Threaded Rod for Benchtops

Re: Threaded Rod for Benchtops

Ron in Kokomo

>I saw no need to do it for mine. It has been in service for 6 years. Only very minor flattening required.

Re: Threaded Rod for Benchtops

Dean J in MN

>In a nutshell -- no need. Probably do more harm than good, the top is going to expand and contract and the rods are not going to stop it. The nuts/washers/whathaveyou are just going to compress into the expanding top, or get lose, depending on the direction the top is headed this week.

-Dean

Re: Threaded Rod for Benchtops

Greg Betit, Vergennes, VT.

>I used threaded rod on a top I made of recycled oak pallets back in the '70's. The 3 X 3/8" threaded rods broke the first summer it went through. The glue held up, though.

Greg

Re: For what purpose?

ThomD

>If you want to keep the top flat against moisture changes, then lamination and encapsulation are your best bet. These can be done so they aren't really visible. Not necesary to hold the top together.

Re: Threaded Rod for Benchtops

RichardR

>Only use I can see for them is maybe to reinforce a shoulder vise, a la Klauz for example. Even then you could probably do without, since a shoulder vice should really only be tightened enough to keep the wood from falling to the floor when sawing dovetails and such...

RR

Re: Threaded Rod for Benchtops

Tom Ryan

>I used threaded rod to put together a workbench top in the early 70's because I didn't have any bar clamps yet and wasn't going to be able to afford more than one or two for a long time. I glued construction 2x on edge, using three threaded rods through the middle. The top glued up very well, and I'm still using the bench. I'm not sure what, if anything, the threaded rods have done for the bench after the top was glued up. My guess is that seasonal expansion of the wood crushed the wood behind the washers and nuts, to they may very well be loose during dry times.

Re: Threaded Rod for Benchtops

Luke Herzberg

>I used 1/4" rod through my benchtop...probably 10 rods over a 6' bench length. They were helpful in glueup as I lacked clamps, and I thought they would add strength, but as others have said, it appears the wood crushes under seasonal expansion and they loosen.

Now if a guy was to get really clever, he could figure out a size of rod which could stretch with the wood movement and an appropriately large anchor plate for each end to avoid fiber crush...area of wood vs. expansion vs. stretch of steel (or other material??) vs. number of rods per unit length etc.

Or you could just go with the thought that they are unecessary which is probably true and save yourself the trouble.

- Luke

Re: Threaded Rod for Benchtops

Todd Stock

>In theory, I'd agree that that beefy dovetail joint (3-1/2" x 3-1/4" on a Klausz bench) at the end apron looks like it will take the load, but in practice, reinforcement is def needed for shoulder vises. Even moderate pressure cannot be sustained without eventually breaking the dovetail. Even faster destruction occurs if you wimp out and use a box, lap, or saddle joint.

With threaded rod, the end apron/shoulder vise arm joint can be a pinned saddle joint and still last for the next few generations - a dovetail is prettier, but not required. The thread needs to go all the way through to keep the top in crossgrain compression (DAMHIKT).

For benches without a shoulder vise, I don't see the need for cross-grain reinforcement, although I doubt it will hurt (unless you drill into a rod while dogging the top).

Re: Threaded Rod for Benchtops

Todd Stock

>...or just use Belleville washer stacks under the bolt head and nut, as we do for bolt-on guitar necks...constant compression loading which may avoid local fiber failure.