Workbench Top

[Velocity]

I had purchased a high quality workbench top to use with my recently finished workbench base. According to the manufacturer:

They are made of Eastern hard rock (sugar) maple and coated with a Durakryl finish. This finish leaves the maple a natural color with a satin smooth, low sheen surface which is virtually maintenance free. The top can be cleaned like any other counter surface using soap and water, bleach or fingernail polish remover. Made in USA.

I do not know much about the wood or the finish, so I would like to know what is the best way to mount this. My fear is that I will drill in an improper fashion and create a hole that is surrounded with flaking wood scraps and finish, ruining the aesthetics of the workbench top. Yes, I understand a workbench top will get abused over time, but I want it to be from working, not from mounting...hopefully you understand what I mean. So, is there a good way to go about this? Will any method work fine? Thanks.

[mark.f]

Drill the hole, expand the top part to the size of the head of the screw you are using, fasten down with the screw, and then plug the hole with a piece of dowel? That's about the only thing I can think of, other than sanding where it'll meet the base and gluing it there.

[Velocity]

Mark: That is an interesting idea...I actually am not worried about the screw head sticking up; I was just worried that the bench top would splinter and such when I drilled the hole. But I REALLY like that idea...it would give it such a clean appearance. Thanks for the suggestion!

[PinHead]

I dont know if this works as well with finished wood, but I do know an old technique for drilling thru a painted panel on a car, without chipping the paint; put a couple pieces of heavy masking tap down, to keep the surface from marring or flaking around the hole.

[grumpy]

Velocity, that is called counter sinking the screws and you can get counter sinking drill bits at most hardware stores and home centers.

[jimmy101]

I wouldn't drill all the way through the top, there is really no reason to. If you counter sink and plug the holes then you can't remove the top from the supports.

Just use L brackets on the bottom of the table to connect to the support/legs. If the top is at least 3/4" thick you can just use wood screws shorter than the top is thick screwed in from the bottom (use a pilot holes). No marks on the top of the table and the top can be removed in the future. You really don't need all that strong of an attachment between the top and supports, 4 to 8 heavy woood screws should be more than adequate.

[Gippeto]

My .02

Use threaded inserts.

http://images.google.ca/imgres?imgurl=h ... %26hl%3Den

I used these to attach the top on my router table. Reliable, easy, and no holes in the top.

[Velocity]

Jimmy101: The idea of L-Brackets seems like a good solution, for even if some chipping did occur, it would be on the underside of the workbench top. My one concern would be whether the L-brackets would hold the workbench top tight enough to the base. I'm pretty sure they would, because the table top has substantial weight.

Gippeto: I'm not exactly sure how I would use/install these threaded inserts...could you elaborate?

One other question:
Since I will probably be mounting my lathe (7x12) on top of this workbench, I would like to reduce vibration as much as possible. I put some 1/16" 60A rubber strips on the feet on the base (which I will probably replace with less firm rubber soon to get better dampening), and that seemed to help keep the table more steady. Would it make any sense to put some thin rubber sheets between the workbench top and the base? I don't know if it would have any effect or not.

[Gippeto]

They are very simpe to use.

Locate and mark where you need the hole on the under side of the bench top.

Drill the appropriate sized hole for the insert.

In softer wood, (MDF) you just screw them in with a screw driver. In maple, you will likely have to cut the threads with a tap.

Screw the insert into your top with some epoxy on the outside.

You now have metal threads in your wooden bench top.

They should be available at better woodworking store.

And since a picture is worth so much;

http://home.comcast.net/~boondocker1/th ... insert.jpg

[Velocity]

Gippeto: I like the idea. If I did use these, would I use them in conjunction with an L-bracket or something similar, or is there another configuration.

If it helps,the base of the workbench consists of four 4x4 legs that are connected with 2x6's. My original plan was to drill a hole into the top of the workbench and into the center of the 4x4 legs.

[Gippeto]

The "L" brackets will work, but it seems wrong to put them on such a nice wood top IMO.

I don't know what woodworking tools you have, but this is what I would do given your base configuration.

Make a frame from 2X4 joining it at the corners with a half-lap joint. (glue and clamp) Make certain that the frame is "square", if you know what I mean. (or at least matches your base )

Locate and drill mounting holes for the bench top in the frame. Every 8-18" should be fine depending on the screw size you will be using. Use at least 2-3 screws on the short ends and 3-4 on the long sides.

Use the frame to mark the hole locations on the underside of your bench top. Drill and install the inserts in the bench top.

Mount the frame to your base using construction adhesive and either wood screws or better, use counter sunk lag bolts with washers.(pre-drill the holes for these)

In either case, the screws cannot be left sticking up from the surface.

Attach the bench top using bolts with washers.

Just in case you don't know what a half lap joint is;

http://images.google.ca/imgres?imgurl=h ... n%26sa%3DG

[Velocity]

Gippeto: If I understand correctly, the frame of 2x4's would serve the purpose of adding an interior "lip" to the workbench frame, which I could then drill a bolt through (instead of trying to drill a bolt through the long portion of the 2x6 and inevitably failing).

I'm not sure how I would make a half-lap joint...my woodworking tools are not really extensive (meaning, I have a drill and some nails ). How would one go about making one of these joints?

[Gippeto]

With only a drill for tools, your options are limited.

Use 1x4 and laminated them together to form a 2x4 with the half laps in place. Use glue and screws.

Plan out the placement of ALL the screws before you join anything.

[jimmy101]

The threaded inserts are really overkill, and they require that you get all the holes lined up exactly. In addition, there is a good chance the assembly will rip itself apart as the weather changes. It might not have a problem for a couple years but eventually is will start to tear itself apart.

Any time you attach a large flat piece of wood (solid or "butcher block" laminate, BBL) to a base you have to worry about expansion and contraction. A piece of wood (or BBL) that is 3' wide may well expand/contract by as much as 1/2" as the humidity changes. Wood expands/contracts mostly across the grain, the change in length (along the grain) is usually much less. Expansion will rip apart even the sturdiest leg assembly and/or table top and/or the fasteners that hold the top to the legs. So it might be a good idea to use L-brackets with slots on the table side. The slots let the top expand and contract and the bolts/screws slide in the slots. You have to get the slots pointed in the direction of the expansion so you may not be able to use brackets on the short sides of the table.

There is a science and art to attaching a table top to legs so that the assembly doesn't rip itself apart as the humidity changes. Woodworkers have been dealing with the problem for several hundred years. With a plywood or MDF top there is very little expansion/contraction. With solid wood or a laminate of 2x2's (typical for shop benches) you have a significant problem.

It sounds like your top is sealed. Sealing will reduce the top's sensitivity to changes in humidity but there is still chance that it'll expand and contract enough to put a massive amount of stress on the assembly. (Massive as in enough force to shear several screws, or buckle the top, or split the side rails, or separate the side rails from the legs, or...)

Bottom line, solid wood table tops are generally not securely attached to the leg assembly. You need to allow for the expansion and contraction of the wood.

Just use the L-brackets, preferably brackets with slots on one leg. Install the brackets on the inside edge of the base frame on the table's sides. Invert the table top. Invert the leg assembly and set it on the top, center it up (by eye is adequate). Use the L-brakets as guides to drill the pilot holes in the top centered in the slots. Screw the leg/bracket assembly to the top, but not too tight.

If your table top is at least 2" thick (which any decent shop bench should be) then something like 4 to 6 fat 1.5" screws should be more than adequate. Lag bolts would be good since they are usually much thicker than standard wood screws, they have unthreaded shanks which will slide in the slots in the bracket a bit better, and the hex head is much easier to torque than are phillips or flat head screws.

[Gippeto]

True enough Jimmy. A bit overstated, I think, but true enough.

Drilling the holes in the frame "oversize" will allow for movement and make alignment easier.

A bit more trouble than using "L" brackets, but better looking IMO.