Diamond sharpening, resources?

Re: Diamond sharpening, resources?

William Duffield, on the Cohansey

>You can get paste in several different grits, in an aqueous carrier, from Joel at Tools for Working Wood. I think WoodCraft also carries it, but their prices are higher and their service is not as quick. I apply my paste to blocks of acrylic, but cast iron plates, and probably even granite will work, if you can find it in useful sizes. I use acrylic because it is flat, and the price was right. It was scrap. Granite scrap is available at tile cutters. You can cut up your tablesaw table. You're not using that anymore, anyhow, are you? :^) A good useful size to start with might be 12" x 3". I think it is useful to look for 3/4" thick acrylic, because thinner flexes if your sharpening station table is not flat and stiff.

Re: Diamond sharpening, resources?

Todd Stock

>I think Joel's stuff is likely a better quality, higher diamond density paste that is not likely to irritate those with chemical sensitivity to certain natural oils (the WC kit's paste carrier and additional oil smells like a castor blend to my untutored nose), but the WC kit is actually cheaper than just about anyone else's basic diamond kit. The catalog says that each syringe is .5cc, but the individual syringes are filled to the 5cc line, so I think some copywriter slipped a digit. Each syringe is about the size of my pinky finger, so you get a lot of compound (about 10-15 years worth at my rate of use)

At $50, the kit includes 30, 15, 6, 3, 1 and .5 micron grits, six MDF plates, a glass plate, a 600 grit 2" x 6" diamond stone, 100 ml of an oil/water soluble lubricant, and a non-slip mat. I recycled everything but the MDF plates (already stamped with grade of paste), paste, and the oil. All plates were screwed to a larger sheet of 3/4" Baltic Birch - less chance of mixing diamond grits than handling each block by hand.

I use diamonds strictly for initial polishing on the back of the blade, so I have not done much more than play around with the WC kit for honing a bevel. The compound provided is fast cutting - even on A-2, and the provided MDF plates are very flat. After nearly two years of use, the worst plate is about .002 out at one corner (probably a rolling error) - the rest show no light at all with a quality straightedge, so likely under .001 or so.

If I were honing with diamond, I'd still switch to hard maple or (better yet) cast iron, due to the fragile nature of MDF WRT blade dings.

Hope this helps.

Unnecessary number of grits

bill tindall

>Disclaimer:I don't sharpen to the refinement that some do. I grind away the dead edge with a power/bench grinder with 80 grit wheel then hone with diamond on acrylic or cast iron. (acrylic is the hardest plastic you can readily buy (MSC a good source) and if not cast iron you need a replacement that will embed the diamond without swallowing it. Porous substances are a very poor choice.

Fact: 15 micron diamond rapidly removes 80 grit power grinder scratches.

Fact: can't judge value by size alone. The concentration of diamond in paste as well as size distribution vary with source. Again consider MSC(they list concentration), lapidary supplies, Joel. I like oil-based on cast iron and water-based on acrylic.

Fact: used properly on a proper substrate a 5 mL tube will last a very long time. A "worm" a couple of mm long is sufficient to charge a 3 x 12 cast iron plate.

Opinion:For my needs I have been successful jumping from 15 micron to 1 micron. I am quite confident that even the most demanding sharpener would see no need to use more than one grit step between 15 and 1, if at all. Steve has shown benefit in going less than 1 micron. Sadly before I realized the redundance of the intermediate grits I charged cast iron with 9 and 3 micron, which I now never use. (Any idea on decontaminating?)

*snort* (re. cutting up table saw)

David W. Dougherty

>

Cleaning plate

Jim in Burlington On

>If you have a guy around who rebuilds race engines chances are he has a ultrasonic parts washer. Places that service aircraft should have one also.

won't work

bill tindall

>my computer decided my keyboard didn't exist for a while. A few ons and offs finally "cured" it if indeed anything is ever cured in MS- land.

Anyway, the diamonds are embedded-that is like stuck, mightly. I have tried every imaginable mechanical means of removing them without success. I suspect some sort of scraping would work, probably whatever the plane makes do to scrape cast iron, but I don't know the procedure or tool used.

Re: won't work

William Duffield, on the Cohansey

>What about taking it to a machine shop and having it surface ground? Maybe one out of town, and don't tell them that it has diamonds embedded in it :^) Alternately, you might be able to scrape a new surface into it. Probably not worth the effort, if you could only find a reliable source of cast iron plates at a reasonable price.

Cast iron and tablesaws

Bob Hackett

>I`ve been collecting cast iron saw tables from the du...err transfer station(that`s the ticket).So far I have more than a half dozen.Any ideas on how to cut them up at home?I`m thinking about using one of my stone cutting diamond wheels on a skillsaw but the irony keeps me from it.

Anybody need old tablesaw parts?How about those cast wing tables with all the square holes in them?

I`ve also picked up about a dozen of those round cast iron covers from woodstoves.I tell myself there must be a way to use these for sharpening but I suspect it`s just the crow in me that made me throw them in the back of the truck.

Mainely,Bob

Re: Cast iron and tablesaws *LINK*

Miles

>Bob - I understand that diamond is not used for fast machining of ferrous metals because at high temperatures the diamond *dissolves* into the iron and so you effectively wear away the diamond chemically, rather than mechanically. At high blade speeds the temperature at the cutting point is extremely high... much higher than is apparent from the outside. So there is a big risk that your diamond grinder blade will dull really fast if you try to cut cast iron with it :-(

CBN (cubic boron nitride) is preferred over diamond for iron/steel machining, for this reason. Searching for 'CBN cutoff disc' brings up lots of hits for CBN, diamond, etc. wheels as these are used in metal shops for cutting bar stock etc. A range of products to look over at the link below (no recommendation but looks good at a glance):

hope this helps

Miles

Cambridge, UK


http://216.197.127.242/index.cfm?reftID=2&tnm=CBN%20(Borazon)%20Profile%20Grinding%20Wheels