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Post by deb193redux on Feb 25, 2011 22:13:16 GMT -5
I don't know where they get the 1400.
1725 is fairly standard, and equal ize drive and driven pulleys is standard for 10" saws. The newer stainless steel sintered blades are actually rated for faster.
I would not run the motor 1/4 smaller than the blade, I would put the 2.5" on the motor and the 2.25" on the blade.
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Post by Jack, lapidaryrough on Feb 26, 2011 1:01:10 GMT -5
Dan B. Its all about surface per-minute Not RPM of Blade!. 3800 SFPM - 4800 SFPM.
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Post by Jack, lapidaryrough on Feb 26, 2011 2:22:54 GMT -5
Blade BD-301 BD-303 Series Recommended RPM Operating Range in Surface Feet Per Minute 3000 - 4500 4500 - 6000 Blade Diameter Approximate Arbor Shaft RPM Range 4" (102mm) 2860 - 4300 4300 - 5730 5" (127mm) 2290 - 3440 3440 - 4580 6" (152mm) 1910 - 2870 2870 - 3820 7" (178mm) 1640 - 2460 2460 - 3270 8" (203mm) 1430 - 2150 2150 - 2870 9" (229mm) 1270 - 1910 1910 - 2550 10" (254mm) 1150 - 1720 1720 - 2290 12" (305mm) 960 - 1430 1430 - 1910 14" (356mm) 820 - 1230 1230 - 1640 16" (406mm) 720 - 1070 1070 - 1430 18" (457mm) 640 - 960 960 - 1270 20" (508mm) 570 - 860 860 - 1150 24" (610mm) 480 - 720 720 - 960 30" (762mm) 380 - 570 570 - 760 36" (914mm) 320 - 480 480 - 640
Find the Ratio of the two pulleys and. figure out the sSFPM and the RPM well work out fine. as long as you follow the chart above. I Have used only Congo Blades, Star, MK-297, 301,303. And i have used this same chart for SFPM since the 60s. for old and new blades. though the new ones with the harder matrix bounding of the diamond in blades. i run in the SFPM, 4500 - 4800 SFPM. The old Gem - king blades & MK-297 run them at 3800 - 4200 SFPM. The chart above is for Lapidary Slab saw.
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charles kuchar
spending too much on rocks
getting ready for the second coming
Member since November 2010
Posts: 300
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Post by charles kuchar on Feb 26, 2011 16:38:12 GMT -5
hopefully i understand you correctly. this is my understanding. 10 inch mk-301 gem king blade 1150-1720 is the rpm of the blade 1720-2290 is the surface feet per minute that you get from the blade with the rpm in that range. the original drive pulley was 1.5", the new one is 2.25 inches, the blade pulley is 2.5". www.csgnetwork.com/pulleybeltcalc.htmlfrom the calculation, original rpm speed of the blade is .6 x 1725 or 1035 rpm new rpm speed of blade is .9 x 1725 or 1552.5. 2290 x .9 gives me 2061 sfpm? hope i did it correctly but if i need correction, it will be welcome. never to old to learn something new. charlie
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Post by parfive on Feb 26, 2011 21:11:30 GMT -5
Charles – Go to the actual Barranca web page to make a little more sense of the numbers. Even that chart isn’t labeled as clearly as it could be. The two columns are recommended rpm ranges for two types of Barranca blades. Those two types of blades have different recommended sfm of 3000-4500 and 4500-6000. Your 10” blade w/1725 motor and 2.25” > 2.5” pulleys calculates to 1552 rpm and 4064 surface feet per minute. So you're close enough for government work. Various other blade speed charts just serve to show it ain’t all that critical, as long as you’re in the ballpark: www.covington-engineering.com/information.htmhome.comcast.net/~eugenemineralclub/rocksaws.pdfRich
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Post by deb193redux on Feb 27, 2011 15:18:37 GMT -5
Dan B. Its all about surface per-minute Not RPM of Blade!. 3800 SFPM - 4800 SFPM. I am well aware of this Jack, but within a given size, RPM is a shorthand for SFPM, and I was responding to a posting about 1400 RPM. It is always good to respond in context. I stand by my point that the recommendations in many charts in lots of old lapidary books are based on the high-carbon crimped blades, and the "standard" 1725-1750 single phase motor. The newer high strength stainless steel core sintered blades are capable of faster speeds. generally. under-driving the blade, with the smaller pulley on the blade, is not going to help with rock creeping up the blade, because the blade will cut less/slower not more/faster. simple point. no need for all the confusing charts and the SFPM red herring.
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Post by Jack, lapidaryrough on Feb 27, 2011 19:22:27 GMT -5
THANKS DAN B.
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charles kuchar
spending too much on rocks
getting ready for the second coming
Member since November 2010
Posts: 300
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Post by charles kuchar on Feb 28, 2011 7:46:52 GMT -5
i do appreciate the information given here. i will try the saw hopefully this week. the motor is a 1/3 horse craftsman. seems to be in excellent shape but i don't know if it has the power to run the 10 inch blade. it did seem ok when it was running the blade at 1000 rpm but now it is 50% faster. will let you know how it goes... and i don't have a problem using oil instead of water. i will probably have to make a cover for it though. when i got the saw it looked like it was running oil in the past. charlie
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charles kuchar
spending too much on rocks
getting ready for the second coming
Member since November 2010
Posts: 300
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Post by charles kuchar on Apr 6, 2011 15:36:50 GMT -5
hooray, i am finally able to saw some rocks. last meeting of the rock club i joined a couple of guys were talking about their ten inch saws. they were saying they could cut through 3 square inchs of rock in about two minutes. i said my saw would take about half an hour, probably exagerating there but it had taken a long time. i said i had the mk-301 blade. they said thats the problem, i need a continous diamond blade to work well. they had ten inch blades from china for about $50. so yesterday i looked at a blade i got for 10 bucks surplus. it was a dewalt 4767 continuous diamond rim. 8 inch radius. put it on the saw and got a 1.75 pulley to put on the blade shaft as well. then put the original 2.75 pulley driven by the 2.5 pulley on the 1725 rpm motor. now i can switch between the blade pulleys and the smaller pulley gives me about 2500 rpm blade speed. the blade can turn up to 7600 rpm so i am not even close to the max speed and am going to try to get a bigger driver pulley for the motor someday. now i can cut about 2 square inches of rock in about 2 or 3 minutes, far faster than i was able to before. i am hand feeding the rock but it's not a problem. before it would take ten or fifteen minutes to cut through the same area. charlie.
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Post by Jack, lapidaryrough on Apr 6, 2011 17:00:17 GMT -5
Charles,
was their a brass rod under the vise?
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charles kuchar
spending too much on rocks
getting ready for the second coming
Member since November 2010
Posts: 300
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Post by charles kuchar on Apr 7, 2011 19:47:24 GMT -5
i couldn't find any place for a brass rod under or over the vice. just the half inch rod it slides on next to the edge of the top of the unit. the folks at the rock club said oil would be better and the best oil is parafin oil. that's what they use. charlie
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