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Post by Hard Rock Cafe on Jan 28, 2012 11:47:57 GMT -5
This summer I re-built my 18" saw so that I could seal some leaks in the sump. I have an old notched rim Felker blade with about 1/8" of notches left. I just fired up the saw again for the first time after re-building it.
Now, the blade is binding. I just finished swaging the blade and cutting through a coarse grinding wheel a couple of times. It seems to be cutting better, but it's still binding unless I have the feed set at barely moving.
I didn't change the carriage alignment and on the few cuts I've completed that doesn't seem to be an issue. There's a little bit of run-out on the blade, but I think that's been there as long as I've had it.
Is it time for a new blade, or do you think something else is going on?
Thanks for your help!
Chuck
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Post by Rockoonz on Jan 28, 2012 12:23:49 GMT -5
1/8 inch is a lot of diamond left. have you checked the blade/carriage alignment? If you had the arbor or feed rails loose to rebuild it you will need to re-align it. Is the carriage running smoothly, I have seen problems with carriages that have lots of wiggle when the feed and/or cross feed bushings get loose. Who is the saw manufacturer?
I use barely moving for everything. You should measure from the front of the vice to the front of the saw tub, then use a timer to time a cut, then re-measure to find out what slow is for your saw. It should be about 1 inch every 6-8 minutes. What are you cutting?
Lee
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Post by Hard Rock Cafe on Jan 28, 2012 12:48:03 GMT -5
Thanks, Lee.
It's a Great Western saw. The rails and arbor came out in one unit, so the only way to opportunity for misalignment is the carriage itself. The carriage is a little funky compared to, say, an HP. There is a very slight play in it that has always been there. I can try to tighten that up as it may be the source of the problem. Everything else is tight.
When I first started cutting this time around I was cutting Flint Ridge material. When it started binding, I switched to a piece of junk sedimentary chalcedony (forms in limestone) to see if I could figure out what was going on.
Yes, I normally cut at 5 minutes per inch. This is more like 10 minutes or more per inch. This saw has a hydraulic piston that adjusts the feed rate from the gravity feed. In the past, I would go very slow at the start of the cut then speed up through the middle, and slow down again at the end. Right now I'm cutting at the very slow speed all the way through and I'm still having trouble with bogging down and binding.
Thanks again! Chuck
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Post by jakesrocks on Jan 28, 2012 13:18:48 GMT -5
Flint Ridge flint is some of the hardest material that you'll be likely to cut. Try slowing your cutting speed down as slow as your saw will allow.
To correctly check for carriage alignment, you'll need a magnetic base dial indicator. Don
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Post by Rockoonz on Jan 28, 2012 15:36:39 GMT -5
I use a dial indicator attached to a block of wood so I can clamp it in the vice. You can also use feeler gauges. It is important to mark a point on the blade and check alignment only at that point so you're not thrown off by blade runout. Heres the process you can use. If you have never used feeler gauges get help. Clean the oil from a small area about an inch in from the edge of the blade and use double stick tape to firmly attach a 1" x 1" flat piece of sheetmetal or bar 1/16 to 1/8 thick. Round the end of a piece of steel bar, preferrably round and clamp it in the vice so it sticks out a couple inches toward the blade. Slide the carriage and turn the blade so the bar and the piece of steel on the blade line up at the front of the saw with the bar not touching, then turn the cross feed in till the end of the bar is about 1/8 inch from the steel piece, if you have it use a piece of 1/8 bar to slide in between till it is barely caught, if not use a stack of feeler gauges. If you can at this point lock down the crossfeed. Next turn the blade and slide the carriage so they line up at the rear of the saw, when sliding the carriage it's best to push or pull the bottom so you don't disturb the cross feed. At this point if you use the gauge you used at the front and it feels pretty much the same you're done, it's aligned. If not you need to start at whichever end has the smaller gap and re-set the blade angle. Pretty much every saw does this differently, if you can't use the instructions above and feel comfortable doing the alignment yourself you probably shouldn't try, get some help.
I am going to reset my 14 inch HP and check and possibly reset the new 24 inch FranTom, I will take pics and start a post whenever I get it done.
Lee
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Post by Hard Rock Cafe on Jan 28, 2012 20:02:59 GMT -5
Thanks, Don! This is my first time cutting Flint Ridge. The Brazilian agates I've cut have been pretty tough, too. I am using the slowest feed rate.
Good advice, Lee. I'm certain others will benefit from it, too.
I've solved the problem. It came down to a combination of the dull blade, the tough material, and my rebuild. My belt wasn't quite tight enough, so when the blade started getting resistance from the rock, the drive pulley started to slip. The dull blade just made it worse.
I changed the position of the motor so the belt is tighter (but not too tight), added a little belt dressing, and the saw is cutting like a champ. I wish I had swaged the blade long ago!
Thanks to you both for your help. It's people like you who make this board so great!
Chuck
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