Which Disc Grinder

A

alexmin

Joined
Nov 16, 2005
Messages
513
I am thinking about buying a disc grinder. I can't get good results blade flattening on my KMG flat platen.

My questions are:
1. Is it important to have reversable motor?
2. Variable speed drive?
3. How many HP?
4. What size disc?

I have an AC 1.5HP motor 1725RMP with three pulleys left after upgrading my KMG to VFD I can use for disk grinder. I think it can be reversed using drum type switch.

Anything else important about disc grinder I need to know before buying or making one?

Thanks,
Alex
 
hey,
you you can find a 9" disc its the way to go. because you can cut the sheets of paper to fit it. instead of buying the pre made discs for big cash.
speed isn't a big matter unless you're looking to finish stuff on it.
reversible ins't a big deal either.
you can buy one rfom rob frink and its as good as it gets
or you can go with a 12" inexpensive model from wherever. such as harbor freight, wholesale tool, enco, etc. good luck
 
I made an attachment for my metal lathe to convert it into a disc sander. I fiqured since it had variable speeds and was reversible why not. My regular disc sander is too fast for most metals but I can throttle the lathe down to 100 RPM if needed. I liked the idea of a second disc sander without having to sacrifice any more bench space for it.

I have seen some very simple and creative home built disc sanders. I also converted both sanders to hook and loop so I can change the pads quickly. The conversions pads cost about $7 and you just peel the backing off and stick them on the disc. The one I have now is almost a year old it still holds the pads fine.
 
Sounds like you've got the right idea.

You don't need variable speed....but if you've got the controller already, all you need is a switchbox between the controller and the motor....add another motor to that box and oila....variable speed for both.

Of course, having the pulley setup will be enough to get-er-done.

Reversible doesn't matter...

1HP is plenty...


Get the 9" disc from Rob Frink...



by the way...you and I are in the same boat...;)....just need to follow through with my plans....:foot:...:rolleyes:
 
As the wise man once said, "opinions are like a$$ holes, everyone has one". Here's mine..........

I've found that 3/4 hp is plenty. Variable speed is VERY nice but not a 'have to have'.
To me, reversing is something I would NOT be with out, it's far easier for me to get both sides of my work even.
Also, if you use a foot switch to start and stop your disc you have A LOT more control over the flatness of your grind and I wouldn't be with out it, either.
As some one else said 9" is the way to go.
If you use the VFD you have on your KMG you can have variable speed AND reversing, assuming you have a 3 phase motor for it.
The best disc grinder I'ver ever seen is the one Tru Grit is selling. It's pricy but damn good. If yo go this route I'd suggest buying it without the motor and go with more hp than they offer.

Mike
 
micad said:
As the wise man once said, "opinions are like a$$ holes, everyone has one". Here's mine..........

I've found that 3/4 hp is plenty. Variable speed is VERY nice but not a 'have to have'.
To me, reversing is something I would NOT be with out, it's far easier for me to get both sides of my work even.
Also, if you use a foot switch to start and stop your disc you have A LOT more control over the flatness of your grind and I wouldn't be with out it, either.
As some one else said 9" is the way to go.
If you use the VFD you have on your KMG you can have variable speed AND reversing, assuming you have a 3 phase motor for it.
The best disc grinder I'ver ever seen is the one Tru Grit is selling. It's pricy but damn good. If yo go this route I'd suggest buying it without the motor and go with more hp than they offer.

Mike
Click to expand...
I assume you need floor pedal because you hold blade against disk and then start it with the floor pedal? What floor pedal do you use and where did you get it?

Thanks,
Alex
 
Hello Alex

I called Grizzly's Customer Service Department last week to ask about buying a replacement 9 inch cast iron disk (part number P1014021) for their G1014Z disk/belt grinder. It was about $16-$17. I don't recall what the shipping cost was. It is shown on the parts list that is linked to on the webpage for that grinder. I think that the guy I talked to said that the hole in the disk was 5/8 inch in diameter (I don't have my notes here). I would buy one first to see what the hole size really was before buying other parts to to go with it.

I suspect that Ron Frink would make his disk with whatever hole size you need to fit your motor. I would also expect that Ron's disk would be a lot nicer but I don't have room in my budget for one at this time. Until then, I will be making do with the Grizzly one.

Phil
 
I have the TruGrit disc grinder. It is great. But it is more for precision flattening and dovetailing than for flat griding. Someone has already mentioned the small (1/2 HP) motor, but the mounts for the table also get in the way for working on blades.

John Frankl
 
I just found this description on KMG website:
Beveled face disks have a 1 degree face angle so that long work pieces can be ground without rubbing the "uphill" side of the disk.
The slight bevel does not cause a wrinkle in the abrasive

I want to be able to flatten or to thin whole blade including handle part and also do some flat grinding. Most of flat grinding will be done on KMG but as final step I want to do grinding on disk grinder with fine grit to make sure blade is absolutely flat.

Do I need a beveled or flat disk?
Can anyone give me more details on that?

Thanks,
Alex
 
I would say it depends on the size of the blade you are working on. If it is no longer than 4.5 inches then a flat disk will do without the blade hitting the other side of the disk. If you do want to work on something longer than 4.5 inches then the 1 degree beveled disk will stop the blade hitting the other side of the disk so go for that one if you have the cash for it :)
 
I want to be able to use my disk grinder for smaller and bigger blades. Sounds like I need two discs.
Can you do blade handle part flattening on beveled disk?
 
Rob has both steel and aluminum discs.
What are advantages/disadvantages of each?

Thanks,
Alex
 
Alex,

Ya, the foot switch sets on the floor, you place your work against the disc and then press down on the foot switch, releasing it to stop the disc before removing your work from the disc. Works GREAT!
McMaster Carr has them as does Grainger. I'll check the catalogs tomorrow and get you a part number.

-Mike-
 
OK silly question here. Anybody have Rob Frink's contact info?? I've got it at home, but its payday and I'm at work....By the time I get home, my check may be gone :rolleyes:
Ed
 
Man, that didn't take long. thanks Fitzo. I knew getting internet at work would catch up with me eventually.....this could be big trouble.:rolleyes:
Ed
 
micad said:
Alex,

Ya, the foot switch sets on the floor, you place your work against the disc and then press down on the foot switch, releasing it to stop the disc before removing your work from the disc. Works GREAT!
McMaster Carr has them as does Grainger. I'll check the catalogs tomorrow and get you a part number.

-Mike-
Click to expand...

Mike,

why do you want to stop disc before removing your work from disk?

Thanks,
Alex
 
Alex,

It is VERY easy to ding your work either applying it or removing it from a rotating disk. This is where the foot switch is key.

John
 
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