lakeandco
off to a rocking start
Member since July 2010
Posts: 10
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Post by lakeandco on Aug 16, 2010 19:54:00 GMT -5
Hi everyone! My name is DJ, 'lakeandco' is my company's name. This is my first post but I have been checking in and getting inspiration on this site for quite a while. If anyone is interested, I'm trying my hardest to make a big 24" slab saw. Hopefully you can get some information/inspiration out of my current project as others' projects have done for me. This person's project in particular really helped in the design stage: forum.rocktumblinghobby.com/index.cgi?board=hmequip&action=display&thread=35160There are things to keep in mind though when you triple the blade diameter, as I have found out. Before you get turned off by lots of text, Here she is. Very much 'under construction' but at least you get the idea of what I'm going for. Also, don't use those scissors by the blade as a size comparison. They are actually foot or so long shears!  For my business I was getting fed up with only having my tiny trim saw and decided it was time for a slab saw. I looked at the large prices of large slab saws and figured I could do a similar job for a fraction of the price. Being macho and gung-ho about it I bought the biggest blade I could afford: 24". I made a big sturdy frame out of 4x4's and tried mounting the blade with pillow block bearings and a threaded rod arbor. Problem 1: the faces of the nuts that went on my 3/4" threaded rod (let's be mature here) are not perfectly perpendicular to the axis of rotation. Meaning that threaded rod won't work for the arbor of a big blade. If you have access to a machine shop, you could turn out an arbor to run in pillow blocks quite easily I imagine. I ended up ordering a Covington arbor, all said it came to about $230 with freight/tax etc. Pricy but worth it. I'm starting to digress here but what I've found with this project is that when dealing with such a large and powerful machine, it doesn't pay to take shortcuts or allow a little wobble here and some play there. All those little imperfections catch up to one very quickly and at best may compromise the saw's ability to cut nice slabs and at worst injure you. Back to the saw. Here again from the back. The threaded rod coming out the back is to hold a counterweight or springs so that I can adjust the cutting pressure.  Detail of the saw arm hinge.  Closer look at the soon-to-be vise. The vise seems like it's almost a separate project from the saw. Maybe sometime I'll make a crossfeed vise for it to make cutting slabs just ever so fun and easy!  Here's that arbor I was talking about. 'Covington ar15r' I believe.  This past weekend I got most of it put together. I ran into trouble though when I was testing the motor. For some reason I thought (but not very hard) that a 1/3HP motor I had kicking around would be powerful enough. It overheats on start up. I can get it running but it gets realllllllly toasty. So now I'm trying to get my hands on a used 1-1.5hp motor. Here's a word of wisdom, before you start building a saw, determine what motor will be needed to drive it. Then get that motor before you start and design it into your plans .. with a bigger slab saw you may just find that you are getting into 220V and Three-phase motor land. At 1.5HP I'll be really pushing it to use a 20 amp/115V household outlet. Live and learn eh? Also, for cooling I plan to use water and lots of it.. I've got a parts washer pump wired into the switch and i'll hose the blade from both sides. Does anyone know if there is a technical reason why oil cools better than water. It seems to me that LOTS of water will achieve the same goal. Opinions? More to come when I get that motor, hopefully this week. Stay tuned! |
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Post by Roller on Aug 16, 2010 23:27:41 GMT -5
staying tuned !!!! Thanks for the pics .... Are you a lefty ?
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Post by Woodyrock on Aug 17, 2010 1:00:08 GMT -5
DJ:
I believe that most lapidary blades over ten inch diameter are designed to use oil as a lubricant/flushing medium. The guys cutting jade in the bush with water are using granite cutting blades that are designed to use water. You could very quickly kill a 24" lapidary blade using water. John Wease (Johns Gems) will know more about the technicalities.
Woody
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drjo
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Honduran Opal & DIY Nut
Member since May 2008
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Post by drjo on Aug 17, 2010 9:20:08 GMT -5
A) Welcome!!!!
B) NICE job!!!!!!!!!!!!!
C) Oil transfers heat better, plus gives needed lubrication
D) You need large flange washers on each side of the blades for stability, and to lessen the chance of warpage
E) What speed are you going to be cutting at? (400-1000 rpm's?)
F) You can use a bucket and sand for a variable counter weight but it could get messy.
G) Did I mention "NICE job!!!"
Keep it comin',
Dr Joe
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Post by Jack, lapidaryrough on Aug 17, 2010 10:16:46 GMT -5
don`t think RPM ,,,,,,,Think Surface feet per minute ...... SPPM......
All diamond blades cut best between 4200 - 5200, Depending on the type our year of blade.
Old Condo`s, 3800 - 4400..
MK-297-303,,,,,, 4200 - 4800 all Dia.
Saber 1000`s...... 4200 - 5400 SFPM
MK-Blades .com has a chart for the table of speeds to use.
I see great DANGER in your project.......Be Careful..
A drop saw in the 24" inch range thin blade. are designed to cut at 6 - 8 minutes to the inch of travel. only in a auto feed lapidary saw.
The saw blades used on old concrete saws are best to use as a drop saw. their much thicker. start with a blade thickness about .125 inch. our thicker.
And use 6" Collars / Flanges on both sides of blade...
Jack ... in Oregon
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Aug 17, 2010 11:00:28 GMT -5
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Post by Jack, lapidaryrough on Aug 17, 2010 16:09:24 GMT -5
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Post by kap on Aug 17, 2010 18:24:40 GMT -5
Good looking saw!!! One other thing make sure you get a sealed motor not a open one like you are showing now. Keep us posted.
Keith
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lakeandco
off to a rocking start
Member since July 2010
Posts: 10
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Post by lakeandco on Aug 17, 2010 21:04:51 GMT -5
Thanks for the input everyone. It is much appreciated!
Roller:
I'm not a lefty but I did put the blade to that side on purpose. I figure that if I need to hold the swing-arm I can do it with my right hand and that way I'm as far away from the action as possible!
Woodyrock:
Thanks for the info... and I'd love to learn more about the specifics of jade mining
I was inspired today to not be cheap and track down a bunch of oil for the saw. After talking about baby oil to some very skeptical and slightly dull people at Walmart I tried some veterinary hospitals and had some confusing (I guess they were not very interested in rock saws) chats about horse laxative bulk pricing. Mineral oil seems to be about $10-12 per litre in my area. Our 'Rockhound Shop' carries some cheaper Esso cutting oil for 5.95/litre but they only have 20 litres left and don't plan to stock it anymore.
I decided to get to the bottom of this so I eventually got a hold of the number for the Imperial oil, Esso 'technical guys'. I got a super knowledgeable man with a deep southern accent; pretty much exactly what one might expect when calling Imperial Oil. He pontificated at length on the various merits and qualities of their water soluble cutting lubricants. We debated the difference between 'neat' oil and water soluble oil on heat dispersion and lubricity.
This apparently is what my lunch hours are coming to.
In short, I'm kind of sold on a product called mobilcut 102, which I'm assured will match any traditional oil. Anyone used it?
Dr Joe:
Thanks for the encouragement!
1.I had planned to run the saw at 700rpm so thats around 4700 sfpm which seems to be in range...we'll see if it works well.
2.I agree I would like to put some big flanges on it...Everyone I've called about that has had no idea where I would find flanges to fit. I know Covington makes some for $30 each, but it's a pain getting those into Canada. The only other option is to get some milled. Am I missing a simpler idea?
3.For the counterweight my current thinking is a pair of springs to take the bulk of the load, and a sand-bucket to make it variable...sounds as if it will work right?
4. Thanks for the reference links to the calculators and charts..I hadn't seen a couple of those-most helpful!
Jack:
Thanks so much for the specifics. I'm pretty handy when it comes to home-built stuff and basic mechanics, but I'm not an expert with lapidary abrasive cutting. Sometimes I don't know what I don't know (e.g. the travel per minute, that was helpful). It seems to me that if i can keep that blade tracking true and stable enough and keep the correct pressure on the cut, it comes to the same thing as a carriage based saw...am I wrong?
Also, I appreciate the caution, because I'm well aware of the potential danger in this project. There is a lot of power and inertia in a small space and I'm trying to do everything I can to make it safe (it doesn't look that way from the photos I know haha.) Do you have any horror stories of blades getting stuck or breaking etc. that I would do well to hear before i continue? (or any absolute no-nos that are not simply common sense?)
Kap:
Thanks, I'll keep that in mind on my quest for new-to-me motor!
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Post by Hard Rock Cafe on Aug 18, 2010 9:26:34 GMT -5
Hi DJ,
Nice work so far! Your design has kind of a funky Arts and Crafts style, which is cool.
You're absolutely right to try to eliminate any play, because it will show up on cuts.
I would start on that cross feed sooner, rather than later, because I would want consistent thickness in the slabs. Of course, you might want to make a trial cut or two just to make sure the saw works before you invest a lot of time in the cross feed.
You probably don't need as much lubricant flowing over the blade as you think. On a carriage saw, only a quarter inch of the blade needs to be in the lubricant. On the other hand, the carriage saw has the advantage of a large sump to help dissipate the heat from the oil. If your flow rate is too high you're going to be throwing lubricant all over. You won't have to do anything to fancy to contain the oil---my 18" carriage saw uses a pair of V-shaped troughs in an L configuration; one leg across the top and one down the back. You may not need the back, unless the saw dips into a sump. You will need something a the front.
I would guess you're planning on a trough to go under the rock to catch the lubricant?
If the threaded rod isn't working for you on the rear "axle", you could go with a regular shaft and locking collars. The advantage of your threaded rod is that you can really lock the arm in tight.
Getting the balance right on the arm is going to require some effort. I'd be tempted to forgo springs in favor of weights on both ends because springs are not linear in their force. You'll want to start your cuts very slowly so as not to dish the blade, as Jack said. With a gravity feed, you'll be able to fine tune the pressure on the blade. Perhaps buckets with sandbags in them? You could add or remove bags as needed.
As for motor, 1.5 hp would be overkill. My 18" saw uses 1/3 hp, which I intend to replace. It does fine, but it could use a little more power. I don't know that you need a 3 phase circuit; a single phase 220v motor would be best because it would be more efficient than equivalent HP at 110v. Capacitor start and run are not necessary. You're not going to be jumping into a cut at the start, so you'll have time for the motor to get up to speed. I think capacitor run might in fact be a liability if the blade starts to bog. I'd rather have the motor take the heat than warp the blade.
Nothing ahead of you is insurmountable and it may take a couple of attempts before you come upon a solution. There will be a lot of people here to encourage you and bounce around ideas.
That's all I can think of for now! Looking forward to the updates!
Chuck
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Post by Jack, lapidaryrough on Aug 18, 2010 10:45:03 GMT -5
about the motors,
My Saws. 24" Fran & Tom 1959 model, stock 3/4 Hp. / 24" Highland-Park, 3/4 Hp. / 18" Lortone 1/2 Hp.
two 16" Highland-parks, both have 1/2 Hp. Motors. The only thing in my shop with a 1/3 hp . my Cab units.
27" Laps Viba-lap / an highland-park. both are 1/3 Hp. motors.
As said use sealed motors !!!. I use Farm duty motors. with cooling fans.
24" blade should have a 3/4" inch arbor min. our 1".
the Flanges need to be Hollow Back cut. the last 1/4 of radius is the pressure point to clap blade on arbor.
jack
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Post by Rockoonz on Aug 18, 2010 22:58:47 GMT -5
Use "neat" oil. Aqueous cutting fluids are formulated specifically for machining metals and are not suitable for cutting rocks with diamond blades.
Lee
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Post by Jack, lapidaryrough on Aug 19, 2010 8:48:54 GMT -5
Tread oil has to high of content of Sulfur in it.
Chevron Shingle oil has a flash point of 351 -F degrees
55 gallon drum runs about $370.00 a barrel now guessing....
in 2004 55 gallon drum was $197.62
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Post by johnjsgems on Aug 20, 2010 14:34:38 GMT -5
Oil cools better than water or water soluble and removes the chance of rusting blades, ruined bearings, corrosion of parts, etc. I would use a pump system to feed oil to the blade from a 5-10 gallon sump. Blade washers need to be 1/6 the blade diameter and as mentioned hollowed. Covington ships internationally. Key points of cutting oils are low viscosity and high flash points. Stay clear of any vegetable based oils. Mineral or food grade mineral oil (synthetic) are the best. With a "hands on" saw odorless would be a plus also.
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lakeandco
off to a rocking start
Member since July 2010
Posts: 10
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Post by lakeandco on Aug 21, 2010 23:06:46 GMT -5
I've been hard at work the past few days. I drove a looong way (halfway up Vancouver Island) to get the motor and cutting oil. I did however get a great deal and a nice drive.  This is the new motor, installed in a half-@ss manner for now until I can get a really long belt and use the motor as a counterweight. Yes I could have probably used 3/4 HP like you guys suggested, but instead I got 1.5HP just to give it a little headroom...and holy mother it pulls. Nice motor actually. It's sealed and thermally protected.  This is the Soluble Cutting oil I got.  I know, I know, use neat oil everyone says. Well I'm willing to give this a gamble. I'm banking on my tech man at Imperial Oil. Apparently this mobilcut 102 has the same viscosity and density as mineral oil (when mixed at spec), super high lubricity, and BETTER heat dispersion than neat oil. It will be interesting to see whether that is the case. Well I wired in the motor and pump to a switch box, and voila...it sprays and spins!  I was concerned about wobble in the arm, so with some rusty t-bar a file and a hacksaw, oh and A LOT of patience I made a guide track to guide the swing arm. Not very elegant but it works. The chrome square tubing you can see there has a locking slider on it that allows the swing arm to rest at any height and lock at the bottom of the cut.  I also used some more of that rusty t-bar (which i unrusted with a wire brush sandpaper and lots of time) to make a crossfeed vise platform. yay! I think it might even work when all is said and done.  last one, from the front  The photos are really amateurish today, but i just finished and it's 9 o'clock and dark outside, hence the flash. |
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drjo
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Honduran Opal & DIY Nut
Member since May 2008
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Post by drjo on Aug 22, 2010 4:53:17 GMT -5
Most excellent work! You've put great thought into this project and it shows!!!! I like the swing arm guide and lock, very interesting creation. (what are you going to do with the rest of the projector screen?  ). And the handle is great too, anyone could have used a piece of pipe but this keeps it in perspective better. Is there a side cover for the blade guide or does this keep oil spray contained? Nice motor, are you running it at @120v or 220v? Again Great job and thanks for sharing.. keep the updates coming, Dr Joe . |
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Post by Hard Rock Cafe on Aug 22, 2010 8:09:53 GMT -5
I agree, it's really looking good!
Nice work!
Flanges next?
Chuck
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lakeandco
off to a rocking start
Member since July 2010
Posts: 10
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Post by lakeandco on Aug 23, 2010 0:46:56 GMT -5
I spent all day getting the saw ready to run. Honestly I've been going so hard (and long hours) on this that I can't wait for Monday so I can take a break by going to work haha. I tried it out and found that the spray was ridiculous. The lubricant just vapourised all around the saw without a guard, as might be expected. 20 minutes of cleaning oily scum off the walls/floor/surroundings later... So you'll all excuse the getting out of duct tape and garbage bags to deal with the overspray  Click on the image to go to some video of the action! It's about as exciting as rock cutting could be ;D  Dr Joe, you were bang on about the slide projector screen...i found it at our local recycling depot like many of the other parts on this baby. As for flanges...I would like to put a couple, but I'm not certain that it needs them and the arbor is not made to fit flanges. If I find that the blade is wearing unevenly or tracking poorly, maybe i'll get some made. Seems fine on the 4"x5" test piece... I was no doubt pushing the blade too hard...but it isn't destroying the blade. There is still paint in some places on the cutting edge. (and that is the first time i've used the words cutting edge literally...ha!) By the way, how loud are normal slab saws of this size?...this seems to make quite a racket. |
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Post by Hard Rock Cafe on Aug 23, 2010 13:46:27 GMT -5
Congrats on making the first cuts!
Not only creative use of a slide projector screen (Joe beat me to it), but a caulking gun, too!
From what I could tell from your video, that level of sound is about right.
Chuck
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
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Post by drjo on Aug 23, 2010 16:51:34 GMT -5
Rube would be proud!!  I'd say you need more fresh air circulation in the shop....but then you might not come up with these great ideas!! Dr Joe . |
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