Explain to me why precision stones

[Paul Alciatore]

That looks like a pretty good collection. My stone draw has about 1/5 that many. So far I have tried to keep them in the original containers but that is getting a bit unwieldy.

One thing that I learned about abrasives while making a telescope mirror was the dangers of a stray particle of grit finding it's way into a finer grade. When making mirrors, that one particle can ruin many hours of work. You may say that is not as much of a concern with stones as opposed to loose abrasive, but it can still happen.

I am thinking about clear plastic tubes for the ones with smaller cross sections. That would provide a lot of protection against banging together and also isolation against abrasive wandering from one grade to the next.

I too have used the ultrasonic to clean stones. It works great with just a few drops of Dawn dish detergent. And they do not fall apart.

Speaking of stones.. A year or more ago I wanted to send my stone collection through my ultrasonic cleaner, they were pretty nasty and I like clean tools.

I was afraid I would come back the next day and there would just be a mud pile in the bottom of the cleaner. There was not.. I said I was gonna share the results and dont remember if I did.. I found these just sitting in a corner of the garage all cleaned up and no where to go.

How do you store a bunch of stones like this? I suspect they shouldn't rub together like files?

Anyway, the U/S cleaner works JR

[J Tiers]

For any of the rougher and more routine flattening tasks, I suggest you make a couple of "burr files" to do those. They are easily made, easily touched up, and can handle rougher jobs easily.

One coarse, and one finer, plus possibly a half-round or other shape to get into corners.

[Peter.]

I made a burr file to remove the myriad of dings in the bed of my Denford lathe, after being advised about them. It did work fantastically well. I wouldn't use it when scraping though.

[J Tiers]

........................... I wouldn't use it when scraping though.

Why not? If properly made they will not damage the surface any more than the (much harder) ground stone will.

I do. They work very well, and are a LOT better IMO than the usual india stone that is widely recommended in the literature. The stone loads up fast, and does not effectively remove everything, unless you work harder at it. And, the traditional stone has cutting particles that actually will remove material from a perfectly flat surface.

The burr file glides over the surface when it has removed all of what you need to remove, which normally does not require much effort.

It's good to actually use the india stone from time to time, as the grinding action is beneficial. Especially as a final finisher. At that point it won't take off anything important, but it will finish the job of flattening any serrations on top of the high spots. If not removed, those will wear down fast in any case, and require adjustments.

You probably could also use a "precision" ground stone. (I surely hate that word "precision".... it is overused to the point of becoming like "billet".)

[JRouche]

I am thinking about clear plastic tubes for the ones with smaller cross sections. That would provide a lot of protection against banging together and also isolation against abrasive wandering from one grade to the next.

Excellent idea, I hadent thought to use those. Keeps them from bouncing off ea. other and keeps the cross contamination down. Im going tube hunting today. Thanks.

I wounder if they come in "Billet Plastic" JR

[JRouche]

Why not? If properly made they will not damage the surface any more than the (much harder) ground stone will.

You probably could also use a "precision" ground stone. (I surely hate that word "precision".... it is overused to the point of becoming like "billet".)

I am assuming you are talking about rotary burr files? If so Im out. I am Lousy with those things.. I have some good ones too. I have tried the 1/4" size all the way down to the dentist size. I just cant control them very well and end up Not doing what I wanted. I think its my inability to "free hand" much of anything.. And yes, I have practiced for 25+ years now, same results. Five slivers all over the place, god forbid Im doing stainless (those slivers suck!). Now if I could CNC the burr I might do ok, no, probably not, just as bad.

Ill get a billet file next time
Yeah, the whole precision thing probably stems from the marketers trying to one-up man the next tool marketer. Cause I do think some tools fall under the precision umbrella, I might have one around here. Certainly not a stone though.. JR

[Peter.]

Why not? If properly made they will not damage the surface any more than the (much harder) ground stone will.

Just personal preference. I don't find that my stones damage the scraping surface. I'm scraping a cast iron square right now and the finish is coming out very nice.

[J Tiers]

The flattened stones don't do any damage. But they have a little less smoothing action than india stones, and the usage is a bit rough for the flattened stones.

[Mark Rand]

I use a 'burr file'* to knock the burrs off when scraping. I also use a relatively soft 'india' stone towards the later stages in order to broaden the points.

*An Oregon brand (actually Vallorbe) single cut, smooth, file that has had the edges taken off with the surface grinder.

[Mcgyver]

I use a burr file as well, but its not going to help much on a hardened part

[mtraven]

someone mind clarifying what a burr file is? when I search, all I get is rotary burs and that doesn't sound like what ya'll are talking about?

[J Tiers]

A standard flat file that you have modified by grinding the tips off the teeth. Same idea as the stones, it has no effect on a flat surface, but cuts off any burrs and dings that stick up.

Good for much rougher work than the stones would be suitable for, but if not used for rough stuff are also suitable for cleaning up after a scraping pass, before wiping clean and spotting.

Most folks make them from broken sections of file, as they are handier that way, after the sharp broken edges and side teeth have been ground smooth..

[Peter.]

This is about as good as I can do in terms of scraping. Scraped with a Biax and using a flat SC stone to de-burr. I'm very happy with it. I ran my repeat-o-meter along the face and it showed less than 1um. Probably less than half actually.



I took it outside to get a good close-up of the scraping.



I don't find that the stone does any kind of damage, it would surely show up in this photo if it did.

[Mark Rand]

What radius tip are you going down to on the Biax?

[Peter.]

I dunno Mark I gave my radius gauge away. Probably 60mm or so I should say.