How to cut this

[sucramuk]

I am going to form the attached with bendy ply, does anyone have any ideas how I could cut the two ends straight. As it won't be perfect when it comes off the form.
Thanks

 

[MattRoberts]

Can you sand them down flat? Otherwise you could make a quick jig and run them through a table or band saw

 

[Glynne]

I'm assuming your former is bigger than the finished piece?
If so, leave the workpiece on the former and run it across a router table with a slotting cutter at the desired height. Obviously if you want to reuse the former you'll need to watch the depth of cut but I use a 1.5mm slotting cutter to remove box lids and the result is remarkably clean.

 

[RobinBHM]

As it is 174mm high, I would make a jig that could sit over the end and then use a router with a bottom flush. You could jigsaw a C shaped cut out of some plywood and then use a router with template guide. It would be accurate, not sure if breakout would be an issue.

 

[YorkshireMartin]

Not the same application, but if you have a table saw and a steady hand: https://www.youtube.com/watch?v=WZFDo1f2tQs

 

[rafezetter]

Not the same application, but if you have a table saw and a steady hand: https://www.youtube.com/watch?v=WZFDo1f2tQs

That's a helluva trick and so simple, definintely one to remember

 

[Rob Platt]

if you dont have a sliding table on your table saw use a sled and clamp it to that. will need three cuts so a stop or reference point will be required. you could do your groove the same way same time should you wish to
all the best
rob

 

[sucramuk]

Guys,

Thanks for the input.

 

[custard]

I am going to form the attached with bendy ply, does anyone have any ideas how I could cut the two ends straight. As it won't be perfect when it comes off the form.
Thanks

I struggle with exactly this problem whenever I laminate. There are loads of different solution out there, some depend on you being pretty brave (or foolhardy).

Given your design you could pass one edge across a power planer, if you've used UF glue which sets glass hard then do it just before changing planer blades. Alternatively you can do the job easily enough by hand with a bench plane. At least with these methods you've then got one straight reference edge which opens up a number of options.

Yes, I've seen plenty of people then do the second edge on a table saw, running the reference edge against a fence. Personally I'm just not comfortable with that (at least not without a big jig that the workpiece can be toggle cramped to), but as I said I've known a few workshops where it's common practise to hand feed it, often taping the falling piece in place after a partial cut to prevent it binding. If your thicknesser is big enough you can pass it through that which will obviously true it up relative to the reference edge. Sometimes I'll use a bandsaw, feeding the work piece against the fence and turning it to ensure the actual cut is taking place down against the table rather than up in the air. Finally, with just one item like this it's really not hard to scribe a parallel line working from your good reference edge, and then just plane it down with a bench plane.

Obviously you won't cut the slot until you've got at least one good reference edge.

Good luck!

 

[dzj]

If it's just a piece or two, I'd use a bandsaw and sneak up to the scribe line on a disk sander.
For larger batches, a well-thought-out jig is in order.

 

[geoffshep]

Video here of doing a similar thing on a table saw - at about the 4 minute mark:

https://www.youtube.com/watch?v=g0ikg9NdUvM

 

[custard]

Sorry Sucramuk, I didn't read your question properly, it's the ends you want to cut, not the edges.

I'd do that on a table saw with a sliding table. If I didn't have one of those, and it's a one off, then I'd scribe a line with a square, referencing from a true edge, rough cut with a hand saw and clean up with a sharp block plane working from the outside to the centre to avoid spelching. It's about ten minutes work tops.

Good luck!

 

[Jacob]

Yes what's wrong with the normal ways? You saw and plane, or plane only, to a line, or line of sight.
You could scribe a straight line on the ends or the sides by standing the thing (on end or side) on a flat surface - adjusting for level, and scribe around.