Saturday, January 2, 2010

Tréteau XIII

Happy New Year one and all, 新年あけましてお目出度う御座います(<-- that's "Happy New Year" in Japanese). May 2010 bring you all your hearts' desires! I thought I'd start out this year with some pictures which I hope will inspire you as much as they inspire me. Since this is the tréteau build thread, I'll keep the theme French, though rest assured I draw a lot of inspiration from other sources besides the French too. I found some interesting pictures in association to a Museum in France which has several carpentry masterpieces in its collection, along with many carpentry drawings. The first is a picture of a post card from the 1940's:


These structures are obviously intended as displays of what a given carpentry school could do, a sort of 'tour de force' of their collective technical virtuosity. While I like the shape of the tower on the left quite a bit, it is the support tables which are most interesting to me, especially the one on the right. I only wish there were more detailed photos available, though I suspect these models may no longer be extant. The table supporting the model on the left is a little ungainly looking to my eyes, but it is based on the Trépied Établi (detailed in the second of my French connection posts from February last year). Speaking of the three-legged joiner's bench, I came across another picture of one such model:


In this piece, they have dealt with the issue of the posts being out of rotation with the beams (and in line with the circumscribing circle) by turning each post to place it in line with each beam (and thus rotated out of line with the outer circle). It seems like a good solution and one I will explore in more detail when I get to making that piece, which I will do later this year, probably in a 5-sided version. This is the logical item to study next, as it forms a smooth progression. In the current tréteau build, the challenge involves connecting braces to legs which are rotated to various positions; in the trépied établi it is the posts which are consistent in slope and orientation, and the brace pairs which are in a variety of rotations.

Speaking of the tréteau, I came across a picture of a model of that too:


I'm not sure what size the model is, though it is clearly a simple nailed-together affair. Upon closer inspection, it looks to me like the maker didn't quite get one of the details of the piece as Mazerolle illustrates it: the interior x-braces are supposed to fill up the available space, reaching to the apex of the crossings for the long side braces. Or maybe the maker just chose to do it differently, who knows?

My long-term plan is that once I have completed an in-depth study of French layout along straight lines, I will then turn my attentions to curvilinear pieces. Here's a few examples of that sort of work:


I'd like to see more of the table underneath that model too!

A half-circular geometrical self-supporting staircase:


This third one is really neat, if you, like me, find conical forms attractive:


You know, if you removed the third horizontally-oriented cone, which pierces the other two, you would have a pretty near looking double conical roof, momma cone and poppa cone, each cone slightly wrapped around and interfering with, the other. This ties in somewhat with the twisted spire CAD video I linked a few posts back. I really like the form of the intersecting cones, and it's just a few hundred hours of study away! Uh, maybe best not to think about it that way....

As for my own tréteau, I have made some small measure of progress. I continue to work on the mitered lap joints. I altered my approach a little in terms of cutting the lap trenches to width with the router - I went away from using a bearing guided straight bit to using a guide bushing, which facilitated the use of a spiral cutter. The solid carbide spiral would give a cleaner cut than the straight cutter:


This would work well, however it also gave me conniptions. Much as I like Festool, their stuff is certainly not the be-all and end-all as far as accuracy goes. I guess I have come to expect that German and Japanese tools is to be associated, by default, with precision and high quality. Not always - while the quality is almost always there, precision sometimes falls a few steps short. If you look at the above picture you can see that the metal plate which holds the template guide is a snap-in affair. Trouble is, it doesn't hold the guide bushing concentric to the cutter, and also is able to move around a little bit, so if you bump it, the guide moves a tad. Not the best design. After discovering that one of the cuts was spoiled (and I need to make another piece as a result), I put on an acrylic base, and used a centering tool to align the thing to the router's collet. After that things were fine, though I was still grumbling about the problem- I hate it when some machine doesn't do what it is supposed to do, and in fact is designed in such a way that it can't accurately do what it needs to do, in this case center, and keep centered, a template guide bushing. Who makes the perfect router? It hasn't been made yet (and I've tried most brands).

If I might continue griping for a moment, that's not the first issue I have had with Festool products. I have also found that the guide tracks in my set (I have three), which are made to lock together, are not cut perfectly square on one end. This means that when you lock two sections together they do not align straight. All three rails I have on hand have this problem. I tried calling Festool about it - obviously the cross-cutting jig in the factory that makes one of the end cuts of the guide rail extrusions is slightly out of whack - however Festool USA is primarily a marketing company and I couldn't actually connect to a tech person who could deal with the matter. A common problem when trying to address such issues to large companies I find. So, I was unable to pass the info along, and have no idea of the problem was ever rectified at the factory. Oh well, I tried, and, oh! - my apologies for the above digression.

Here's the MDF template I made to work the half lap trenches to width:


The spiral cutter certainly gave cleaner results:


Though one piece was ruined by the guide bush fiasco ("Guidegate"), I did manage to get three pieces done. After the trenches were put to the correct width, I processed the cross-wise reductions:


Another view:


Then it was chisel time:


Once the mitered abutments were established, it was a try-and-trim affair until the laps could be started:


Down and together, with a few judicious hammer blows on a block of oak:


And fully home:


It came out fairly cleanly.

That's it for pictures in this post, and I'll be returning to the other project for next time. Thanks for dropping by today. --> Go to post XIV

3 comments:

  1. Interesting to read that about the Festool router. I've never used one but they sure to look nice. My favorite router is the Bosch 1617 evs, very smooth and accurate. Have a great New Year.

    ReplyDelete
  2. Dale,

    I used to have one of those 1617's. Yes, smooth and accurate (with reservations about that), and fairly quiet, though it has some drawbacks, IMO:

    -poor dust collection

    -compatibility with template guide bushes was not the greatest. It required an additional adapter ($50) to fit the standard type Porter Cable bushes to the base, and the adapter takes about 1cm of plunge depth capacity away and was a pain to center to the collet.

    -the on/off switch was prone to failing from dust intrusion, requiring semi-regular dis-assembly to clean. That got old after a while.

    -the depth setting device, while accurate, eventually wears to the point where it begins to freewheel of its own accord when the router is operating. There should be a wave washer in the stack to prevent that. I resorted to taping it in place, which again, got old after a while.

    -the main bearing at the bottom only lasted about a year on mine before it required replacement.
    I'm speaking in reference to the original 1617 EVS - current models may have addressed these defects for all I know.

    ~Chris

    ReplyDelete
  3. I must have got lucky, so far I have had no issues with the two I have. I have had many issues however with Porter Cable routers. These issues include motor housing and base galled on three routers, base bushing holes not concentric with collet and speed control failures as well as plunge mechanism failures. I was a diehard Porter Cable user for 15 years but not any more. I also had issues with their sanders and drills. I've given up most of my power tools when I left my old shop, http://timberwerksstudio.blogspot.com/2009/11/my-old-shop.html the few I own now are Makita or Bosch. If budget permits I may give Festool a go someday but I'd like to expand on my Japanese tool collection first as well as my hand tool skills. Your Blog helps to inspire learning these skills.

    ReplyDelete

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