Shear for cutting Meccano angle strips

[BobParticipant @bob17059]

I find myself needed to crop some Meccano angle girders (1/2″ x 1/2″ typically 0.033″ to 0.035″ thick Part No. 8) into 1 1/2″ lengths to make Part No. 9f. I need a lot of these short lengths for a large model. I have seen various angle croppers that either have a rotary shearing action or a simple guillotining action in a press. Have any designs been published in the Model Engineer or MEW for such a tool. I have access to a flypress and hydraulic press.

 

[bernard towersParticipant @bernardtowers37738]

If you need a lot of them it would be worth making a jig to accurately saw them with a junior hacksaw or find a friendly laser cutting company

[Martin ConnellyParticipant @martinconnelly55370]

At work we had a modified battery drill driven din rail cropper. It used a straight guillotine type shearing action.

Martin C

 

[Martin ConnellyParticipant @martinconnelly55370]

This may give you some ideas.

Martin C

[bernard towers]

On bernard towers Said:

…or find a friendly laser cutting company

Please have a look at part numbers 8 and 9f here:

https://www.meccanospares.com/mid-green-angle-girders/page/1/

Please suggest how a part 8 might be cut into a number of parts 9f using a laser cutter that generally only cuts contours on the XY plane.

Please suggest how you would arrange and secure the parts on the bed of the machine so that the cuts are square to the axis of the part.

Please advise effect on the multi-thousand pound laser apparatus from cutting a painted (or zinc plated) item.

I am quite sure that being a mature and sensible poster here you would not just blurt out ‘laser cutting’ without having considered these issues in some detail, so please share your wisdom with us.

[Michael GilliganParticipant @michaelgilligan61133]

It’s much too big … BUT

For design inspiration:

https://www.roperwhitney.com/our-products/no-4-shear-wstandard-blade-72-handle/

MichaelG.

[BobParticipant @bob17059]

This is the sort of press tool I envision

But scaled down a bit. Probably get the cutting parts waterjet cut by the usual place. Re Laser cutting the angle quite a few laser cutters have rotary head attachments primarily used for engraving glass and trophies so one of these might be pressed into service but the aforementioned usual place has not been keen to take on this sort of job in the past probably too much setting time.

 

Bob

[Speedy Builder5Participant @speedybuilder5]

Another shear on the same principle.

IF you had a small fly press, you could make a shear block up out of silver steel – as I sad IF !!

[Paul LousickParticipant @paullousick59116]

How many is “a lot” ?   Unless you are talking hundreds, it is not worth making a special cutting tool. Instead use a simple guide and hack saw as already suggested. Clean up the ends with a file or belt grinder.

[Martin ConnellyParticipant @martinconnelly55370]

My personal method would be to fit a fine tooth belt on my bandsaw and batch cut a nested horizontal stack of them to length because I have a bandsaw with controllable rate of decent and some fine tooth blades.

Martin C

[Martin Connelly]

On Martin Connelly Said:

My personal method would be to fit a fine tooth belt on my bandsaw and batch cut a nested horizontal stack of them to length because I have a bandsaw with controllable rate of decent and some fine tooth blades.

Martin C

Well, try it and see!   Difficult to stop delamination and other unwanted nastiness as the teeth break through each piece.   A jig that grips a stack of angles firmly on both sides of the cut comes to mind.

I  think Bob is very much on the right track with a die, but quite a lot of Gauge Block needed!

Bob having a fly-cutter suggests he has experience in sheet metal work, where shearing is often the best way of cutting it.    Word of warning to Model Engineers – the metal-working techniques most of us have available are extremely limited compared to what a manufacturer can deploy.   Meccano would never have used a saw, laser cutter, water-jet, lathe, milling machine or grinder to make ½” angle.   They’d have a line of shearing, pressing and stamping machines churning them out very quickly by the thousand.

Much depends on how many Part 9fs Bob needs to make.   Less than 20 could be done tediously using ordinary techniques, junior hacksaw etc.   Making more than 50 definitely calls for a production method : saw or shear jigs etc.

I have some experience modifying Meccano strip by sawing and milling, and it didn’t go particularly well. Needed several Part 6a (flat strip with 3-holes), and have plenty of mangled long strips to recycle.   Hacksawed them to length and made a fixture to hold them in a rotary table to mill the rounded ends.  Left me convinced there must be a better way!

I don’t know where Meccano got their steel from, but I found it to be gritty soft stuff that didn’t machine well.   My guess is Meccano strip was manufactured from a roll of dead mild-steel plate normally used to press parts.  No problem for making models from stampings, but the steel isn’t structurally strong and is more than obviously less machinable than EN1a!

What are you making Bob?   Do I detect a proper grown-up Meccano modeller aiming to win prizes at Skegness?

Dave

 

[Adrian R2Participant @adrianr2]

The usual suspects in China offer a “Universal Manual Angle Steel Shear” which you could use for inspiration for a tool to use in your fly press, they have likely made the simplest and cheapest design.

It’s basically a piece of inverted angle iron as an anvil and a V slotted shear in two runners. You might not even need the runners if you can attach the shear to the punch of your press.

 

[BobParticipant @bob17059]

Dave

I am working on a model of the Fishguard Titan Blocksetting crane using Peter Harwood’s plans as my starting point. I tend to work with Meccano+ ie Meccano system plus bits and pieces I engineer using model engineering principles. I have been busy making the narrow strips which abound in the design. There are 210 of these special strips rumbling around in my vibratory deburrer machine as I type this! . I have had some specials laser cut by Model Engieer’s Laser and am working on these at the moment. I have also turned up the 32 flanged wheels from steel as the brass flanged wheels in Meccano are very prone to buckling.

https://www.hsomerville.com/mwmailorder/MWModelPlans/MP169.html

 

[Martin ConnellyParticipant @martinconnelly55370]

Well Dave, I would constrain the stack with some of the stainless steel cable ties I have or Jubilee hose clips if they were not holding the stack tight enough. As I said, I also have controlled descent on the bow of my bandsaw so I can control the aggressiveness of the cutting action. Batch cutting like this is standard in raw material stores, just think how many blanks are needed for a turbine when you are machining single blades from a billet.

Martin C

[Bob]

On Bob Said:

Dave

I am working on a model of the Fishguard Titan Blocksetting crane …

 

Excellent.   I’d have to buy a bigger house!

Dave

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