Fritz
noticing nice landscape pebbles
Member since May 2016
Posts: 77
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Post by Fritz on May 5, 2016 14:54:10 GMT -5
I've been reading the forums here for a while and finally made an account. Been field collecting local bits and pieces for a few seasons and recently stumbled across an 8" saw for a pretty good price. I want to make a few changes but it seems to be decent. No play in the bearings. I think it's an old Lortone. Took a close up pic of the edge of the blade and am looking for opinions as to it's condition. It's not very straight either which is a bummer. I read about straightening blades in a sticky post but I'm not much of a smithy. From what's left of the label I think it's a MK-301. Here are a couple pics.   |
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Post by woodman on May 6, 2016 9:36:37 GMT -5
With some dressing up, the blade may cut like a champ. One of my 18" blades has some wobble in it but still cuts good. It is what you all straight. How much does the blade wobble when it is mounted on the arbor?
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Post by johnjsgems on May 6, 2016 10:10:54 GMT -5
One of the original notched rim 301 blades. It will cut pretty much to bottom of the notches. They were mild steel cores to allow the blade notching so did warp and bend pretty easily. Make sure when you install blade you don't over tighten. Just snug enough to prevent slipping. If blade was severely over heated it would lose tension and really wobble. Try cutting and see if it works. 8" blades are fairly inexpensive.
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Fritz
noticing nice landscape pebbles
Member since May 2016
Posts: 77
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Post by Fritz on May 6, 2016 11:57:02 GMT -5
Cool, thanks. It isn't a drastic wobble but it's noticeable when I spin it by hand. I haven't actually cut with it yet, adding a grounded plug and GFCI tomorrow and then I'll be giving it a thorough testing. The nut holding the blade on was pretty rusted (rest of saw is not rusted) which leads to my next question. The seller said they used water with a little borax. I'm going to be cutting mostly agate and jasper and am wondering if I should be using oil instead?
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Post by woodman on May 6, 2016 12:15:47 GMT -5
Cool, thanks. It isn't a drastic wobble but it's noticeable when I spin it by hand. I haven't actually cut with it yet, adding a grounded plug and GFCI tomorrow and then I'll be giving it a thorough testing. The nut holding the blade on was pretty rusted (rest of saw is not rusted) which leads to my next question. The seller said they used water with a little borax. I'm going to be cutting mostly agate and jasper and am wondering if I should be using oil instead? I would use mineral oil, that is what I use in my 10 and 18 inch saws. |
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Fritz
noticing nice landscape pebbles
Member since May 2016
Posts: 77
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Post by Fritz on May 8, 2016 18:03:00 GMT -5
I have another question about calculating blade speed. First I used this calc to get the arbor RPM and came up with roughly 875: vintagemachinery.org/math/arborrpm.aspxI then used this surface feet per minute calculator: www.mkdiamond.com/tile/tec_cal.htmlMy question: for the MK calc, is the diameter field the blade diameter, and RPM field is arbor RPM? I came up with roughly 875 arbor RPM and 1832 Surface Feet per Minute. If I did that right it seems a little slow according to the chart (link below). If it is slow the easiest way to change is via pulley size right? I'm kind of learning on the fly here. www.barrancadiamond.com/home/tec_speed.htmlquick rundown: motor rpm: 1725 (plate is gone, had a friend look at it who thinks 1725) motor pulley: 2" arbor pulley: 4" blade diameter: 8" |
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Post by Drummond Island Rocks on May 8, 2016 20:02:29 GMT -5
I have another question about calculating blade speed. First I used this calc to get the arbor RPM and came up with roughly 875: vintagemachinery.org/math/arborrpm.aspxI then used this surface feet per minute calculator: www.mkdiamond.com/tile/tec_cal.htmlMy question: for the MK calc, is the diameter field the blade diameter, and RPM field is arbor RPM? I came up with roughly 875 arbor RPM and 1832 Surface Feet per Minute. If I did that right it seems a little slow according to the chart (link below). If it is slow the easiest way to change is via pulley size right? I'm kind of learning on the fly here. www.barrancadiamond.com/home/tec_speed.htmlquick rundown: motor rpm: 1725 (plate is gone, had a friend look at it who thinks 1725) motor pulley: 2" arbor pulley: 4" blade diameter: 8" I have two 8" saws and both were purchased with the same size pulley on the motor and arbor so the arbor is spinning at 1725 on both saws. I have not seen any issues. The newer style blades like the 301 and 303 can run faster then some of the old school blades. Chuck |
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Post by johnjsgems on May 9, 2016 13:33:20 GMT -5
Your arbor speed is 862.5 so I would speed it up myself. 1:1 would probably work well. If you change to new style 301 or 303C you can bump up a little more. If you can find adjustable motor pulley you can fine tune as you wish but I don't know how easy they are to find. We used them on every drive motor when I was in commercial HVACR trade.
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Fritz
noticing nice landscape pebbles
Member since May 2016
Posts: 77
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Post by Fritz on May 9, 2016 16:44:24 GMT -5
Much thanks to ya'll. Would it be better to increase the motor pulley size or decrease the arbor pulley size? Currently 2" and 4", respectively.
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Post by Rockoonz on May 9, 2016 23:22:49 GMT -5
Bigger is almost always better with pulleys as long as it fits in the belt guard or whatever else might interfere.
1725 RPM is about 3600 SFPM, which is about right.
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Post by johnjsgems on May 10, 2016 10:33:17 GMT -5
Doesn't matter really which you replace. 2" arbor pulley may cost a little less as may the shorter belt if you have to replace.
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Fritz
noticing nice landscape pebbles
Member since May 2016
Posts: 77
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Post by Fritz on May 10, 2016 16:41:41 GMT -5
I finally used the saw. It sounded bad when cutting so I stopped. Almost like a hammering or bouncing sound when I would feed it some agate, even when held down tight. Chattering or skipping against the blade might be a better description. It cut a small piece of petrified wood well but the sound was bad. The arbor looks good when I take off the nut and blade and put a straight edge against it and spin by hand. Really hoping the crazy sound is the blade wobbling and not something else. Either way it's looking like I need a new blade just for testing. ---> EDIT <--- Here is a short video I made if anyone wants to hear for themselves. Once it starts to cut deeper into the piece the chattering blends into the rest of the noise on cam but in person you can still hear it, really stands out. The small slab is shaking even though I'm pressing down hard and only gently pushing forward. Has anyone experienced this before? |
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