Morning all

Monday morning head scrather for you. I have some sheet approx 2.5mm thick. I'm trying to create a flat shape out of a piece with a lip 20mm which is only 1mm thick.

I only have access to basic tools and I'm trying to think of the best/easiest way to thin the outer 20mm from 2.5 to about 1mm leaving the centre part at it's original 2.5mm thickness.

Any ideas? I was considering using a mouse sander but welcome other methods. Hope the explaination makes sense.

Cheers all as usual

Can you get to a milling machine?
Your local secondary school tech dept may get their technician to do it for you if you offer them some free timber or something.
Depending on the density of the plastic, if you want to do it at home, I would use a powerfile and stick a steel rule along the edge to mask it off. That said, 1 mm is thin.

Would it be a better idea to buy some 1mm thick sheets and stick two more smaller sheets of same plastic as lamina, leaving the bottom sheet sticking out as your lip? We used to have some superb liquid adhesive that you simply paint around the join and it would suck in by capillary action.

Good luck!

A router seems the way to go, a router table would give better control.
Cheers,
Bob

as above ^^ will make a really nice job of that

think a router table would really be the only way to get that.

how big is the piece overall ?
i may be able to help

electric planer?

I'd use a router, you can buy a basic "own brand" one quite cheaply from one of the DIY sheds and you won't need much power to take light cuts from ABS. You can mount it upside down onto a piece of MDF to create a simple table router. It will also come in useful if you do any woodworking jobs, and it's even possible to use them on aluminium if you are careful.

If you go this route (pun not intended!) I'd be tempted to temporarily bond (e.g. double sided tape) the sheet to another piece of MDF to ensure enough stiffness for consistent routing depth.

IMO you will never get a clean lip from using a sander.

Dave

There will be two pieces of slightly less than A3 in size. They'll both need a 20mm wide lip.

I'm quickly considering after thinking about it bonding two different sizes together to create a lip as per the suggestion further up this thread.

if bonding dont work, i am prepared to give it a go on the mill
trouble with 1mm thick is it will tend to try and lift into the cutter