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grinding/sanding disc epiphany

Posted: Tue Jul 24, 2007 11:54 am
by sprangalang
I have been using a disc grinder, 9" and a 1" belt sander, both with 80 grit for shaping. The disc grinder is kind of clunky, with a 1/2" thick steel plate. I really could not do too much with it. The 80 grit only cut so much and clogged right up. The sanding discs I had bought were 8", so didn't go to the edge.
On a whim I bought a 7" 24 grit disc. Took it home and wondered how to use it. Finally decided to make a mandrel and lock collar, took off the clunky disk and installed the mandrel. Glued the 24 grit disc onto a piece of cardboard. Made a few discs with 320 and 400, backed by paper plates. Now I can make discs of all grits and change them out easily. Wow, what a difference. Shaping with the 24 grit takes a fraction of the time I have been spending. The best part was finishing out a stummel with the 320 grit, then the 400. The control with the thin backing is superb. Woohoo! So that's how you do it!

:idea: :D

Posted: Sun Jul 29, 2007 1:08 pm
by Calumet
Hi Jeff

Can you post pics. off the mandrell and lock sys.?

kind regards from Belgium

maybe this will help

Posted: Mon Jul 30, 2007 8:56 am
by GbpBulgaria
Hello

as far as I understand the problem this picture maybe will help.
I have made 2 sanding disks like this and I use both for rough and more precise shaping.
The hem of the sandpaper provides the opportunity to use the disk for sanding of the angles and it works fine. You need to consider the folding of the sandpaper with rotation direction to avoid the rupture on the edge of the disk. Also, the shape of the edge of the disk is rounded and I use textile sandpaper.

the pic: Image
George

Posted: Mon Jul 30, 2007 3:32 pm
by hazmat
George.. what materials did you make the discs out of and what is "textile sandpaper"?

Matt

Posted: Mon Jul 30, 2007 3:45 pm
by sprangalang
Hi,
Nothing so complex. The original grinder setup simply has a driven shaft going through 2 bearings. The original steel plate served as a mounting disc and as a stop against the front bearing. My "mandrel" is aluminum, so I needed a steel stop. I just used a locking collar for that. The mandrel is simply a cylinder of aluminum 1"diameter, threaded hole on one end, to fasten a disc of sand paper; smooth hole with setscrew on the other end to mount on shaft.




Calumet wrote:Hi Jeff

Can you post pics. off the mandrell and lock sys.?

kind regards from Belgium
:)

H

Posted: Tue Jul 31, 2007 3:03 am
by GbpBulgaria
hazmat wrote:George.. what materials did you make the discs out of and what is "textile sandpaper"?

Matt
Hello
The disks are two they, made out of steel plates. First – diameter 140 mm - welded to the shaft \diameter – 10 mm for regular chuck of the hand drill\ and the second one is a washer diameter 130 mm, the hole is with diameter 10 mm and fit exactly on the shaft. The thread on the shaft is millimetre starts from the first disk and finish after about 20 mm to fit the nut. The nut can be tighten so the second disk press on the sandpaper and it can’t go out.
textile sandpaper is the sandpaper but based on textile not on paper. Aluminum oxide on textile.

George
Image
Image

Posted: Tue Jul 31, 2007 8:06 am
by hazmat
Thanks! I got it now. Much appreciated!!

Posted: Wed Aug 01, 2007 3:07 pm
by Calumet
Thanks a lot for pics. and info!
Thinking of converting my regular disksander into one of these.
Are there many advantages working with the paper bent over the edge?

Posted: Wed Aug 01, 2007 3:37 pm
by sprangalang
George, although your setup is much more robust than mine, I do like the paper plate backing, for the finer grits, 320, 400.
My setup looks similar to Tokutomi-san's:
Image
Notice how it is possible to flex the wheel, and focus on a particular spot.
Now if only I could absorb some of his magic powers from this photo.

Posted: Wed Aug 01, 2007 3:44 pm
by hazmat
Sprang... when you say paper plates, do you literall mean paper plates?? I can't see the picture(network police are holding me down!)..

Posted: Thu Aug 02, 2007 9:38 am
by sprangalang
I take a piece of paper, 400, 320, whatever, spray adhesive on back of sandpaper and on one side of a paper plate, then cut in a circle. This I simply mount onto the mandrel, flappin in the wind. It gives fantastic control and precision. I suppose you could glue paper on the rim of the back side too.

Posted: Thu Aug 02, 2007 10:35 am
by hazmat
Interesting.. I'll give it a try and see how it works out. Thanks!

Hi

Posted: Sat Aug 11, 2007 12:40 pm
by GbpBulgaria
Hi

Before the producing of these disks, I have made many attempts with regular disks for sanding like those produced of Bosh. The problem was that I need the edge to sand with it the difficult parts. I’ve try with paper (glued or not to the disk) under the sand paper I’ve try with a cloth glued on the disk too – it was better.
I know the picture of Tokutomi san it was posted in smokingpipes.com few months ago. An as far as I can remember the photo was made in Tods workshop. The point is that I am sure that in this workshop there is a belt sander! The belt sander will be very helpful for complex parts to be sanded out. Am I correct?
I do not have belt-sander (unfortunately I do not have late too). This was the reason I think about the method for use of the edge of the disk with sand paper for proper sanding. The other method was – hands and hours
At that time I saw the picture in pipemakersemporium of something called French disks and after some calculations on my budget I’ve got the paper and pencil and draw it and go to my friend how tells me he have a proper material. The material was very rust-eaten wafer without any form but flat.
That was the history.

I found few pictures of similar disks in hands of Italian pipemakers and one in PT magazine in article for Tsuge. So there is not anything new.

Now I thing, and many of you will confirm that the point is in the speed! The speed is important. I use a regular motor for sharpening and it is fast – 2950 rpm and I control the speed with hand.

That is all!

Regards
George

Posted: Sat Nov 03, 2007 5:16 pm
by Briarfox
Very cool idea! I recently decided that i needed a new Sanding disk (needed a thinner edge). I found one at woodcraft that is 5" and is velcro! I picked up 80,180 and 320 grit velco backed pads and it works perfect!

Posted: Tue Nov 06, 2007 1:33 pm
by kkendall
Here is a sanding disc that I made from a Dewalt random orbital sanding pad. It's fairly easy to find center, then drill a hole from the back side (bottom surface in the drawing below)

If you use a Beal arbor on a motor, use a 3/16-18 UNC-2A flat head screw. When you tighten the nut, the top of the screw actually pulls down below the velcro surface so there isn't a lump in the center of the sanding disc.

Can also mount it in a drill chuck just as easy.

Image