Cutting and joining 6mm plywood

[Bkn]

I'm trying to make some small plywood boxes from 6mm plywood. I've been having trouble with cutting it without splintering as well as joining it together. I tried finger joints but that hasn't worked out too well and is quite time consuming + shows the not too attractive end grain.

I was thinking of doing mitre joints but again I'm confused on the best way to go about it. Also I'm aware that with joining end grain to end grain I'll need to prime the edges with a layer of glue and then re-glue.

Here are the tools I have available:

Bandsaw (6tpi blade)
Circular saw (rubbish blade, going to buy a 40tpi freud one I think)
Router table
Crosscut circular saw workstation thing I built

What would be the quickest method that produces decent results?

Thanks

 

[JohnBrown]

I'm no expert, but I would guess finger joints are probably your best bet. I have seen plywood boxes from Ikea that used finger joints and looked fine, but I suppose you need good quality ply with few voids.
If you are cutting the fingers on a router table you might need some sort of sacrifical backing piece to help minimize splintering.

 

[Dibs-h]

I have seen plywood boxes from Ikea that used finger joints and looked fine,

Birch ply IIRC and they may well be laser cut - at those sorts of volumes laser cutting would be very cost effective.

Dibs

 

[JohnBrown]

I have seen plywood boxes from Ikea that used finger joints and looked fine,

Birch ply IIRC and they may well be laser cut - at those sorts of volumes laser cutting would be very cost effective.

Dibs

I'm sure you're right in both respects.
I can't help feeling that attempting to mitre 6mm ply is going to be very tricky though, although I could be wrong.

 

[WhyDi]

Good evening,

Here is a way amongst others of jointing 5mm thick plywood sides with a bottom. The outer bottom is rebated so that accommodating the four sides. Two of the four sides hold rabbets too but only on their right and left so that they cover the edges of the two remaining sides. I removed about 3.5mm of the 5mm and the joint looked enough satisfactory for me.

You may find a way of cutting plywood without splintering in that paper about scroring and the pictures of that document show the box completed. Of course you won't be interested in the content of the box :wink: .

Best Regards

 

[Bkn]

Thanks for the advice

In regards to cutting without splintering I have to do so many cuts that doing a shallow scoring one first followed by a through cut isn't really practical. The edges of the box will be have a 1mm or so bevel on them so as long as the splintering doesn't go any further than that it should be ok.

If I were to cut on the bandsaw using an auxiliary MDF base or something so as to create zero clearance on the underside of the cut would this help? Also I'm assuming a blade with more teeth might be better. If so what spec blade would be best?

WhyDi I like the idea of doing rabbets as it's quick and easy + I can do it it a way that only shows a couple of mm of end grain on the sides of the box. It'll also be a lot easier to align when gluing than mitre joints.

 

[Jonzjob]

A while back I made a box from 8 mm beech ply and mitred the joints.

I just cut the pieces to the outside dimentions, set my router in the table with a 45% cutter and it all slotted together very easily. I just held it all together with ratchet straps. Once the sides were glued and strapped it just dropped onto the base and that squared it all up.

I didn't get any splintering when I was routing it..

 

[mailee]

I would build it using Why di's method, this is what I use when joining thin ply for boxes. Also use a stanley knife and score the line before cutting and you should get a clean edge. HTH. :wink:

 

[Bkn]

So something like that? (Top and base are rabbeted too. Measures about 130mm cubed)

 

[Pvt_Ryan]

To cut without splinters use a sharp stanley knife, and just go over the same bit again and again.

when you get to the last bit either keep going with the ply resting on something thinker you don't mind cutting into or flip it and cut from the other side.

It's not the quickest method but short of a table saw it gives good results, I did it for my son's toybox.

 

[Carlow52]

[Preamble: not a skilled woodworker.. but I offer this anyway]

Sticking with the finger-joints idea, have you considered stacking the pieces and use a piece of precisely cut timber to create the necessary 'finger offset'.
The very bottom/back piece of the stack could be sacrificial

This idea comes from one of SM's video where he uses 'filler' pieces so as he is always working off the same reference face when doing tenons so the same idea would work here.


IIRC he had the jig for making them on a table saw, and once the 2 precise cuts were made there was not much material left to remove.

ps

The theory of band saws suggests a min of 3 teeth in material at any time so 6 tpi in 6mm material is 'not good'

 

[WhyDi]

Good Morning,

I have only seen the nice drawing but pictures wider than 640 pixels make me unable to read the messages. I need to scroll so that reading each line, one after another, on the whole page ](*,) . So I just can't reply to any matter .

Best Regards

 

[John. B]

I would suggest buying a scroll saw.
It's about the best machine other than Routers to cut thin ply.
mind you, a lot does depend on the quality of the ply.

John. B

 

[Thomas]

Hi, just catching up with this thread.

I am trying to figure out a similar box. Did you find a solution?

 

[MARK.B.]

Never occurred to me to look at date of the post , but Thomas if you do mitre Your box you could add a couple or three splines across the joint for looks and a little extra strength. Using a contrasting wood can look good.

 

[TheUnicorn]

BKN,

what are the dimensions of the boxes (sorry if you've said already somewhere and I've missed it), and how much strain are they taking?

Also you seem to be making / needing quite a few boxes, is it worth buying them in?

(edit. hadn't realised the original post was 11 years ago!)