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[Jimbaloney]

Yesterday I was cutting a new chunk of moss agate on my 10inch Star saw, heard a rattle and saw the blade had snapped. I am almost positive the rock didn't slip in the vise. Unfortunately, I also CAN state that I did NOT dress or flip the blade in some time, and also did NOT start the cut on a flat surface of the rock, but rather on the very end to try to shave off an uneven piece. I have cut some (15-20) 4"-6"x2" slabs of agate very successfully up to this point in the past couple of weeks. Those cuts are NOT uneven, and I have not noticed the blade dishing while I have been cutting. I did notice that the end cap for the blade holder gimmick on the arbor (I am sure it has a real name - I'm holding it in the picture) got a bit chewed up a bit on the outside rim.

So other than making some classic errors - making sure that I am cutting on a an edge that will not flex the blade out, maintaining a proper dress on the blade, making sure that the vise is absolutely locked in place & rotating the blade from time to time, what else should I do I look for as I get another blade and put it back together? Any recommendations as to the type of blade to get? It looks like there's a bunch of different ones out there. I'd like something that will cut cleanly with a minimum of waste and last for awhile. Many thanks in advance.
--Jim

[peruano]

Wow its hard to see what exactly happened, but it looks something like a train wreck.  It appears that your blade slide off of or on the shaft (was the blade secure, did a bushing slip inside the flange washer to allow the blade to suddenly slide into an out of round relationship with the arbor shaft.  I would make sure to have good flange washers that hold the blade securely and spinning in a true plane.  You don't really state whether you are feeding by hand or with gravity or power feed.  You can not beat the agate cutter, or hot dog blades if you are not feeing by hand. 
I have a 12" MK225 (hot dog) blade that has been run for years, seldom dressed, never reversed, and loves to cut agates all day long.  Blades are like automobiles, everyone has a fav and everyone has had  a bad experience with a diff brand.  Its all a matter of how much you want to spend and how hard you want to drive them.  Good luck of figuring out what happened.  Could you have had a bearing self-destruct?

[Jimbaloney]

Thanks for the replay, Peru. Yeah, it's a power feed. You can see the screw thread for it along with the bottom of the vise in the second picture down. The blade didn't slip off; rather, it broke...kind of like a hole punch. I am assuming from too much outward pressure from either  poorly aligned stone or a slip in the vise. I heard no weird noises that might indicate a bad bearing. Here's a shot of the blade and the remaining circular piece of the blade I found on the arbor once I took off the arbor end cap. I've ordered another blade since I'll need it anyway and run it to see what might've happened.

[peruano]

OH! Maybe I see it now.  Your flange washer (the part you thought got damaged too) is possibly too small for that size of blade.
There is a rule - the flange washer that holds the blade straight on both sides, has to be something like 1/6 the size of the blade.  This is to prevent lateral flexing and blade destruction.  I'd guess that a badly dished blade or one under a lot of lateral pressure would create enough stress to break the blade at the perimeter of the flange washer, but measuring that flange washer and replacing it with a new pair would be in order.  Cigarbox lapidary sells new ones (pricey but quality) but they should be available through Grainger or your favorite industrial supply.

[vitzitziltecpatl]

I've been following this thread - mostly because I read all I can about saws - and have never seen this happen to a blade.

If that is a "Star" blade, I'm thinking it was pretty old. Who knows what it might have been through.

Side Note: Tim and his crew at Cigar Box Rock are good people to deal with. We've been customers for over ten years.

[Jimbaloney]

Thanks! I just looked Cigar Box up and will call them tomorrow. I prefer giving a small business my $ & appreciate the tip!

[vitzitziltecpatl]

You're welcome. Cigar Box Rock also has some flange washers and other items on eBay.

If you do talk to them on the phone you could tell them Hummingbird Stones from Arizona recommended them. I don't think they'll hang up on you, and it won't get you (or us) anything extra, but they'll know you already have the low-down on them. :-)

[ToTheSummit]

There was a vendor at Quartzsite (Desert Gardens) yesterday that had a whole pile of flange/arbor washers on a table.  I didn't pay close attention to it because I don't have a need right now, but I did notice it because I have looked for them in the past.

[Jimbaloney]

Thanks again y'all. I called Cigar box (https://cigarboxrock.com/contact-us/ - thanks Vitz!) and they hooked me up. 30 bucks included the shipping. Sent them my pics, then called them 2 minutes later to ask about it at about 4 EST, (they had me measure the existing non-damaged flange) and got an invoice/ confirmation by 9. Great folks to deal with.

[vitzitziltecpatl]

You're welcome.

They are great people to deal with. A lot of places talk about providing good customer service - CBR just does it.