jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 20:40:04 GMT -5
This is the way to go. If the brazed diamond will handle coring and sphere making, it will laugh at a tumbling application.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 3, 2014 20:40:43 GMT -5
yeah, standard flux, but powdered so it can be "poured" into the tubing thru a tiny funnel.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 20:42:35 GMT -5
thicker might be a bit better as you need some brass to hold the diamonds. I actually added powdered brass too and then felt it was too much. Thicker walled tube may need more heat, but will braze at the same temp as any other brass. Just need a bigger flame. I am sure you have plenty of torch to make this happen. Yep. I can get the brass. $2/pound. Can melt it to make sure it behaves, before adding diamonds. there are many brass alloys though. That may be a concern.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 20:43:41 GMT -5
yeah, standard flux, but powdered so it can be "poured" into the tubing thru a tiny funnel. Ah, I did not catch the 'powdered' detail. I got it.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 20:44:38 GMT -5
Yea, this is trippin me out.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 3, 2014 20:45:44 GMT -5
yeah, dry flux.
alloy unimportant at this level. If what if you get is slightly harder/softer, so what?
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 20:46:42 GMT -5
Have a feeling that bowl will shred some rocks in a hurry.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 20:48:02 GMT -5
Brass is always pretty tough and dense. I see your point.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 20:56:01 GMT -5
THANK YOU SCOTT
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 3, 2014 21:18:54 GMT -5
Yea, this is trippin me out. You are welcome. So, what was trippin' you out?
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 23:10:50 GMT -5
Yea, this is trippin me out. You are welcome. So, what was trippin' you out? If a long lasting diamond coating can be applied affordably some headway can be made on a grit less rouging tumbler. It is worth a try.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 3, 2014 23:27:55 GMT -5
Imagine the marketplace for a "grit free" rough tumbler.
Diamond is cheap, and getting cheaper. Two years ago it was $150/kg now it looks to be closer to $100 and those prices include shipping from the superabrasives factory in China.
I just saw $20 kilogram plus freight.
Unfortunately, the technology for the cheap diamond coating is patented. A lawyer will be required to determine if self made is allowable. This because the product patented is not for sale. Only the product produced from the tech.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 3, 2014 23:39:00 GMT -5
Food for thought.
How tall is the brazed bead going to be? 1/8"?
Use 1/8" x 1/2" x 1" segments soldered in spiral spokes in your 'critical' area. Have the segment matrix for "hard material" and call out 16 mesh diamonds. Definitely a marketable method.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 3, 2014 23:59:34 GMT -5
There were some 5 X 10 X 40mm for a smaller saw. But 30 grit was smallest. If this works I will do segments. I ordered 40 grams of 20 grit diamonds and the flux. And will give the braze a go. Not sure how much coverage 40 grams will do. Guessing a good bit of surface.
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 3,786
|
Post by gemfeller on Dec 4, 2014 0:14:18 GMT -5
Interesting ideas being tossed around here by all. But keep in mind that diamond monocrystals have perfect cleavage parallel to their octahederal faces. They must remain sharp to cut fast but being hammered against hard materials promotes cleavage and can make them lose cutting efficiency pretty fast. I imagine bort and Carbonado are more expensive than man-made diamond and slightly softer but they don't have cleavage planes. Neither does polycrystalline synthetic diamond which might be the best choice. The polycrystalline form has equal physical properties in all directions, providing greater resistance to cleaving and greater strength. It's widely used in industrial drill bits.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 4, 2014 7:51:18 GMT -5
Interesting ideas being tossed around here by all. But keep in mind that diamond monocrystals have perfect cleavage parallel to their octahederal faces. They must remain sharp to cut fast but being hammered against hard materials promotes cleavage and can make them lose cutting efficiency pretty fast. I imagine bort and Carbonado are more expensive than man-made diamond and slightly softer but they don't have cleavage planes. Neither does polycrystalline synthetic diamond which might be the best choice. The polycrystalline form has equal physical properties in all directions, providing greater resistance to cleaving and greater strength. It's widely used in industrial drill bits. Was researching these diamonds last night Rick. These diamonds are more involved than I first thought. They have different ratings for some of the very things you mentioned. it is hard to imagine a mineral like this holding up to impact. They certainly hold up to heat, pressure and friction. But impact force, hmmm. and it takes a good bit of force to get them to cut deep enough to remove material. I was looking at coating the areas on the tumbler where the most scrubbing occurs, which is starting at the center being maximum, and decreasing radially outward from that point, of the walls of the barrel. And that is with a standard tumbler barrel 3/4 full of rocks. So this tall, narrow barrel with lots of wall surface area. Being 3/4 full, perhaps impact will not be such an issue on the side wall, but the scrubbing can do it's work on the rocks without impact. With the help of the weight of the tall rock column of a 20 inch barrel. The samples I bought on Ebay are 20 grit. The bigger diamonds cost more. And I would guess they are more susceptible to impact damage. And what bought the subject up of their quality ratings was the mention of 'light to medium duty' in the Ebay ad. Looking at ads on Aliexpress, ratings for saw blade diamonds were rather involved. And the quality ratings climbed over my mind. Another involved subject. My thoughts were if they can grind a sphere, they may survive and serve well on the low impact area of the center area of the walls of a rotary tumbler barrel. But impact may be an issue there too. And having tumbled a batch of saw blade diamond segments in a rotary with agate I am suspicious of fractured/missing diamonds in the sintering. But not qualified to make the judgement. It had no effect on the agate, as there was not enough relative movement/scrubbing. Or/and the diamonds were ruined Was thinking about running a load of agate in the Viking with the 70 saw blade diamond segments. The vibe famous for breaking down abrasive, and for some reason being gentle on the rocks being abraded. Which is still an enigma to me....but that is what the vibe does. Guessing that it will shatter the diamonds.... May try anyway. But your input is a reality check. Valuable to know. Nothing is as simple as it seems LOL. In this case, a tall crushing rotary tumbler was the main goal. The diamond issue is secondary, but sure intriguing. Perhaps the bowl set more horizontal and spinning faster would be a sort of 'bowl lapper tumbler' arrangement with good rock mixing but little impact, may be an approach. I do have some little 12 inch diameter bowls that the diamonds may be used on for such. A mini test. Maybe set the little bowl at 30 degrees or so, and spin it fast to create lots of relative movement on a slowly rolling/mixing batch of rocks in the bowl. Again, thanks for the reality check on the diamonds. You have saved me a lot of time and trouble. I will do tests on a smaller rig for sure.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 4, 2014 12:56:26 GMT -5
#1) Somehow diamond segments get around the issue of cleavage.
#2) This application is not one in which there is "impact" so much as "sliding over"
#3) the diamonds are supported by the matrix they are held in
#4) #3 is why "in matrix" give a smoother finish than loose grit of the same size. Only some of the diamond is exposed for cutting.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 4, 2014 13:26:28 GMT -5
#1) Somehow diamond segments get around the issue of cleavage. #2) This application is not one in which there is "impact" so much as "sliding over" #3) the diamonds are supported by the matrix they are held in #4) #3 is why "in matrix" give a smoother finish than loose grit of the same size. Only some of the diamond is exposed for cutting. That diamond cup wheel takes some serious abuse. Diamonds seem fine. Slow to wear. It is spinning fast, and I put some pressure on it. #4 Makes good sense. #2 also makes sense. My diamond segments that got tumbled may not have the matrix even exposed yet. Hard to say. The diamond cups cut slow initially, after the matrix is worn a bit it grinds much faster.Exposing the diamonds...
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
|
Post by jamesp on Dec 4, 2014 18:35:39 GMT -5
Under powered, 1/4 HP is getting hot without rocks. probably a 1/2 HP needed. May have worked if all reduction was done at the motor and worm gearbox input, still pushing it.
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 3,786
|
Post by gemfeller on Dec 4, 2014 20:26:32 GMT -5
#1) Somehow diamond segments get around the issue of cleavage. #2) This application is not one in which there is "impact" so much as "sliding over" #3) the diamonds are supported by the matrix they are held in #4) #3 is why "in matrix" give a smoother finish than loose grit of the same size. Only some of the diamond is exposed for cutting. #1) Not exactly. If the diamond segments are similar to sintered diamond wheels, new sharp diamond is exposed as the metal wears to compensate for cleavage damage and other wear on the initial layer of diamonds. #2) Agreed, although impact won't be totally avoided if I understand the design. #3) True, depending on what you mean by "matrix." The metal on plated diamond grinding wheels would be considered "matrix" but any cabber knows plated wheels only cut like demons for a short while. When the sharp diamond crystals are degraded by cleavage loss their efficiency slows abruptly. They still cut but much more slowly. Dressing may help temporarily but the diamond layer is thin. That's why I've invested in sintered wheels which, as mentioned in #1 above, constantly expose new diamond. #4) While I agree it's recommended to order sintered grinding wheels one grit size larger (coarser) compared to plated or brazed wheels to achieve the same "scratch pattern," I'm not entirely sure why that is. Logic tells me sintered diamonds are not worn away at the same rate, so as new sharp diamond is exposed there are still plenty of worn diamonds in use. And if being suspended in a matrix is the cause, why do diamonds of the same grit in a plated "matrix" cut less aggressively? Maybe it's the density or hardness of the metal?
|
|