would this kind of disk work to make a disk grinder?

[kungfucowboy]

So finding an actual metal working disk grinder in shanghai seems impossible. However some stone working supply places have aluminium disks with a 19mm shaft mount and attaches with twin set screws. Would something like that work ok to make a knife working disk grinder? Anything I would especially need to look out for?

 

[Kevin McGovern]

i don't see why not, as long as it works for the shaft size ( and it must be a precise fit) of your motor. It's a good idea to get a disk that is NOT larger then the size of your available sanding sheets, so you can use less expensive papers.

 

[Frank Niro]

If it fits properly well then it should be fine. You may be able to overlay the disc with a very thin piece of cork. I get mine from an automotive store with a non drying glue and on the outside as well to make attatching and taking off sandpaper easy. If your motor is going to turn very fast it may end up being a tool seldom used. Did you look at the hubs an d discs being sold by Rod Niesen? -
Frank

 

[Stacy E. Apelt - Bladesmith]

Frank - Niesen discs are great, but they may be hard to find in Shanghai.

Ni-Hao Cowboy,
That should work if it runs true. The size and long shank are right. At the worst, you may need to have the face trued up by a machinist with a lathe.

 

[kungfucowboy]

Thanks everyone for the advice. I'll try it out then

Frank:The Niesen disks while very nice are already a bit outside my budget and when you add in shipping and customs even more so. How fast is too fast? Would 1400RPMs be a reasonable speed?

 

[Mahoney]

it depends on what you are trying to do with the disk sander if 1400 rpm is too fast. If I did the math right the outer edge of the disk will be traveling at about 990 meters per minute, or 3200 feet per minute, about 53 feet per second. I'd prefer a slower speed for fine work, but that's just my opinion

 

[Stacy E. Apelt - Bladesmith]

I believe that most commercial disc sanders run at 1750RPM. 1400RPM should be fine.