Question about belt sanders

[deadin]

I have a 4"x36" belt/6" disk benchtop sander. Is this something I can use with metal? (I think it's made by Delta)
If so, what type of belt/disk do I need? In looking through some supplier catalogs there doesn't seem to much of a selection for these sizes. Grit appears to be from around 60 to 150 . Will these work with metal or will it just tear them up?

 

[kcmillin]

deadin, I have a belt/disk sander of the same size.

I use it exclusively for metal. Aluminum, steel, brass, pretty much any metal will work, even hardened steels Try it, grab a scrap piece of anything metal and give her a go.

I use pretty much any grit, but the finer seems to work better. I just buy whatever they have at the hardware store that will fit, I have not tried using any metal specific paper, I just use the stuff made for wood. Works like a champ.

Kel

 

[Tin Falcon]

I have a little bit bigger one a 6x48 and a 9" disk.
But what you have should work fine. an alox belt should do fine a zirconium belt will last a bit longer. I have found that get a bit courser grit than you think you need. a 60 grit seems to work well for most work . Although you may want to keep a 120 on hand as well. use a good dust respirator hearing protection and no gloves.
I use mine for wood metal and plastic. A cleaning block is an essential accessory.
Tin

 

[GailInNM]

They work fine with metal.
Two precautions.
1. If it has an open frame motor, a shield to keep most of the metal dust out of the motor is a good idea.
Vacuum the motor area frequently to keep the motor clean.
2. Pay attention to the arrow on the belt for rotation. It has to do with the way the lap joint on the belt is made.
The edges on metal tend to catch more than on wood so the direction is more important.
Gail in NM

 

[GWRdriver]

Pay attention to the arrow on the belt for rotation. It has to do with the way the lap joint on the belt is made. The edges on metal tend to catch more than on wood so the direction is more important. - Gail

I can certainly endorse what Gail says, . . . however (and?) . . .

I've had one of those typical industrial size 1x42 belt grinders for many years and I've bought a lot belts for it. What shouldn't come as a surprise to anyone is that good domestic abrasives (ie, Norton, 3M, etc) wear better and outlast "imported" belts but they cost. I still buy mostly imported belts, or used to, but the last couple of batches I've had the belts were all butt-joined rather than scarfed and therefore had no direction and no direction arrow and they fail more often than scarf-joined belts.

A couple of years ago (after almost 30 years of almost daily use) the cheap piece of crap Taiwanese motor gave out (that'll teach me) and I decided to increase the horsepower of the motor and increase the speed from 1725 to 3450rpm. This raised the belt speed in FPM to where it should have been for metal removal in the first place. Overall I was OK with the changes but one major difference was that while metal removal was faster the belts (and the workpieces) heated up considerably faster resulting in an increase in belt failures (and burnt fingers.) I found I needed to be much more careful of pressure on the belt as all that would need to happen is for a belt to get a little edge nick or too much pressure from the workpiece and it would be gone, and they invariably break at the joint.

 

[rickharris]

On occasion the kids at school would want to use the belt sander for aluminium. Experience with cut and broken belts quickly showed us that using the disc sander on the side was a better option as the disc has no join to catch and rip. Watch those fingers!

 

[Babba]

I bought one of these :

http://www.machinemart.co.uk/shop/product/details/clarke-cs4-6d-belt-and-disc-sander

It's a fairly generic Chinese made item, sold all over the world with differant badges & sometimes higher quality & spec' than this particular doorstop.

I've only ever found 1 supplier (UK) with belts up to 800. I've used 80 for fast metal removal, 120/150 for linishing & up to 800 for pre polishing. They're great at fast metal removal but this particular model (I assume all its brothers & sisters as well) has one MAJOR flaw.

The bed that the belt runs over is thin sheet metal, put any kind of heat into it & it warps/distorts. Put any kind of flat metal surface onto the belt & you will struggle to get an even finish.

If I place a 3"x6" flat piece of Aluminium on mine, keep it in one place at whatever pressure, then the sanded finish is very uneven & blotchy. I find that I have to move the piece around at very light pressures to get any conformity in finish at all.

Other than that It's been very reliable & very usefull (with quality belts).

 

[Tin Falcon]

The pad behind the sanding belt aka platen should befirm and slick>alittle research shows graphite coated canvas
some discussion http://bbs.homeshopmachinist.net/showthread.php?t=39413 Here
and info here http://pecfrictionfighters.com/product-category.aspx?catID=1
Tin

 

[Colh]

Hi All

I thought this might have come up in the thread by now but as its hasn't thought I should raise and give warning.

I have read reports in several different forums of the dangers of mixing the grinding/sanding of aluminium and steel on a grinder/sander.

Below is an extract from a post on another site.

"The incident in which the craftsman was injured began when his son used his belt sander to remove the heads of some aluminum pop rivets.This loaded the sander belt with fine aluminum particles and deposited more on the surface of the grinder stand. When he then used the sander to smooth the edge of a piece of rusted angle iron, the conditions were right for existence of what was, in effect, a small amount of thermite. A brilliant two-foot diameter fireball erupted, then instantly vanished, leaving dense white smoke with little odor. The intense heat blistered his hands and arms and removed a good bit of his hair and mustache. Fortunately he was wearing eye protection, so has fully recovered."

Please take care and clean up at the end of each session or before changing materials.

Others may be able to confirm the risks.

Col

 

[Omnimill]

I've got a Record 6X48 and use it for all kinds of metal removal including sharpening woodworking and metalworking tools. The modifications I've made make all the difference:

http://www.britishblades.com/forums/showthread.php?t=78653

Vic.

 

[GWRdriver]

Col,
Thanks for passing that along. In all my years I've never heard anyone mention the potential for an accumuation of Thermite under those conditions but obviously the potential certainly exists. I tend not use mine for ally because it clogs belts in a hurry but then maybe I need to use a different belt.

Babba mentions the sheet metal tables, and mine (being Asian) also has a sheet metal table. I've intended to replace it with something more substantial but I'm currently more of a tool-improver/modifier than I am a model builder and need to reverse that trend.

The first 1x42 belt grinder I ever saw was made by Rockwell in the mid-1960s. The grinder I presently have is about 1980 vintage (and cheap Asian) but there is very little difference in the basic construction which is mostly sheet metal and die-cast belt wheels. The difference is that the Rockwell has a well-supported cast iron platen and stiff belt backing plate and was capable of doing quite exacting grinding with no flexing or warping of the table or backer.

 

[Tin Falcon]

Col Thanks for posting that. I considered mention it myself.
While the potential for a thermit reaction is real,and good housekeeping habits are encouraged. In my experience I would say metal fires are pretty rare. I have worked in several metal working shops professional I have never witnessed a metal fire or have I heard account of any in those shops. In the Air force shop we regularly shaped aluminum steel and Titanium on the same belt sander that got cleaned once maybe twice a year. Usually when it was cleaned several pounds of powdered metal was removed. For those of you that do not know Titanium throws a very bright white spark , Like a cigarette lighter. One of my concerns was that one day that sparks would start a thermit reaction, but it never did thank God.
As far as aluminum buildup in disks I have not had that problem either. IIRC my belts are open coat maybe that is the difference .
So respect all tools take proper precautions but I do not think that a accidental thermit fire is a likely problem in a home shop. Possible yes likely no.
Tin

 

[jmshep]

Thanks for the warning about cleaning and the potential for fire.
I have another reason for cleaning my sander up after using it on metal - On a couple of occaisions it tripped the RCD in my workshop and would then run ok. At first I thought the motor was on its way out but found that metal dust had found its way into the switch area where all the electrical connections are. Not enough to cause a big bang but enough to produce some leakage to trip the RCD. Unlike a previous post my motor has not been a problem as it is well sealed but whatever your machine there is good reason to keep the dust at bay.
This brings another problem to light - using vacs to clean metal dust can cause problems of potential explosion and fire I understand. (My method involves an air line but lets not go there either).

Regards

 

[lee9966]

I bought a Delta about a year ago. Cast table and heavier back thing behind the 1x42 belt. It also has an 8" disk, although I don't seem to use the disk that often.

I have had very little problems with belts. I generally only replace them when the edges get too worn out. Watch for belts on sale, I bought a few dozen for 49 cents each, can't remember where. Enco, MSC, or the like. Mostly I leave an 80 grit on, seems to me to be a general purpose grit for use on aluminum.

The one thing that can't be avoided is HEAT. Ouchy on the fingers. Probably if I changed belts more often it wouldn't be as bad.


Lee

 

[Omnimill]

I've found the best belts to use are the butt joint rather than scarfed joint ones as the work doesn't jump every time a joint comes round.

Vic.

 

[shred]

I picked up a little 1" belt/disk sander on a whim a while back and now use it all the time. Much nicer for grinding on aluminum as it doesn't load up nearly as badly as a grinding wheel. Enco puts the belts on sale for $0.49 or $0.99 every so often. Stock up when they do.