1x30 2 wheel grinders?

[M&J]

I found myself in an in between place for polishing up stone. I have diamond wheels but not in the higher grades and the SC belts I use go up to 600 grit. Talking with some stone hounds the 9 micron diamond belts would work quite well. (Would also like 25 and 15 micron sizxes.) So I hit up Tru Grit and found out that a 2x72" is in the $100 range and I have a minimum order of 2. Scott suggested a 1x30" belt.

Looking at 1x30" sanders they tend to be 3 wheel types. I would like to be able to grind on a contact wheel. The other issue is that they run at high SFPM rates so grinding stone wet needs to be done at low speeds.

To build up a variable 1x30 rig I may as well just pop for the 2x72" to use on the big Burr King.

Thoughts? Sources for 2x72" diamond belts?

[jimmontg]

Trugrit also has 2x72 silicon carbide belts to 15 micron which is 1200 grit, $4.95 ea. They also have no grit 2x72 cork belts you can use to put diamond compound into. Use an oil based compound and it won't come out using water if my experience with leather is any experience. Those belts are 6.50 ea. Diamond compounds are not that expensive when you consider how long they last. I use Boride Engineered Abrasives for mine, there are many others. I like Boride as their quality is high and customer service is great. Try Ebersolesrocks on Ebay too for the compound and Amazon sells it too, but I had some problems with DiamondTech sending me the right stuff. You want medium to heavy concentration too. You do NOT want light. (10% concentration). I do not think you will find diamond belts much cheaper if you can find them at all btw. 9 micron is 1800 grit by the way and therefore the scratch lines will be barely visible held in the right light..

The diamond compounds are not exactly like grit, for instance my 500 grit seems more like 800 grit sandpaper. At least on hardened steel. What gemstones are you polishing? Some like turquoise or beryls like emeralds are not very hard. I use compounds to 4 microns which is 8000 grit. It lends itself to being worked into leather very well so I would think it would work well in cork too. A 2x72 belt would take up at least 3 grams or more. I use Tap Magic cutting oil to thin it and work it into the leather, then the Tap Magic mostly evaporates. I also use medium hard felt buffs, if you have a variable speed buffer you may want to consider that route, but as the buff loads up it will need to be cleaned. I don't think you will need water to just polish the gemstone, to shape it yes, but polish I don't think it would be necessary. Boride has water based too, but I do not know how long it would last with water dripping on it.

Shape it and take it to 15 microns with the sc belt and then polish with diamond, I polished out some scratches in my daughter's opal by hand using 500 to 1200 to 5000 grits on leather glued to small boards or sticks if you will. Took me 15 minutes, if that.
Here is a grit-mesh-micron conversion table.
http://www.gessweincanada.com/category-s/11328.htm

[jimmontg]

Trugrit has an AO 2x72 belt at 2000 grit too. The high grit belts are on the last pages of the 9 pages of 2x72 belts they have. They also have some 1200-2500- 3000 grit Norax wet dry belts too, AO. They are 7.50 each. says not to use excessive water, so diamond isn't necessary unless you are going to polish ruby, or sapphire which are made of Aluminum Oxide, only diamond is harder. Actually you can polish sapphire, but the belts would wear out faster. I used to collect gemstones and know a thing or two about them.

[M&J]

Great info Jim, thanks!

I have some agate and softer jasper level stones that will be used shortly. The tiger iron piece is in the finishing stages which triggered the question. I've felt that a much better finish could be attained. The lapidary guys have these big setup's in use which I don't want to approach as far as machine/gear purchases.

I've not taken the handle down enough to get a really nice finish with the cerium oxide so these finer belts and or pre-polish techniques are a step in that direction.

[jimmontg]

Your welcome. There is another trick I forgot to tell you about the diamond compound. If you use SC high grit sandpaper to hand finish a blade you can add the same grit diamond onto the sandpaper and use a good cutting oil like Tap Magic, you will be surprised at the results and time saved. I add 1500 grit diamond to 1500 grit sandpaper and it works very well to take those small scratches out. I use a 1/16" cork backing on the stick I tape the paper too btw. Helps to keep things even.

[M&J]

Excellent! Anxious to try these techniques out.