Re-visiting the end cap bolts.

[Derek Cohen]

Wood moves, expands and contracts as moisture levels change, whether it is a process of drying out or the humidity levels in the air. The need to ensure that future adjustment - when required - would be easy, has motivated me to redo the end cap bolts for a third time. There will be no fourth time.


I have incorporated features from a discussion on the Ubeaut forum, plus added a design feature of my own (although no doubt this is not new - is there anything "new"? ... probably just re-inventing the wheel).


The probability is that, over time, the bolt and nut will weld themselves together through rust. Tightening the connection will be difficult unless the nut can be immobilised. One way is to remove enough waste to slide in a wrench or spanner. Another is to immobilise the nut from the outset ...


The forum suggested using a square nut. However, while it has its advantages over the old nut, a square nut still requires a spanner to immobilise it. So I have made a elongated rectangular nut, where the shaft runs the length of the bolt hole (and so is restrained by the hole, per se).


Here are the three methods I had used. From the left ... First I tried coach bolts. These were removed as I did not trust their holding ability in end grain. In the middle is the recently removed nut-and-bolt connection. Finally, on the right, is the new system, a bolt and elongated rectangular nut.


http://i13.photobucket.com/albums/a262/Derek50/Bench%20build/bolt6.jpg


The nut plate was made from 1/4" thick x 1" wide O1 steel. Mike Wenzloff gave me an 18" length a few years ago. Nice to add a connection to a friend.

The second feature was the tapered ends to the bolt. Having used them this way now I can confirm that this makes connecting nut and bolt a much easier job.


http://i13.photobucket.com/albums/a262/Derek50/Bench%20build/bolt7.jpg


Here is the set up ...


http://i13.photobucket.com/albums/a262/Derek50/Bench%20build/bolt8.jpg


And here are the end cap bolts installed ...


http://i13.photobucket.com/albums/a262/Derek50/Bench%20build/bolt9.jpg


Tightening now can be done completely from the end cap alone.


Regards from Perth


Derek

[Paul Saffold]

Derek,
How about using a brass or bronze nut if rust is a concern? Of course it is always good to use material one has on hand and I see the advantage of your elongated nut.
Paul

[Jessica Pierce-LaRose]

Hrm - I like that! It's an interesting idea, a cheaper version of bed bolts that probably works easier in this application. When I mounted my vise into endgrain, I used coach screws like your first example, but then had the hole intersect 3/4" oak plugs set into the top, so the thread grabbed face grain (someone here recommended this idea to me) it's worked well so far, but I like how your idea is probably a little more future proof with regards to adjustment as things move.

[jason thigpen]

we use those type of nuts in the automotive field. nuts on certain suspension components can be difficult to access with a wrench. several manufacturers are using nuts with a "tail" on them to facilitate removal and installation. its an excellent innovation. I never thought to use it on a workbench. great idea!

[Jim Koepke]

If you are worried about the nut and bolt rusting together there are couple of things you could try.

One would be an anti-seize compound. Usually available at auto supply stores or machinist supply outlets. Simple to make your own with a 50-50 mix of grease and graphite. The commercially available mixes of my acquaintance are a mix of grease and aluminum powder.

Another option would be to give the bolt a loosen and tighten cycle every few weeks. That is a lot of hassle.

Finally, I am wondering if just a light wrap of teflon tape would keep the metals from rusting together.

jtk

[Marko Milisavljevic]

Lee Valley Bench Bolts http://www.leevalley.com/us/wood/page.aspx?p=31147&cat=1,41637 or Benchcrafted Barrel Nuts http://benchcrafted.com/Benchbuilding.html can be tightened by turning bolt alone and the price is not terribly more expensive than getting bolts from Borg.

[Matt Sullenbrand]

Hi Derek,

Another option might be Spax lag bolts/screws. I used 12" long 1/2" bolts. The threads run about 8" so there are 4" unthreaded. That unthreaded section was in an elongated hole to allow the top to move and not split. They are zinc coated so rusting hopefully will not be a problem. With 4 bolts and 8" of threads, I don't expect them to ever let loose! I love overkill.

[Derek Cohen]

Hi JIm, Marko and Matt

Other than adding a little 3-in-1 white lithium grease, which is excellent protection against rust, I now hereby retire from the end cap bolt business! :)

Regards from Perth

Derek

[Zach England]

Not to sidetrack the original issue, but can someone explain to me the virtue of using bolts over some for of joinery--e.g. slicing dovetails?

[Derek Cohen]

Hi Zack

Wood moves. As it dries and when there is moisture in the air.

And then there is grain direction. In this bench the end cap runs perpendicular to the bench, per se. It will expand and contract differently.

The aim is to keep the end cap tight against the bench. A mechanical connector has the advantage of being adjustable. At some stage the bolts wil need to be tightened as they loosen as a result of the movement between the parts. This thread has been about making this as easy as possible (as well as an easier method of installing bolts in the first place).

Regards from Perth

Derek

[Zach England]

Interesting. When it is convenient would you mind posting a picture of the side profile of the bench end?

I am ABOUT to start building a bench that will have a veritas twin screw as the end vise and have been agonizing over how to join the inner jaw of the vise to the end of the bench. I'd love any ideas you have.

Could I fabricate those bolts out of a more malleable metal? I don't think I could drill and tap 01 with the tools I have at my disposal. Would it make sense to make them out of brass so they will not rust? I happen to have just gotten a big box of brass bar stock for another project.

[Derek Cohen]

Hi Zack

There are lots of photos and descriptions on my website. Follow this index page to the end .. http://www.inthewoodshop.com/ShopMadeTools/index.html

The O1 was easy to drill and tap as it was not hardened. You could make them out of brass as well. I am not sure about the interaction of steel and brass over time.

Regards from Perth

Derek

[Zach England]

OK, thanks. Would you still do the dovetails on the end if you weren't installing the wagon vise?

[John Coloccia]

Why is the bolt offset? I would think you'd get higher overall strength if the bolt was centered in the nut. I'm sure you know this so you must have had a reason to do it as you did.

[Derek Cohen]

Hi Zack

It is not about the vise. It is about connecting an end cap. So, yes.

Regards from Perth

Derek

[Derek Cohen]

Why is the bolt offset? I would think you'd get higher overall strength if the bolt was centered in the nut. I'm sure you know this so you must have had a reason to do it as you did.

Hi John

The bolt is not offset. The nut, however, has a shaft attached (creating an elongated look) for ease of installation and to prevent it twisting.

Regards from Perth

Derek

[Zach England]

OK, please forgive me for belaboring this point, but I am trying to understand. If connecting the end cap with dovetails on the end but bolts in the middle where are we allowing for seasonal wood movement? It seems to me that the dovetails negate the room for movement that the bolts provide.

What am I missing?

Thanks for the info.

Edit: So I went back and re-read your webpage about it. Are you saying that the end cap sort of "pivots" on the corner that has the dovetails?
If so, then why the dovetails at all? Why not bolts all around?

[John Coloccia]

Hi John

The bolt is not offset. The nut, however, has a shaft attached (creating an elongated look) for ease of installation and to prevent it twisting.

Regards from Perth

Derek

Ah...it's just something to hold on to. I thought he bolt was down at the bottom of the end cap. Makes perfect sense, thanks.

[Derek Cohen]

Hi Zach

The end cap is attached to the bench with a dovetail at ONE END ONLY. The other end is free to move (you must not attach both sides). Look at my articles and pictures. It is all there.

Regards from Perth

Derek