# How to move a thin metal piece with a tiny string or anything else?

Recently I was experimenting with a metal piece, and I came across a challenge.

A small piece of thin copper metal (5cm x 3cm x 0.2 cm) has to be pushed forward and to be rotated. The problem is how to get a force behind the metal piece and have a force to rotate it. The metal piece must go from left side to the right side of the picture2.

The initial idea was to bind the metal piece with a metal bar and to rotate it so that metal will rotate accordingly. However the bar is too thick. I need to use a thin, ideally <5mm, string, metal piece or anything else to control (to move forward and to rotate) the metal piece (see picture below). Using a 0.2 cm copper wire after tying a knot with the metal piece I failed to be able to rotate.

Can you give me some hints what kind of thin string or bar or anything else I may use to accomplish a forward movement through the gap of 0.5 cm between object 1 and 2 (see picture 2) and the rotation of the metal piece afterwards?

Picture 1:

Picture 2:

• So, this can only move along the axis if the "string" and rotate about the "string"? Oct 7, 2015 at 13:37
• Are you doing this by hand or is this automated? If you are moving and rotating the copper piece manually, why not use tweezers or small pliers? Oct 7, 2015 at 13:55
• Why are you tying a knot? That right there should show you that your material is too flexible. Use aa thicker wire.
– hazzey
Oct 7, 2015 at 14:39
• @ GisMofx I think so..it must be moved forward first and then rotated Oct 7, 2015 at 16:45
• @ am304 I doubt that a tweezer might get rhough the gap of 0.5 cm between the object where the piece of metal has to be pushed..do u under stand what I mean? Oct 7, 2015 at 16:45

Unless I am missing some major constraint, you have answered your own question just by stating it.

• You have a gap that is 0.5cm = 5mm. (This is the upper limit.)
• You tried a wire that was 0.2mm. (This didn't work.)

You therefore need something between those two sizes. Either make something that size or get some wire that is that size. Literally the first chart that a Google search brought me was this. It shows many different sizes of wire within your range.

Now, all of this seems very simple, which leads me once again to think that there are constraints that are missing from your question.

• Thanks! The problem I am facing is that the force I put behind the copper plate using a wire by lead was weak. It is possible to move forward however it doesnt move smoothly. Afterwards the rotation part didnt work at all. There I was thinking whether I should another wire with another material. I even thought about using a fishing line which is too thin I guess.....u see my problem? Oct 7, 2015 at 21:27
• @Sathees I see your problem; you can't push on a string (or rope). So you need something that is stiffer than either of those (i.e. a wire usually works). You could even use a wooden toothpick. Why do you keep on offering to use things that plainly won't work as you want them to (string or fishing line)? Use something that naturally can hold its own weight as a starting point.
– hazzey
Oct 8, 2015 at 0:54
• thanks! well I just tried using a toothpick ...the result was not bad..there it really depeded on the strength of the used glue....are there other things then a toothpic u might recommend? Oct 8, 2015 at 17:26

Something like that should do it, probably better to be made of metal (brass?) given the thin walls. Just have to make sure it won't damage the part it is pushing (may need to replace the chamfer by a filet to round it off and specify a "smooth" finish for the surface in contact with the pushed part):

The 4.5mm diameter should just about fit in the 5mm gap and the 2.5mm slot should accommodate the 2mm thick plate. I have added a chamfer to help guide the metal plate in the pusher. You will need to get this machined by a machinist on a lathe or similar.

• @am 304 thanks! well one question that confuses me all the unit above are in cm right? A re these kind of stuff made of 'peek' easily availble? Oct 9, 2015 at 23:09
• No it's all in mm (all engineering drawings are normally in mm except for civil engineering where it's in m - nobody uses cm) and I've just realised my mistake: your piece is 2mm thick, not 0.2mm thick. You'll have to get part machined by a machinist from raw material. Oct 10, 2015 at 6:25
• Thx a lot., it sounds reasonable, In this case the measurement of 2mm has to be very precise so that the fitting of the metal and the "tool" u designed is perfect and s that the metal piece does not slip from the tool, right? Oct 10, 2015 at 13:22
• Well, you probably want the tool to be slightly bigger than 2mm to allow for some tolerance on the thickness of the part. What kind of tolerance do you have? Is it 2mm +/- what? You don't want it too tight, but not too loose either. I figured 2.5mm was about right, it gives 0.25mm clearance (nominal) on either side of the plate. Oct 10, 2015 at 13:26
• doesnt the tolerance depend on the material of the tool? Oct 10, 2015 at 13:32