zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Jul 26, 2016 1:21:55 GMT -5
I'd like to build a rock saw for cutting up small - large rocks. I'd like to make a 14" saw because I feel it would be a good size to cut up basically anything I might need to now and in the foreseeable future (good idea? Too small? Too big?).
What I'd like help with is figuring out which design to use.
I already bought a 1/2 HP motor, and will get a KBIC 120 or 125 controller to run it. The arbors and bearings I can figure out based on previous posts. And I'll be making the frame out of thick aluminum plate that will be tig welded together.
I realize this is quite a lot to ask for, but I'm hoping the great help I've seen people offer in other threads might help me out too! Thanks in advance!
Some Questions: How long does it usually take to cut through a piece of granite with a diamond blade? Minutes? Hours? If it takes a long time then I'd like to hear about what designs people have used to automatically cut the rock.
What kind of blade is good to use? I've seen extremely thin ones on ebay and also very robust thick ones you can buy from places like home depot. Which blade do you use and why?
For the long time members of this site, do you remember any threads that had impressive or good designs that you wouldn't mind linking to in order to give me some options and ideas? I'm particularly interested in the layout of the machine, what works well and what doesn't. I need to figure out what kind of structure to TIG weld together (where the blade goes relative to the water reservoir and where the motor would fit).
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Post by manofglass on Jul 26, 2016 13:20:24 GMT -5
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Post by manofglass on Jul 26, 2016 13:39:53 GMT -5
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Jul 26, 2016 18:03:35 GMT -5
A lot of information to look through. Thank you Walt. It will take me a little while to digest it all.
If anyone has more to add I'll gladly read through it and come back with questions for you!
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Jul 30, 2016 0:56:08 GMT -5
Hey Walt, I'm still looking through all those links you sent me (thank you!!!!!). I sketched out a rough plan of the saw I'd like to build (see below). What do you think? I'll be adding support struts all over and tig welding the thing together out of aluminum plate. I'm thinking 1/8" thick plate or maybe 1/4" aluminum would make it sturdy enough for the long haul. What kind of pump do you use for water (would an aquarium powerhead pump work)? What kind of pump for oil? I read in a one of the posts (that didn't really go into great detail), but do you just use mineral oil for cutting or is there some other kind of oil that is used? If I was going to make the saw body strong enough with large enough bearings and a strong enough axle for a 24" blade what size shaft would I need? A 1" diameter shaft, less? I think what I'll have to do is start off with a 14 inch blade, then at a future point upgrade to a 24 inch blade if I need it. It would be nice to design the saw so that it can be upgraded from a 14 inch blade to a 24 inch blade if I ever save up the hundreds of dollars it costs to buy that sized blade. Having a motor platform in the back allows me the option to upgrade the motor if the 1/2 HP turns out to be under powered. Since I already have the motor I think I'll give it a go and see how it works. I can always cut slowly. I noticed in several threads the people have their saw blade dipping down into the water that collects in the trough below the blade. Why is this? Is it necessary or just a fluke of their design? Since my motor runs at 1750 rpm, I think that means I need a 2:1 pulley ratio to cut down the speed into the range needed for the 14" blade. The smaller pulley goes onto the motor shaft right ? I'm trying to think how I want to design the slide part. I saw on another site that someone used a split nut and spring vice (not sure what the spring vice is for) to make their carriage. I was thinking that stuff sounds expensive so perhaps a teflon slider with a brace on the sides of the carriage to keep it clipped on to the rails would work. I would like to use an aluminum rail since it should be easier to tig weld that to the trough walls (I assume aluminum would work for a rail?). Some kind of auto feed system would be wonderful since it might take a lot of time to cut through hard rocks with an under powered motor. I was thinking of attaching a pulley system and just using a weight off the side of the trough to pull the carriage along into the saw? It would be pretty controllable, I could vary the weight load to adjust the speed of the cut and pressure on the blade. I think I remember seeing someone else mention this in one of the threads you posted above.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Jul 30, 2016 1:21:45 GMT -5
I think aluminum would prove way too soft for slide rails, wear rapidly. I may be all wet, assuming the blade will run clockwise in your side view, undercutting a rock [rock running against underside of blade] would cause a pulling action on the rock, maybe to the point of being somewhat uncontrollable.
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Post by johnjsgems on Jul 30, 2016 9:25:30 GMT -5
Is this a "chop saw" or sliding tray? Why would you want a speed control? 14" is nice size. BD power feed saws run 1" in 5 minutes to give you an idea on cutting speed. Hand feeding with good blade faster. You can use evap cooler pump in the reservoir or a separate submersible pump in tank or bucket below saw.
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Post by manofglass on Jul 30, 2016 11:12:35 GMT -5
Do you sell the oil pumps john
walt
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Jul 30, 2016 14:12:33 GMT -5
Good question john. I think I'm partially reinventing the wheel here which is why I made this thread to ask for advice before I start buying the rest of the components.
I saw some sliding tray saws which look pretty good, but they don't seem to allow for different depth of cuts, just straight through the rock, no way to take multiple passes at the rock cutting deeper each time.
I'm not sure which way is best, all through in 1 go, or multiple passes?
I'd love to make an auto feed system rather than a slide only. A member on another forum brought up a potential issue with the slider system that I originally envisioned - that it might not be stable enough and furthermore the gravity weighted part might not provide good enough force on the rock as the blade goes from thinner parts to thicker parts during the cut. What do you think?
Are the pumps aquarium pumps? Should I be using oil instead?
Quartz - so I should set up the blade to cut in the clockwise direction so the blade pushes the rock into the slide table. That makes sense.
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Post by Peruano on Jul 30, 2016 14:16:05 GMT -5
You can easily use swamp cooler pumps to pump oil to the blade. Any hardware store if you live in the arid west, but not the boiling west.
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Jul 30, 2016 16:21:39 GMT -5
Here is an update on what I'm thinking on the saw design. (also what is a swamp cooler?? Not sure if I've ever heard of that before, perhaps you can post a link? Thoughts on the saw bodyI think you are right, I just have to make a decision and not waffle back and forth between 14 and 24 inch blades, I'd love to have the option to cut through 1 foot of material, but I do not have the right sized motor for that. I'd also like to use a 14" blade if possible since they are not expensive to replace. So, I wonder if changing my design to something that looks like a table saw where the blade sticks up out of the table would be a better way to go. That way I'd still be able to cut only 6 inches deep at a time, but I could then rotate the rock and clamp it in position to cut through the other side, cutting 6 inches from the top, and 6 inches from the bottom of the rock. That way I'd be able to cut through a full 12 inches (maybe closer to 13") if I absolutely had to while still keeping everything cheap and not having to replace my motor or make any stability compromises. Something like this for the body of the saw. Then I could make a fancy vice that can hold the rock in place and then rotated around 180 degrees to cut the other side of the rock without taking the rock out of alignment with the blade. The more I think about this project them more I think I need to use steel instead of aluminum. Aluminum would be nice but I don't own a tig welder (I was going to get a shop down the road to weld aluminum for me) so after it is made I wouldn't be able to make repairs or adjustments with it. A steel frame would be much easier to make repairs and modifications as needed since a good friend of mine has a mig welder I can borrow any time. I'll just have to figure out how to paint it with something that won't wear away or rust. Powder coating would be great but I don't have a kiln big enough to do the whole piece in one go. I'll have a think about that minor issue later on. Carriage Ideas:I cannot embed these pictures for some reason so here are the links to them. The 4th picture shows the underside of the carriage where it attaches to the lead screw. What is the part called that locks onto the screw? It looks like a split nut but seems to rotate and clamp onto it instead. Looks like a very easy way to lock the carriage onto the screw. Might be worth building or casting this part. www.hplapidary.com/p/1355/highland-park-14-inch-slab-saw-model-ht14#This is a split nut design (3rd picture) that seems to the much the same thing. Also looks fairly easy to make. My question is, what happens when the carriage gets to the end of the lead screw? How does the motor know to stop forcing the carriage along and into the side of the box? Wouldn't the threads in the split nut get damaged when it touches the unthreaded part of the screw? www.hplapidary.com/p/965/highland-park-style-16-inch-slab-saw-model-16#They have a 14" saw for sale on this site www.hplapidary.com/p/1355/highland-park-14-inch-slab-saw-model-ht14 which says they use " -ARBOR SHAFT – Tool steel machined to 3/4 inch bearing diameter. 5/8 inch diameter for blade arbor." But on their 24" model they say " -ARBOR SHAFT – Cold rolled steel machined to 1-3/8 inch diameter. 1 inch diameter for diamond saw arbor." So for some reason they are using cold rolled steel instead on the larger blade but tool steel on the smaller one? I wonder, can't I just use cold rolled for the smaller blade or possibly even stainless steel? Trolley Design:You make good points. Scrap the slides and gravity feed, enter DC power feed plan. This picture shows a good example of what I think I'd like to do for a trolley. It has rollers (not sure what they are called?) and a diamond shaped rail (hollow steel square pipe?). www.hplapidary.com/p/965/highland-park-style-16-inch-slab-saw-model-16#This other design has a V shaped slider on the top of a round rail and rollers underneath (not sure why). But this might also work. www.hplapidary.com/p/1355/highland-park-14-inch-slab-saw-model-ht14#I found out that the designs where the blade dips into the liquid at the bottom are meant for oil cooled saws. The tip of the blade should dip into the oil by 1/4 to 3/8" and that action cools the blade and doesn't need a pump. It seems that this design is more centered around larger blades, not really 14" blades. So I suppose I'll not be using this design and will just go with an aquarium pump flushing the blade with water.
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Aug 1, 2016 22:04:21 GMT -5
Here are the most recent plans I have for the saw. I'll have to give the vice and swivels a bit more thought before buying the materials. Hopefully the exploded view makes sense. It is the first time I have made one. goo.gl/photos/zdp1ovVru3Ln48Bv9Hopefully this edit to the hyperlink makes the image full size and legible. If not click the above link and zoom in (also let me know if it doesn't embed right).
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Aug 21, 2016 0:44:05 GMT -5
I've done a ton more design since I posted this, I started buying the components and am looking forwards to starting the build in the next few months.
My question is: for the power feed motor, to get a feed rate of 0.125 inches per minute it seems I need a 2 RPM motor speed using a 16 TPI threaded rod.
Does anyone know what kind of torque the motor needs to generate to be adequate as a power feed mechanism?
Does anyone have any advice or info on power feed motors and what might be a good choice?
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Post by pauls on Aug 21, 2016 3:32:42 GMT -5
An oven rotisserie motor. They are generally a small shaded pole induction motor with a decent gearbox attached. Here's a link just to illustrate. www.motors-biz.com/item/790377/Heavy-Duty-Rotisserie-motor.htmlIt should be easily scroungeable if you know an electrician who replaces old domestic electric ovens. Newer ovens don't seem to come with rotisseries, not surprising really, a chicken cooked like that in your domestic oven made a hell of a greasy mess.
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inbtb
Cave Dweller
Member since May 2016
Posts: 351
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Post by inbtb on Aug 21, 2016 9:03:01 GMT -5
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Aug 24, 2016 22:01:11 GMT -5
Thanks for helping me narrow down the motor choice.
I'd like to see a picture (or several) of the way the gearbox motor is connected to the threaded rod. If anyone has a few photos of this connection (how is it done? Directly or via pulleys?) I'd really love to see it. It would help me out quite a bit. Thanks!
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Aug 24, 2016 22:35:44 GMT -5
Depending on your location, summer items will be on closeout soon (if not already). I'd look for a rotisserie kit for a gas grill. May find one for a really good price.
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Aug 30, 2016 10:03:00 GMT -5
Can someone post a photo of how the power feed shaft is connected to the motor that drives it?
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Post by Peruano on Aug 30, 2016 11:02:17 GMT -5
Hooking up a direct drive should be easy to envision if you have a motor slow enough or you can gear it down. Here's a homemade drive train for a slab saw involving an old gear box from an air craft and a second stage of unknown origin. The feed is driven by the same motor as the blade and hence if the latter stops or slows so should the former. Speed is adjusted by changing pulley sizes. In answer to an earlier question in case it is still floating. The feed rod has space with no threads so that if the vice sled reaches that point the feed essentially goes into neutral and does not continue advancing (if the auto shutoff was not engaged or adjusted). My auto shut off is nothing more than a chain attached to the sled that will pull a toggle switch to off if the chain is taut. I hope this helps. Covington has a complex clutch system in its feed system that ideally can be adjusted to slow the feed if it hits a tough rock, but I'm not a fan and it probably would be hard to duplicate at home. It basically involves a spring that pushes a heavy washer against the other half of the drive shaft, much like a motorcycle clutch or primitive automatic transmission.
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zapins
starting to spend too much on rocks
Member since March 2016
Posts: 116
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Post by zapins on Sept 7, 2016 17:26:20 GMT -5
Getting much closer to finalizing my design now.
I am curious. I see some factory made saws use rather large axles, for a 24" saw one company used a 1 & 3/8" thick axle to run the 24" blade with a 1 inch bore. Is this enormously thick axle necessary? Would a 1 inch thick axle work instead or would it bend and wobble over time?
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