Larry
spending too much on rocks
Member since June 2008
Posts: 267
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Post by Larry on Aug 7, 2010 15:34:51 GMT -5
Well, I think I'm finally done with one of my saws and it's time to ask for help. A year or so ago, I bought a 10" Covington saw, brand new. I used it for a while and was a happy camper. For some reason, the blade had an incident and ended up with a big chunk of the rim (maybe 1/2") folded over to the side. John (jsgems) was kind enough to help me out with a replacement blade, which shows his top-notch service, as we all know. Basically, my enjoyment with this saw died along with the blade. First off, they put the table top screws in a place where only people with teeny-tiny hands can screw them back in, but that's just a terrible design. So I put the new blade on and used it, after a short time it wobbled. Removed and resecured and tried again and after a short time it wobbled. (*I did clean the areas where the blade attached in case something was stuck in there*) After about 5-10 times of that, I stopped and it's been sitting about a year. Sooo... today I get it all out and ready again. Took off the top, secured the blade and got ready to go. Auto-fed one rock and it was good. Slowly hand fed something and it wobbled after about 30 seconds. At this point, I hate the fact that I even bought this saw. Unfortunately, hating it doesn't get the rocks cut so I need to get it working. Does anybody have any ideas what the problem could be? I appreciate any help I can get from you more experienced slabbers. Thanks a bunch in advance for any ideas and thanks for at least making it this far in the post
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Post by bobby1 on Aug 7, 2010 15:46:33 GMT -5
Maybe the saw oil isn't deep enough and as you are cutting the blade dries out and starts overheating. That will cause the blade to wobble after you have it running for a short while. Bob
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Larry
spending too much on rocks
Member since June 2008
Posts: 267
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Post by Larry on Aug 7, 2010 22:27:13 GMT -5
Thanks Bob. I will double-check, though it seems there's enough. It does seem to be running hot though. Thank you.
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Post by snowdog on Aug 8, 2010 19:30:08 GMT -5
Hi Larry you don't say what type/hardness rock you were cutting ? was it the same as the one that you auto-fed ? ---- sounds like you may have been hand feeding it too hard and the blade over heated --if it was an agate then that's prob the cause -- remember the autofeed is usually spring loaded and will jump the threads if too much pressure is there ( until it cuts enough to move forward) -- when hand feeding it is hard to wait for it to cut ( "it's only a little rock , why should it take so long ? ) and not put too much pressure on it--remember, let the blade do the cutting -- only enough pressure for the rock to be against the blade -- if I'm hand feeding , alot of times I will push a little then back off , then push again -- this gives the blade enough time to cool and clean out the chips without over heating -- hope this helps
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Larry
spending too much on rocks
Member since June 2008
Posts: 267
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Post by Larry on Aug 8, 2010 22:17:08 GMT -5
Thanks for the tips. I had the vise up and was hand-feeding manually, just like if the saw had no vise. I auto-fed a moss agate and hand-fed a noreena jasper. The one thing I did notice was heat. Maybe I just need to clean the whole thing out and start over. Perhaps I am having a sludge problem.
The thing that has me confused is how the blade wobbles like it has come loose. Can it act that way if the blade is still on tight? I wish I was more of a tool guy so I could figure these things out. I know a lot of tool guys but not a lot I'd want to stick with the mess of figuring out an oil saw.
Thanks again. I do appreciate any help I can get.
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Post by johnjsgems on Aug 9, 2010 10:07:12 GMT -5
Larry, if it cuts ok autofeed but not hand feed it sounds like you are pushing too hard. Dress the blade and see if that makes a difference. Also make sure blade is installed in correct direction and tighten only enough to keep blade from slipping. Overtightening can cause a blade to wobble.
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Post by Donnie's Rocky Treasures on Aug 9, 2010 10:13:38 GMT -5
Thank you Larry for asking your questions! This info has been helpful for me too (I like to get things done fast, so I have a tendency to push too hard!!). Donnie
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Post by jakesrocks on Aug 9, 2010 10:37:15 GMT -5
Another thing you might consider when hand cutting. Are you pushing harder on one side of the rock than the other ? I've made this mistake myself. Watch while cutting to make sure the blade remains centered in the table slot. You may be pushing harder with one hand than the other. Don
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Post by deb193redux on Aug 9, 2010 12:11:41 GMT -5
I am a little confused. Does it only wobble when hand feeding? It works OK on autofeed - or did you have autofeed problems too? When you take the rock away, does the wobble stop?
What thickness replacement blade did you buy. Formy 10" handeef, I use .050 or .060 necause anything thinner is too easy to bend the blade.
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Mudshark
fully equipped rock polisher
Diplomacy is the art of saying 'Nice doggie' until you can find a rock. Will Rogers
Member since December 2008
Posts: 1,083
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Post by Mudshark on Aug 9, 2010 12:14:19 GMT -5
I have that saw and like you loved it at first.The problem most people have with it is the blade will bind during a cut.I found that the round metal rod that the vice is attached to is weak and will bend if the blade is the slightest bit worn.Hard stone is always difficult to cut unless the blade is brand new. The wobble is most likely a poorly seated blade or a bent arbor.Make sure that blade is seated right,it's a royal pain getting the arbor nut on correctly because of the poor design of that saw.It takes me 2 or 3 attempts before I get it right.Pop the belt off and spin the blade before you go through the aggravating experience of putting the table back on.If you are absolutely sure the blade is seated right check the arbor,it might be bent.
Mike
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Post by jakesrocks on Aug 9, 2010 12:23:41 GMT -5
I have an older 10" Covington. Probably made in the 60's. I've had no trouble with it. Maybe they used cheaper materials for the newer saws. Maybe if the guide rod was replaced with stainless steel it would cure the problem. Don
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Larry
spending too much on rocks
Member since June 2008
Posts: 267
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Post by Larry on Aug 9, 2010 16:01:07 GMT -5
Thanks again for the responses. It's going to be a couple days before I will get some time to look into it more.
Don, I was trying to be very careful with the equal pressure. After a year of avoiding using it, the last thing I wanted was to see the wobble once again, thus I was trying really hard to send it through straight. Now, my workforce, I abuse that one bigtime, but that's another story.
Mike, at least I know it's not just me that hates many of the design elements. Covington is a hihg-quality manufacturer but they bungled this design in more than one area.
deb (Daniel if I remember right), it's been so long since I used it last, I don't remember if the wobble happened on auto-feed or not. I thought it did, just can't say for sure. The wobble will continue until I reseat the blade and try again.
I'll just auto-feed from now on next time I get it back on and see what happens from there.
I do appreciate all the advice. I hope it's just user error and I can correct it with some of the tips here. Thanks again!!
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redrummd
starting to shine!
Member since July 2009
Posts: 38
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Post by redrummd on Aug 9, 2010 22:18:24 GMT -5
Contact Covington if you cannot resolve the matter. They do warranty their saws and may be able to identify the problem from your description.
My first question is what does the saw do if you just leave it running without cutting? If it runs fine without a wobble for 15 to 20 minutes it cuts down a lot on the potential issues.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,352
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Post by quartz on Aug 13, 2010 20:53:24 GMT -5
You didn't say what cutting fluid/ coolant you are using, can be contributing to the problem. A fellow club member was having great difficulty cutting some agate mtl. using mineral oil in his saw. He asked what we use [hudraulic oil], tried it ,and said the difference was remarkable, the stuff cut as would be expected. Different rocks seem to like different coolants, perhaps others will offer advice on this.
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jcinpc
has rocks in the head
Member since April 2009
Posts: 722
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Post by jcinpc on Aug 13, 2010 22:04:48 GMT -5
water
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Post by tortuga on Aug 17, 2010 22:06:45 GMT -5
as redrummd said, Covington has a great warranty on their equipment. you are covered for as long as you own the equipment. they've actually given me some help with an old 14" that is from the 40's or 50's and i'm not the original owner. they just really care that people are happy with things that have their name on it.
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