Replies

1. 
   UncleDunc | May 09, 2002 12:43am | #1

   Mesquite. Low dimensional change with humidity change and high hardness for wear. Finding straight grain mesquite might be a trick.

1. 
   sschefer | May 09, 2002 12:46am | #2

   Yes, definitely you must take dimensional change into account. Either that or make them really sloppy in which case you might experience an off center bind problem.Steve - in Northern California

2. 
   Sancho | May 09, 2002 05:48pm | #3

   Im not to familiar with sliding dovetails for drawers but a guy demonstrating at the woodshow last weekend suggested using 2 different species for them. He said you'll have problems down the road if you use the same species. I dont know but passing the info on.

    Darkworksite4: When the job is to small for everyone else, Its just about right for me"

1. 
   Froed | May 10, 2002 01:20pm | #4

   Did the demonstrator give a reason?  Using the same species for both would ensure that both parts expand and contract the same amount, as long as the grain orientation is consistent, right?  Like using qs for both pieces, as was suggested previously.  I'd think you'd have more potential binding problems using different species (different expansion rates), unless there's something I'm missing.

   Froed

1. 
   user-131649 | May 10, 2002 05:26pm | #5

   Good morning to all of you and thanks for your responses.  I must admit that I already milled these parts out of kiln-dried 4/4 birch, but I haven't made the drawers (of of cherry) yet.  The slot part is 1-1/2 inches wide, and, according to the shrinkulator (at http://www.woodbin.com), with an expected 3% seasonal variation in m/c (it will stay in my house), seasonal movement across a 1-1/2 inch piece of birch should be at most 0.03 inches, or less than 1/32nd inch!  I milled the parts with a 1/16-inch gap, so, I therefore don't agree that seasonal movement is a potential problem.  Mesquite isn't in their database, so I couldn't calculate it's potential seasonal movement.  Also, because both pieces are from the same species, and with the same grain direction, I don't see how seasonal movement could affect this joint.  Warping, on the other hand, due to stress release from original milling, may become an issue, as I didn't rip/mill to close dimensions, let stabilize, then do final milling.  However, I hope I can "love" out any warpage when I attach these parts to the drawer and supports. 

   With respect to long-term wear, however, that's where I was concerned.  I don't know how well the birch will hold up over the long term - with the drawers full of heavy cotton sweaters, for example, and pulled almost all the way out, there could be a significant torque/stress on the birch joint.  I perhaps would've been better off with a harder wood, such as 1/4-sawn oak, as one of you pointed out.  But, since I've already taken about 5 hours to mill these parts (and I don't have other wood to use), I'd like to use them.  What type of sealant would you recommend?  Maybe I can coat all of these in a 2-part epoxy resin, to give a hard armor and make for smoother sliding??

   Thanks for all of your thoughtful and helpful comments.  Erik Andersen, Edmonds, WA

2. 
   Sancho | May 14, 2002 06:12pm | #10

   No it was more a issue dealing with the wear of the wood. He said it would last longer made of 2 different species rather than the same something like a oak and maple for example. Darkworksite4: When the job is to small for everyone else, Its just about right for me"

3. 
   user-131649 | May 11, 2002 05:14pm | #6

   Thanks, Jack:  I'll run the slot parts thru the router table again and take off 1/64 from each side prior to sealing.  Best regards, Erik

1. 
   Alan | May 12, 2002 09:42pm | #7

   Erik,

   If you want to seal the wood with epoxy, to stabilize it, but aren't anxious for it to wear off, you can always put some 2oz. fiber-glass along the runners, using the epoxy as the resin.  I've fiber-glassed quite a few outdoor wood projects I've made, like a boat and a truck tonneau cover.  It's not at all difficult.  The fiber-glass has excellent abrasion resistance.  Keep a little wax on it and it should last forever.  (Of course fiber-glassing your drawer runners does sound a little too intense.  Yes?  But then you could do it all in one operation:  mix a large batch of epoxy--a slow set-up time mix--completely immerse the runners in the epoxy and then glue in the runners and fiber-glass them at the same time.  The 2oz. fabric doesn't really need much more than the initial "stick down" coat.  Though it would be better if you came back later and filled the fabric completely...Man!  For just some drawer runners this sounds like way too much work to me.  I'm sorry I suggested it.)

   Alan

1. 
   user-131649 | May 13, 2002 05:47pm | #8

   Alan - yeah, that sounds a bit too intense, but a good thought!  Thanks, Erik

1. 
   capiron | May 14, 2002 05:56am | #9

   the explanation ive heard for using  different species in wear prone areas is that abrasion is reduced. not sure why, i usually try to use 1/4 sawn sycamore for drawer sides and hard maple for the area they run on, once i glued dogwood strips to the bottom of the drawer sides but i think this was overkill. sycamore has excellent abrasion resistance and huge ray flecks on the quartered surface, making real nice drawer sides and its a nice light colour to show off dovetail pins. hope this helps jc