PDA

View Full Version : Double Bladed Cutter



cameby
01/04/12, 08:07 AM
Is anyone here familiar with the double bladed circular saw they are advertising on TV at the moment. Sorry I can't remember the name of the damn thing, but I've developed a resistance to TV advertising that even I can't overcome when I want to. Basically it was like a largish angle grinder, but it had two tungsten tipped cutting blades. These blades turn flat out (5000 rpm from memory) but in opposite directions. The idea is to neutralise the forces that we fight when we work against the direction of the blade. It seems to run off the differential principle, with a shaft through the spindle driving the outer blade one way and the spindle driving the other in the opposite direction.

OK, it's TV, and they pumped this thing up until even I was starting to try and remember where my phone was, but it cut through timber and steel and aluminium and plastic like it was butter. Moreover, the people using it weren't struggling with the effort, and on metal it didn't produce many sparks. It looks like it could be a good thing if Makita or Festool or someone decent could make them. No idea how much they were selling them for.

Huey
01/04/12, 09:58 AM
I'm guessing that it has contra-rotating blades?

cameby
01/04/12, 10:09 AM
I'm guessing that it has contra-rotating blades?

That's another way of putting it! Are you familiar with it?

Wongo
01/04/12, 10:17 AM
How funny, my daughters and I watched the same ad on 73. My first reaction was wow that is a great idea. No tear out, no kickbacks, blades generate less heat, etc. But like all the stuff they sell, 9 times out of 10 they turn out to be absolute rubbish. I am not sure what this one is like, and how many blades did they use to cut the steel. Then again if it was that good then how come no big name has copied it already. They don't tell you how much either which is annoying.

Huey
01/04/12, 12:07 PM
That's another way of putting it! Are you familiar with it?Not the tool but the concept has been around in aviation for quite a while to counterract torque so the principal should work well in a tool like that provided they take care with the gearbox design. It would require two concentric shafts driving the blades so the gearbox would be heavy and complex. If the tool is cheap I don't think I'd be game to use it, I have had an Ozito grinder disintegrate in my hands and it was not a pleasant experience, although I was very lucky not to be injured.

Joker
01/04/12, 12:32 PM
I have had an Ozito grinder disintegrate in my hands and it was not a pleasant experience, although I was very lucky not to be injured.Putting a positive spin on it ... maybe it was designed specifically not to injure you when it ultimately disintegrates. :)

cameby
01/04/12, 12:35 PM
Not the tool but the concept has been around in aviation for quite a while to counterract torque so the principal should work well in a tool like that provided they take care with the gearbox design. It would require two concentric shafts driving the blades so the gearbox would be heavy and complex. If the tool is cheap I don't think I'd be game to use it, I have had an Ozito grinder disintegrate in my hands and it was not a pleasant experience, although I was very lucky not to be injured.

Almost certainly the one they're advertising would be badly made. But it looks like a great idea.

Tolovar
01/04/12, 03:00 PM
Putting a positive spin on it ...:)
actually it puts a negative spin on one blade and a positive on the other one

Huey
01/04/12, 03:17 PM
Putting a positive spin on it ... maybe it was designed specifically not to injure you when it ultimately disintegrates. :)Very clever how they designed the bearings to bounce off my glasses and not penetrate into an eye. Also the ones that hit my belt but travelled no lower. Mind you, the one that hit my neck did sting a bit.

Pat
01/04/12, 11:33 PM
Have a look at GraysOnline (http://www.graysonline.com/lot/0001-2043286/power-tools/tru-blue-twin-blade-big-brother-155mm-or-6-1-8th-inch-package). This is were a lot of shit goes when the telemarketers cant move it.

journeyman Mick
02/04/12, 02:56 AM
I've seen the same ad, I think it's called a dual saw. I googled it and there's a number of similar saws on the market in the US. The only real advantage is the ability to cut in both directions and the elimination of kickback. Cons are the added weight and complexity and the small size of the blades and therefore depth of cut. The test where they had the big muscly bloke trying to cut into a safe with a 4" angle grinder VS lady with a dual saw was a sham. The bloke was not doing it right, didn't sink the blade in full depth and then cut against the direction of rotation. He was only doing a shallow cut and then trying to go with the rotation resulting in the blade rising up out of the cut. A fair test would have been dual saw VS a circular saw with a TCT steel cutting blade, like for like. There would not be much in it.

Mick

Bleedin Thumb
02/04/12, 04:02 AM
I haven't seen the ad, but I have used wall chasing saws. Wouldn't one disadvantage of this saw be that the width of cut would be a shocker. A normal blade gives you 2mm odd so this would be cutting at least 5mm I assume.

Gyro
03/04/12, 04:42 PM
Reading a Electrical "Circuit" magazine, I came across the Blokes Mate 650SN, distributed by Ampere.

I googled it and cannot find it, so I found a PDF version of the mag and its on page 33 http://en.calameo.com/read/000373495442ab024e129

http://theblokeyshed.com/forums/attachment.php?attachmentid=8839&stc=1&d=1333453288 (http://en.calameo.com/read/000373495442ab024e129)

Bunyip
04/04/12, 02:06 AM
I saw (pun not intended but I'll take it) the ad yesterday, kerf is massive, greatly exaggerated wrong cutting techniques (bit like the bra ad with the sheila hauling her tits around in an effort to get them where they belong) and funnily enough no mention of price, just call our operators who are waiting to hear from you.

Coldamus
04/04/12, 03:19 AM
What about oscillating cutters? They are certainly safer, though much slower. The Fein MultiMaster seems to be regarded as the best but they are available in many other brands, corded and cordless. I saw a brief demonstration at a wood show a couple of years back but haven't tried one myself. Are they any good?
http://www.youtube.com/watch?v=uq3V-MfGzFk&feature=related

Wongo
04/04/12, 04:13 AM
I must say I like the idea of a multimaster. It seems like a great idea. If I had enough of home improvement jobs I would certaily get one.

Wombat
04/04/12, 04:22 AM
it only cuts 28mm, it's use is very limited

Bunyip
04/04/12, 05:12 AM
I have a Bosch oscillating cutter, good for cutting skirting boards and sawing in confined spaces, I cut square holes in plasterboard to mount coax wallplates, works a treat and no danger of unexpectedly finding power cables.
Aldi had one a few weeks ago for about $35 which pissed me off as I paid about $160.

Tolovar
04/04/12, 06:34 PM
The Aldi one is great :clap

Wongo
05/04/12, 03:24 AM
What about the renovator?

http://www.psmarketing.co.nz/images/291/large/Renovater-Delux-4390.jpg

Bunyip
05/04/12, 03:29 AM
Free with the ladder they won't give you a price on, our operators are waiting to hear from you now...

Wongo
05/04/12, 03:39 AM
Looks like a GMC don't you think?

Gyro
07/04/12, 05:19 AM
Was on TV this morning
http://www.dualsaw.com

http://www.dualsaw.com/product_images/14294.png
(http://www.dualsaw.com)

dentuso
07/04/12, 11:55 AM
I reckon this is the usual " hit and run " sort of thing.

If companies like Metabo, De-Walt, Bosch, Makita and Hitachi are not either making it or thinking about it ... it won't work.

Most of the blades I use on my saws cost more than the whole saw and blade from the likes of Ozito.

Counter- rotation has been around for years.. look at the Volvo -Penta sterndrives.

Why has this technology not been represented in the marketplace until now?

dentuso
07/04/12, 11:56 AM
Looks like a GMC don't you think?

Yep Wongo.. Cheap tools come in cheap cases!!

Wongo
07/04/12, 12:58 PM
If companies like Metabo, De-Walt, Bosch, Makita and Hitachi are not either making it or thinking about it ... it won't work.


Great point

dentuso
07/04/12, 03:40 PM
Myf naked ... easter tits .. recent

That should net a few newbies

Wongo
07/04/12, 04:03 PM
Apparently the inventor is a Frenchman. What does that tell you? :tw

In the ad it claims that the Dual saw took 8 years and millions to develop. As if...

Jack
09/04/12, 09:57 AM
Are the Fein Multimaster type tools any good for cutting polycarbonate roofing sheets?

Bunyip
09/04/12, 10:54 AM
Should work just fein although I use a sabre saw, a lot quicker unless you want to hack a piece out while it is in place.

Jack
09/04/12, 10:57 AM
No, I want a very neat and square cut.
I need to cut 3 x 1800 long sheets into 6 x 900 pieces.

Do you think a sabre saw following a straight edge would suffice?
I don't have a sabre saw or a multi tool thingy but would be happy to buy a cheapy just to do the job.

Bleedin Thumb
09/04/12, 11:43 AM
If you are talking about a reciprocating saw when you say Sabre saw ...I wouldn't use it on poly carb sheeting, I would go a jig saw with a plastic cutting blade. You will have more control and less likely to have splintering because of the sole plate being in contact with the sheeting plus you can use a straight-edge as a guide. You just have to make sure your sheet is really well supported either side and close to the cut.

Charlie
09/04/12, 11:49 AM
Do you think a sabre saw following a straight edge would suffice?
I don't have a sabre saw or a multi tool thingy but would be happy to buy a cheapy just to do the job.

I got one you can borrow but I just don't live that close anymore!

Jack
09/04/12, 11:50 AM
I might try a good pair of scissors first.

Bunyip
09/04/12, 11:51 AM
The fein is very slow, I have busted a lot of jigsaw blades cutting corrugated iron and find the sabre saw foot is more flexible, just my thoughts.

Madbugger
09/04/12, 11:53 AM
I used the 4" angle grinder with one of the thin kerf (1mm thick I think) metal cutting blades.

Obviously do it outside and use a suitable dust mask.

Jack
09/04/12, 12:04 PM
If you are talking about a reciprocating saw when you say Sabre saw ...I wouldn't use it on poly carb sheeting, I would go a jig saw with a plastic cutting blade. You will have more control and less likely to have splintering because of the sole plate being in contact with the sheeting plus you can use a straight-edge as a guide. You just have to make sure your sheet is really well supported either side and close to the cut.BT, it is not flat polycarb sheeting, it has a profile.

It's not standard corrugated, I can't remember what it is called.

I do have a jigsaw though, that may just do the job.
I'm pretty sure I could get a straight edge on there that will still guide the saw.

Tolovar
09/04/12, 12:04 PM
4" angle grinder with one of the thin kerf (1mm thick I think) metal cutting blades.

Gets my vote, though a mulit tool would do the job as well and a good excuse to buy one

Jack
09/04/12, 12:09 PM
I bought the sheets at bunnings, the "sales person" said angle grinders were no good as the heat from the disk melted the poly.

Perhaps that should tell me an angle grinder is the correct tool for the job.

A little more difficult to get a perfect line with a grinder though.

Hey MB, dust?
Seriously? How much dust do you get from polycarbonate sheeting?

Madbugger
09/04/12, 12:25 PM
Probably not much dust, but you are grinding it, not shearing like you would with scissors. Anyway,it is not the kid of shit I would want in my lungs.

You could also stick a metal cutting disc in a circular saw and use a straight edge it a really straight cut is necessary. If you cut quickly enough, and it doesn't have to be real fast, then the poly doesn't have enough time to melt. Now that I think about it, I think that is what I did, not use the angle grinder. Either way, it was a metal cutting disc.

Tolovar
09/04/12, 12:25 PM
Get a pack of three diffrent blades for an angle grinder and try the segmented one for cutting crramics

Wombat
09/04/12, 12:54 PM
a hand held fine toothed wood saw cuts it very easily

journeyman Mick
09/04/12, 01:31 PM
I usually cut it with aviation snips. If I use a hand tool to cut something it's not from lack of powered alternatives.

Mick

Jack
09/04/12, 01:33 PM
I will try one of these methods when I get home.

Tin snips were recommended by someone at bunnings but I never get a perfect cut with them.
If my heavy duty scissors will cut it I will go with them.

I agree that power tools aren't always suitable but having never cut polycarbonate roofing sheets before I thought I should ask.

Cliff Rogers
09/04/12, 04:13 PM
No, I want a very neat and square cut......
:clap
http://www.videojug.com/film/how-to-play-the-square-cut

bodgy
10/04/12, 05:22 AM
I just cut mine with big scissors. No problems, clean cut. The other option is a Stanley knife with new blade