ISO Special Discussion Groups for Spiral Saw (Rotozip)


I am not much familiar with all the things that can be done with and cautions about using the spiral saw.
Is there a discussion which specializes in using this tool for home woodworking?
I'm interested in the sorts of routing that can be done with the tool and preferred bits and jig adapters for rabbetting and circle cutting.
My main application is doing the final trim work on audio speaker cabinets: driver cutouts, terminal cutouts and finish work for flush mounting drivers and edge trimming (roundover) of 3/4 birch plywood on small surfaces with other larger projects to come. No veneering at this time, but that is another likely application
Any help or how to articles also appreciated.
My unit is made by Tool Shop. It is 30,000 rpm with an accessory kit.
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Weeeellll that tool is Great at cutting sheet rock, that is what it was designed to do.
After that, its like a lawn mower salesman showing you how this particular lawn mower can also power your car, pump the water in your well.
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wrote:

Why do we need such a specific group? It's not like we have alt.tablesaw or rec.jointer!

Post some specific questions.
Roto-Zips and their clones were originally developed for drywall cutouts. I'm sure others have developed other uses for them.
The tool should be able to do what most other light duty routers can do, check out <http://www.patwarner.com for 1router info, or visit your local library for some good router books.
Ping "Trent", he's really into his Roto-Zip.
Barry
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AH ha! Got it at Menards, I betcha. Their house-brand special.
The bad news -- That tool, and *any* similar one, regardless of manufacturer, are the WRONG THING for the type of job you propose to undertake.
Spiral saws are designed to work in _brittle_ materials -- ones that 'powder' when 'hit' with a sharp edge. They're _great_ for drywall, and, as long as you're careful about heat build-up, you can do amazing things on ceramic tile, too.
For cutting wood, on the other hand, they are 'medium dreadful', to put it charitably.
The bits don't have big enough 'flutes' to clear the wood chips, so they are *very* slow cutting, Like only a few (maybe 5) _inches_ per minute, in 3/4" stock, *IF* you can keep from breaking the bits.
Due to the small diameter, they don't have the structural strength for the side pressures, and you'll break bits *real* often. Like, if you're lucky, you'll get 4-6 _inches_ of cut in 3/4" material, per broken 1/8" bit. Don't even _think_ about using the standard 1/16" ones.
For any sort of a powered cutting edge, you want more-or-less the same lineal speed at the cutting edge, regardless of the size of the cutter being used. What the 'correct' lineal speed is, does depend on the material, but the speed can be regarded as a constant for any specific material.
_Standard_ setting on a router will spin a 3/4" diameter bit at around 22,000 RPM. This is equivalent to about 17,000 RPM for a 1" dia. bit.
To get an equivalent 'cutting edge speed' from a 1/8" diameter bit, you have to spin it 8 times faster than that 1" bit -- or around 135,000 RPM. More than _four_times_ what your tool is capable of.
A reasonable light-duty router can be had for under $100. See the Skil 1815, for one example. It has an 'edge guide' option -- which includes circle-cutter capability -- that sells for about $15.
For less than double the money (i.e. under $200) you can get a "good" router. And under $300 will get a top notch 'commercial grade' unit.
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Robert Bonomi wrote:

Don't know about the model he has, but a Rotozip takes standard router bits in addition to the special purpose cutting bits.
--
--John
Reply to jclarke at ae tee tee global dot net
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On Mon, 14 Jun 2004 04:07:41 +0000, snipped-for-privacy@host122.r-bonomi.com (Robert Bonomi) wrote:
[snipped]

Aha!, Yest I did, but I didn't use it yet until I post a few more questions or take it back or a combination of both.

Well, here's the lowdown. I manage to do my little projects in an apartment on a single small worktable. I'm also asthmatic and so the use of the spin drill sends the waste mostly down instead of into the air.
I've played with a a hand drill and drill guide plus RotoZip bits and had a few break.
The point is that I need a low profile, non-industrial or non-"shop solution"... not the proverbial "More Power!" from Tool Time. Before I made the purchase, I studied a project from a Canadian gent who had his flatpack (pieces to be glued together) cut buy a shop and then did the trim work including roundover of baltic birch ply in his shop. I do not recall what sort of bits he was using. His completed project looked fine.

I believe I have tried to have this discussion in the past and there were no takers, now there are. The timing was just a bit wrong for my purpose. And yes, I like the feel of the fixed base Skil model at Menard's and was hoping for a deal on it for Father's Day and I would set up a small Workmate (tm) outdoors to use it.
Before using the Spin Saw, if it is going to be totally uselss even under the described conditions, I could exchange it for the Skil router but with no discount. I'm aware also that a Jasper Circle cutting jig is the tool to use for this type of hobby work.
--> But as stated I was looking for a lightweight solution and minimal waste material flying about. Given that criteria but not wanting to go through another package of bits is the device a waste of time?
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If you are working in THIN materials, these are acceptable, under the circumstances you describe.
Having used one to cut a sink cutout in 3/4 plywood, my jigsaw having taken a hike, it is not a task I would plan on asking of the tool more than once or twice.
But light duty hobby work might succeed. As with any tool, take it at the appropriate pace. And if your cutter sounds like mine, you'll want some hearing protection. It's still loud.
Patriarch
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http://www.freewebs.com/ulzog/fe208espage3.htm
Here is the Canadian project. Note the flute size in the spin drill.
On Mon, 14 Jun 2004 04:07:41 +0000, snipped-for-privacy@host122.r-bonomi.com (Robert Bonomi) wrote:

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If there's a finished surface involved, yes. If he's going to cover it with black carpeting or something, the circle jig that comes with the rotozip does a reasonable job.

I used mine this weekend cutting some 1/8" plexiglass, both straight cuts against a clamped straightedge, and a circle-cut (freehand for non-critical circle-ish shape).

Hm, I find it about as usable as a saber saw.

You're using the wrong bit, then. Lots of options. Sounds like you were using a tile bit on wood, maybe?

Mine came with 1/8" bits, never saw a 1/16" bit. Sure you're talking about a RotoZip? Don't get me wrong, I'm not saying that it's high-art of toolmaking or anything, but what you're describing isn't consistant with my personal experience.
Tool edge speed aside, for the fwe times I use it, it works great. Like anything else, using the right bit for the job is critical.
Dave Hinz
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Dave and All,
thanks for continuing the discussion.
For those of you who are doing some of these things like Dave and Patriarch, can you see from the photo link up there at the other post if the roundover bit used is something off the shelf or maybe supplied with my Canadian friend's spin saw kit? Mine is not the same. I have sent a mail to the guy but didn't get any replies yet... it's vacation season.
Anyway, today from the added messages I feel a little bit better about keeping the thing. But still I'm hoping for more discussion.
And yes, what I'm doing is very casual: what I have is a flat pack of baltic birch plywood to make 2 desktop speakers for computer use. The longest length is 16 inches for roundover. The cutouts for this project will be made with a 3" fly cutter (hole saw) and I am wanting to do a rabbet to flush mount the driver plus a chamfer on the back side for relief of the "backwave".
So what are the chances of significant kickback from the tool?
As you can see from the picture the guy used the roundover for a lot of pieces. I re-read the whole thing and no mention is made of the job being really slow.
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<snippage>

I use a 1/4" shank, 45 degree chamfer bit, or a 3/32" radius roundover bit in my Porter Cable trim router quite a lot. I'm a lot more comfortable with that tool, than with the Dremel cutter. I don't know that I would attempt it with the Dremel. YMMV.
In fact, of my 5 router type tools, the PC trimmer gets the most frequest use, lately. My son, OTOH, uses his Dremel for almost everything. Prolly just using whatcha got...
Patriarch
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On Mon, 14 Jun 2004 23:01:31 GMT, patriarch

Same here, only mine's a Bosch.
I find the little guy GREAT for cleaning waste from dovetails (especially half blind), small hinge mortises, many roundover and chamfer operations, etc...
I find almost any non-plunging, non-table routing is better with the small, light machine.
Barry
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Lon Ponschock wrote:

It looks like a typical off-the-shelf 1/4" shank roundover bit.

Same as for any other router. "Kickback" isn't usually an issue.

Roundover speed should be the same as for any other router, assuming that your saw has enough power to keep the bit spinning. It's sawing wood with the standard bits that's slow.

--
--John
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Using it for long saw runs would not be the objective. I'd prefer having the flexibility of a fixed base router and router base mount for shaping. But I'm still pretty tentative about the jobs I can tackle.
The consensus seems to be that it'll work for small jobs with the right bits and will take (with the right collet) standard router bits for chamfer and rabbet and roundover.
Thanks to all who answered.
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Lon Ponschock wrote:

First thing--if you're looking primarily for a cutting tool then get a good saber saw--Bosch isn't cheap but they're worth the money. You can use a drill to start the cut for inside cuts. While a rotary tool will cut wood and with the right bit even gives a fairly clean cut there's a lot of waste, a lot of chips produced, and they're hard to guide freehand--while with much practice you may be able to follow a line a moments inattention can make a big mess (you can do that with a saber saw too but it doesn't tend to hare off at right angles to the cut line and pull itself along by brute force). The saber saw will actually produce fewer chips than the rotary saw and the ones it produces will tend to be a bit larger, so despite it moving the chips up instead of down I would expect it to be more friendly to your asthma--I'd get a good dust mask anyway.
Next, a rotary saw is a small router or a big hand grinder, depending on how you want to look at it. It can with the right accessories do some of what either does but except for the one task of cutting drywall and plaster it doesn't do any task as well as the purpose-made tool--it's too bulky to be a good hand-grinder and it's very low-powered for a router, not to mention that by the time you have it fitted out to do what a router does you've pretty much paid for a decent router.
The "wood cutting" spiral bits cut very slowly and not very cleanly. There's a reason for the slow cut--it gives you enough control to be able to actually cut wood with the thing hand-held. It's still going to be trying to wander all over the place but it will do it slowly enough that you have a chance of catching it. Put a real router bit in the thing and it will cut a lot faster and a lot cleaner, but if you try to use it handheld odds are that until you get a _lot_ of practice with it it's going to ruin a lot of work for you and it's always going to be a lot happier with a guide or template or fence. This is why a standard router would be a bad choice for you--while there are small diameter bits for them they have a short cutting depth and so can't be used for sawing anything but relatively thin stock, and the smallest shank most routers will take is 1/4" so you can't use the rotary-saw bits in them.
If right now you can afford only the one tool then the rotary saw is the only one that will do everything you say you need, albeit poorly. Two things to look for--the ability to take 1/4" shank bits and the availability of a plunge base--if those are not available for the tool you have take it back and trade it in on one that does--the Dremel Advantage is not horribly expensive, and the variable speed should give you a bit more control. The Rotozips have a wider range of accessories available and the low end fixed speed model is under $60 so if you're on a super tight budget that would be the way to go--if you can afford a bit more then the RZ10 or RZ20 would be a good choice. You're going to need the plunge base--the standard base that comes on rotary saws is fine for sawing but it's not wide enough to give you good stability when routing edges and the like and the depth adjustment is not very precise or convenient either--you'll find that that's important later--being able to take several small cuts and reliably return to the same final depth setting is the way you work around the relatively limited power of the tool when doing such things as rounding edges.
For cutting with a fence or guide get yourself a 1/4" diamater downcut spiral router bit (Amana 46202 for example)--it will make a lot of chips but you'll find that it cuts cleaner and faster than the "rotary saw" bits, but it's going to be hard to control without a rigid guide. Like the rotary saw bits it will send the chips down instead of up.
--
--John
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