bryan22
off to a rocking start
Member since April 2024
Posts: 12
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Post by bryan22 on Sept 8, 2024 10:47:26 GMT -5
I buy rough stones to tumble by mail, and they are all crushed from bigger pieces with many sharp corners. I have wanted a way to soften edges for tumbling. Not keen to buy a real flat lap, I built a homemade tool with a DC motor and an 80 grit Chinese diamond disk from Amazon.
It seems like my first piece of quartzite substantially consumed the diamond disk. I am wondering if the problem is expecting too much, going too fast, using a cheap $10 disk, or what. I have read that a flat lap disk might last a year. Mine felt sharp and was sparkly when new, it now feels smooth and a microscope shows flat faces worn on the grit.
Do you have any suggestions on how I might do better short of buying a $600 tool?
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bryan22
off to a rocking start
Member since April 2024
Posts: 12
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Post by bryan22 on Sept 8, 2024 11:25:42 GMT -5
Some images.   |
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Post by opalpyrexia on Sept 8, 2024 12:23:29 GMT -5
Were you applying a fair amount of pressure? Using less force and "letting the diamonds do the work" would help. If a stone has a sharp edges, initially working the edge longitudinally will help (rather than 90 degrees from the direction the diamonds are moving).
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Post by vegasjames on Sept 8, 2024 18:53:21 GMT -5
Are you using plenty of water to keep the laps cool?
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bryan22
off to a rocking start
Member since April 2024
Posts: 12
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Post by bryan22 on Sept 8, 2024 19:50:51 GMT -5
Thanks for the help.
I'm trying to figure out how to use the diamond disk as I go. I started with firm pressure, but I'm coming to the conclusion that it's not needed and that you can't "hurry" the diamonds.
I have a slow drip, about once a second, because my understanding is that the purpose is cooling, and as long as the disk does not get hot I'm okay. The disk stays cold.
I'm now thinking the worn material I see on my disk is the bonding agent (metal?), and the diamonds are undisturbed. Maybe I was fooled by how rough the bonding agent felt to my finger tips, and maybe the diamonds are still intact even though the disk seems smooth to the touch. I have run it for a couple of hours now and it's still cutting quartzite. When I accidentally touch the spinning disk it seems to do no damage.
I'm surprised that you can buy a disk with diamond grit for $10. Would I be well-served to pay more from Kingsley North?
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Post by pauls on Sept 13, 2024 18:05:39 GMT -5
Plated disks wear out very quickly doing this sort of thing, regardless of where you buy them.
For something that lasts a long time you need to buy sintered, they are expensive initially but last forever, a good investment in the long run.
Rather than taking the edges of first I always run the stones for a month or so to take the edges off and remove dirt and soft weathered bits. Whenever I have a bit of time I just grab a handful out of the tumbler, wash them and refine the edges, remove fractures and holes and put them back. After a while I start to get stones that are ready to move on, nicely rounded and no flaws, these get put to one side until I have enough for a run in the vibe.
An exception to this is saw nubs, they should get removed first as they stick around and are always obvious what they are. Leaving them results in odd misshapen rocks.
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bryan22
off to a rocking start
Member since April 2024
Posts: 12
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Post by bryan22 on Sept 14, 2024 13:37:46 GMT -5
Having no experience or instruction for use of a flat lap, I'm not doing too badly. One question I have is "How much water to use?" My understanding is that the purpose of the water is to keep the wheel cool, and if the wheel is not getting warm, I'm okay. Is that correct? Of course it also helps to remove the ground residue, but apart from that, is a modest drip that keeps the disk cool sufficient? My tool is working well to round off my split rock in preparation for tumbling. I posted files for anyone who might want to make their own copy of my homemade tool: www.thingiverse.com/thing:6765505 |
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Post by liveoak on Sept 15, 2024 6:21:04 GMT -5
That's pretty slick that it all fits into a 5 gallon bucket ! Looks like it's working great. Nice build !!
On my flat lap I've found a moderate drip works fine, enough to keep it all wet.
Too much & the rock skates.
Patty
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Post by pauls on Sept 15, 2024 21:27:50 GMT -5
Ooh no, the water does a lot more than just keeping the lap cool.
Keeps the diamonds on the lap from getting clogged with sludge
Keeps your lungs from getting clogged with sludge.
Keeps the rock cool, any heating of the rock and you will get cracking.
The point about lungs is the most important, you can get new rocks, getting new lungs is a bit more costly.
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Post by 1dave on Sept 16, 2024 13:01:34 GMT -5
Ooh no, the water does a lot more than just keeping the lap cool. Keeps the diamonds on the lap from getting clogged with sludge Keeps your lungs from getting clogged with sludge. Keeps the rock cool, any heating of the rock and you will get cracking. The point about lungs is the most important, you can get new rocks, getting new lungs is a bit more costly. Amen! Somehow, lungs seem important.  |
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mirkee
starting to spend too much on rocks
Started tumbling a couple of months ago but now have four tumblers. Very interested in the hobby.
Member since March 2024
Posts: 128
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Post by mirkee on Sept 17, 2024 2:23:47 GMT -5
If using a water drip, how do you keep the water out of the motor area?
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Post by pauls on Sept 19, 2024 22:56:48 GMT -5
If using a water drip, how do you keep the water out of the motor area? For me the motor on all my machines is the length of a V belt away from the wet area, nothing is direct drive. |
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lapidary1234
spending too much on rocks
"If you like rocks you can't be all bad!!" ~ old timer quote
Member since October 2021
Posts: 325
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Post by lapidary1234 on Sept 26, 2024 21:16:54 GMT -5
So I've been trying to calculate the lifespan of electroplated discs/wheels as well. In particular the "textured" variety that cut more aggressively. I have my suspicions that although textured wheels will cut more aggressively, they likely wear out faster as well. Time will tell on that question.
There are a few different variables that come into play such as hardness of the material being worked, pressure, etc, etc. That said electroplated products will cut faster the first 10-15% of their life, then settle down and cut consistently until they are down to their last 10-15% of life when they really slow down.
It is probably better to calculate lifespan in hours used rather than months/years. For instance i cab about 12-15 hours a week and im hoping to get at least a year out of my lap discs.
I can't comment on the cheapest Amazon products but I will say I've been extremely impressed by the laps I got from treasures Hong Kong (thk.hk). I went with the magnetic no hole laps and they cost i think $12.00 each.
I bought all the normal grits but I find that I really only use the 60,80, & 150 discs. As soon as I'm able I take the piece to my genie. If its really big ill try and finish it on the lap but I've also been throwing them in the vibe tumbler to finish!
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