355mm hand held circular saw

[philiplemon]

Hey,

I am looking for a 355mm bladed circular saw that can do a cut of about 110mm - 120mm at 90. Is there such a beast? I have been browsing the web but haven't had much luck. Is anyone using one?

Cheers,
Phil

[Kyle]

14 inch circular saw:oo:. That would be one beast of a saw. Don't think you'll ever find one though.

Makita do a 270mm saw that cuts 100mm.

5104-270mm Circular Saw (http://www.makita.com.au/index.php/products/power-tools/sawing/item/circular-saws/5104-270mm-circular-saw?Prodid=147)


Any bigger and I would be looking at an electric chainsaw or a 12 inch slide compound saw.

[Batpig]

Dear Phil,

This would probably fit the bill quite nicely:
PROTOOL Large diameter saws for carpentry (http://www.protool.com.au/mediandoweb/index.cfm?ID_O_TREE_GROUP=4929)

Don't let the innocent looking litte photo of it all by itself put you off. I've seen another photo of a man using it, and "It's Wrong!" :no: (as the young set have a habit of saying nowadays...)
Anyhow, I'd say you were fairly lucky that they even bother to sell it down here. But you'd want to want it pretty-darn-bad (in other words - make sure you're sitting down when you scroll down to read the price...:()

Best Wishes,
Batpig.

[Kyle]

Dear Phil,

This would probably fit the bill quite nicely:
PROTOOL Large diameter saws for carpentry (http://www.protool.com.au/mediandoweb/index.cfm?ID_O_TREE_GROUP=4929)

Don't let the innocent looking litte photo of it all by itself put you off. I've seen another photo of a man using it, and "It's Wrong!" :no: (as the young set have a habit of saying nowadays...)
Anyhow, I'd say you were fairly lucky that they even bother to sell it down here. But you'd want to want it pretty-darn-bad (in other words - make sure you're sitting down when you scroll down to read the price...:()

Best Wishes,
Batpig.


Never mind the price.

weight: 22kg :)(

[ecsk]

14 inch circular saw:oo:. That would be one beast of a saw. Don't think you'll ever find one though.

Makita do a 270mm saw that cuts 100mm.

5104-270mm Circular Saw (http://www.makita.com.au/index.php/products/power-tools/sawing/item/circular-saws/5104-270mm-circular-saw?Prodid=147)


Any bigger and I would be looking at an electric chainsaw or a 12 inch slide compound saw.

+1, only Arnold Schwarzenegger can handle 14" circular saw :D

[orraloon]

Just what I was thinking. I would hate to be hanging on to it. A kickback would put your arms out of the sockets.http://cdn.woodworkforums.com/images/smilies/standard/eek.gif

[Kyle]

What about this.

Spear & Jackson Predator 22" Laser Guided Saw #SJ-B98LASER (http://www.justtools.com.au/prod5678.htm)

It's got 550mm depth of cut, under $50 and you'll have arms like Schwarzenegger if you use it enough.

Plus it's 'laser guided':rolleyes:

Seriously is there anything tool makers won't fit a laser to these days?

[gerhard]

Hi from Amsterdam!

Yes, there are several options. The best known ones are the Makita 5143R and the Hitachi C13U.

The Hitachi weighs in at 13 kgs, has a 2000 Watts motor, comes standard with a 335 mm TCT blade and turns at 2700 rpm no-load. It manages 128 mm cuts at 90 degrees and 85 mm cuts at 45 degrees. It is a rugged but simple machine, a typical eighties Hitachi design following the firm's principle "all details that are left out, can't break down". Which means that the machine has no safety clutch, no soft start electronics, no electric brake and a stamped steel sole plate instead of a cast alloy one. So it is a relatively expensive machine for what you get, with Hitachi's only excuse being the fact that it has its metallurgy and "functional choice of materials" in shipshape order. Anyone having used Hitachi tools for years, knows what i mean.

The Makita weighs 14,5 kgs, has a 2200 Watts motor, comes standard with a 355 mm TCT blade (yes, 355 instead of 335) and turns 3400 rpm no-load. It cuts 130 mms deeps at 90 deg. and 90 mms at 45 deg. It features soft start and electric brake and Makita's anti-seize safety system, which it calls "SJS". If the blade should stall or seize very suddenly (e.g. because of a very thick hidden nail in the wood), a spring system behind the motor pinion acts as a friction clutch. Makita also uses this system in some of its angle grinders.

The choice of Hitachi to get the most out of a 335 mm blade comes at a price; the gearcase has to be very compact in order to achieve that. Would it not be for the quality hardened gears, i would consider this a drawback. The Makita has a lusher gearbox, but then it has to use a 355 mm blade to reach approx. the same saw depth. The Makita (at 94 deciBels) is also a bit louder than the Hitachi (91 dB).

Both machines have motors derived from angle grinder models. They can cope with heavy loads. The Hitachi is a simple on/off-machine, the Makita is much more sophisticated. I own both and the term "beasts" is indeed applicable. Both are good machines, but personally i favor the Makita, because of features and value.

There are several other very large circular saws. Festo had a very large one (powered with a 2200 Watts Ackermann + Schmitt angle grinder motor), but it is now discontinued. Mafell makes several types, many of them with three phase direct drive induction motors; one of these models is even laid out for operation by two men! These are typical solutions for timber shops making the components for roof constructions, and for wooden boat shipyards. These saws are mainly used for ripping massive oak beams. Oak is the wood of choice for such constructions in Europe.

My personal favorite is the Holz Her ring circular saw, managing 185 mms saw depth. I have the luck of owning one and it is a difficult machine to achieve long steady cuts with, but what technology! Alas Holz Her no longer exists, even all the spare parts are gone.

So don't go for such expensive exotics, go for a known brand available in your area and go for models that have been around for some years, which is often a good guarantee that spare parts will be stocked for at least a decade to come.

The Hitachi C13U and the Makita 5143R are shown in the pics below.

Success and greetings!

gerhard

[gerhard]

Forgot two other things.

The Hitachi's hind grip, situated really at the rear of the machine and truly in line with the blade, is a definite plus when handling is concerned. The Makita has a more conventional outlay, with a slightly larger risk of wrenching the blade inside the cut, when the user applies his forward pushing forces a bit crooked.

The Makita's plus is the fore and aft mounted parallel guide, which is rugged and precise. The tiny guide on the Hitachi is too flimsy for this size machine. In practice it indeed doesn't offer much guiding help, the user has to make up for that with more careful steering. With the hind grip sitting really at the rear, the Hitachi fortunately can be steered directly and precisely. The Makita has slightly more of a "midship feel", like most circular saws with a grip outlay close to the motor housing have.

cheers!

gerhard

[gerhard]

Just for fun, i looked up pics from the machines i mentioned above, like the Festo and the Mafell models. Where the 5143R and C13U cost around 700 Euros, the machines in the pics below are 2000 Euros and way beyond. So it's mostly something to drool over, with little chance of owning it, let alone having any justifiable use for the scale of these monsters.

As for the Holz Her ring saw, i already presented that in various other posts. But if you want some pics of it in this thread, than i'll be glad to add them. The models in the pics below are the 132 mm Festo, the 130 mm and 145 mm and 185 mm Mafell models with brush motor and gear drive, and the Mafell 165 mm and 245 mm direct drive three phase induction motor models, the last of which being the machine designed to be operated by two men. Mafell is still one of the worldwide kings in the department of circular saws these sizes, and is unsurpassed by any other German brand.

Gerhard

[Batpig]

Lieb Herr Gerhard,

Solid posts - as ever! That must be quite a collection of Toys you have up (and over) there...:rolleyes:
If I squeeze my eyes closed tightly emough, I can see a picture of a Theme-Park in my mind: "Kraut-Tool Wunderland" :D

I'd give you a Greeny for the effort, but the system wont let me send anymore your way at the moment...:?

Best Wishes,
Batpig.

[Ben from Vic.]

A two man circular saw!!!!

The widow maker.

Balls of steel.:2tsup:

[gerhard]

Haha, thank you for the compliment, Herr Fledermaus! And yes, Ben, as long as they don't come too close to the magnetic field, their balls will be all right. As you see in the pic, it's no joke! A 640 mm blade and almost 5 hp!

Gerhard

[masoth]

Can't tell if the blokes are actually cutting (I guess not) but OH&S people would go crazy. Nevertheless, the monster would be 'fun' to use for a few minutes.

soth

[Batpig]

Dear Gents,

A 640 mm blade and almost 5 hp!
Hmmm. Nice Circ. In fact - very nice Circ...:cool:


But...


Will it fit into a Triton?...(you'd want to check that out before you mail-ordered it Phil...:doh:)

Best Wishes,
Fliedermauspig.

[Kyle]

Perfect for doing plumb cuts on rafters!

The kickback would send you back to the last century!

[justinmcf]

hi gerhard, you are still the man!
once again you have delivered in spades!

have you ever heard of an accident using these types of saws?
is kickback a common thing?
or does the parallel guide and the riving knife eliminate kickback?

i would be happy to be the man pulling, (no pun intended folks), but i would certainly not want to be standing behind that puppy!

keep up the great work gerhard.
regards, justin.

[justinmcf]

hi phil, with regards to your original question.

i would buy the Protool CSP 132 E. this model weighs ONLY 18kg!

model no. 638 480

it costs 1842 euros. thats AU$2975!

but if you need something this big, then obviously you are prepared to pay a premium for a high quality specialized power tool.

you should try calling your local festool dealer, for more info about this saw.

regards, justin.

[TP1]

Haha, thank you for the compliment, Herr Fledermaus! And yes, Ben, as long as they don't come too close to the magnetic field, their balls will be all right. As you see in the pic, it's no joke! A 640 mm blade and almost 5 hp!

Gerhard

This is what Triton should have used for their saw "system". Would have got a bit more interest I reckon.

[gerhard]

Hi all,

Soth asked if the two guys in the pic were actually sawing. The pic indeed looks a bit engineered, with the clean shirts and showerfresh hair and whatnot, but in fact they are really sawing and this is indeed one of the ways how this thing should be used. No matter if an OH&S should flip over it, this machine is exported worldwide and gets the approval of many safety testing organisations. But then this is no tool for leymen, and especially in Germany the rules of practice are very strict when handling machines known to be dangerous. No apprentice is to touch this tool, without at least direct help and oversight of master carpenters on the same workfloor. When a firm lets any harm come to an apprentice or unqualified not-yet-trained person with a tool like this, they are in very big trouble and may have all their licenses and insurances revoked. So it's a serious self-regulating thing that has worked well over the decades, but the commercially hyped anxiety of the overobsessed Anglo-American lucrative safety bandwagon is also creeping in on Germany (much like the asbestos-astronauts and the HACCP-foodstuffpolice).

So the guys operating this thing know a bit about wood and tools and circ kickbacks. I've seen such a machine in action in a large workshop near Passau, making prefab roofing and ceiling units, much like the sort of workpiece that is being treated in the pic. In such shops the timber is cut and jointed to size, the readymade unit is flung on a truck, hoisted in place by a rented crane and adapted to exact size if necessary. This is common practice in Germany, where there is a a lot of woodframe housebuilding going on. They are even able to build all-wood high-rise constructions up to 7 stories and probably more than that.

The hazard is mostly in the ripping; experienced guys will be able to make any cross cut without a blink, even with such a large saw and even freehand. When selecting and judging the wood beams, they will first make a good study of the wood grain, to predict the hidden forces in the wood, which will make themselves known while the beam is ripped to size. If they suspect a risk that is too unpredictable, they don't use a saw like this but go for a vertical chainsaw instead. The wider cut of a chain means more loss of expensive wood, but less chance of accidents because of the narrower chain blade assembly, that will get stuck less likely and will merely leave a very rough cut finish instead.

This saw in action is an event to watch. The machine is used either freehand (which requires many years of practice) or is used with a guide rail. Mafell offers a standard 3 metre rail with 1.5 metre extension units, and all sorts of stands and clamps to keep the rail assembly at proper height and width. The two guys working the saw are a seasoned team, they discuss their plan and what they decide to do when things aren't going to plan, and then they just proceed. If necessary, they have other guys standing by with hardwood wedges or axes and sledges, to pry open the cut after the saw at the slighest hint that it should jam. The riving knife in this machine is big and relatively thick, but as an only measure it's not enough when forces in the wood pinch the cut together or skew it.

And then they start. These machines of course have a star/delta switch and spinning up the blade takes about two seconds. There is this sharp low pitched acceleration whirr that reverberates in the big blade and when the thing is up to speed, there is the sharp gnawing sound of the teeth in the wood, the loudest circ noise i ever heard. The standard blade choices have either 56 or 26 TC-teeth and at nominal load speed of 900 rpm that leaves a sharp sound pitch of 840 or 390 Hertz. 840 Hertz sounds about the same as the blade of a smaller handheld circular saw with a 16 teeth blade at 4000 rpm. So in spite of the low rpm, this machine doesn't sound much out of the ordinary with the 56 teeth blade and only sounds darker and more monstrous with the 26 teeth blade fitted. That darker sound resembles the sound of the man-high circ blades used on the Indonesian islands, with which they rip tropical forest trees roughtly to size, on site.

There is indeed the risk of kickback, but the operators are well aware of this and hear one coming by the blade sound. The front guy pulling the saw dictates the forward pace and actually does most of the work. You can see it in the pic, the front guy strains more at the saw than the hind guy does. Both guys watch the progress and the right direction together, but the hind guy is better able to steer than the front guy. So, between the bits of steering now and then, the hind guy can afford to bear down on the handle bar a bit and he can grip the saw tightly with both arms anyway, which is a big difference with mastering a large circ saw on your own with only one arm holding the rear. The arms of the guy behind this saw should preferably be stretched (unless there's a steering manoeuvre), whereas your pushing arm behind your own circular saw is often bent. Stretched arms can control sudden upward forces much better than bent arms can.

As for this machine, it's not so Neanderthal as many three phase machines are. Most induction motor driven machines keep going on until their thermal over-current cut-out trips, but this one has built-in electronics, which also offer a quick brake function. Besides, the torque curve of induction motors is different from series wound brush-motors, anyway. Induction motors have the best torque and efficiency close to their no-load rpm. At 50 Hz, the "field speed" is 1000 rpm for a 6-pole motor, and the rotor of this saw follows the field regime asynchronously at 940 rpm no-load. The saw's nominal load is 900 rpm, at 800 rpm and below the torque quickly collapses to a fraction of nominal. So as long as the load rpm stays steady and the blade noise pitch sounds the same within a few percents, the going is good. The torque is high at that moment, but without a sudden change in inertia, there is little chance of a kickback. When the rpm drops in spite of the same forward speed, there is a sudden higher friction, which could mean a stalling in the making, and a risk of kickback if the stalling occurs very sudden. Upon hearing the sound change, the front guy immediately relaxes and eases the saw at a slower pace. If the friction is overcome, the trouble was only local (resin inclusion or grown-in branch crossing). When the friction remains or increases, it's probably due to lateral forces in the cut and it's time for the guys standing by to jam in a wedge and split open the cut. At sudden stalling, the kickback with the approx. 18 kgs worth of blade and rotor mass, is of course bigger as usual . But the amount of static mass in both machine and workpiece are also big. It takes a lot of energy to suddenly lift a 66 kg machine. And the workpiece is also likely to be heavy, so it won't be launched in the worker's face as a plank will be, on top of a kicking saw table. It's often the circumstances that dictate the happening. Remember angle grinders; the heaviest are in the 2800 Watts range; that's almost 3 hp pulling at your wrists when the disc suddenly snags. Yet you don't hear much about angle grinder kickbacks, and when they occur, it's mostly because of ill advised reaching or poor foothold or some impossible working posture against better judgment.

The guy in the pic below, handling the 185 mm version on his own, is at slightly larger risk than the two guys with the 245 mm version. His single bent arm is all he has to keep the machine under control if it should jump up. Still, it's an original pic from Mafell itself, used in their advertisements and product presentations. You can rely on the machines genuinely being in use in pics like these, because German craftsmen hate fake set-ups and expect to see no less than real-life situations. They want to see machines in action, to judge their size and bulk and to judge how the guys in the pics go about using them. With that information they can judge how they would fare themselves and if this machine could be a worthwhile purchase. But they still won't buy yet, based on mere pictures, they will first visit forums and throroughly discuss the machine with users and they will visit fairs and colleague firms to see the things in actions or to try them out for themselves. There are many power tool forums in Germany and fairs always offer a lot of demonstrations and masterclasses, which attract huge amounts of serious visitors. After that, the product will be bought, often already at the fairs themselves, preferably at club member or discount prices. Festool by no means is alone in this, it may be a wordlwide well known brand for investing in customer relations, but in Germany this is the obliged and expected way to go. That's why serious tool brands like Mafell stay alive and keep enjoying good sales figures, in spite of crises and hefty price tags. With reputable machines customers often already know what they're going to get before they buy it, and they want to keep it that way.

Greetings from Holland!

gerhard

[gerhard]

Little mistake in the post above. The guy singlehandedly managing the large saw, uses a FSG165K, which has 165 mm saw depth, and not 185 as mentioned above.

I used this occasion to present a further pic of heavy duty machines as used in Germany. The beam planers, for instance, have 300 and 320 mms width capacity!

gerhard

[masoth]

Wonderful report, Gerhard. Thank you.

soth

[gerhard]

Thanks!

Just found a pic of an Indonesian saw mill, and this is just a medium sized and reasonably well maintained one. The blade is driven by a 6 cylinder diesel engine by means of a drive belt and an angled gear box. The logs are pulled up and led along the saw blade by a hydraulic motor winch, the controls of which are seen in the foreground (valve handle and pressure hoses).
I've seen a far bigger one in action on TV. A big log bounced through the saw, the blade wobbled wildly and i could swear i saw people running for a safe distance until the situation appeared sound enough again for them to immediately return and process another log. Talk about an OH&S flipping, now there was a spectacle that really made me cringe! I still can't look at one of those pieces of Asian teak furniture without picturing people with limbs missing.

gerhard

[philiplemon]

Jesus I can't get over how big that 640mm sucker is. I like the look of the Protocol but $4K in Oz is a bit out of my league. I'm mounting it on an adapter for my slabmaster so I'll miss out on building up killer guns by handling 18kg of power tool. I'll have to settle for something that cuts about 130mm so that I can dock 250 x 250 posts.

[philiplemon]

I'll mount this on my slabmaster


What about this.

Spear & Jackson Predator 22" Laser Guided Saw #SJ-B98LASER (http://www.justtools.com.au/prod5678.htm)

It's got 550mm depth of cut, under $50 and you'll have arms like Schwarzenegger if you use it enough.

Plus it's 'laser guided':rolleyes:

Seriously is there anything tool makers won't fit a laser to these days?

[gerhard]

Hi Phil,

a 120 mm saw needn't cost 1800 Euros or 2900 Aus Dollars. The link below shows one of the offers that can frequently be found in Europe. The suggested 600-something price is not even fixed, it's negotiable. Okay, it's Ebay and in this case it's Germany, so shipment to Oz would cost an extra arm and leg, but -with Hitachi's home country Japan being even closer to Austriala than it is to Europe- offers like these should be possible in your part of the globe as well. Especially because the influence of other competing Asian products (notably Chinese) must be even intenser over there than it is over here.

As for Hass + Hatje, it's one of the good German dealers also selling through Ebay, from which i regularly buy stuff. Depending on the weight, i have the goods shipped to my doorstep near Amsterdam for 20 to 30 Euros. They're professional people, they pack the items well. There must be firms like these in Oz or NZ, i guess. You even have stuff like Festool over there, so there is sense of quality and probably some degree of competition like there is over here, especially in these times of recession and slow sales!

Hitachi 128 mm Zimmerei - Handkreissäge C13U neu+ovp bei eBay.de: Sägen (endet 15.11.09 21:51:17 MEZ) (http://cgi.ebay.de/Hitachi-128-mm-Zimmerei-Handkreissaege-C13U-neu-ovp_W0QQitemZ120470492264QQcmdZViewItemQQptZDE_Haus_Garten_Heimwerker_Elektrowerkzeuge?hash=item1c0c99d468)

Success!

gerhard

[Ben from Vic.]

so shipment to Oz would cost an extra arm and leg

And there should be a few of those lying around after the use of the machines shown in this thread.:;

[weaver]

So if you have a spare $4k you can go for the Protool saw. Why are the hitachi and mikita big saws not available in OZ? I could buy a 16 and 5/16" (401mm) Makita but could any one tell me if it well work over here since the USA electricity grid distributes at 120v instead of 240v. If I could run it here that would be great since the Makita is less than $700US which given the $AU at momment would be less than a 1/4 of the cost of protool saw.

[gerhard]

Hi Weaver,

yes, with a "step-up transformer" you could perfectly well run a 240 Volts machine on a 120 Volts mains grid. For a 2200 Watts machine be sure that the transformer can handle a net output of 3000 Watts. Which means it is a big and heavy item that may even have a set of wheels attached. With the cost of such a large transformer added, it remains to be seen if the whole undertaking is still profitable. A used transformer will be much cheaper, but be sure the channels through which you purchase it, are trustworthy and willing to provide some sot of warranty.

Success

gerhard

[gerhard]

Hi, Weaver, me again,

i read your post too quickly. Happens to me more often.I reread it and you didn't live in the USA, but you wanted to import a 120 Volts machine from the States and use it on 240 in Oz, right? In that case the transformer story still goes, but you need a "step-down transformer" from 240 to 120, which are easier to obtain but still expensive. The 3000 Watts net output spec remains unchanged.

regards

gerhard

PS; Strange that the Hitachi C13U and the Makita 5143R are not available over there. Probably something to do with these models not complying to a few of your safety standards. We have that in Europe as well, especially France is very nitpickerish about imported tools which do not comply to French wishes within a distinct molecular exactitude. Just protectionism, if you ask me.

[gerhard]

Two examples of step up- / step down transformers:

the first ons is shown in this link:

TC-3000B 3000 watts Step UP and Down Voltage Transformer (http://www.world-import.com/3000b-1.htm)

but it looks skinny and for 70 US dollars it can't be much quality. The stated 3000 Watts is probably a short-term rating of a few percents duty cycle instead of continuous rating, which it should be for power tools. The ad claims "heavy duty continuous use", but at a mere 34 pounds of weight, i know from practical experience that this can't possibly apply to the full 3000 Watts continuously. There's just not enough solid material built into this thing to convert that much energy without serious overheating.

The second example is shown in the little pic below. This transformer is sealed watertight, truly manages 3000 Watts and costst about 650 US Dollars. Just to give you an impression what you're in for.

gerhard

[Chas]

The TC-300B is most certainly a cheap auto-transformer, ie non-isolating, which would be prohibited in Australia for use with any tools. In general terms, an auto-transformer is only permitted when it is fitted in an appliance, and the appliance has had the appropriate approvals.

Regards,

Chas.

[gerhard]

Hi Chas and Weaver,

that's something i didn't know. In Europe the use of auto-transformers is permitted in certain cases, provided that the risk of a live potential as measured against earth, is notified clearly on the casing as a clear warning. Furthermore the use is solely intended for trained personnel and the responsibility for use and consequences rests with the employer, never the employee.

Since you bring up the topic of auto-transformer and since i'm answering anyway, i might as well explain what an "auto-transformer" is. With "step-up" and "step-down" and "auto", the jargon may have gotten a bit rich for some readers.

A transformer has an iron core, through which runs a magnetic field in a closed loop, when a copper wire coil wound around the iron core, is fed with electricity. A second coil, wound on a different spot around the iron core, can convert the magnetic field back again into electricity. Hence the term "transformer"; the primary voltage is converted into a secundary voltage through intermediary magnetism. The nice and simple thing about a transformer is, that the primary and secundary voltage can be predicted by the number of coil windings. If you use a primary coil with a 1000 windings and feed 240 Volts into it, you can be pretty sure to obtain 120 Volts from the secundary coil when it has 500 windings. If a transformer is used to obtain a lower voltage than the primary value, it is called a step-down transformer. E.g. every power block containing a transformer, meant to feed a battery radio or a calculator or to charge a set of batteries, is a step-down device. If a transformer is used to multiply the primary voltage, it is called a step-up transformer. E.g. a microwave tube needs 800 Volts to operate, so there is a step-up transformer in your microwave oven. Just make a secundary coil of 3333 windings against the primary 1000 windings and presto, there's your 800 Volts.

Also a nice and simple feature of the two-coil transformer is, that is truly separates the primary and secundary voltage. The system of the mains power supply is such, that there is a certain resemblance between the neutral wire and the earth connection. They are not exactly equal, but the story would get too long to explain why. In effect the truly dangerous wire is the live wire. Its potential measures 240 Volts against neutral and also against earth. The risk of electrocution is there when your body makes contact with earth and also touches a live wire. A secundary coil of a two-coil transformer has only a potential difference between its two secundary coil terminals and no potential whatsoever against neutral or earth. So a two-coil transformer can also be used to get rid of the potential risk of live-against-earth. In such transformers , the primary and secundary coil have the same amount of windings. So if 240 volts is fed into the first coil, 240 Volts comes out of the second, and neatly isolated from the mains. These "one-on-one" isolating transformer are used for "wet system" (stone cutting or polishing with electric grinders combined with water cooling, etc.).

The auto-transformer is a skimped-down version with one coil only. E.g. by tapping a 1000 windings coil in the middle, you can obtain the lower secundary voltage in a cheaper way. There is no secundary coil, which saves a lot of expensive copper. So the primary coil is also used to deliver the secundary voltage "by itself" ("auto" is Latin for "by itself"). Auto-transformers are lighter and cheaper and often slightly more compact, but the cheapness comes at a price. By tapping the single primary coil for a secundary coil without the provision of a second coil, the dangerous live potential as measured against neutral or earth, remains present. The nice electrical isolation from the mains was skimped out together with the second coil.

Since auto-transformers are often hard to distinguish as such from outward appearance (unless clearly advertised by a mentioning on the type plate or a specific danger warning sticker on the housing), they can cause dangerous situations if you don't realise that they still carry the dangers of mains live potential to you, and are therefore not advised and sometimes even forbidden for use with power tools, especially outdoors or in environments with lots of conducting steel or water.

gerhard

[gerhard]

Textual mistake:

By tapping the single primary coil for a secundary voltage without the provision of a second coil,...

[TP1]

I wasn't aware of the legalities of transformers in Australia, but I have a pair of 5KVA balanced step down transformers that I was previously using in an audio application. This has encouraged me to buy some 120V tools from the USA where there are on occasion, big price differences with Australia. This applies to a variety of tools but usually to the more expensive easily shipped type like certain Festool gear (Festool don't ship internationally but I have it shipped free to a US address then to Australia),

With the balanced transformer, the voltage is delivered in halves by two outputs which are 180 degrees out of phase with each other, and a centre tap to earth. When combined, the total voltage is achieved but any extraneous signals in the wire is eliminated. This does make a difference in most situations to audio quality, but I guess it won't make my tools run any better.

[gerhard]

Hi TP,

your post invokes yet another peculiarity about tranformers, having to do with output current and copper wire gauge. If a transformer has a certain size large enough to, say, handle 10 Amps at 240 Volts in its primary "input" coil, the secundary "output" coil can handle something close to 2400 VA (10 x 240) as well; with a few percents of conduction losses in iron and copper to be substracted, of course. So if the secundary coil is laid out for 120 Volts, you could in theory tap almost 20 Amps (16 to 18 in practice) from it. But this means that the wire gauge of the output coils has to be laid out in twice the diameter to handle this higher current.

Your balanced transformer yields the same voltage output across the two secundary winding halves counted together, meaning that their wire gauge is probably the same as that of the primary windings. This means that both secundary windings may only be fit for 2500 Watts each, so you probably can't draw the full 5 kVA from one secundary winding only.

gerhard

[weaver]

The Main thing I would want such a saw for is to break down cants from my chainsaw mill. Cutting 150mm x 20mm or 12mm boards is a bit of a waste of timber with the CSM. I think the best option is going to be spending the money on a band saw that can handle that sort of ripping consistently. However, since I don't have the readies currently either way I'll have to wait and save up :)

[peter radclyffe]

to cut 4" & 5" austrian larch hull planking building the jeanie johnston we used a compressed air circ saw, as it will stop rather than burn out, one lad pulled it on a rope , one man guiding it

[weaver]

to cut 4" & 5" austrian larch hull planking building the jeanie johnston we used a compressed air circ saw, as it will stop rather than burn out, one lad pulled it on a rope , one man guiding it

Cool another option. Were do I get info?

[peter radclyffe]

<TABLE id=rsltwrap><TBODY><TR><TD id=rsltl> </TD><TD id=rsltc>Saws: Hand, Portable, Compressed Air Suppliers

Displaying 1 to 17 out of 17 results
<SCRIPT language=javascript type=text/javascript><!--document.getElementById('utillinks').innerHTML = "http://www.woodworkforums.com/images/icons/email_multiple_rollover.png (http://www.woodworkforums.com/\"/multiselect.html?which=prod&heading=70870407&goto=%2Fproducts%2Fsaws-hand-portable-compressed-air-70870407-1.html\")http://www.woodworkforums.com/images/icons/save_rollover.png (http://www.woodworkforums.com/\"/mythomas/saveresults.html?which=prod&heading=70870407&goto=%2Fproducts%2Fsaws-hand-portable-compressed-air-70870407-1.html\")http://www.woodworkforums.com/images/icons/forward_rollover.png (http://www.woodworkforums.com/\"/emailresults.html?which=prod&heading=70870407&goto=%2Fproducts%2Fsaws-hand-portable-compressed-air-70870407-1.html\")http://www.woodworkforums.com/images/icons/print_rollover.png (http://www.woodworkforums.com/\"/print/products/saws-hand-portable-compressed-air-70870407-1.html\")";//--></SCRIPT><TABLE id=rsltlist><FORM name=comparesupp action="" method=post><TBODY><TR class=compbtnrow><TD style="BORDER-TOP- PADDING-RIGHT: PADDING- 3 BORDER-LEFT- BACKGROUND: url(/images/images/compare_toparrow.gif) #fff no-repeat left 50%; BORDER-BOTTOM- PADDING-BOTTOM: 6px; PADDING- 12px; BORDER-RIGHT- 0px" colSpan=4>http://www.thomasnet.com/images/images/chk.jpg to http://www.woodworkforums.com/images/images/compare_suppliers_rollover.png</TD></TR><TR id=row587988><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'1','CS Unitec, Inc.');" type=checkbox value=587988 name=selectco></TD><TD class=toprow>CS Unitec, Inc. - Norwalk, CT
Manufacturer, Custom Manufacturer, Service Company
http://www.csunitec.com/concretesaws/concre... (http://www.csunitec.com/concretesaws/concretemain.html#circ)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=1&cid=587988) Manufacturer of hand held saws including portable, hydraulic, electric & compressed air hand saws designed for cutting cut concrete, asphalt or metal. Hand held saws can cut wet or dry. Features include 3/4 in. water connection port, maximum cutting depth up to 7 in, motor power up to 9.5 hp,...
Brand Names: Unibroach, CS Unitec, Plantex, Varilex, Trimtex, Airband <DL><DT>Portable Compressed Air Hand Saws Product Catalog: (http://www.thomasnet.com/catnav/list.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=1&cid=587988) <DD>Portable Power Hacksaws (http://www.thomasnet.com/catalognavigator.html?cid=587988&cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=1&cnurl=http%3A%2F%2Fcsunitec.thomasnet.com%2FCategory%2Fportable-power-hacksaws&prodpos=1&searchpos=1) <DD>Concrete Pneumatic Cut-off Saws (http://www.thomasnet.com/catalognavigator.html?cid=587988&cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=1&cnurl=http%3A%2F%2Fcsunitec.thomasnet.com%2FCategory%2Fconcrete-pneumatic-cut-off-saws&prodpos=1&searchpos=1) </DD></DL></TD></TR><TR id=row1301046><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'2','Grainger Co., Inc.');" type=checkbox value=1301046 name=selectco></TD><TD>Grainger Co., Inc. - Lake Forest, IL
Distributor, Custom Manufacturer
http://www.grainger.com/Grainger/wwg/search... (http://www.grainger.com/Grainger/wwg/search.shtml?op=search&Ne=10071&N=11963)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=2&cid=1301046) Distributor of a wide ariety of saws. Featuring power saws including band, reciprocal, abrasive cut-off, chop, circular, jig, diamond & table saws with corded & cordless varieties. Hand saws include tri-fold, wallboard, drywall, coping, miter, dovetail, jamb, PVC & hacksaws. </TD></TR><TR id=row424725><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'3','MSC Industrial Supply Co.');" type=checkbox value=424725 name=selectco></TD><TD>MSC Industrial Supply Co. - Melville, NY
Distributor, Custom Manufacturer
http://track.did-it.com/n?lid=50009517&tid=... (http://track.did-it.com/n?lid=50009517&tid=4372070a9eb2d&url=http://www1.mscdirect.com/CGI/NNSRHM?KNCT7L391316886&cm_mmc=Didit-_-SEM-_-ItmDtl-_-PypClk&LID=50009517)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=3&cid=424725) Supplier Of 450,000 Products From 2,500 Manufacturers: Cutting/Machine/Hand/Power Tools, MRO Supplies, Abrasives, Fasteners, Precision Instruments, Machinery, Electrical Supplies, Safety Equipment, HVAC, Welding, Hose, Tubing, Fittings, Material Handling, Pumps, Power Transmission, Janitorial; Same... </TD></TR><TR id=row10061335><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'4','Airmatic Inc.');" type=checkbox value=10061335 name=selectco></TD><TD>Airmatic Inc. - Malvern, PA
Distributor, Custom Manufacturer, Manufacturers' Rep, Service Company
http://www.airmatic.com/tool-group/cutting/ (http://www.airmatic.com/tool-group/cutting/)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=4&cid=10061335) Distributor of hack (power) saws, hand saws, portable hydraulic hand saws, compressed air portable hand saws & portable electric hand saws. Portable cut-off saws available with 1/2 hp motor with 4 in. abrasive cut-off wheel & 2 in. finishing & deburring wheel. Portable cut-off saws for cutting hard... </TD></TR><TR id=row186468><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'5','L. C. Miller Co., Inc.');" type=checkbox value=186468 name=selectco></TD><TD>L. C. Miller Co., Inc. - Monterey Park, CA
Manufacturer, Custom Manufacturer, Service Company
http://www.lcmiller.com/Tigair%20Saw/tigair... (http://www.lcmiller.com/Tigair%20Saw/tigair_saw.html)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=5&cid=186468) Custom manufacturer of portable pneumatic reciprocating saws. Specifications of portable reciprocating saws include 1-5/8 in. W x 5 3/4 in. H x 16 in. L size, 5.58 lbs. weight, 3/8 in. hose size, 0 to 1200 strokes per min., 1-3/4 in. stroke length, 6.5 cu. ft. air consumption & air pressure ranging...
Brand Names: Tigair </TD></TR><TR id=row10018278><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'6','High Precision, Inc.');" type=checkbox value=10018278 name=selectco></TD><TD>High Precision, Inc. - Hamden, CT
Manufacturer, Custom Manufacturer, Service Company
http://www.highprecisioninc.com (http://www.highprecisioninc.com/)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=6&cid=10018278) Manufacturer of a wide range of rugged industrial equipment including machinery for pipe cutting, sawing, threading, drilling, clamping & more. Many for use in harsh environments including oil fields & underwater. </TD></TR><TR id=row10017255><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'7','H & S Tool, Inc.');" type=checkbox value=10017255 name=selectco></TD><TD>H & S Tool, Inc. - Wadsworth, OH
Manufacturer, Custom Manufacturer
http://www.handstool.net/www/Sawing.html (http://www.handstool.net/www/Sawing.html)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=7&cid=10017255) Manufacturer of portable, electric hand-held, compressed air powered hacksaw, abrasive wheel tube & pipe saws for cutting single tube, pipes up to 24 in. (609.6 mm) O.D. Available in track & wrap saw models for pipe cutting & long cuts in waterwall panels. Blades are available in a variety of sizes... </TD></TR><TR id=row853785><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'8','The Walter A. Wood Supply Co., Inc.');" type=checkbox value=853785 name=selectco></TD><TD>The Walter A. Wood Supply Co., Inc. - Chattanooga, TN
Distributor, Manufacturer, Custom Manufacturer, Manufacturers' Rep, Service Company
http://www.walterawood.com/productline/hand... (http://www.walterawood.com/productline/hand.asp)
Company Profile: (http://www.thomasnet.com/heading.html?cov=NA&what=circular+saw+compressed+air+portable+for+wood&heading=70870407&searchpos=8&cid=853785) Stocking distributor of hand, portable & compressed air saws including bandsaws. Other products include pneumatic, radius, steam, engraving, electric tools, hammers, screwdrivers, ratchets, sockets, hexdrivers, pliers, nailers, dead blow hammers, striking wrenches, precision tools, woodworking,...
Brand Names: AMPCO, Armstrong, Channel Lock, Goldblatt, HILTI, Kennedy, Skil, WILTON, Milwaukee, Bosch, makita,... </TD></TR><TR id=row397759><TD class=listchk><INPUT onclick="compareSuppliersCnt(this,'9','Esco Tool');" type=checkbox value=397759 name=selectco></TD><TD>Esco Tool

i dont remember the make but try these guys
</TD></TR></TBODY></FORM></TABLE></TD></TR></TBODY></TABLE>

[gerhard]

Hi Peter,

amazing choice of air powered tools, i never knew there were so many!

Yes, Weaver, for consistent heavy use with lots of abuse and probably heavy (over)load, the electric circular saws don't offer much of a reserve and will burn sooner or later. Air motors stand up to it much better, although between electric, hydraulic and compressed air, air tools have the worst efficiency. You'll need a big compressor to drive a machine with more than 100 mms cutting depth.

[weaver]

I'm perfectly prepared to be called an idiot for this idea but.....

Since the large 12", 16" circular saws are powered by electric motors taken from angle grinders why not take an angle grinder and mount a circular saw blade onto it.

If this was then mounted onto a bench you could get a table saw capable of cutting more than 100mm depth.

Two of the mounts could be into the screw holes for the handles while a thrid to prevent tilt would need to be made.

[peter radclyffe]

yeah we wre cutting in the rain , when is it not raining in ireland, so electrics were out
id love to see a hydraulic saw, yeah probably more power,
weaver, why not, good idea, upside down with handles , a cheaper saw
i have used the big makita's , but look out, if they jam

[gerhard]

The gearboxes of angle grinders are much bigger, so you'll loose a lot of saw depth when using the same blade that you would use in the original circular saw with a motor of the same wattage. Mounting a bigger blade would seem to be the answer to that, but with the bigger circumference you would lose a lot of torque and the rpm would be too high for the bigger diameter (somewhere between 6600 rpm no-load and 3800 rpm nominal load, whereas the large circular saws are more in the region of 3000 no-load max. and 2200 to 1500 nominal load). Breaking TCT teeth would be like bullets and there would be frequent burning in the cut, especially when hitting resin inclusions or lateral forces in the wood grain.

As an experiment i once used a Bosch 2200 Watt masonry cutter, since it already provided a suitable base (adjustable guiding sole plate, better adapted front grip and a no-load rpm of 5000/min). I found a cheap saw blade with the same arbour hole size and indeed it worked its way through plyboard. The gearbox of this machine is especially bulky, so not much depth was to be gained from this layout, but it worked. The inline motor array of such an angled setup gives a very good balance, so in principle this would be a practical option. I also have a Flex 2000 Watt 2000 rpm angled stone polisher, i may try that one out and see how it fares, since it has huge torque and a fitting rpm. But i may have to invent something in the way of a riving knife, because a kickback would also be huge.

On Ebay i frequently see accesories meant for angle grinders, consisting of a disc with a bit of chain saw length wrapped around it. I don't know about safety rules and countries in which this thing would be permitted, but it shows that more people have entertained the idea of doubling a grinder as a saw. See the link below:

230 MM KETTENSÄGE KETTEN SÄGEBLATT FÜR WINKELSCHLEIFER bei eBay.de: Maschinenwerkzeuge (endet 25.12.09 22:18:11 MEZ) (http://cgi.ebay.de/230-MM-KETTENSAGE-KETTEN-SAGEBLATT-FUR-WINKELSCHLEIFER_W0QQitemZ280429279607QQcmdZViewItemQQptZGartenbauwerkzeuge?hash=item414ae33977)

cheers

gerhard

[urban]

i frequently see accesories meant for angle grinders

There is a much smaller woodcutting attachement for angle grinders but I have not tried it myself.

Search Results (http://www.axminster.co.uk/product.asp?pf_id=22389&name=arbortech&user_search=1&sfile=1&jump=44)

They claim it is usefull for trimming skirting boards but I would have thought a Multimaster would be simpler (but much more expensive).