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Post by Mel on Apr 17, 2023 18:54:56 GMT -5
So today has not rocked, in any manner.
Saw is running, yeah! Let's cut some rocks! Nope!
Saw is binding and pulling, even when cutting some geodes I had set in plaster. First I thought it's gotta be the blade, but then happened to give the vice a nudge. Not good. Vice has a fair bit of diagonal play in it; sort of makes a rocking motion if you put pressure on the top right & bottom left corners of the platform. I tried googling for other people having similar issues and didn't find much which surprised me. To add insult to injury, yesterday I found a brand new MK303 blade in my shop. Yeah, turns out it fits a 14" drop saw, which makes sense because I didn't buy the blade but I did buy a 14" saw last summer and it came with that (I am not a smart woman!).
Now I have two issues:
1) What's the best blade for a 16" saw, 5/8" arbor that can handle hard material? The saw was running the original gold Covington notched blade. Would it be worth even bothering with a continuous rim blade? I'm mostly cutting agates & petrified wood, losing material is not really of any concern to me.
2) How does one go about correcting the play in the vice platform? Can I beef up the feed rod, or should I just suck it up and replace the whole thing?
EDIT: Updated the title for more clarity!
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Post by chris1956 on Apr 17, 2023 19:09:40 GMT -5
I have a Series 1100 Covington saw which sounds about what you might have. So far I haven't had a "play" issue with the vice. But I did have the saw bind in a rock once. Turned out that the set screw on the arbor pulley had come loose and the belt was just spinning with the blade not moving. I would suggest calling Covington. I have quite a few times and they seem very willing to help. It might take you a call or two to get them to return your call if you don't get them right away. I think the person I have talked with the most is Brian but you can ask the person that answers the phone to give you to the technical person that knows about saws.
I have been thinking about getting a new blade and wondering the same question. I think there are some threads somewhere about different blades. I need to search for them but may not get to it for the next couple weeks.
Good luck.
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Post by Mel on Apr 17, 2023 21:27:24 GMT -5
Thanks for the reply! Calling them is definitely in my plans; their service is always great! Mine is the combo trim/slab saw but a bit older; no viewing window in the hood (bummer). From what I can tell, it looks like the vice deck is cast of aluminum and just wearing out due to friction against the steel feed. I'll check the set screw as well. I put a new motor in the saw last winter and if I have to buy a vice & a blade...  |
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Post by Rockoonz on Apr 17, 2023 23:26:15 GMT -5
If it tips it sounds like whatever serves as a crossfeed guide is sloppy. If you can post pics it would help, never had a covington slab saw other than a 10" trim/slab that will be totally different. I am not a fan of their rail design, so I have stayed away, but it should be fairly easy to at least figure out.
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Post by Peruano on Apr 18, 2023 5:59:00 GMT -5
I'd still vote for the blade being you issue. All the Covington problems I've seen hinged on the combination of the finicky adjustable clutch for the feed screw and in conjunction a blade that was sufficiently worn to cause the feed to be faster than the cut, which caused the clutch to act up. If you have that special Covington clutch check it, and then think about trying to resurrect or replace the blade. A bit of vice give should not be lethal unless your feed is too fast or your blade is too dull. It seems to me that a bit of pressure on the work will move the vice to its "desired" position and it should stay there unless the whole shibang meets resistance (slow cut/too fast feed/clutch surging). There are many factors affecting slab saw performance and you have to carefully evaluate them before seeking expensive unproven fixes (new vice or bearings or blades). Try cutting something soft - same issues? Try clutch adjustment?
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Post by Rockoonz on Apr 18, 2023 10:54:39 GMT -5
I'd still vote for the blade being you issue. All the Covington problems I've seen hinged on the combination of the finicky adjustable clutch for the feed screw and in conjunction a blade that was sufficiently worn to cause the feed to be faster than the cut, which caused the clutch to act up. If you have that special Covington clutch check it, and then think about trying to resurrect or replace the blade. A bit of vice give should not be lethal unless your feed is too fast or your blade is too dull. It seems to me that a bit of pressure on the work will move the vice to its "desired" position and it should stay there unless the whole shibang meets resistance (slow cut/too fast feed/clutch surging). There are many factors affecting slab saw performance and you have to carefully evaluate them before seeking expensive unproven fixes (new vice or bearings or blades). Try cutting something soft - same issues? Try clutch adjustment? Do they have the clutches on the cabinet style saws? I thought it was just the trim/slab saws, but again I have never owned or worked on one, it's the only larger brand of saw I have no experience with. The 10" I recently bought and sold seemed pretty straightforward but it was so like new that I didn't do much with it. All the other Covington equipment I have had seemed well made, but the photos of the large saws and the unique (you neek away from it) carrige slide arrangement has kept me distant. |
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Post by Mel on Apr 18, 2023 11:03:39 GMT -5
I'd still vote for the blade being you issue. All the Covington problems I've seen hinged on the combination of the finicky adjustable clutch for the feed screw and in conjunction a blade that was sufficiently worn to cause the feed to be faster than the cut, which caused the clutch to act up. If you have that special Covington clutch check it, and then think about trying to resurrect or replace the blade. A bit of vice give should not be lethal unless your feed is too fast or your blade is too dull. It seems to me that a bit of pressure on the work will move the vice to its "desired" position and it should stay there unless the whole shibang meets resistance (slow cut/too fast feed/clutch surging). There are many factors affecting slab saw performance and you have to carefully evaluate them before seeking expensive unproven fixes (new vice or bearings or blades). Try cutting something soft - same issues? Try clutch adjustment? All my attempts to photograph it turned out like crap. The vice slides easily, and I made sure the locking pliers are on securely. I have the shut-off screw set so that it disengages the motor about 1" from the end of the feed rail. I went back and played around on the vice a little bit, tightening where I could and it's a fair bit better but still has a few mm of diagonal movement if I push on it. I'm less concerned but still keeping an eye on it. As for blade, it seems like material hits the blade, kicks back a bit and the saw starts thumping. It became super noticeable when I was cutting into plaster (so not hard at all) that I had embedded with agates. There's maybe 1-2" of plaster matrix, then an agate about the size of 1/2 a small coconut. The blade cut about 1" into the plaster, just barely scratched the agate surface, and started thumping that I've never heard before. Blade is running straight, lots of coolant. This is why I think blade. As for blades, I only have this one saw running notched blades so my experience is basically nil. Found another blade in my shop I was thinking about trying but after a second look, I think it's ready for the trash. In comparison the gold Covington blade seems like it has more life in it since the notches are decent but the cutting experience says otherwise. Thoughts??   |
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Post by Rockoonz on Apr 18, 2023 11:04:11 GMT -5
Mel if you haven't already you could try this, I suggest removing blade first to prevent arbor bearing issues. Yeah, arbor bearings. Try pulling and pushing on the blade and arbor pulley to see if they move at all from sloppy bearings there. If they are loose even slightly it will cause the blade to shift sideways as pressure is applied to the rock in cutting. Usually they get real noisy before they get loose though.
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Post by Rockoonz on Apr 18, 2023 11:43:39 GMT -5
Well, now I remember how to screenshot and stuff, and I may even have input.  Large red circle to the right is lash adjustment. You can use it to eliminate side to side slop on crossfeed, I will turn the handle one way till it moves, then reverse direction and note how far I have to turn the handle before it moves the other way. It should be at least something, and up to about half a turn. I like 1/4 turn if it is fine thread like it seems to be, less if it's coarse. 2 smaller circled bits are what I call gibs, they adjust the slop on the guide rod. I hope there is also a guide rod in the back of the carriage, but the "design" (sic) causes me to think there is not, and a problem in my mind. If it looks sloppy there, which sounds like your "diagonal" description, those 2 screws can kinda sorta fix it a little. Again, the pic is a little grainy, but it looks like there's a lock nut behind the screws, if so do this to both of them one at a time. 1) put a good fitting wrench on the lock nut, and while holding the screw in place with a screwdriver turn the nut counterclockwise to loosen, make sure it's good and loose. 2) While still holding the wrench so the nut will stay loose, tighten the screw clockwise with the screwdriver and note how far it turns, make it snug but don't force it, then back it off counterclockwise either half the distance or 1/4 turn, whichever is less. 3) Hold screw with screwdriver and turn nut clockwise to tighten. It will lock it in place After that wiggle the vice again to see if it's better. If you were able to tighten it significantly it should be. The crossfeed rod may also have replacable bronze or brass bushings, not possible to tell in pics. If so it may also be time to replace them, but I would have to be there to be sure the process on that. The people at Covington are very knowledgeable as well, I have been on the phone with them, so they will have even more insight. |
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Post by Rockoonz on Apr 18, 2023 11:53:38 GMT -5
Your blades are crimped edge blades, the swaging/sharpening process may help a little but they don't perform as well as sintered, I never use them except on 4 or 6 inch saws and then only if I get them in an estate or something, I don't buy them anymore.
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Post by Mel on Apr 18, 2023 13:37:32 GMT -5
Rockoonz - Blade was running straight & strongly mounted, so don't think bearings are the issue. I realize when I say "binding" maybe I'm using the wrong word; it's like the vice platform gets up to the blade fine, but when the rock & blade touch, then it starts thumping. When I open up the lid nothing looks amiss, other than the uncut rock.
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Post by Mel on Apr 18, 2023 13:50:24 GMT -5
Your blades are crimped edge blades, the swaging/sharpening process may help a little but they don't perform as well as sintered, I never use them except on 4 or 6 inch saws and then only if I get them in an estate or something, I don't buy them anymore.Yeah , can you hurry up and buy my neighbors place so that I can pick your brain more?  You have been IMMENSELY helpful with all my saw questions (just about have that Beaconstar ready to reassemble too!), thank you. I did dress the Covington blade once but I don't think it really made much difference, was probably too late in the game. Was thinking about a continuous edge blade but also curious about the Agate Eater blades sold by Highland Park however the cost is not cheap once I add shipping/duty/punishment for being Canadian. What blade would you buy? What do you run in your largest saw? |
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Post by mohs on Apr 18, 2023 13:52:01 GMT -5
Sounds like they don't make diamonds as hard as they used. Ha. Good 😊
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Post by Peruano on Apr 18, 2023 14:32:10 GMT -5
What you are describing is a situation that occurs only when the blade contacts tough stuff. If the blade is shoved against something it does not want to cut, its bound to protest. Or if something is shoved against it at a wrong or moving angle its likely to protest too. You have to decide. The blade depicted in front of the other appears to have a flat contour (maybe a visual distortion?). If you can afford an Agate Eater, buy it. I have its analogue MK225 that has run on my 12" saw for several years cutting agates all day long. I also run 303's on my HP 14". I have an old 20"Covington but used a new covington with the trick slip clutch at our local senior center with much tooth gnashing.
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Post by oregon on Apr 18, 2023 18:39:06 GMT -5
This is the saw model I have. All my attempts to photograph it turned out like crap. The vice slides easily, and I made sure the locking pliers are on securely. I have the shut-off screw set so that it disengages the motor about 1" from the end of the feed rail. I went back and played around on the vice a little bit, tightening where I could and it's a fair bit better but still has a few mm of diagonal movement if I push on it. I'm less concerned but still keeping an eye on it. As for blade, it seems like material hits the blade, kicks back a bit and the saw starts thumping. It became super noticeable when I was cutting into plaster (so not hard at all) that I had embedded with agates. There's maybe 1-2" of plaster matrix, then an agate about the size of 1/2 a small coconut. The blade cut about 1" into the plaster, just barely scratched the agate surface, and started thumping that I've never heard before. Blade is running straight, lots of coolant. This is why I think blade.
What is the frequency of the 'thumping'? Should be either related to the blade turning, or the feed motor turning. If the blade is dull, vice binding etc, you'll get a sound from the autofeed mechanism skipping back a thread or two on most saws, they're designed for this. Sharp blades can hide a lot of alignment/wear problems but don't fix them.
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Post by victor1941 on Apr 18, 2023 20:54:40 GMT -5
I think excess pressure is causing the clips to skip and/or worn clips (The threads on the clips loose grove dimension and can't maintain normal pressure) that makes the thumping sound when they release. Excess wear on the glide rod holes will also allow the vise section to move out of perpendicular to the blade and cause extra pressure.
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Post by Rockoonz on Apr 19, 2023 1:47:03 GMT -5
Peruano Tom I believe she was asking about the HP agate eater, not the Barranca/MK version. Huge difference. Mel I moved away from where it snows only a little. I run BD/MK 301 or 303 blades, but recently got a 14" blade from Advanta Tools on Ebay that just might finally make it into the saw this week. I have bought their trim saw blades for awhile and they work good, and they are made in S Korea like BD/MK so possibly even in the same factory, other than label they are identical. Here's their listing from the US ebay site, you can possibly use the link to the seller to get the Canada info. I need to hurry up and get that blade into the 14, been running a 12" blade in it to test since I rebuilt it many months ago, have probably cut 50 lbs of slabs testing. There is a 16" saw not too far behind it so I will be blade shopping soon too. www.ebay.com/itm/121038698484?hash=item1c2e77f7f4:g:9m8AAOxygo9Q9LVIOh yeah, and I don't recommend the HP blade, at least not the one that arrives with uneven teeth that supposedly wear even.
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Post by Peruano on Apr 19, 2023 13:04:58 GMT -5
Let's test the thread jumping idea
Wedge a wine cork or something of the correct size in the handles of your feed pliers. You want to prevent them from flexing open when the vice sled hits resistance
. I have an older covington with slightly larger pliers but regularly lock the grip on the drive shaft with a cork wedged in the pliers. Weak spring or shallow threads. Query me if this is not clear
.Tom
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Post by stardiamond on Apr 21, 2023 22:02:45 GMT -5
I came up with a fix for my 16inch combo saw; I bought an HP14. I was waiting for it warm up before disassembling the Covington and setting up the HP.
Slab saws should require a training program like driver ed. I had no experience and no one to help so I'm sure I'm responsible for some of problems.
My biggest problem was the crossfeed drifting which produced uneven slabs and the blade binding, which resulted in rocks slipping in the vise. I tightened it so much that I broke it. I replaced the clip with a new one that was heavier duty and that helped the feed. The clutch system is a pain and a lot of problems that seem clutch related can be something else.
Their clutch idea is good that allows for faster cutting and their support is wonderful. I don't do a lot of slabbing and I don't care how long it takes. A person should be able to put a rock in the saw and go off and do something else. That wasn't my Covington.
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Post by Mel on Aug 21, 2023 23:28:01 GMT -5
Good thing my head is securely fastened to my neck these days.
After months of having no saw, I got fed up and made time today to actually go and figure it out. Double checked the blade, tightened up the vice and rails, tightened the arbor, dressed the blade. Seemed a bit slow but I figured I was just imagining things. So then I tried a rock, just to see if I still got the same behavior as back in April. Sure enough, the thumping noise didn't take long to show up (when cutting the dressing stick I got the actually terrible speed but no thumping). Turns out I was right and it was feeding slow. It also turns out that the arbor pulley set screw had come loose and the whole thing would drift over/run off kilter when trying to cut anything of any hardness. I used to have the saw set up on the right side of a shelving unit so didn't even think to look at the pulley despite everyone's incredibly valuable feedback.
So tomorrow I'm off to the hardware store once again and hopefully it'll be back in action. Thank you to everyone who weighed in, now I know what to watch for if the behavior ever returns and it's not the pulley or the vice.
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You have been IMMENSELY helpful with all my saw questions (just about have that Beaconstar ready to reassemble too!), thank you. I did dress the Covington blade once but I don't think it really made much difference, was probably too late in the game. 
