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Post by DirtCleaner on Dec 21, 2014 9:56:12 GMT -5
I have been stewing an idea around about making a two bladed saw. The blade width would have to be adjustable. The feed table would be gravity feed for simplification and to avoid any binding. Has anybody produced one before? Would love to see some pics. I just photoshopped this together for a basic idea.
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Dec 21, 2014 10:18:28 GMT -5
If the idea is to cut two slabs at once, then I would think this arrangement would be a rock thrower. Because of the variation in rock, if the inside blade came through the base chunk first, the outside piece would no longer be held and perhaps "rocket".
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Post by DirtCleaner on Dec 21, 2014 10:24:26 GMT -5
What I am looking to do is make parallel cuts for one rock. So that it can then go into my sphere pre-form cutter. It works really well with parallel cuts. If they are a bit wonky then it doesn't work so good. (Nope, I was not running it dry. Just some maintenance and hadn't put the oil back in for the photo.
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Post by jakesrocks on Dec 21, 2014 11:46:25 GMT -5
First problem I see is the inside nut holding the outside blade. Being a right hand thread, it may tend to loosen while cutting. You'd be much better off using spacers of various thickness to set the space between blades. Tighten everything with the outside nut.
With that long of an arbor shaft, wouldn't you run the risk of the shaft flexing under load ?
If you could invent something to clamp the rock between the blades, it would for the most part eliminate chances of the saw trying to spit the rock out.
Where did you get your sphere preformer ? I need something like that.
Don
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gerard
starting to spend too much on rocks
Member since April 2011
Posts: 218
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Post by gerard on Dec 21, 2014 12:56:16 GMT -5
I use multiple blades on one arbor, BUT right next to each other - I stack old worn blades together and use them for rough grinding or to cut an exact width channel. I dont think two blades separated would work too much chance for things to get squirrely
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Post by catmandewe on Dec 21, 2014 13:38:12 GMT -5
I think it would work. You would probably have to redesign everything but I think it is possible and it should work fine as long as the center part stays clamped.
Tony
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Dec 21, 2014 15:05:24 GMT -5
Somewhere, perhaps on this forum (eBay?), I saw a picture of a rock saw with several blades for cutting slabs in mass. I think it was a drop saw. I remember thinking, no way could this work without a huge prep time. Maybe it was designed to only cut part way through.
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blackout5783
starting to spend too much on rocks
Member since November 2011
Posts: 248
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Post by blackout5783 on Dec 21, 2014 15:58:02 GMT -5
If you're taking brainstorming ideas, you could have a mirrored version of the "normal" left side blade/arbor on the right side. You'd have to figure out a way to drive the two blades at the same speed and have your vise in the center of the tank. I don't know if it would be better to "slave" it off of the other arbor or to have both directly driven off of one motor.
I've been wondering for a while if a ratchet strap would work as a vise (not just for this idea)? The rock would sit on a platform with no regular vise jaws. And have the strap crank down to hold it in spot. It would make grabbing those awkward rocks a whole lot easier. In your case, it would be able to secure the rock from the center and have both ends available for a cut.
Most of this is thinking out loud, so I don't guarantee that any might work at all!
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Post by Rockoonz on Dec 21, 2014 17:40:29 GMT -5
I remember seeing the multiple blade drop saw too. I think the best way to do it may be if the rock were cut flat on one side first then glued to a piece of wood at the end of the cut that would hopefully hold it all together at the end of the cut. Like your sphere cutter clamp, is it the sphere products unit from Rod?
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Post by DirtCleaner on Dec 22, 2014 9:52:15 GMT -5
I well remember the multi-blade saw. That was a rock eating machine. The Sphere indexer is from Rod at www.sphereproducts.com It does exactly what they show on their videos. The left hand nut would be crucial to keep it from coming apart. The photo was just a quick picture to show what I was trying to explain. But I would like it to be adjustable which creates an interesting circumstance trying to figure out a moveable spacer system. One would either have to partly remove the shaft for every width change or have spacers that could be put on over a shaft. Holding vibration down with that might be tricky. As my saw, and probably most are, the blade "hangs" off the far side of the shaft. Not the most stable way of doing things but it makes it easier to add the carriage. A shaft going all the way through would be sturdier. Thanks for the input everybody. I would like to see somebody else jump on this and have one up and running by the end of 2015.
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Post by Drummond Island Rocks on Dec 22, 2014 10:07:21 GMT -5
This is the gang saw I remember seeing. Never seen a two blade version for what your looking for. Chuck
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Dec 22, 2014 19:29:25 GMT -5
Hmmm... more than one way to skin a cat I see! How would you adjust the width? Back when I used cubes to make spheres I needed parallel cuts for the same reason. Even now I want 5" tall cores for my 5" bit. I clamp the rock in the with plenty hanging out, made the first cut, moved the vice over 5" (or whatever) and made the second cut. Two cuts may be just as fast as adjusting your second blade for width. I dunno. Does this mean one saw for the parallel cuts and one saw for the sphere pre-former jig?
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Post by DirtCleaner on Dec 23, 2014 0:23:19 GMT -5
Definitely a two saw system.
And it would have to be adjustable. That is where things get tricky. Also, the carriage would have to be completely above the blade shaft. (Well, below would work too if the rock were to go under the blade shaft.) So the blade size would end up being larger than a traditional saw to be able to handle cutting through a certain size rock. But if it worked it would be a neat tool to have in the shop.
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Post by Rockoonz on Dec 23, 2014 1:30:27 GMT -5
I assume you are looking for a fixed width cut to make the sphere preforms as symmetrical as possible. Here's what I would do... I would base it on a drop saw design, a saw like that needs to have the blades move and the rock held firmly. The arbor shaft would be threaded with a flat and one blade would be fixed and the other would be able to be moved up and down the shaft and locked in place on the principle of a variable speed pulley. The arbor would be on a wishbone like frame supported on both ends of the arbor shaft.
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Post by phil on Dec 23, 2014 15:16:35 GMT -5
You could do it fairly easily if you switched your thinking from round blade to drag chain or even metal toothed straight reciprocal blade set up like the commercial marble and etc manufacturers do.
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Post by Rockoonz on Dec 24, 2014 0:05:28 GMT -5
phil you're a genius Dual dragsaws or wire saws Or single wire with a rotary clamp that would cut a cylinder?
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Post by DirtCleaner on Dec 24, 2014 10:44:30 GMT -5
Maybe I am overthinking this. What I want is parallel cuts on a rock with adjustable width. The real problem is clamping a rock twice never really works. So how about a clamp that can turn 180 degrees? It could even be a clamp that grabs the rock and then itself is clamped in the factory clamp. Thoughts?
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Post by jakesrocks on Dec 24, 2014 11:15:46 GMT -5
Too bad you couldn't use one of those indexing tables, like they clamp to a milling machine.
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blackout5783
starting to spend too much on rocks
Member since November 2011
Posts: 248
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Post by blackout5783 on Dec 24, 2014 11:45:05 GMT -5
Too bad you couldn't use one of those indexing tables, like they clamp to a milling machine. I'm not familiar with milling machines, but is that like an x-y axis adjustment with two screw feeds? I was just thinking that a vise carriage with a crank that could turn the "table" would work as long as there was a way to keep the vise jaws (or other clamping method) out of the cutting path. A second crank for cross feed and you could cut just about any shape! Edit: Should have researched before posting. I was describing exactly what an indexing table is!
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Post by jakesrocks on Dec 24, 2014 12:34:07 GMT -5
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