Diamond paste sharpening questions

Re: Diamond paste sharpening questions

Fred Krow

>The basic principle of diamond sharpening is the diamond particles should be imbedded into the base material, cast iron, plastic or ceramic etc.

The steel will be abbraded by the fixed diamond edges.

Commercial hones are available with fixed diamonds bonded to steel plates (Nickel is used to bond the diamond to steel) Norton, DMT and EZ-Lap are popular brands. The pressure used on these hones should be very light, excessive pressure will tear out the diamonds and the hone will be become smooth and not cut rather quickly.

In addition, water based and oil based compounds are designed for spreading on a strop. The strop surface could be ceramic, granite, plastic or cast/ductlie iron as well as hard leather.

If used correctly, diamonds are not expensive and cut tool steels very efficiently.

Here are some links to sites selling diamond paste.

http://www.kemet.co.uk/diamond_compound.html

http://www.microdiamant.com/diamond/diatypes.htm

http://www.gravescompany.com/polishin.htm

http://www.diamondtool.com/dialapng.html

http://www.smg-diamond.com/Compound.html

http://www.hartvilletool.com/product/11519

http://www.kemet.com.au/diamond_compound.html

Regards,

Fred Krow

Re: Diamond paste sharpening questions *LINK*

L Robins

>Add Joel at :


http://www.toolsforworkingwood.com

Re: One more question...

Luke Herzberg

>The paste comes in both oil base and water base. If I use the water based paste on cast iron, will it rust up if I leave it on, rather than completely cleaning the plate between uses?

Thanks,

Luke

Re: One more question...

Fred Krow

>No, the water based indicates it is water soluble for washing up. Many prefer it to the oil based type that stains wood, etc.

Joel at Tools for Working Wood is a good source for the Norton water based diamond abrasives.

http://www.toolsforworkingwood.com/Merchant/merchant.mvc?Screen=PROD&Store_Code=toolshop&Product_Code=ST-DIAMLAP.XX&Category_Code=TBBCND

I purchased some 45 micron from Joel for cleaning up old chisels, works great.

Regards,

Fred Krow

Re: One more question...

Fred Krow

>To protect my ductile iron plates from rust, I use a light coating of mineral oil.

If I am using the Shapton/Norton water stones with Shapton grit, I will clean the mineral oil from the iron surface with window cleaner (without amonia).

Note: The diamond paste and water stone ductile iron plates are single use dedicated. I have a friend who owns a large machine shop and he made me several ductile iron plates with ground flat surfaces.

Regards,

Fred Krow

Re: One more question...

Wendell @ Murphy, TX

>Fred,

Did your buddy supply the ductile iron for the plates too or did you find it yourself? Machine shops in large metroplex I can find but I haven't found a cheap source for ductile/cast iron plates.

Wendell

Re: One more question...

Fred Krow

>My machine shop friend had the ductile iron as excess material from a project. Unfortunately that was the only piece available, I was able to obtain four nice pieces 4"x14"x1.5" thick. Two have cross hatched grooves machined at 45 degrees and two are plain surface.

I will research sources for ductile iron and post if any are discovered.

Regards,

Fred Krow

Re: One more question...

Luke Herzberg

>Thanks for the info, guys. For my cast plates, I planned to use my 6" jointah. I figured the fence would be useful for squaring up some plane bodies as well.

- Luke

PS - It's a HF jointah...nuff said.

An issue that has not been discussed....

bill tindall

>The important elements to diamond sharpening are the nature of the substrate used and the grit size. The only effective substrates I have used are acrylic and cast iron. Diamond embeds in these materials without embedding so deep as to render the diamond greatly less effective or so shallow that the diamond is crushed or rolls around without cutting.

With most of the world using oil based paste I have to wonder why one would use water based. You will have to use additional lubricant, be it water or some other liquid. I have heard the arguments and in my hands oil based paste has none of these claimed problems. One would suppose that if water was better then that is what would have been used for the last 200 years. Commercially, for diamond cutting, olive oil is a historical and popular lubricant. We have found that WD 40 has excellent properties for this task. I dismissed this claim, prefering mineral spirits, but after I tried WD40 I now use it exclusively. Oil based paste is available from any machine shop supplier or lapidary supplier at competitive prices. 5g will last a life time if used properly.

But back to grit size. It is not clear to me how you can use a jointer for this task.

Coupled to a proper grinding wheel, or other fast coarse material removal technique (it could be sandpaper on glass) for initial sharpening it is possible to sharpen with one grit size. This approach is highly desirable because it eliminated grit carry over when more than one size diamond is used, a problem I never learned to solve. Once you contaminate a plate it is useless for finer grit sharpening. It can only be saved by regrinding. This might be a problem with a jointer bed.

Re: An issue that has not been discussed....

Luke Herzberg

>Hi Bill, I was hoping you'd chime in here. So is an additional lubricant required whether the paste is oil or water based, or are you just using the dry powder abrasive plus a lubricant?

Also, when initially charging the plate, how does the diamond get evenly distributed, or does it just roll around until it finds a vacant chunk of cast iron to embed itself in? And do you have to occasionally (or every time?) add more powder or paste to the plate?

Regarding the carry over of particles, are you saying that some particles will embed in the iron, tool, whatever you are sharpening and get transfered to the next plate, or are they carried over by some other means? What I was thinking was using a coarse grit on one jointer bed and a finishing grit on the other, so I'd have a 6" x 20"+ surface for each grit. The jointer isn't much other than a boat anchor now (as when it was new).

Thanks,

Luke

answers

bill tindall

>So is an additional lubricant required whether the paste is oil or water based? YES to wash away the grinding gunk. Without additional lub a sticky mess results. I put the plate on rug antiskid mesh over newspaper and let the gunk run off the edges. are you just using the dry powder abrasive plus a lubricant? I USE both, bulk powder is cheaper but more inconvenient, will likely not buy dry again, but what I have will last lifetime

Also, when initially charging the plate, how does the diamond get evenly distributed? I PUT a condom made from a scrap of grocery bag over finger (to reduce contamination) and smear diamonds around. Find a lapidariest and ask how to do it correctly. I doubt this is the preferred way, but it works until I encounter the lapidariest)

And do you have to occasionally (or every time?) add more powder or paste to the plate? YOU can hear the diamond cutting on cast iron. it rings the plate. Recharge when it stops cutting. Beginners way over-charge. If using paste a worm 1/4' long is sufficient for a 3 x 12 plate.

Regarding the carry over of particles, are you saying that some particles will embed in the iron, tool, whatever you are sharpening and get transfered to the next plate YES, in spite of every removal technique I could imagine trying.

What I was thinking was using a coarse grit on one jointer bed and a finishing grit on the other... I HAVE come to the conclusion that it is not practical to use a coarse followed by a fine loose diamond abrasive due to carry over of particles. It would be practical on cheap throw-away acrylic, but the acrylic works great with coarse particles and not as well as cast iron with the 1 micron, backwards from what would be desirable. I suspect a quick grind on fixed abrasive, eg 3M sheets, will remove embedded diamond so this approach might be useful in some cases.

My latest technique is to power hollow grind the bevel on wheel. It takes a bit of technique to get a perfect straight grind on 2 3/8" of plane iron so for beginners an intermediate step is handy. Intermediate step until you get good with step 1: Get the bevel straight by stroking a few laps on sandpaper on glass, 15 or 30 micron 3M film abrasive. Finish with 1 micron diamond on cast iron. Learn to free hand these steps or the whole operation is tooooo slow to be practical.

Diamond cuts boggling fast (80 grit wheel to 1 micron BAM) and it is vastly cheaper than any alternative. You can grind the hollow grind out from a 7"- 80 grit wheel with 1 micron on cast iron and it won't take long to do it!! These advantages keep me experimenting on how to best take advantage of these attributes. I doubt that I have reached an optimum so I encourage others to keep experimenting and report success and failure.

Thanks,

Re: Thanks, Bill. Good info.

Luke Herzberg

>

Re: answers

John in Ks

>Bill,

Thanks for the detailed information. Have you ever experimented with a slow speed horizontal wheel with a acrylic or MDF platten charged with diamond paste? I wonder if this would speed the process even quicker. I have seen where some have made platters for the Makita slow speed horizontal grinder with quite a bit of success. It would be similar to the Veritas MKII.

Thanks,

John

Vast overkill

bill tindall

>If the bevel is straight it takes about 10 strokes to turn an 80 grit grinder edge into a 1 micron sharper- than- a- razor edge, and that is on highly abrasion resistant CPM 3V.

Re: answers *LINK*

john in KS

>Bill,

Do you think this plate would work sufficiently with diamond paste?

Thanks,

john


Hartville lapping plate

It seems to be steel, not cast iron

bill tindall

>When I talked to someone at a diaomnd fabricating company I asked about using steel plates. They said they didn't work very well. I have not made a comparison. I will try to find some steel and try it and report. It could work for 1 micron but I'll bet it is will be poor for larger sizes.

silicon carbide is a near useless material. It crushes quickly to doodle dust.

Thanks Bill, I will keep looking!

John in Ks

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