Housing joints in ply

[dedee]

Should I be able make quality housing joints in birch ply with a router plane? Or is it a daft idea and should I use a tailed one instead?

I need to make a dozen or so housing joints for the seat and footrest for the Tripp Trapp. As these components will slide in & out the housing needs to clean but not too tight.

Andy

 

[Roger]

It'd probably be a 'try and see' at best, due to the basic nature of ply with all the cross grain cutting involved. I would just use the tailed beasty to cut that many if you need the consistency you do.

 

[dedee]

Roger,
perhaps I should have said that I was half looking for an excuse to buy a new tool, the router plane not the router :wink:

Andy

 

[Roger]

You don't need an excuse for that ......... you'd just be 'increasing the range and capability of your hand tools allowing you to move towards that ultimate goal of hand-crafted perfection' 8)

 

[SketchUp Guru]

I imagine you'd have no trouble with them if you are using Finnish ply or similar. These aren't going to get used a lot. We've had a Tripp Trapp chair for our little guy since he was first able to sit up and I think it has been adjusted twice in his nearly 3 years.

 

[Anonymous]

On this one I think a lot depend's to what degree you are "copying" the design, what level of faithfulness to the original version. I'm not a big router fan, but if your used to using it I'd say use that to do the housing's as the precision you need to line them up and get 100% consistent parallel cut's and also consistently acurate depths could be difficult with a hand router plane as you'd be on a learning curve?? Its only a short pass going across the uprights (well at a 60 degree angle or thereabout's), it looks like youd be able to make a simple jig like what Norman Abrahms uses to do his louvre doors where you could mark out the spacings, then clamp the jig in place for each pass, and end up with book a matched pair? Are you doing square housings or with a half round bottom as on the original? I find that the half round is VERY useful for cleaning up food etc, its easy to get everything out :lol:
PS What did you decide on in the end for the curved seat back's?

 

[dedee]

Dave,
much as I'd like to use it Finnish ply it is just too expensive to obtain in small quantities. I'll be using Latvian Birch which I've had before. I'll be laminating 1/2" to get the 1" width (so I will get a good face on both sides) for the frame and using the 1/2" as is for the seat and foot rest.

Mr S,
You're right about the learning curve but without the need to do it I'll guess I'll never learn. I'm not too concerned in making an exact copy so rounded edges and housings are not necessarily my goal but I agree with you in respect to cleaning. I also reckon that I do not need to make quite so many housings (re Dave's point about adjustment).
Do you have a link to the jig you refer to? If I do use the tailed router I have in mind a jig that with use the previous housing as a reference thereby insuring equal spacing.
For the chair backs I will be cold forming 1.5mm Finnish Birch Ply.

Andy

 

[wrightclan]

Its only a short pass going across the uprights (well at a 60 degree angle or thereabout's)...

Why not make the housings in a square-edged panel first. Then cut the sides to the correct angle and size?

Brad

 

[dedee]

Brad,
I'm not sure if I'm picturing this right but wouldn't that mean cutting 12" long housings? 12" being the distance between the top and bottom in the vertical plane.

I do wonder though if I can cut the housings for both sides at the same time before I cut the actual sides out of the ply. My head hurts trying to visualise it. Will have to try it out when I get the ply on Monday.

Andy

 

[wrightclan]

Brad,
I'm not sure if I'm picturing this right but wouldn't that mean cutting 12" long housings? 12" being the distance between the top and bottom in the vertical plane.



Andy

Took me a few seconds to follow that, but yeah, I think you're right. I'm just thinking it would be easier to set up accurately at 90 degrees than at 60 or whatever. But then, I'm thinking more from a tailed router/router table perspective. In fact you could cut 24" across one panel, and cut both sides from the one piece. A lot of wastage, but your housings would be guaranteed to match up (as long as you get the angles right when cutting them from the panel.)



Brad

 

[Anonymous]

Hi Andy

i think you will get away with the router plane in the ply as long as the sides are cut with a saw first.

Best try a scrap piece first :wink:

 

[Anonymous]

Andy
The jig I saw Mr Abrahms use was similar to like a mini worktop jig, with a pair of fences to go along the face edge and opposite edge, and 2 parallel connecting arms going off at whatever angle he needed with the apropriate gap for the collet thing to slide along and yes some sort of repeating location peg type thing to get equal spacings. Maybe they have it on their site? If I could get the damned photobukcet to work for me :roll: :wink: I'd do a sketch for you its a simple and fast method he showed.

Are you cutting the updide down 7's out of 2 solid ply's or are you doing a M&T corner like the origonal version? If you did it M&T could you machine the 2 angled upright part's side by side in one sequence of passes without any wastage??

 

[dedee]

If I could get the damned photobukcet to work for me :roll: :wink: I'd do a sketch for you its a simple and fast method he showed.

if you can't get photobucket to work PM me the drawing and I'll post it here for others to see too.

Are you cutting the updide down 7's out of 2 solid ply's or are you doing a M&T corner like the origonal version? If you did it M&T could you machine the 2 angled upright part's side by side in one sequence of passes without any wastage??

My initial thoughts were to get the the "7s" in one piece, my thinking being that this would be stronger than any joint - and simpler.

Now I have to weigh up the ease in which I can make the housings vs the M&T joint.

Andy

 

[Shultzy]

How deep are these housings. If you make them 1/2" doesn't it mean you can cut the pieces which are between the housings and then glue with spacers between.

 

[dedee]

Shultzy,
that's an interesting idea - thanks. Considering I'll be laminating 1/2" ply that does seem like an obvious solution providing I have sufficient confidence in the glue holding although I could easily add a dowel or two for added strength.

No need for any new tools though

Andy

 

[Shultzy]

Make the housing 17/32, then you will have to buy your router :lol: :lol:

 

[stef]

I have just read the whole post a couple of times.
i have a 13months old boy who could do with a nice chair.. and his dad could do with a project.
have you got some plans to work from you wouldnt mind sharing ?

maybe i'll keep an eye in the WIP section, and follow your steps !

 

[Anonymous]

Just a thought :?: :lol:
On reflection I dont think it would work as I sudgested earlier machining the housings for both uprights in one go, I did a little layout with strip's of paper, I think you'd have to do them as a right hand stringer and a left hand stringer. You could do a pair of 7's in one sequence of passes BUT it'd be a nightmare as they wouldnt be assembled in the same order they were machined IE the top housing on one stringer would relate to the bottom one on the other stringer when you put the chair together? So if your spacings are out only a tiny bit-potential disaster. Sketch it on paper and you'll see what I mean. Shultzy's idea is original but a bit fiddly and chancy for accuracy, I think some people do dog hole's that technique?
If you made a jig to do the angled housings you could do it like a run and rise template for setting out stair's where the fence protrudes either side so it can be used either way for angles to the left or right and they come out exactly symetrical so that the tread and riser housings stay like a mirror of each other.

How do you send a diagram via PM :?: Is there an attachement like on outlook express?

Cheers Mr Spanton

 

[dedee]

Stef, no plans I'm afraid. I'll be using an existing chair as a template.

Mr S,
this has been an interesting and thought provoking thread. I've been playing around with some paper a suggested as can see what you mean. I am now erring on the side of making the sides from two pieces with the M&T (and maybe additional bracing). Thus enabling the housings on both sides to be done at the same time - tailed router probably.

I can see a fair bit of trail and error coming up with a few practice pieces.

Sorry to confuse you are right it is not possible to attach an image to a PM.

Andy

 

[Shultzy]

Shultzy's idea is original but a bit fiddly and chancy for accuracy

Can't agree with the lack of accuracy. Each housing is the same width, so cut a piece of mdf that width and then cut short length. Same with wood between housings, cut ply the the width you want and length overhanging each side. Put double sided tape on the spacers so that the glue doesn't leak under them. If you make the spacers from slightly thinner material, you can lay all the pieces out and put a batten over the top and cramp.