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Post by Jugglerguy on Jul 31, 2013 20:59:50 GMT -5
Ok, I finally got out to my saw again. My niece is getting married this weekend, so I have a sister from Tennesseee staying at my house for a few days. My wife is a neat freak, so yesterday was a lot of cleaning stuff in the basement where my sister is staying in the spare bedroom. We have to go up to Mackinaw for the weekend, so I don't think I'm going to get much saw time. The girls were all at the shower this evening, so I got a couple hours to my self. So things went a little better, but I still have a problem. I made another wire for the table, so it's straight now. I got the fence/depth gauge out of the way, I think that helped a lot. I tried the pencil test before I started and found that the blade is not parallel with the vice. The front is a little less than 1/16 of an inch to the right of the center. On the smaller rock, there was no problem, but when I cut a larger rock, as it got toward the middle of the blade, it slowed down, and on my last rock it jammed again. The paint is wearing off the blade more in toward the center on the left side and more toward the outside of the blade on the right side. In fact, I wonder if the paint coming off and jamming in the saw kerf was part of the problem. Either way, the blade is not straight. I did manage to get a few slabs: I'm don't know how to straighten the blade. This is the outside of the shaft: On the inside, there are some set screws on the shaft, but I didn't take a picture. My wife, daughter and sister are back, so I can't right now. The rod that the vice rides on is not adjustable. Any ideas?
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Post by deb193redux on Jul 31, 2013 21:06:12 GMT -5
I would take a rock with a flat bottom and slide it onto the blade by hand. you can periodically back up a little and there should be no resistance. if you can cut by hand without binding then the vise/blade alignment is not a problem 1/16" should be OK with a .032 blade because they can bend that much.
I am worried that the blade bent or dished a little when it slid on that 1st petosky stone.
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Jul 31, 2013 23:10:00 GMT -5
>My wife, daughter and sister are back, so I can't right now.
For some reason that line cracked me up Rob. I don't think rock cutting is so bad, but been there myself.
I agree that 1/8" offset across the length of the blade is not a lot with your fairly thin blade, but certainly is much better if you can get it more true. Did you check to see if the blade is dished or bent? Use your pencil setup on the outer front edge of blade and slowly turn blade by hand and see if the gap varies a lot. I don't see any easy way to adjust the carriage guide rod either, but maybe someone with your saw has a trick to suggest.
Those slabs you got are really nice looking! That petoski is terrific.
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robsrockshop
has rocks in the head
Member since August 2012
Posts: 715
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Post by robsrockshop on Aug 1, 2013 7:06:25 GMT -5
What size motor is on the saw? It should be 1/3hp 1725rpm. If it's 1/4 it might not be strong enough, or even a weak 1/3hp could stall. Did you by chance time the slabs you were cutting to see how fast they were cutting?
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Post by Jugglerguy on Aug 1, 2013 7:37:06 GMT -5
The motor is a 1/3 HP 1725 rpm blower motor from a furnace (I think). I got it used from a furnace repairman. The pulley on the saw is 3" and on the motor it's 2.5", so I'm running the saw faster, but losing a little power. It still doesn't seem like the rock should bind up as it's progressing through the saw though. I didn't time the slabs, but I had it cutting very slowly. I was going for an inch every five minutes. I started them by moving the rock into the blade very slowly so the blade wouldn't deflect. The rocks would start out faster and get progressively slower. I think that's partially from there being more friction due to the increasing area of the rock contacting the blade as it moved through, but mostly because it was rubbing against the blade on the left side.
Mark, I just did the pencil test while rotating the blade. I rotated the blade by hand pulling the belt, so my hand wouldn't bend the blade as I turned. I tried it at the outer edge and about in the the middle of the blade. In both cases, there is a section of blade that seems very slightly bent. There was about a 40 degree wedge of blade that moved 1/16" or less.
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Post by deb193redux on Aug 1, 2013 8:42:35 GMT -5
a runnout of 1/16 inch should not be bad enough to cause complete stall.
with 2.5" motor and 3" saw you are actually running the blade a little slower, and gaining power. I am still suspicious of a blower motor because they are not intended for much load. Having capacitor start and capacitor run might be overkill but it would eliminate the motor.
when it does stall, is the motor stopped or is just the blade stopped?
I still think you can learn a lot by doing one by hand. the flat bottom is important because any roll could cause binding too.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Aug 1, 2013 11:02:41 GMT -5
Hey Rob! I hope you don't mind...
I am learning from Obi Wan Daniel, Jedi master of the force (and rock saws too). This is a great thread!
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robsrockshop
has rocks in the head
Member since August 2012
Posts: 715
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Post by robsrockshop on Aug 2, 2013 6:57:35 GMT -5
Try dressing the blade. I know it's new but I had some larger blades of that style that were new and I had a couple bad go rounds the first couple times as it was some more or less experimental reverse drop saw thing. After that it started stalling. After I dressed it the blade started cutting again. If you don't have a dressing stick you can use an old grinding wheel or a red brick. Don't cut all the way thru it maybe a 1/3rd or so then try it.
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Post by Jugglerguy on Aug 2, 2013 8:37:11 GMT -5
Hey everyone, I really appreciate all the help. I'm going out of town for the weekend and won't be back until Monday. I just wanted you to know I'm not ignoring all this great advice, but I don't think I can get back to my saw until at least Monday.
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Post by Rockoonz on Aug 2, 2013 11:24:55 GMT -5
The FranTom I built... The thing I noticed when slabbing with mine is the vice assembly would try to swing up over the slope of the blade if I tried to force a cut, causing it to bind up. Lee
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grizman
freely admits to licking rocks
Member since July 2011
Posts: 878
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Post by grizman on Aug 2, 2013 13:54:08 GMT -5
I am not an engineer, or even much of a rockhound, so take this not as fact, but just a "maybe". In looking at the feed & clamp unit, it looks like it has the capacity to bind on the saw blade edge because there is only ONE solid shaft on the left side for the feed unit to move along? It may cause the binding on a relatively thin blade when it makes contact. It also looks like maybe? it could use some lube on the shaft and on the insides of the guides of the feed unit?
Again, just a "guess" to add to the other's professional opinions. Don't kick me out of the club just for being a "dummy"! ; > )
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robsrockshop
has rocks in the head
Member since August 2012
Posts: 715
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Post by robsrockshop on Aug 3, 2013 8:08:43 GMT -5
Grizman.....if the holes in the vise were worn out and sloppy it's possible it would bind. Lube couldn't hurt. Some models have replaceable nylon bushings I think these are just metal on metal and it's probably ok. Your one shaft idea makes sense but that's why the gravity feed cord is attached to the side of the vise that has the shaft and that keeps it from binding it wouldn't work if it were on the opposite side.
Covington puts a washer somehow underneath the table connected to the vise that keeps the vise from riding up the blade of course the saw isn't perfect in many other ways.
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Post by Jugglerguy on Aug 13, 2013 19:26:37 GMT -5
Yesterday I finally got out to play with my saw again. I've had company or been out of town for over a week. I took the bolts out that hold the arbor assembly and shimmed it out a little. That seemed to fix the problem and I managed to cut some rocks. After several hours of cutting, the last couple slabs took forever. I ended up pushing the vice the last little bit by hand. Adding weight didn't seem to work. It wasn't binding like before, but wasn't moving either. I noticed some black gunk starting to build up on the rock. I thought maybe my water was just too dirty, so I cleaned the whole saw and tried again, but it was still slow. I think I'm going to go buy a brick and cut it. Here's the nice stuff I cut:
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Post by Drummond Island Rocks on Aug 13, 2013 20:31:24 GMT -5
cool! you had some success. Nice looking slabs. I really like the unakite and it cabs up pretty nice too. It sure sounds like you need to dress the blade but those are all really soft materials so I wouldn't expect that yet. I don't have any experience with the type of blade you are using though.
Chuck
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