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George, yeah I'm talking about a 1" x 42" unit. From your comments I conclude that the smaller abrasive area of the smaller belts would reduce their life (that makes sense). Are there any other downsides I should know about??
thanks
Glen
As George mentioneb the belt on knife grinders moves in the other direction, the blade does not dig into the belt.
I just did the bevel on 8 plane blades no problem.
What you need is a good platten, a very flat smooth backing for the belt where you are grinding, some people use a glass plate. 2X27 belts come in the most types used for steel, including cork. The longer belt also runs cooler and lasts a little longer. In fact you would be amazed how long a GOOD 2X27 belt lasts if used properly.
Cheers Ron.
Ron,Do you mean 72,not 27?
On my Square Wheel grinder,the platen is cast iron,and years ago cost almost $100.00 to replace. It doesn't take too many month's use to develop a divot across the cast iron right above the tool rest. I developed the practice of making a steel plate out of fully hardened,and not drawn A2 steel to screw onto the original platen.4 flathead screws,one in each corner are drilled and countersunk into the A2 steel before it is hardened. The cast iron platen is also drilled and tapped to receive the screws. The screws are not where you use the belt,so pose no inconvenience. When the A2 is fully hardened,it is about 65 R.C.,or as hard as a file. It has chrome in it,and wears much longer than the cast iron.
When the A2 plate does get worn,I turn it over,having countersunk the plate from both sides.
A2 has to be hardened inside a stainless steel envelope. I add some Kasenit to add even more carbon to it to make it even harder.
The best grinders I have seen are for grinding auto window glass,and have a carbide platen behind the belt. I think they are made by Hammond.They are huge,and not easy to find,though.
Another very good and versatile abrasive belt grinder (also known as a polishing machine) is made be Stephen Bader. They have a floor machine that uses a 132” belt and a bench model that uses a 72” belt. They also sell all kinds of attachments and contact wheels. There web site is http://www.stephenbader.com/
I agree with what another person said about the belt speed. You will get better results and longer belt life with speeds in the 3500 to 10,000 feet per min. range.
As far as belt life goes most people replace the belt way before it is used up. I ran a polishing shop for about 12 years and I found that you could turn 10 pounds of brass into dust with one 120 grit belt 132 inches long by 1.5 inch wide.
All of the advice that George Wilson gave is very good, I would like to emphasize that an abrasive belt grinder can be a dangerous machine. You can get a serious and painful cut by bumping the edge of a belt going 8000 ft/min. Use proper safety equipment including gloves, safety glasses and a dust mask or respirator.
Nonsense,Wayne. I NEVER got burned on a belt.:)
Actually,I'm lucky I didn't get severely slashed by a thin mylar belt. I had a few violently blow up.
You can find a Shopsmith and belt sander for cheap on craigslist.
You can slow the belt way down. and change the belt direction by mounting on the opposite end.
http://www.shopsmith.com/ownersite/c...BeltSander.jpg
I saw one of these Shopsmith belt sanders for sale somewhere but I didn't know if it would be easy to attach an electric motor, so I passed on it. How is it driven? Would it be difficult to attach an elelctric motor, keeping in mind that I'm not much of a welder but can do a pretty decent job of machining.
It would not be hard at all to mount it on a stand. Shopsmith makes a "Power stand" but not too sure how slow it would run.
http://www.shopsmith.com/ownersite/c...tandsGroup.jpg
Some people are buying old Shopsmiths and cutting them down to make a mini to run tools.
http://www.shopsmith.net/forums/imag...ine=1206644762
I too have a Bader III 2x72" variable speed belt grinder that I use for sharpening chisels. I have both an 8" wheel and the 'knifemakers' flat platen/wheel combo.
I currently have it configured with a Nova Sharpening Center (from Teknatool)
I'm also experimenting with final honing/touchups using scary sharp method on plate glass.
You do grind bevel upwards into the direction of the rotating belt with norman cloth backed belts. Just do not try it on those paper thin mylar belts.
If you don't grind with the cutting edge upwards,you can't tell how thin your edge is getting.
Interesting discussion... I have a 3x21 Bosch belt sander (portable, not benchtop) that I was thinking about using as a grinder for chisels, plane irons &c. The sander has a clamp attachment for clamping flat or vertical on a bench, and also a fence attachment. Any tips or things I should watch out for?
I've done this for rough sharpening. I use it in place of a grinder to get nicks out of a blade or to change a bevel angle. It doesn't get as hot as quickly as a grinder, but it can still burn a blade. I keep a bowl of water near by to dip the blade into so that it doesn't get hot.
I have some wooden 25° and 30° angled blocks which I use to keep the blade at the right angle. I'm not fully satisfied with that system though.
I still hone the blades after use, but it seems to be a real improvement on a grinder.
Contaminating your belt sander with steel dust may come back to bite you. If you haven't truly gotten rid of the steel dust and get it on your wooden projects,any water or water based stains,fillers,etc. will give you indelible blue (on oak) or brown spots that you will find a chore to remove.