Home Made angle plate for disk sander

[jamesjinks]

This is a genuine question not a criticism.
Why are disc sanders popular? I have always failed to see any benefit over a belt sander. The surface speed varies over the face whereas it is constant with a belt.
I have a combined belt and disc sander but I have removed the disc because I could not find any application which the belt did not do better.

What am I missing?

Tony,

I would imagine it's an issue of time. Time on production, ease of adjustment (none - belt takes a bit longer time to replace and the guy replacing it 'should' know what he's doing), ease of replacement, and since Joe production worker used that at work... him and all his buddies knew that was what they had to buy...

Jim

[will52100]

For me, bladesmith and metalwork, I primarily use a belt grinder, 2x72", but would not want to be without my disk sanders. Where disk sanders excel for me is getting things flat and for precise angles. The belt grinder just doesn't get as precise as the disk. The disk is even used in some applications after using the surface grinder, which as been converted to belt. I also use sheet sandpaper and spray adhesive for the disk sander.

If I was more into wood working, a disc sander would be a nice to have, but a belt sander would be a must.

[Tooler2]

I own too many sanders to count, both belt and disc. My prize is an Oliver double end 30'' discs with precision tables. I have an old 30'' that uses regular sand paper it has a clamping ring around the perimeter. Glue is the majour disadvantage to disks. I have a couple of 16'' also, it is cheaper to buy paper for that size. Disks are superb to sand to a line after rough bandsawing the outline. If the table is set off a few degrees you can undercut the line so when you push the two pieces together you get a perfect joint. My best belt grinder is a Porter Cable G8, a waterfall sander weighing over 1000 lbs. It is over 70 years old and the platen is still perfectly flat, great to face manifolds on.

[Beserkleyboy]

Tooler, found a YouTube video on a G8 for sale...awesome machine! ....now where could I fit that...

Jim

[Tonyg]

I am with Tony on this, I find it much quicker to change the belt on my combination unit for different grits as opposed to the adhesive disks. Also found that I only used a narrow portion of the disk due to the feed rate. I removed the disk about 30 years ago and have never missed it.
I do appreciate that it is easier for a lot of users to make a disk unit with limited tools.
I have made a few belt sanders over the years, but would not have been able to do it as easily without a lathe.
However those few parts that need turning could always be done by a small engineering firm for a relatively small cost.

[tonyfoale]

Thanks to all who answered. To summarise the replies I have formed the ideas that:

1. Disc sanders are easier to manufacture, both DIY and commercial.
2. Discs are cheaper than belts, but in my experience that is offset by the need for more frequent replacements.
3. It is claimed that discs are better and more accurate for fine work, but I suspect that a lot of that is because disc sanders tend to be fitted with better work piece rests than belt sanders. I made a good rest for my belt sander and since then I have never come across a job that the disc would do better. If I want accuracy I use a milling machine but I understand that not everybody has a mill.
4. Disc sanders seem to be preferred more by wood workers than metal workers, although I am not sure why. I work with both but predominately metal.
5. It is claimed that discs are quicker and easier to change than belts. i am not convinced. This will depend a lot on the design of the machines. It only takes seconds to change a belt on mine but when I had the disc fitted it took minutes to change because of the adhesive fixing. I often change belts between different grits because it is so quick, I would never have done that with a disc.

My overwhelming conclusion is that discs have a real or perceived economic advantage and belts are largely the preferred option. So if you have a belt sander with a good work rest there is little reason to change it for a disc.

Now I have another but related question. I am not a knife maker. I notice that belt sanders seem to be essential for knife makers for sharpening.
WHY are belts preferred to a solid grinding wheel?

[Tooler2]

You cannot appreciate a disc until you have worked with a big heavy machine, the disc alone is about 100 lbs each side. You can push much harder on a disk because a belt would stall due to the drive. Belts certainly have the advantage of changing grits in a few seconds, that is why I have multiple disc sanders. Most shops only change the bigger discs once or twice a year, they last many hours with skilled use.

[olderdan]

Something that may be of use to this thread and many will know already is get yourself a rubber belt cleaning block, most abrasive belts or discs will clog long before wearing out and these will clean them up like new without blunting them saving a lot of money.

[N00b Machinist]

... I bought some stick on sanding discs to fit my calibration plate for my table saw and boom I instantly had a powerful disc sander....

My concern here would be introducing a dust much finer than sawdust, as well as abrasive sanding medium, into the table saw motor and bearings. I loves me a hack as much as the next guy, but you can run these things out into “penny wise, pound foolish” territory, say when you compare the price of a HF sander, belt or disc, against a replacement table saw.

How long you been running that set up on your table saw, and how often? Observe anything wonky?

[N00b Machinist]

Something that may be of use to this thread and many will know already is get yourself a rubber belt cleaning block, most abrasive belts or discs will clog long before wearing out and these will clean them up like new without blunting them saving a lot of money.

I never knew about this until I saw a video of a guy cleaning his sanding belt with the sole of an old tennis shoe.