went with a mechanical solution:

http://img.photobucket.com/albums/v186/JoelinTX/SWCover2.jpg

You have to place your finger under the guard to go into reverse. It took only a couple of minutes to bend this up from a small scrap of aluminum.

BillH
11-05-2004, 05:21 PM
Joel, how do you like your HF tool grinder? I was at the store one day, and they had a store special on it for 99$
I kick myself for not buying it at that price.

Joel
11-05-2004, 05:51 PM
It works great. I would recommend buying a white wheel for HSS (available from J&L), and a diamond for carbide.

jaybird
11-05-2004, 06:38 PM
Joel

When you bought yor grinder were the wheels painted? It seems to me the desplay model wheels were painted but at the time of purchase I didn't remember seeing white wheels.

J

[This message has been edited by jaybird (edited 11-05-2004).]

Joel
11-05-2004, 07:18 PM
No, there was no trace of paint on either wheel. Mine came with 2 green wheels. As I also wanted to use it to final grind HSS, I immediately bought a white wheel (generic terms, I know betterhalf http://bbs.homeshopmachinist.net//smile.gif ). I am surprised that the paint didn't dress right off for you. I wouldn't worry about it too much, but HF does owe you some functional wheels, if only for back-up use.

Bill, I am confident that a polite conversation with an agreeable manager will get you a grinder for $99.00. Look it over before leaving the parking lot. This is a good rule of thumb for any HF purchase.

JRouche
11-05-2004, 08:23 PM
<font face="Verdana, Arial" size="2">Originally posted by Evan:
You can't go by color. The color of a wheel is whatever the manufacturer wants it to be. .</font>


You are right, I should have said silicon carbide wheels are for carbide grinding and aluminum oxide are for steel.

I have never personally used a silicon carbide wheel that was not a shade of green but I'm sure they are available in a multitude of colors as determined by the manufacture.

Also I have never used an aluminum oxide wheel that was not white, I guess maybe because aluminum oxide "is" white in color so why dye it.

I would like some blue SC wheels and hmmm, yellow, bright yellow AO wheels (no pink). http://bbs.homeshopmachinist.net//biggrin.gif JRouche

jaybird
11-05-2004, 10:05 PM
I will have to take a very close look at what I have. When I looked at the inside of the wheel I thought I was looking at white A/O. It the wheels are green silicon, HF did an outstanding job matching their tool paint to the wheels. I did order an Aluminum Oxide wheel today. I received the diamond wheels a couple of days ago and I see I will have to bore the center a bit to fit the grinder. Now I need to find four flat head socked M8 screws to mount the wheel. The local hardware store couldn't help and I really don't to buy a hundred of them. If someone knows where I can buy screws somewhere around the Minneapolis St Paul area let me know.

J


[This message has been edited by jaybird (edited 11-05-2004).]

billr
11-06-2004, 07:12 PM
question:

why would you have to bore the center of the wheel? is it a standard plate backed diamond wheel? the center hole should be 1-1/4". i suppose that assumes that is is a domestic wheel and not one from china, india, of afghanistan.

i noticed that the new wheels i put on mine were *snug*, but did not require boring. the center hole of the wheel is what insures concentricty. between the shaft and wheel.

there should also be 4 M6 holes in the back plate of the grinder. [where the wheels bolt on] at least that is how mine is.

i put mine back together today and dressed the aluminum oxide wheel. tried it grinding both an hss bit and a carbide insert on the diamond wheel. grinder runs smooth. i am happy. and the $112.00 i paid for it sure beats the price of a baldor carbide grinder. actually, i am impressed and somewhat amazed to buy such a machine at harbor freight. i have been burned there before.

i think that before i tried boring the center of a wheel, i might look closely at it and the shaft for burrs. also i would carefully measure both the wheel and the shaft 'just to make sure' before i did anything else to it.

you can probably find the screws at lowe's or home depot. they might have a phillips head, but they will work. also, the wholesale tool company sells these screws in lots of 10 or 25 or more if you have to order them.

my $0.02. probably overpriced at that.

peace.
bill

jaybird
11-06-2004, 10:11 PM
I suppose I could take my 3lb hammer and pound the sucker on...... http://bbs.homeshopmachinist.net//rolleyes.gif

[This message has been edited by jaybird (edited 11-06-2004).]