I previously posted a question about a Harbor Freight 4.5" angle grinder I
got which is this model:

http://www.harborfreight.com/cpi/cta...emnumber=31309

regardless of the quality of Harbor Freight tools, and since I bought it
just to work on a small part of a project I did not want to spend too much
on it.

I wanted to use it to cut some concrete blocks and it came with a depressed
center metal cut off disc, so I went and got a 4.5" diamond blade (which
turns out to be about the same price as the grinder itself!) I ran into
difficulty installing the diamond blade because with the center not
depressed there is no room to put in the locking nut.

Here is a picture of the ginder:

http://i173.photobucket.com/albums/w...p/P1010674.jpg

You can see there is a "backing flange" and the locking nut removed.

Closer view of the body showing brand/model:

http://i173.photobucket.com/albums/w...p/P1010676.jpg

Now I put back in the backing flange, you can see it is quite deep and
almost the same depth:

http://i173.photobucket.com/albums/w...p/P1010677.jpg

Now I put on the locking nut:

http://i173.photobucket.com/albums/w...p/P1010678.jpg

Some of you suggested that I flip the locking nut around. This will not
work, because the tool that tightens the nut needs to be applied to that
side with the four small holes.

I then went to HD and looked at their grinders and I do not see a backing
flange like the big one I have. I did find this:

http://i173.photobucket.com/albums/w...p/P1010679.jpg

a special backing flange.

So it seems like I could use this flange and the diamond blade instead of
the original backing flange?

Question #2: why are some blades "continuous" and some are segmented? What
are the pros and cons?

Thanks,

MC

"MiamiCuse" writes:
I previously posted a question about a Harbor Freight 4.5" angle grinder I
got which is this model:

http://www.harborfreight.com/cpi/cta...emnumber=31309

Here is a picture of the ginder:

http://i173.photobucket.com/albums/w...p/P1010674.jpg

You can see there is a "backing flange" and the locking nut removed.

That particular sort of large backing flange is intended only for use
with depressed center grinding discs. It's not appropriate for a flat
diamond wheel, because it won't grip it in the center

(By the way, this looks exactly like what Makita used to include with
their 4.5 inch grinders maybe 5 or more years ago. Makita has now
switched to a smaller flange and larger nut, both about 45 mm in
diameter, and that's what new grinders come with.)

I then went to HD and looked at their grinders and I do not see a backing
flange like the big one I have. I did find this:

http://i173.photobucket.com/albums/w...p/P1010679.jpg

a special backing flange.

So it seems like I could use this flange and the diamond blade instead of
the original backing flange?

This is closer, but may not be appropriate for your grinder. The flange
is cut in some way to ensure that it doesn't rotate on the grinder
shaft, but the method isn't standardized. For example, that DeWalt
flange won't work properly on my Makita grinder. So you need something
that fits properly on *your* grinder's shaft. I can't tell from the
photos what exactly your grinder does to key the flange to the shaft.
Makita and Hitachi use two flats on the shaft and a slot in the flange.

Since your HF grinder's flange and nut looks like old Makita gear, they
may be a copy of Makita right down to the dimensions. If that's true, a
new Makita flange and nut set ought to fit it.

Here's a photo of Makita flanges. You want something like the leftmost
one for flat discs like your diamond wheel:
http://www.makita.com/menu.php?pg=ac...g=136&tbl=1&f=

You also want a larger nut, one that's the same diameter as your new
(smaller) flange - not the small original one in your photos. Here are
some Makita ones; looks like the leftmost nut probably matches the
flange in the previous paragraph:
http://www.makita.com/menu.php?pg=ac...g=137&tbl=2&f=

To find something that will work, go to a real tool store, one that
carries spare parts for name-brand grinders, and find a flange+nut pair
that fits your grinder that holds a thin cutoff disc properly.

(Or just buy another grinder with the correct hardware. I have a cheap
"Superior" brand 4.5 inch grinder that cost all of $20, and it comes
with the correct flange and nut for thin discs. The Makita flange+nut
would cost me $10 or more, so a second grinder for $20 isn't a bad
deal.)

Dave

MiamiCuse wrote:

I previously posted a question about a Harbor Freight 4.5" angle grinder I
got which is this model:

http://www.harborfreight.com/cpi/cta...emnumber=31309

regardless of the quality of Harbor Freight tools, and since I bought it
just to work on a small part of a project I did not want to spend too much
on it.

I wanted to use it to cut some concrete blocks and it came with a depressed
center metal cut off disc, so I went and got a 4.5" diamond blade (which
turns out to be about the same price as the grinder itself!) I ran into
difficulty installing the diamond blade because with the center not
depressed there is no room to put in the locking nut.

Here is a picture of the ginder:

http://i173.photobucket.com/albums/w...p/P1010674.jpg

You can see there is a "backing flange" and the locking nut removed.

Closer view of the body showing brand/model:

http://i173.photobucket.com/albums/w...p/P1010676.jpg

Now I put back in the backing flange, you can see it is quite deep and
almost the same depth:

http://i173.photobucket.com/albums/w...p/P1010677.jpg

Now I put on the locking nut:

http://i173.photobucket.com/albums/w...p/P1010678.jpg

Some of you suggested that I flip the locking nut around. This will not
work, because the tool that tightens the nut needs to be applied to that
side with the four small holes.

I then went to HD and looked at their grinders and I do not see a backing
flange like the big one I have. I did find this:

http://i173.photobucket.com/albums/w...p/P1010679.jpg

a special backing flange.

So it seems like I could use this flange and the diamond blade instead of
the original backing flange?

Question #2: why are some blades "continuous" and some are segmented? What
are the pros and cons?

Thanks,

MC






If you happen to own a hand cutoff saw ("Skilsaw") you can buy masonry
cutoff wheels which will fit it almost anyplace that sells power tools.

That's what I use.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.