9" Aluminum disks - Beveled Verses flat

D

Dennis Paish

Joined
Jan 3, 2007
Messages
302
Greetings,
I have a varible 2x72 grinder and a 9" varible disk grinder minus the plate. Which plate is most common, if you only had to choose one; beveled or flat face disk?

Thanks for your input.
Dennis
 
I have used flat discs from the start. A slight bevel can be of benefit as it prevents the hairy swing back a flat disc can give you if you cross the center in the wrong place. A normal bevel is 1-2 degrees.

Chuck
 
I've used both, and due to the "flip back" you get on the flat disc, I am partial to the beveled disc. Beaumount Metalwork (Maker of the KMG grinders) sells both the flat and beveled discs. The prices may not be the "cheapest", but the quality and balance of Rob's disc make them a bargain for the price.
 
I have a flat (cheap) Asia disk. It is not very heavy, as I think it may flex under heavy loads. The Beaumount Disk (per the pictures on the net) look of a better quality.

Dennis
 
Why doesn't he want an aluminum disk? I've had one for 10 years and thought I loved it. I wish somebody would have told me I didn't want it!
 
Nick, Didn't mean to insult your disk.

Aluminum disks will work fine, but since he is buying it for the first time, he should invest in a steel disk. They are harder, resist flex and warp better, and have more mass.

If you have to scrape the goo off a steel disk, not much problem, do it on an aluminum disk and you can gouge it.

Run a steel disk at high speed and have the blade tear the paper - annoying ,but not much of a problem usually. Do that on aluminum, and you will probably be going to the lathe to resurface the disk.

A new maker won't have the experience that a seasoned maker ,like Nick, has, so a steel disk may help avoid some expensive heartaches.

Stacy
 
So do you think 3/8" is thick enough for steel disks. I am building my own set up, and was going to go with 1/2" aluminum. I plan to have interchangeable disks for my hubs. 4 or 5 12" and 5 or 6 at 8.5" Would be way cheaper to do steel for me.
 
Thanks for the input regarding steel verses aluminum. However, I am still not clear to order a beveled or flat disk. Any input, Stacy?

Dennis
 
Steel disc is available at K&G. Flat disc can be a little harder to control. It tends to kick back at you when you grind in the wrong spot, above centerline with longer blades. I have ground blades up to 22" with little problem. the beveled disc can give you clearance on the upward travel of the disc. Therefore no contact or kickback. Either will work fine and it is up to you as to which you would like to buy. I have a flat disc and love it. If i wanted to make it beveled i could have at any time since I made my own discs.

Chuck
 
(disclaimer first, I sell the Beaumont Metals flat and beveled disc's that are aluminum.)

the disc's Rob makes are t61 milled aluminum that you can't move or bend at all. I've seen think steel disc's that can be bent from pressure and also thicker ones that are too stout to move. I'd put Rob's discs up against the thicker steel discs. The Beaumont discs are simply too thick to bend under hand pressure. The beveled disc's have a 1degree bevel to them. The purpose of this is the other side of the disc doesn't grab (you have a 2degree total difference on the 'far side') when grinding a blade. There is a slight hollow ground affect, Rob calculated it to .0005" concave depth over a 1.5" surface. That's really, really flat when hand grinding. Peopel worry about the sand paper cupping on the disc when bonding it to the disc. The bevel is so small, it is invisible to the paper. It will lie perfectly flat.

Stacey is right about possibly gouging an aluminum disc vs. steel and the steel will have more mass (momentum). It's a trade off I think.

Lots of guys use flat discs, lots of them use a beveled. Kinda what you grew up on. I have both and prefer the beveled one.

The beveled discs seems to sell better than the flat ones from what I've seen.
 
I have used aluminum, steel, and micarta faced aluminum. All work just fine. I would not scrape the micarta and aluminum. Just use the 3M adhesive remover when thinks get built up too much. The last disc I made was massive. It was made from a 6" thick piece of 10" dia mild steel. When I was finished the face was 9" dia and 1" thick, the hub was 6" dia and over 4" deep. Talk about kinetic energy. I had to face the front off to 3/4". It has zero flex and runs truer than any of the other discs I have made. I also put it on a motor with a 1" shaft and had to press it on. I hope I never have to take it off or I will have to cut the shaft.
 
Slightly OT, but I do a trick on my disk grinder that makes disk changing much easier. I have a new 220 grit disk on it. I apply the grinding disks on top of that one. They hold great, but peel off much easier. The 220 has been on for quite a while. If there is a gouge, no problem. It also seems to act as a bit of a hard pad. Eventually the edges will wear and I'll change it.
Stacy
 
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