Crazy Idea Implemented - Fast, effective, low cost

25 Strokes on 1 micron diamond

Phil Smith

>I have attached a picture of a CPM 3V plane iron that I ground to the edge to produce a wire edge on the 100 grit wheel and then gave 25 stokes to the bevel on a cast iron plate loaded with 1 micron diamond paste. At this point I have a polished bevel across the width of the blade with the exception of a small place on the corner where I slightly radius the corner by mistake on the grinder. All that is needed to finish sharpening the blade is a couple of strokes on the back to remove the wire edge from the bevel and produce a razor sharp edge ready for work.

Re: 25 Strokes on 1 micron diamond

ThomD

>That is one clean shop!

Re: Crazy Idea Implemented - Fast, effective, low

paul womack

> In front of the grinder is a set of cast iron plates that we had a local machine shop make.

What was the cost of these?

And how fixed/embedded are the diamonds. Clearly if the diamonds remain "free" there will be substantial wearing (and undesirable hollowing) of the plates.

BugBear

diamonds don't move, plates don't wear

bill tindall

>Historically diamonds have been "cut"( but ground would be a better word) by charging diamond powder onto cast iron plates. When investigating this approach to sharpening I talked to a company that fabricates diamond products about plate wear. They told me that plates last a very long time; they may have said for ever. Consider the advantages over stones- plates stay flat, only one grit necessary for sharpening right off the grinder, any tool steel cuts rapidly, a $25 bottle of powder will last for years of sharpening. But, until someone offers inexpensive pieces of cast iron for this task it will be impractical for most to impliment.

There is economy of scale. We went together and ordered a batch of cast iron bars, then had a machine shop prepare them for plates. Cost per plate was less than $25. It is a good club project. For one plate I would prowl the junk yards for a chunk of cast iron I could take to a machine shop and flatten.

Re: diamonds don't move, plates don't wear

Dan Donaldson

>How about buying an old junk plane and using the bottom of that?

Re: Crazy Idea Implemented - Fast, effective, low

Tony Zaffuto

>What is the speed of the grinder?

Table saw tops?

Bill Houghton, Sebastopol, CA

>I've picked up at garage sales for about $2 little "homeshop" table saws - I've got one top now that I've been saving for a few years, thinking I'd find some use for it. I think I have.

What about oil stones & paste?

Frank D. in montreal

>I read a passing comment once about how Garrett HAck uses diamond paste on his oil stones. Does anyone know more about this? Would flat oil stones be a good substrate for diamond paste?

thickness??

Bruce, a MN Galoot

>Bill or Phil,

What thickness cast iron are we talking about? As soon as the snow melts, I'll start prowlihg the local scrap heap, but I need to know what I'm looking for.

Also, do you back up that cast iron so it doesn't flex?

I had thought of doing this with a bar of mild steel, say 1/2", milled flat. Cast iron seems to have better properties for this application.

Thanks.

Bruce

right on!

bill tindall

>

Re: thickness??

ThomD

>I have one of the Kanabans that LV used to sell it is about 1/4 inch thick, and I think it is iron but not necesarilly cast. It just looks like a piece of cold rolled plate really. I mounted mine on a piece of flat cherry, using boatbuilding epoxy, and I encapsulated the cherry to keep any warping to zero.

Re: thickness??

Phil Smith

>The plates are about 1/2" to 5/8"finished thickness. We purchased 1.25" X 2.25" X 12" exturded cast iron from Metal Express. We had a machine shop rip them in half to make two plates and then had each side blanchard ground to give a finished thickness somewhere between 1/2 & 5/8". The plates are just loose in the boxes. If I ever dish on side then I will simply turn over and use the other side. I don't expect that to happen.

Re: Crazy Idea Implemented - Fast, effective, low

Phil Smith

>I don't expect to dish the cast iron plates in normal use. With the 30 micron plate I have flattened the back of 4 CPM M4 plane irons and 8 CPM 3V plane irons, and the plate still looks good. The M4 is very hard and simply cannot be effectively flattend or sharpened with other stones. Each of the M4 plane irons required somewhere around 500 strokes on the 30 micron diamond to remove the surface grinding marks from the surface grinder. I would still be grinding and would have worn out one or more water stones by now on the M4 alone.

If the top side ever does dish I will simply turn over and use the other side.

Bruce Norton and I have considered making some of these for others. Price would likely be somewhere around $60 for materials, machining and our aggravation for making. I have a good bit less than that in these.

Is cast iron cookware really cast iron?

Jonathan Kaplan (OR)

>If it is, than that might be a source for relatively cheap, relatively flat cast iron....

jk

Re: diamonds don't move, plates don't wear *LINK*

Fred Peake

>Another source of cast iron to consider might be angle plates. These are precision ground to .0005 inch/ 6 inches and are available at a reasonable cost. My thought was to hack saw one apart to provide two plates. You might even be able to mount and use these without modification. A 6x6x6 should provide two usable surfaces for less than $40.


Angle Plate

Re: diamonds don't move, plates don't wear

Christopher Fitch @ Memphis

>I have an extra bandsaw table from Grizzly. The original table that came with my bandsaw had a tiny crack and after reporting it to Grizzly, they sent me a replacement and told me to keep the original.

It would perfect for that...but I have water stones. Maybe I'll try this when I wear them out...

:)

angle plates

bill tindall

>Good thought. In fact this was our first source of flat cast iron to experiment with the process. Enco runs them on sale from time to time.

How about using these?  *LINK*

Pam Niedermayer - Austin, TX

>


Grizzly cast iron face plate, many sizes

Model Number of Radiac Wheels?

Bryan in Broad Ripple, IN

>What is the model number of the Radic wheels that you use?

-Bryan

wheel description, many choices

bill tindall

>The Radiac grit is their RAA (pink) with a very soft bond-G or H. The 100 grit wheel we use was custom made by them. The 46 grit is a stock item and I think 60 and 80 are also stock. The 100 gives more control on a 3600 rpm grinder ( metal goes away less fast). But the diamond will remove even 60 grit scratches. It may be difficult free handing to the tool edge with 60 grit and 3600 rpm. I have used 1/2" wheels and they are fine. Again, control is more difficult with the 1/2" and 3600 rpm.

A Norton near equivalent is their 25A. I think the Lee Valley white will work fine too, especially for the easy to grind A2 and O1. I tried Joel's 3X and they worked fine. If the 3X works then the tool room version, Norton 5G, would also work.

what does not work well for grinding to the tool edge at 3600 rpm is a hard bond, like J and harder, except the J was OK in the ceramic 3X wheel.

Confused? there are lots of wheel/grinder combinations that do fine. Our club had custom made the 100 grit wheels as an experiment. they are not expensive to custom make in lots of 10. PS I like the hollow that a 7" wheel makes.

Sign me up!

Ed Mulligan, Cape Cod

>Phil -

My thanks to you and Bill and your club for sharing your experiments with us on WC.

If you do decide to market a kit, I'd be interested in one.

Ed

difference between cast iron and mild steel?

Bruce, a MN Galoot

>Is there a difference between iron and mild steel in the way they would grab onto the diamond particles? I remember the LV plate and also recall that Garrett Wade had one years ago, too.

Bruce

yes

bill tindall

>When I talked with the company that fabricates diamond products by grinding them into shapes, I asked if mild steel could be used. They said it was not suitable as the diamonds would not embed properly. It might be interesting to try aluminium, especially a machinable alloy (not plate). I suspect the plate would be grabby. I have used aluminium rod mounted in a lathe to grind inside bevels of gouges and it seems to work ok. I think some of the aluminium goes away but for this application making a new rod is cheap and easy.

I tried copper coated circuit boards. The diamonds embedded fine but the material was not very flat.

Re: difference between cast iron and mild steel?

Wendell @ Murphy, TX

>If these are the same plates that Japan Woodworker sells, my experience is that they do not work at least for the finer grits. I tried 1/2 and 1/4 micron paste of the Kanaban plates and it did not work at all. It left the edge in worse shape than coming off the 15 micron paste. I haven't tried the course paste on the plate because they work fine on acrylic for me.

Wendell