Replies

1. 
   Jamie_Buxton | Mar 16, 2003 08:53pm | #1

   I did a somewhat similar job on beams that were 12' off the floor.  I didn't want to be doing careful joinery standing on top of a ladder.  Also, the beams themselves were construction-lumber quality.  That is, they weren't all exactly the same size, and some had warped and twisted as they dried.   My solution was to build U-shaped covers in the shop.   I could make them all the same size, use good furniture-style joinery, and varnish them in the shop.  My last step was to trim the ends to fit, and hang them on the beams. 

1. 
   UncleDunc | Mar 16, 2003 09:53pm | #2

   This makes a huge amount of good sense to me. I can imagine it getting awkward with wide or very long beams, but even in those cases it would make more sense to wrestle with the covers than to try and do fine woodworking overhead.

2. 
   CANTSANDIT | Mar 16, 2003 10:04pm | #3

   THANKS,

   BUT WHAT JOINTERY TECHNIQUE? I'M TKINKING 45 LOCK JOINT I WANT TIGHT AND SEAMLESS IN THE LONG RUN.

1. 
   Jamie_Buxton | Mar 16, 2003 10:39pm | #4

   As I recall, I used a simple butt joint, with biscuits to locate the planks for glue-up. 

   I had smaller beams than you, so I could use solid lumber and single planks.   If you use solid lumber, you probably will need to glue narrow planks into wider panels, so you'll be using butt joints and maybe biscuits there too.  

3. 
   clampman2 | Mar 17, 2003 04:38am | #5

   Cant,

   Lock miters work beautifully. With material as wide as you have, though, all pieces will have to be perfectly straight before milling the lock edge. If not, you will never get them together.

   Clampman

4. 
   goldhiller | Mar 17, 2003 06:11am | #6

   My two cents………

   I agree that using a lock miter in this situation could be courting exasperation if not diaster. I've gotten some remarkably and reliably tight mitered edges though on very long joints by doing the following.

   Make yourself a straightedge guide from a piece of 3/4" mdf or the like that is at least as long and wide as the longest, widest board in your layout. Try your best to use/mill lumber that is flat, meaning free of cup, bow, or twist. Joint and rip your boards to width. Now lay a board on top of the guide board and put one of its edges exactly in alignment with the straight edge of the guide underneath it and clamp it in place. Use an appropriately sized chamfer bit in your router to miter the edges of your boards. The guide board you made will provide the surface for the router bit's guide bearing. Repeat for each edge involved. Done carefully, this should provide you with a much more exact set of miters than you'll likely achieve by running the boards over the table saw as the router can follow any existing undulations (hopefully there are none) of the lumber better and it's frequently easier to control the router over the board than the board over a table saw or other piece of equipment.

   If you decide to use the three-sided box approach, you'll need to make up one extra piece (mdf again, perhaps) to use as the fourth side while gluing and clamping these edges together with a series of band clamps and /or whatever else may be necessary. I'd recommend doing a dry setup on each set prior to applying your glue. It's sure nice (and recommended) to have at least a couple of extra experienced/trained hands to assist at glue-up time with large pieces like this.

   I'm not sure from your post exactly what size the collar ties are but I'd be inclined to build your covers so that they are at a minimum, just a bit larger than the ties to eliminate any possibility of joint stress due to a tight fit and differing rates of expansion and contraction between the two different species involved.

   Knowledge is power, but only if applied in a timely fashion.

   
   

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   Edited 3/16/2003 11:20:25 PM ET by GOLDHILLER

1. 
   TRIGGER | Mar 18, 2003 05:50am | #7

   Climatize,  assemble, seal , then install over sealed lumber.