Grinding wheel for holes?

[modirt]

Was working on a project......oblong, irregular shaped hole.....about 2" x 3" that had been cut in 1/4" plate steel with a cutting torch. Hole wasn't big enough and I needed to enlarge it....basically grind down all the burrs left by the torch and smooth up the edges. Could have used a torch too, but I don't have one. And where this is mounted up, that kinda fire isn't a good idea.

Is there a serious tool for that job?

They make sanding drums and some grinding wheels to chuck up in a drill, but those have never done much for me. They don't turn fast enough to grind anything. Needs to be something like a drum wheel on a dremel grinder, except about 1 1/2" to 2" in diameter and high speed. Like something you might mount up on an angle head grinder.

Use is the same as what you might do with a high speed grinder, except its on the inside of a hole where you can't get to it.

Any help???

 

[jniolon]

Mo try a die grinder with carbide burrs

john

 

[dr sportster]

I agree --carbide burrs

 

[modirt]

What tool is used to spin em?

I've got a Dremel......seems dinky for this degree of use.....got an angle head grinder....and hand drills.......which I suspect drills turn way to slow to do anything.

I found some that run off air grinders, etc, but I don't have one of those either.

I had hoped to find something like a 2" diameter flap drum sanding disk for the angle head grinder........like in a 50 grit or so....?

 

[MJMJ]

Most are used in air die grinders, but you can chuck one in a drill also. Little harder to apply pressure, but it sounds like you don't have a lot of material to remove.
They make drum sanders for angle grinders, though they don't seem to be common so I'm not sure how well they work. Check Amazon.

 

[Mike(NEOhio)]

Carbide burr is best for that. I got an air grinder from wally world for $15. WEAR EYE PROTECTION!!! They throw nasty chips.

 

[wingnuttx]

Modirt..... An air die die grinder is what you need. Lots of attachments available but a deburring attachment would work well. Die grinders on average
probably turn 25,000 rpm. Models vary. But air compressor cmf must match grinder specs. Amazon has them starting at about $20 and up depending
on the make and model. Wingnut

 

[Janicholson]

You can use a quality stone from Granger to do the job. In a drill, it might take a bit of time,
but not a problem. A die grinder is best (air or electric) Jim

 

[Geo-TH,In]

When I rebuilt the Dana rear end on
terramite, U tube videos showed using a
flat sander to make the ID of carrier
bearings larger so you didn't need to
press bearings on and removed many times
to get carrier in proper position.

The only place I could find a 2 inch flap
sander was Amazon and Ebay.

Ebay had faster shipping.
I'll post a picture of a flap sander
below
George

 

[Geo-TH,In]

Flap sander with quarter inch shaft. I use it on a drill.
George

 

[modirt]

Hmmm.....not sure how I got this far in life and have not heard of a die grinder. Seems to be the souped up, heavy duty version of the dinky little Dremel tool. In which case, it looks like I now want one.

Mine will have to be electric, as my little pancake air compressor works OK for nail guns, but probably does not have the cfm to run one of these?

Best brand or mostly all the same?

 

[modirt]

(quoted from post at 13:29:05 05/04/20) Flap sander with quarter inch shaft. I use it on a drill.
George

<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto3660.jpg">

That might work too.......still seems odd to me that something like that is not available for an angle head grinder....to get the rpm up to where they would do some good. I use flap sanding disks on those to sharpen my lawnmower blades. They cut fast.

 

[kcm.MN]

Another option that hasn't been mentioned is the old school approach - a half-round file. A new file can remove material quite quickly. It also allows you more control for better overall accuracy. It's also easier to lay down a file to test your fit rather than to constantly wait for a bit to stop spinning.

No worries with air compressors, die grinders or CFM, or worries of chips flying into your eyes. Just need a decent file and a pair of gloves.

 

[TimV]

Like most things, you get what you pay for. Pro-grade ones electric like a Dumore are big bucks, but even a cheapie (or, better yet, one or two steps above the bottom of the line) will probably hold up well for occasional use. A little pancake compressor won't do you much good--a 1/4" grinder will suck a lot of air if run continuously. Link below is a typical good starter carbide burr for what you're looking to do. Just a thought-starter to show you what it looks like--the same basic thing is available lots of places, and getting sets or multiples of the same thing is usually quite a bit cheaper per piece. I wouldn't be without one like I linked--nearly every drill I have has one in its case, as they're the cat's meow for smoothing, deburring, and opening up holes in any drill that turns a decent speed, though that's just for "get by" jobs--serious stuff requires a die grinder, and I have multiple air and electric ones depending on what's needed.
quarter inch carbide burr

 

[flembo]

Here is what I use, a Pneumatic Die Grinder and carbide burrs but like others have said use eye protection they throw nasty chips.
They make all shapes and sizes of Carbide Burrs some are end cutting.

 

[DoubleO7]

They make cone shaped stones for angle grinders with the 5/8-11 thread.

Cone grinding wheel

 

[Jim in rush co]

Here is my 5/8/11 on B&D 9" sander/grinder. The rubber cone expands when tightened and the sleeves are Norton brand in 36 grit.

 

[Steve@Advance]

You will be much better using a cone grinder wheel on your 4" grinder.

Carbide burs are more for fine work. They will try to grab the inside of a hole and take you for a very unpleasant ride!

Trying to file torch slag is going to be a slow process.
Cone Grinder

 

[glennster]

harbor freight has an electric die grinder for about 50 bucks. for occasional use it would get you in the game
poke here

 

[Russ from MN]

You need a die grinder, we used them a lot in the maintenance dept at the paper mill, very useful tool. When I retired I bought one from HF, works great. 1/4 collet, many tools available for it. I think it turns about 20,000, but I may be wrong. the Milwaukee ones in the PM turned 14,500. Sanding flap wheels are great for polishing/cleaning, but really don't remove much metal. for softer metal a carbide burr is good, for harder metal a grinding wheel works best.

 

[Dusty MI]

Maybe a hole saw.

 

[modirt]

Looked all over for something like those cones......which is what I suspected I needed. Will try one.

Have also ordered an electric die grinder and a few basic bits. Probably messed up on the die grinder, as I got an entry level fixed speed one. Had I popped for the higher end one, it would have been variable speed, which would allow one to use the flap sanding wheels....which max out at 12,000 rpm.

 

[M-MAN]

Die grinder, carbide burrs, baseball
cap, and a pair of goggles that seal
against your face. Those chips are
dangerous!

 

[OregonAaron]

Honestly the cheapo die grinders from harbor freight are great. I have had harbor freight ones and decent quality ones and for the most part they both last a long time even with heavy use. Do yourself a favor and pick up a straight and a 90 degree die grinder, cheap harbor freight brand will be just fine for home use.

 

[modirt]

epilogue......

Die grinder and metal grinding bits finally arrived. Got a chance today to put it to use. At first, it didn't seem like much was happening......then I looked down to see flecks of bright new metal shards showing up. Bottom line is I was able to enlarge the hole in the area I needed in about 30 seconds vs. the 20 minutes I it had taken me with the Dremel and dinky grinding wheel.

Instructions for the die grinder only mentioned the use of grinding stones.....not metal bits.

But now that I got the die grinder, looks like an assortment of stones to go with it might be in my future too.

Appreciate the advice and help!

 

[RoadsideGeo]

Thanks Steve!
Never knew these existed!
7 bucks and Norton to boot...
Are these heavy grit for fast/coarse removal?
Thing now is, I need ANOTHER grinder (makes 5)! lol