Using a grinder for sanding (?)

[Jim Grieco]

Can't really describe how sick I have been all week other than all I have been doing is watching YouTube videos lol

Anyway, during this video marathon I have seen that some turners use what looks like a grinder with a sanding pad & disc for sanding.
The only benefit I can think of is higher rpms. Is this correct or are there other reasons?

Any grinder I have ever used was heavy and cumbersome. Any recommendations?

Currently just use a right-angle drill

***I am not asking for suggestion on what to use or what you use unless it is a grinder

 

[Kevin Jenness]

Some people use high speed grinders for sanding. Al Stirt, for instance, uses a pneumatic die grinder, and a local turner, Kevin Kelley from Hawaii, uses several pneumatic right angle grinders. They both achieve an excellent result. Part of it, I think, is that they get a good result off their tools. Even if they start with a coarse grit they don't spend much time with it and they have a light touch. I have tried using a die grinder and made a mess, but it can be done.

 

[Jim Grieco]

Some people use high speed grinders for sanding. Al Stirt, for instance, uses a pneumatic die grinder, and a local turner, Kevin Kelley from Hawaii, uses several pneumatic right angle grinders. They both achieve an excellent result. Part of it, I think, is that they get a good result off their tools. Even if they start with a coarse grit they don't spend much time with it and they have a light touch. I have tried using a die grinder and made a mess, but it can be done.

Thanks!
All my grinders seem heavy and bulky to me to use for sanding but I'm sure they make them smaller (?)

 

[Darryl Fective]

I got a deal on a set of 4" flapper type disks, but haven't used them yet. I was really picturing it more as a broad area carving system, more than for sanding.

 

[Don Wattenhofer]

I assume that you are talking about right angle hand held grinders, which would work but a right angle random orbit sander would work better. The two right angle RO's ( a 6" and a 3") that I have are also equipped with variable speed as well as the 5" RO's.

 

[Richard Coers]

High rpm is usually not a benefit. You can melt velcro mounted discs and overheat the abrasive. You can buy right angle grinders that use 3" discs. Is that light enough?

 

[robo hippy]

Sanding is all about finding the correct speed so that the abrasives can actually dig in and cut, and to me this translates as traction. Too fast and the abrasives just won't cut as well. For me, this is around 600 rpm on my angle drills. The high rpm angle grinders just go way too fast. You will also generate more heat with the high speed grinders, and this can result in friction cracks, usually around the end grain parts of the bowl. This is more common in hand sanding if you are going at high speeds and using a pad to keep your fingers from getting hot. The heat is the best indicator that you are going too fast and/or using too much pressure. Low pressure, and low speeds.

robo hippy

 

[Kevin Jenness]

Sanding is all about finding the correct speed so that the abrasives can actually dig in and cut, and to me this translates as traction. Too fast and the abrasives just won't cut as well. For me, this is around 600 rpm on my angle drills. The high rpm angle grinders just go way too fast. You will also generate more heat with the high speed grinders, and this can result in friction cracks, usually around the end grain parts of the bowl. This is more common in hand sanding if you are going at high speeds and using a pad to keep your fingers from getting hot. The heat is the best indicator that you are going too fast and/or using too much pressure. Low pressure, and low speeds.

robo

Believe it or not, the two guys I referenced use pneumatic grinders running above 10,000 rpm and are getting consistent, excellent results. Obviously they are using a reasonably light touch to avoid burning. It doesn't work for me (tried it) but it does work for them. They use contact adhesives and mechanical attachments with foam and leather backers on mandrels. They also are sanding dry wood after a second turning which probably helps. I get reasonable results with velcro discs running at 2800 rpm on a rotary sander polisher for initial sanding. For finish sanding inside bowls use a Grex random orbit sander with velcro discs and a crude limiter on the trigger that keeps the speed down to maybe 3-4,000 rpm. Yes, heat is the limiter but there are more ways to the woods than one.

 

[Rusty Nesmith]

Believe it or not, the two guys I referenced use pneumatic grinders running above 10,000 rpm and are getting consistent, excellent results. Obviously they are using a reasonably light touch to avoid burning. It doesn't work for me (tried it) but it does work for them. They use contact adhesives and mechanical attachments with foam and leather backers on mandrels. They also are sanding dry wood after a second turning which probably helps. I get reasonable results with velcro discs running at 2800 rpm on a rotary sander polisher for initial sanding. For finish sanding inside bowls use a Grex random orbit sander with velcro discs and a crude limiter on the trigger that keeps the speed down to maybe 3-4,000 rpm. Yes, heat is the limiter but there are more ways to the woods than one.

I use a 20,000 rpm right angle pneumatic die grinder to power sand. They don’t have a lot of torque and are variable speed so are no where near the 20,000 rpm’s when I am sanding. I used to use a 120 volt angle drill and like the die grinder much better.

 

[Jim Grieco]

I use a 20,000 rpm right angle pneumatic die grinder to power sand. They don’t have a lot of torque and are variable speed so are no where near the 20,000 rpm’s when I am sanding. I used to use a 120 volt angle drill and like the die grinder much better.

Thank you for answering my question!
what attachments do you use to use it as a sander? Is a die grinder smaller than a traditional grinder?

 

[Rusty Nesmith]

Thank you for answering my question!
what attachments do you use to use it as a sander? Is a die grinder smaller than a traditional grinder?

I use one of the kits from Woodturners Wonders. Mine is the 3” kit. The die grinder is just a little bigger than my hand and very light.

 

[robo hippy]

I have one person who buys my 'reject' bowls and sands them out. She uses a drill press and abrasives.

I do have an old Sioux pneumatic air drill, and tried it a few times. It kept my 60 gallon compressor running non stop. I consider the angle drills to be far more efficient.

robo hippy