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Need to cut long thin strips of steel (& plastic) - e.g. with an angle grinder?

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Mike Poole22/01/2022 15:39:03
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I have worked on a sophisticated hydraulic shear that the top blade could be adjusted for shearing angle, I think as the thickness of material increased the angle of the blade shearing action would increase. The burr on the edge can be negligible with the blades sharpened correctly and adjusted properly. Worn trim dies could produce extremely sharp burrs and edge distortion. A well set up guillotine should produce parts that require very little fettling. Industrially they would probably be tumbled with an abrasive to produce safe to handle burr free parts. A tumbler is not hard to make, Google will probably take you to lots of rock polishing sites but the principles and equipment are similar.

Mike

noel shelley22/01/2022 16:58:28
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SODave If you have not seen or used a 1mm x 4.5"cutting disc you really aught to, makes a hacksaw look old fashioned, the only stumbling block is you need to be skilled to use it ! Noel.

JasonB22/01/2022 17:04:13
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Yes in the right hands a small grinder is quite accurate and the thin disks little wider than a full size hacksaw, add a thin diamond disc if cutting stone or tile to get more use out of it.

The larger blade actually helps you keep a straight line in much the same way you would not use a coping saw for straight cuts in wood as a Tennon or panel saw would be far more likely to cut a straight line.

Maurice Taylor22/01/2022 18:36:19
211 forum posts
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Posted by SillyOldDuffer on 22/01/2022 14:33:54:...

Better than a hacksaw, No. The Dremel Angle Grinder isn't a precision tool. They're good for fast hacking not accurate cutting. Mine is the same size as Dremel and I use it on paving slabs, to chop lumps of metal into approximate shape, and demolitions! Based on earlier answers, an Angle Grinder isn't fit for purpose. Could be used to rough out metal which would have to be considerably cleaned up by other tools.

The Dremel multi-tool is slow, but used carefully it's capable of accurate work. Based on earlier answers, the multi-tool is a runner.

In summary:

  • Angle grinder: fast, noisy, messy, broad rough cuts. Inaccurate.
  • Hacksaw: slow, quiet, narrow cuts, accurate in skilled hands, or with a jig.
  • Dremel Multi-tool: slow, slightly noisy, versatile, good for fine cutting, delicate grinding, polishing, and small diameter drilling. Much favoured for delicate accurate work, skill required.
  • Not available: a small cheap tool for unskilled users that quickly makes precision burr-free straight steel strips!

Compromise or buy a big expensive tool.

Dave

Hi, Can you please explain why an angle grinder is messy ,has broad rough cuts and is inaccurate.

Have you ever used a 4.5inch with a 1mm blade on steel sheet ,this will cut accurately.

Maurice

SillyOldDuffer22/01/2022 19:01:53
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Posted by Maurice Taylor on 22/01/2022 18:36:19:
Posted by SillyOldDuffer on 22/01/2022 14:33:54:...
....

Hi, Can you please explain why an angle grinder is messy ,has broad rough cuts and is inaccurate.

Have you ever used a 4.5inch with a 1mm blade on steel sheet ,this will cut accurately.

Maurice

It's because I'm wrong Maurice!

My metal cutting discs are 3mm, which was the thinnest on sale in my local Builders Merchant. I assumed they were the thinnest available - silly me.

blushblushblush

Very educational this forum!

Ta,

Dave

Speedy Builder522/01/2022 19:54:02
2590 forum posts
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Pen nibs are split with a thin diamond impregnated disc something like this. Mount the disc onto a cheap plotter table with hub etc and let it spin away all night ?

Maurice Taylor22/01/2022 20:06:38
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Posted by SillyOldDuffer on 22/01/2022 19:01:53:

It's because I'm wrong Maurice!

My metal cutting discs are 3mm, which was the thinnest on sale in my local Builders Merchant. I assumed they were the thinnest available - silly me.

blushblushblush

Very educational this forum!

Ta,

Dave

Hi Dave , Thanks for your reply, regarding the 3mm discs ,I agree with your angle grinder comment.

Maurice

Ian P22/01/2022 21:17:48
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Posted by Speedy Builder5 on 22/01/2022 19:54:02:

Pen nibs are split with a thin diamond impregnated disc something like this. Mount the disc onto a cheap plotter table with hub etc and let it spin away all night ?

Did you mean to show a link to whatever 'this' is?

Must be extremely thin and fragile if its anything like any fountain pen I have ever seen

Ian P

John Smith 4725/01/2022 23:06:16
393 forum posts
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Dave

> Angle grinder: fast, noisy, messy, broad rough cuts. Inaccurate.

My point was just that if used against a straight edge and with a fine metal-cutting blade, surely the Dremel DSM20 would be pretty accurate.



One thing slightly worries me - do these things ever suffer from kick-back?

Talking of which, out of interest, in order to increase accuracy on longer cuts, is it possible to get as an attachment an equivalent of the "riving knife"/"splitter" like table saws have?  i.e. That would go into the cut left by the cutting wheel... to keep the cut straight.

> Dremel Multi-tool: slow, slightly noisy, versatile, good for fine cutting,
> delicate grinding, polishing, and small diameter drilling. Much favoured
> for delicate accurate work, skill required.
Yes but - back to the question - how would you cut long thin straight lines through metal, using a device whose spinning wheel tugs you sideways when you make a cut?

J

Edited By John Smith 47 on 25/01/2022 23:19:08

Robert Butler25/01/2022 23:11:48
382 forum posts
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I wouldn't

Robert Butler

Maurice Taylor25/01/2022 23:27:18
211 forum posts
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Hi, My angle grinder doesn’t tug sideways ,you have to practise on scrap first .What sort of angle grinder do you have ?

Maurice

Nicholas Farr26/01/2022 09:09:48
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Hi, with any tool, it takes a certain amount of skill and practice to achieve the results that you want. You can cut straight neat lines with thick or thin discs. You can get a kick back with these and is more prone on thin metal, but on thin metal there is a tendency for a narrow stripe to sag, which will tend to close the gap and the the cutting disc catches and it will often put a kink in the metal that you are trying to cut off. The best way for cutting thin metal with a angle grinder of any size, is to have the sheet that you are cutting, placed on a flat surface like a piece of thickish plywood. So if you mounted two pieces of plywood onto two or three cross timbers, with a gap between them, a little wider than the cutting disc, it would give support to both sides of the metal you are cutting. Cutting will always generate some amount of heat, but thinner discs should produce less heat, but with any tool, you must allow it to do the job within its capabilities, no good trying to force it to do the job faster. The smaller diameter discs of the DSM20 will probably be suited better to thin materials than a 4-1/2" grinder. There are quite a few videos on the internet, demonstrating the Dremel's.

Regards Nick.

Edited By Nicholas Farr on 26/01/2022 09:11:49

Nicholas Farr26/01/2022 09:34:38
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Hi, I know these are not thin steel, they are 6mm and I had to cut about ten of each of these with a 4-1/2" angle grinder with thin discs, in my last job and of course I had to start the cut between the lugs with plunge cutting, nothing messy about them that I can see.

2016-12-20 08.24.53.jpg

2016-12-20 12.12.04.jpg

Regards Nick.

Stephen Cassidy26/01/2022 10:41:29
6 forum posts
11 photos

I have built my own solution to this using some aluminium extrusion as the work platform and box steel for a gantry rail. I then made a base and adjustable slide for the angle grinder and other tools

You could build a smaller version for not a lot of money. I normally purchase metal in bulk and in large sheets so I needed my saw to be a good size.

I have a number of different saws but only angle grinders for long straight cuts . If you look on YouTube for angle grinder track saw that will give you a few was to make it , there is also a precision track saw that is incredibly accurate.

My track saw will take up to 1.2m sheets which can be clamped down , however I am adding mag locks soon .

I am making a fixture plate for my lathe and cut a 16mm thick sheet with good accuracy ,1mm x 125mm disc

512b6a32-8952-44e3-921d-397119c0f6da.jpeg

1ad9ae31-40a2-4cec-bc28-410ccc92f505.jpeg

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John Smith 4726/01/2022 11:21:18
393 forum posts
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> there is also a precision track saw that is incredibly accurate.
Stephen - could you possibly provide a link?

TBH, I don't really have the workshop to do much making of my own tools, but what these guys have made caught my eye:
"Universal Rail System for Grinder, Circular Saw, Router and Film Cutter"

Wonderfully inventive, no?
If/when I get a large workshop I might even buy one! One can but dream...

Re this thread, to be completely honest, no only have I now done all the cutting I need the hard way (by hacksaw) but also for me personally, the physical size/scale of this whole conversation is getting rather out of control, as I am only looking needing to make precision cuts to create lengths of stainless steel sheet (c.1mm thick) that are about 20cm to 30cm long.

Good fun to think about though.

J

Edited By John Smith 47 on 26/01/2022 11:27:19

peak426/01/2022 11:39:53
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1671 forum posts
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That last rail system is neat.
On a smaller scale, you can fabricate something similar using draw runners.
I did so when I had some 8" planer blades to re-grind, and my Clarkson doesn't have enough table travel.
Use the heavier industrial runners rather than the very light ones in kitchen cabinet drawers.

Bill

Stephen Cassidy26/01/2022 12:36:29
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11 photos

Hi John

**LINK**

there are lots of ways to make one, I took tips from a few projects to make mine. I haven’t motorised the axis on mine just yet .


Stephen Cassidy26/01/2022 19:26:23
6 forum posts
11 photos

Also a cheaper option for the accurate cutting is making this type of track saw made from cheap mild steel and a few bearings

**LINK**

Pete White26/01/2022 20:37:09
162 forum posts
16 photos

I like that, we are in the days of the tig these days, limited distortion. I think one of those is my next purchase.

Gone are the days of oxy / acetulene and mig for me, for what I do these days. yes

Pete

P.S. still have a 275 amp Oxford stick job under the workbench, for bigger jobs when needed, nice for small stick jobs as well smiley

John Smith 4727/01/2022 21:41:00
393 forum posts
12 photos
Posted by Stephen Cassidy on 26/01/2022 12:36:29:

Hi John

**LINK**

there are lots of ways to make one, I took tips from a few projects to make mine. I haven’t motorised the axis on mine just yet .

I'm not entirely sure how relevant it is but yes,
"Challenge to recycle Coca-Cola!/ Make a simple alcohol stove (soda can stove)"
is very zen/meditational. If one has a few minutes to spare... Good fun.

Thanks

J

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