On Sat, 13 May 2006 17:02:49 GMT, "Brynk" <[email protected]> wrote:
>Do I use a coarse or fine threaded screw to fasten an 3/4" oak table top?
>
>Can I allow for expansion/contraction by making the hole in the fastening
>cleat larger than the screw, using a washer and leaving the screw somewhat
>loose ?
>
>Thanks
>
>Barry
>
>
Barry:
I've put a sketch up on ABPW showing what I use to fasten tops of the
kind I believe you are talking about.
These can be easily made and you can make enough for the whole top by
sizing the wood, forming the rabbet, and drilling the holes - then
ripping out the individual pieces.
The quarter inch tongue fits into a quarter inch groove in the rail
and the single #8 or #10 Wood Screw allows the fastener to pivot with
wood movement.
If you make the top of your rail groove just slightly lower than where
the top of the tongue would hit if it was flat, you will get a nice
tension on the top.
HTH
Regards,
Tom Watson
tjwatson1ATcomcastDOTnet (real email)
http://home.comcast.net/~tjwatson1/
I would believe that the accepted rule would be course threads for
softwood and fine threads for hardwood.
Don't know if you're a purest but...I've been using pocket hole
screws for this application for a few years with excellent results (no
flames please, this works for me.) With a =BE" top, I'd use a #8
like http://www.mcfeelys.com/product.asp?pid=3D0814-SPR .
I would slightly oversize the hole by creating an oval shape that's
parallel with the wood movement. I'd drill a properly sized pilot
hole in the top, a washer (flat) and tighten the screw snug by hand.
It's good you're thinking about the wood movement.
"Brynk" wrote in message
> Do I use a coarse or fine threaded screw to fasten an 3/4" oak table top?
Usually 'fine' threaded screws are used in hardwoods.
> Can I allow for expansion/contraction by making the hole in the fastening
> cleat larger than the screw, using a washer and leaving the screw somewhat
> loose ?
Slightly slotting an oversize hole in the direction of movement on the the
exit side is a time honored method.
Another convenient method, one that makes the top more secure when moving
the table around by the top and still allows for wood movement, is a figure
8 fastener (often called a "desk top fastener"). There are also other
mechanical fasteners that use a slot in the apron, as well as similar ones
that can be made easily in the shop.
--
www.e-woodshop.net
Last update: 5/6/06
"Nicky" <[email protected]> wrote in message
news:[email protected]...
I would believe that the accepted rule would be course threads for
softwood and fine threads for hardwood.
Don't know if you're a purest but...I've been using pocket hole
screws for this application for a few years with excellent results (no
flames please, this works for me.) With a ¾" top, I'd use a #8
like http://www.mcfeelys.com/product.asp?pid=0814-SPR .
I would slightly oversize the hole by creating an oval shape that's
parallel with the wood movement. I'd drill a properly sized pilot
hole in the top, a washer (flat) and tighten the screw snug by hand.
It's good you're thinking about the wood movement.
Two things - oak is coarse-grained, and would be better, in my opinion, with
coarse threads.
Second, I'd get stainless.