Grinder vs Buffer

Hi all,

I am putting together my tool lists for an RV-14 build. I have a question regarding the need for a "grinder". I know Cleveland Tools sells the Baldor 111 buffer and from what I've read this seems to be an excellent machine that would work ideally for the edge duburring that it is needed. Is there a need during the RV-14 build for an actual "grinder". This question would be from someone who doesn't plan to make a lot of modifications.

Thank you,

David

I know some will see this as a sacrilege, but I have an inexpensive Harbor Freight bench buffer/polisher that works just fine. I have a Scotchbrite wheel on one side, and really that's all I use for the plane. I have a bench grinder with a buffing wheel and grinding wheel but haven't needed it since starting my RV-7 build.

I would have liked to just have the one, but the shrouds that enclose about 3/4 of the wheel circumference on my ancient Crafstman grinder are non-removable. I couldn't use the SB wheel to debur the edges of longer pieces. You kind of need most or all of the wheel exposed.

A stationary motor equipped with a Scotchbrite wheel is a highly desirable tool for sheet metal work.

You want it to be (1) floor mounted on a pedestal stand, (2) with the wheel on a long shaft. A bench mounted motor, with the wheel tucked in in close to the motor case, is kinda useless because there is no room to maneuver the sheet metal.

A lot of us use an ordinary electric motor with a shaft arbor. Here's an example of a long arbor:

http://www.globalindustrial.com/p/p...l5l-lefthand-type-d-214l-thread-fits-58-shaft

As an aircraft mechanic for over twenty years, I have never used a bench grinder to debur, or fabricate any aircraft structutral parts. A 90 degree die grinder will do everthing the bench grinder will do, and do it better, faster, with more precision....etcetera. 3M Roloc scothbrite and sanding discs are you're friend!

http://www.homedepot.com/p/Husky-1-4-in-Angle-Die-Grinder-Kit-H4230C/204671969

Bench grinder

Which ever you get, make sure the motor is smaller diameter than the wheel.
I have a Ryobi. The guards are removed. 7a scotchbrite in one side and buffing wheel on the other. Only takes one hit to figure out why there's a buffing wheel on the other side.
I use a vixen file for skins. The scotch brite wheel is handy for smaller stuff.

I don't have a grinder or a Scotchbrite wheel (except for the tiny one on a die grinder) and see no need for them.

I use files and sometimes sandpaper. These work very well with minimal particles in the air.

Dave

Mike H said:

As an aircraft mechanic for over twenty years, I have never used a bench grinder to debur, or fabricate any aircraft structutral parts. A 90 degree die grinder will do everthing the bench grinder will do, and do it better, faster, with more precision....etcetera. 3M Roloc scothbrite and sanding discs are you're friend!

http://www.homedepot.com/p/Husky-1-4-in-Angle-Die-Grinder-Kit-H4230C/204671969

Click to expand...

Mike,
I have the blue roloc Scotchbrite discs and for the life of me have trouble figuring out what they are good for. They seem to wear down to nothing very quickly. What do you use the discs for? Edge deburring??

I also have a HF cheap bench grinder which is useful but generally use the Scotchbrite 2" or 1" disc in a die grinder. My smaller compressor runs constantly though when using it.

Buffer for Scotchbrite wheels, etc

I've been an A&P since about 1975 and I use my buffer almost every time I'm in the hangar.

Harbor Freight has two that are cheap and suitable for bench mount:
Search for their models 61557 or 94393. Both are on sale for $39 now.

The angle die grinder is also a must-have for step drills, grinding, 3" cutting wheels, and burrs. In fact, you probably would enjoy having 2-3 cheap ones like the Husky's from Home Depot so you don't have to waste your time changing appliances. That's also true for air drill motors as well. Keep a #30 in one and a #40 in the other. Saves time.

Step drills

Vern said:

I've been an A&P since about 1975 and I use my buffer almost every time I'm in the hangar.

Harbor Freight has two that are cheap and suitable for bench mount:
Search for their models 61557 or 94393. Both are on sale for $39 now.

The angle die grinder is also a must-have for step drills, grinding, 3" cutting wheels, and burrs. In fact, you probably would enjoy having 2-3 cheap ones like the Husky's from Home Depot so you don't have to waste your time changing appliances. That's also true for air drill motors as well. Keep a #30 in one and a #40 in the other. Saves time.

Click to expand...

What a great idea. Gotta try putting a step drill in the die grinder.
As for Harbor Fright, do an internet search for 20% off in store coupon. Keep your phone ready at checkout. Save, save, save.

I started out with a Scotchbrite wheel / bench grinder and soon found the 1" Scotchbrite wheel in a die grinder to be faster and a whole lot easier to use. I use a 3" blue Roloc Scotchbright disk to edge dress for punch flashing and rounding points, then the 1" wheel to polish and round edges. On thin material you need to keep a light touch, especially at the corners. I have a three die grinder set up; 3"Roloc (90 deg), 1.5"Roloc (90 deg) and 1" SB wheel (straight) so changing abrasives is quick. For lightening holes in ribs and other areas, you cannot beat the 1" wheel setup. For big parts like wing skins, the handheld tool is a lot easier to use.

Clevland Tool has the 1" Scotchbright in CP7AM and EXL2, I usually use the CP7AM. I used about a dozen building my RV-12.

John Salak
RV-12 #120116/H896HS

JDBoston said:

Mike,
I have the blue roloc Scotchbrite discs and for the life of me have trouble figuring out what they are good for. They seem to wear down to nothing very quickly. What do you use the discs for? Edge deburring??

I also have a HF cheap bench grinder which is useful but generally use the Scotchbrite 2" or 1" disc in a die grinder. My smaller compressor runs constantly though when using it.

Click to expand...

I use the 2" blue and red discs for most everything to include skin edge debuting, radiusing corners, tapering skins at lap joints.....the blue discs do wear quickly, especially the 1" blues. The 2" red discs work better for on the edges of thicker die formed parts and punch cut parts such as spar doublers.

The 2" Roloc sanding discs are a must have as well. Theses are great for spar doublers and trimming fiberglass parts.

I would definitely try drilling some scrap first if you want to try a step drill in a die grinder!

I use the Roloc discs in a die grinder as my main deburring tool. I have 1-inch and 3-inch sizes, depending on the size of the part I'm working on.

My usual procedure is to start with a flat file to get rid of the bumps from the punch press at Van's, then I give the piece a quick hit with a maroon disc to clean up the file marks. Next, I use the blue disc for most of the smoothing. And finally, I hit the part with a gray Roloc disc. I'm not sure the gray makes that much difference, but I have some gray discs on hand, so I figure I might as well use 'em.

I haven't noticed that the blue discs wear out any faster than the maroon or gray discs--except for the fact that I use blue more than the others. I do notice that if I smooth the file marks with a blue disc, it seems to take a lot longer than it does with a maroon disc. I don't know for sure, but it seems like by using the maroon disc before blue, it means I spend a lot less total time on a part than if I just used blue alone.

I also like to use the 1-inch Scotch-Brite wheels in a die grinder for lightning holes in ribs.

I've got a Ryobi belt/disc sander that I find indispensable. The belt portion is great for deburring edges of straight sections. After that, I'm a file and sandpaper guy, plus the scraper type of deburring tool with the swiveling, U-shape blade.