success with band saws or ring saws?

[stdenis_jd]

Haven't seen any threads addressing this, so here goes...I have a 10" slab saw, but it is far too messy to try to use as a trim saw. Plus, it seems that using a full saw blade would make it difficult or impossible to make angle/arc cuts as the blade would have to flex and could end up breaking or ruining your cab material.

Anyone have experience with band saws or ring saws? Those seem to be the most logical machines to buy for trimming anything other than squares, triangles, etc but how do they hold up? Am I wrong about trim saws and they can make the curve cuts? I'm using a dremel with a diamond cutoff wheel right now Haha..gonna be getting a trimmer of some sort, leaning toward a wet band saw but don't want to waste my $ if it doesn't hold up.

[slabbercabber]

Trim saws should never be used to cut arcs.  That's a recipe for bent blades.  I have a band saw but only use it for special purposes.  Blades do not last long and they are expensive.  It is also a very slow cutting process and if you get impatient and push too hard the diamond coating will strip off in seconds.  The blades must be plated as sintering or notch filling would crack when going over the sheaves.  Micheal Hoover may chime in.  He uses one a lot.  I've never used a ring saw but the one person I knew who had one never used it after the first few blades due to cost of operation.

[stdenis_jd]

Trim saws should never be used to cut arcs.  That's a recipe for bent blades.  I have a band saw but only use it for special purposes.  Blades do not last long and they are expensive.  It is also a very slow cutting process and if you get impatient and push too hard the diamond coating will strip off in seconds.  The blades must be plated as sintering or notch filling would crack when going over the sheaves.  Micheal Hoover may chime in.  He uses one a lot.  I've never used a ring saw but the one person I knew who had one never used it after the first few blades due to cost of operation.

So how do you cut preforms out of slabs? Use a trim saw and make multiple cuts at increasing angles? I'm pretty new at this so I'm making do so far with hacking away at slabs with a dremel cutoff wheel, carborundum bench grinder, and just getting as close as I can with my slab saw...

[vitzitziltecpatl]

A good question. Per what Slabbercabber said, band saws and ring saws are used mostly for pieces with more intricate shapes. The preforms most of us work with are trimmed out with saw and then ground to the desired outline.

Lay out everything you'll want to use in your slab, then draw straight lines between the areas to be cabbed. If you draw multiple cab outlines on your slab, you'll wind up with lines between them that will usually require multiple partial cuts with the saw.

You can trim excess material at the corners of the blanks after they're cut out of the slab. Just always cut parallel to the cab outline! Most saws will cut farther into the bottom side of your material due to the angle of the blade rim. To see this, place a slab on the saw table and slide it up against the blade (with saw off) and notice the distance from the top surface of the slab to the saw blade rim.

It is possible to flip your slab over and run the blade back into the existing cut in order to make the cuts meet at an intersection, but it is also very easy to bind and kink a blade in doing so!

Some grinding will always be required to finish your preform shape.

Hope this helps.

[Michael S Hoover - Redrummd]

I pretty much never use a trim saw.  I use my Gryphon bandsaw for about all the slab cutting I do.

I get my bandsaw blades from China - one of the very few things I do get from China as I do not think there are any US makers.  All of the ones sold are re-packaged from China manufacturers as best I can tell.

I pay about $12. a blade with shipping and when cutting expensive stone that is saved in a very few cuts.  Occasionally there are sales on the bandsaw blades and I will post the sale notices.
 
Do a search of my past posts.  You will find posts about modifying the Gryphon to use Inland blade guides as the Gryphon guides are total JUNK.

[stdenis_jd]

Awesome guys, thanks for your wisdom...looks like best bet for me is to make my straight cuts with my slabber and band saw for any non straight cuts. I actually had planned on getting a Gryphon, so I will have to check out Michael's recommendation for modification.

Thx for your help guys :)

[mirkaba]

Good questions. I have an old HP 6" trim saw that does the job but you can also start out with a tile saw equipped with a Lapidary blade. Draw the out line of your cab and use a straight edge to mark your trim saw lines. Get as close to your shape as you can leaving room so the blade kerf does not mess up your cab. Trim up corners and such freehanded. Then use your grinder to get down close to your cab shape. I have a Gemini 3 ring saw that is good for cutting shapes (hearts, crosses etc.). I started out with the standard diamond blade which worked really well but my tendency to be a bit heavy handed broke it in short order. I bought the Mega blade which is a little thicker, slower and doesn't maneuver  as well as the standard blade but I haven't broken it yet. (4 or 5 years) Good luck with your trimming! :)

[stdenis_jd]

So it seems the rule of thumb for band & ring saws is to be extra careful to not get overzealous and put too much pressure on the blade...similar to buffing/grinding, let the paper/wheel/blade do the work. I can see how easy it would be to want to push the issue with a trimmer of any kind, especially if you are used to using a power or weight feed. Doing it freehand, you wouldn't be as used to feeling out the pressure to know what is too much or too little pressure. So:

Trim saws are more durable and are limited to straight cuts.
Band saws are less durable than trim saws, requiring less pressure, but can cut arcs and such.
Ring saws are basically the same as band saws except less durability and very delicate, but more freedom for shaping.

Is this a reasonable summation?

So rule #53 is the same as rule #1 in lapidary...patience :-)

[vitzitziltecpatl]

So Michael - you use your Gryphon even for ovals and other "standard" shapes? I get the part about expensive materials, but how much thinner is the cut compared to, say, the thinnest Pro-Slicer?

Robin has a ring saw - she used to have a band saw, but she says "it didn't like her". I've often thought of using it to do fancy shapes but have yet to try it. We lay out cabs to frame patterns or other features within a slab, so usually a trim saw is good for what we do.

I am interested in the the material savings for some things. Maybe someday this old ironworker will try the ring saw - and try very hard not to kill it... .

[Hummingbirdstones]

That dang band saw hated me!  I finally ended up putting it in a corner on double-secret probation until I found someone willing to take it off my hands.  Bought a Gemini II ring saw instead which liked me much more and I it  (the III's weren't out yet).
This was back when I was doing stained glass work (before rocks).  Worked a treat on the glass, as I was making a Tiffany style lamp (that I never finished because - opals).  Someday I'm gonna finish that thing.  Maybe I'll drag it out from wherever it may be hiding and see if it still works. I know I needed to replace the yellow and red gizmos.

[Jhon P]

I have a Taurus ring saw, I bought it from an estate sale about 1 1/2 years ago. I am still using the blade that came with it. It is a little slow cutting but I only use it for knife scales [I can cut the stone closer and save a lot of time not grinding as much] or a odd shaped cab where I don't want to waste material because of all of the cuts and extra grinding I would have to do. and I cut preforms for carving also saves a lot of grinding. It will cut any direction, forward is best with the mega blade but it will cut backwards or sideways.
 I don't have any experience with band saws but did a little research before I bought the ring saw, and found out that the band saw blades don't last long.
I may need to buy a new blade but haven't wanted to spend the $100.00 yet.
 Most of the cabs I cut on the trim saw, you have to make multiple cuts and than grind to shape, but much faster and saves the ringsaw blade.
That's my two cents worth,  I am sure that there are people out there with a lot of bandsaw experience that can be of more help.

[Michael S Hoover - Redrummd]

The bandsaw kerf is about 1/32 inch.  If your time is valuable why waste it using a grinder or risk stone to potential harmonic vibration damage on a rougher grit grinding wheel?   I use the bandsaw for all my slab cutting even for straight lines.  I just buy the bandsaw blades when I can get them for $12. or less and buy a bunch of them.

[vitzitziltecpatl]

That's good to know. Bandsaw kerf about .030". So if I could get the hang of using a bandsaw without breaking blades it would be a good thing. Maybe even more so the ring saw - if Robin will show me how to use it. I started into lapidary work without a mentor of any kind, so the extent of my experience is limited in many areas.

Thinnest saw blades I have here are .012-.015", but they're only for things like opal, sugilite, or other small higher-end rough.

Damage from coarse-grit wheels is always a consideration too. Very good point to always keep in mind. I'm pretty merciless in hogging off run-of-the-mill materials, but won't even cut some things until new wheels are well broken in.

Thanks so much for sharing your experience here.

[southerly]

I also have a Gryphon C40 band saw. I love it, really good for saving quality material. Takes a little longer than a trim saw however I save that in less grinding time, and as Michael says it is usually gentler on the stone than a course grinding wheel.

David