I am in the process of making myself a new rod building base. The top is going to be a 24 inch wide - 12 foot long section of counter top.
Because of the way that I use the full length of the work surface and want to be able to slide from one end of the bench to the other end without backing away from the bench - causes me to want a base that will only be supported at the ends.

i.e. I will have a 12 foot span - with a single corner post in each corner of the bench.
I have decided that I do NOT want it attached to either the walls or to the ceiling. I have further decided that I want no shelves, cupboards, brackets or anything else under the work bench.
I want to be able to slide from one end of the bench to the other end, without backing away from the bench in my roller chair.

I have thought about using lumber, timbers, aluminum, and or steel as a base top and legs.

Right now I am thinking about using 2X6 lumber for front edge, back edge, and for each of the legs. I think that the 2X6 lumber on edge should be a stiff enough beam to prevent bowing of the work surface.

I have also thought about building a torsion box for absolute stiffness, but I have decided not to build such a box with its work and overall weight.

Any other thoughts or good suggestions to mount this work surface in a free standing type environment, no center bracing with legs, wide open underside of the bench - and achieve a sag free 12 foot long surface?


Thanks in advance for any help or suggestions.

Take care
Roger

Roger , here is a suggestion; On your 12 ft span you have a support and legs on each end. Put 2 more support timbers, 2x4 will work, equidistant between each end. These supports go from front edge to wall underneath the counter top and down the wall to the floor.
Run a knee brace from the floor , against the wall, upward to about midway of the 25 inch counter top. Two of these should give all the support you need and you should be able to roll your chair the full length and not hit your knees on the angular knee braces. Will this work ?

J.B.Hunt
Bowling Green, KY

Roger

Most likely your counter top is not made of plywood but mdo. It has no real inherit strength alone. 2X6 @12 foot long will not stay straight-even my 8 foot bench did not do that and I was hoping it would (I used a set of modified relloading bench plans with material sizes and grades up graded did not work as well as I had hoped for, although it is straight and strong) I would support back into the wall at a 45 degree angle at a maximum of 4 feet 0 inches on center using Jays suggested method at 48 inches but to the full outside edge as it is most likely a rolled/formed outside edge and a 90 degree inside that is glued. (use 2x6 and taper from 2x3 to 2x6 at the center both ways.)
Good luck
Mark



Edited 1 time(s). Last edit at 11/17/2009 10:24PM by Mark Mulanax.

Roger another option to stiffen it if that 2x is not going to hang down too far on the front edge take a piece of 1/2 or 3/4 plywood ripped same width as 1x4 and sandwiched between.Use wood glue on both sides of plywood and nail or screw together between 1x4.The nongrained plywood and glue combo make a heck of a strong beam when sandwiched between 2 boards on outside.



Edited 1 time(s). Last edit at 11/17/2009 10:40PM by Bruce Kemp.

Roger, sit in your chair and roll down the length of the bench and see how much space you need underneath to clear your knees. Then use the biggest 2x's that will clear. Mark is right, the MDF will sag if not supported good. Put all the 2x's on edge for best support, with the crown up.
Knee braces are the only way you can accomplish what you want. Only way I can think of anyway. Even if you made the braces out of steel , you would still have to knee brace it like a shelf bracket.

J.B.Hunt
Bowling Green, KY

use angle iron instead of 2X's90 degree brace with short cross brace from 16 from back under top to about 12 off floor bolt together or weld

Roger, one #2 Southern Yellow Pine 2 x 6 spanning 12 feet will support about 35 pounds per lineal foot with a deflection of about 1/2 inch. You will need several of them or you will need to shorten the span. BTW, 3/4 inch plywood weighs about 2.4 pounds per square foot and MDF is denser than plywoood.
Bill

Barry and all,
I appreciate all of the suggestions.
Although I have considered the use of a knee brace, I really don't want to attach anything to the wall. So, that puts knee braces out of the picture.

Barry - you mention angle iron.
I have considered the use of just that.
Any thoughts on the size angle or box that would be required to obtain a non sag length in the 12 foot distance.

i.e. I was considering to simply have a welding shop weld up a 2X12 foot box, with 4 - 36 inch legs on each corner of the box and place the top on top of the box.

I was considering the use of 2X2 inch angle for this purpose, but am not sure if the 2 inch width would be sufficient to stop the sag.

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I also like the idea of another poster suggesting the use of a fabbed beam made of 1X stock with plywood inbetween.

This is on the same vein of a "torsion" box where a person places a matrix of vertical boxes of 1X stock between a top and bottom that are well glued together. The gluing of the top and bottom between the matrix of vertical boxes prevent any sagging or movement between the top and bottom sides of the box.



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Certainly the cleanest and likely most practical solution to the issue - as evidenced by some of the pictures on the photo section of this forum as well as the suggestions - is the one which suggests the use of multiple knee braces - attached to wall studs and allowing the top to rest on top of the braces.

Thanks in advance for any further thoughts.

Roger

Roger, a 2 x 2 x 1/4 angle will not support as much as a SYP 2 x 6. PM me & I will may be able to help you.
Bill

Have you looked at the Rodmaker article on the mobile rod building workstation? Could be exactly what you want plus it can be easily moved from room to room. The foot control board alone is one of the best ideas going.

How pefect does it need to be? Everything sags some, even a biggggg I beam.

I'd start with the top. Build it along the line of a cutting board and make it about 2" thick. A bunch of oak strips laminated together won't require the support that mdf/particle board/plywood will.

I understand what you want but can you afford a center leg on one side of the table? That would help tons and allow for a knee brace to the front. If not, how about a cable from above as a support? A support leg in the middle of the entire table shouldn't cause a problem for what you want. If you fit something in somewhere it will work better and reduce the cost/size/weight of the rest of the support frame.

Only other thing you can do is use some big angle iron. Aluminum would be best and I'd be thinking along the lines of 6" by 3" by 3/8". Square tubing is even better. Count on running something from the corner legs, at an angle, to as far out as you can tolerate (cross brace). I'd put a frame around the bottom of the legs too but that doesn't need to be all that strong.

Look at McMaster part# 4882T24 for an idea on the top.

be a lot easier if you could secure it to the wall, or maybe a corner of the room. try talking to a home builder store like Home Depot.

All structural members will (must) deflect under load. (i.e., a fishing rod) The trick is to select a member that will handle the required service load with a deflection characteristic that is tolerable for the intended purpose. That is what I do in real life to support the vices of fishing, rod building and home brewing.
Bill

Properly constructed, it may deflect, but you'll never know it unless you have some pretty high resolution measuring tools. I can assure anyone that a well made bench is still going to read flat by a standard steel rule or level gauge. None of my benches record even a half millimeter of deflection in the very middle, and that's with me standing on them.

Beyond that, you never want to mount any sort of lathe so that it is fastened solidly at both ends. Mount the headstock end fast, and allow the tailstock end to float. This keeps the lathe bed from flexing if the bench does (assuming you have a very rigid lathe bed such as the Renzetti, etc.

Another thing you want to do with a long rod lathe bed, is set the ends on small sections of plate or shim so that they are not in direct contact with the bench across their mid-sections. This also keeps the lathe bed from being affected by any deflection or warp of the bench top.

Even so, a lot of this is getting beyond the requirements for what we do in building rods or what's really required to handle a standard rod lathe or wrapping machine. You can get stiffness and strength 2 ways - large, heavy, stout materials or lightweight yet rigid framing such as the torsion box Roger mentioned. For a rod building table where you shouldn't need mass to offset the spinning or turning of large out of balance items, I'd opt for a torsion box type arrangement, or simple framework under a plywood or MDF top. And if you can find one at a reasonable price, a formica covered countertop is outstanding for a rod building benchtop over some lightweight 1x4 framing.

And remember, if you want to maintain complete clearance under the bench, you can always support your frame and benchtop from above - look to the ceiling.

...............



Edited 2 time(s). Last edit at 11/18/2009 01:17PM by Tom Kirkman.

Roger,

This may not be anything at all close to what you're wanting to build, but if you can get any ideas from it I hope it proves helpful. Good luck.

As you can see, it started life as a commercial industrial steel bench.

[www.rodbuilding.org]

................

There ya go. Maybe you can find some used.

Thanks for all of the help and pictures from everyone.
The key requirements are that there be nothing at all under the bench. That it not be connected to either the ceiling or wall and that there be no interior supports between either end.
Having said that, I think that the solution that I am headed toward is a double I beam construction at the front and back of the bench to give me the required non sag support for the 12 foot span.
Hook up legs at each end and I should be good to go.

In particular I appreciate the comments from Tom and Bill to help me get back on course.

I will post a picture when it is finally done.

Thanks again
Roger

Roger,

Have you considered running a few stringers of square aluminum tubing under the top to prevent measurable sagging?

Dave

Dave,
That is a pretty good idea.
Easy to work with and light.

Take care
Roger

roger

consider using a couple lengths of heavy "unistrut". it is steel framing used on construction sites to support plumbing and electrical conduits. it's a square shaped steel "c" channel with (or without) holes spaced along it's length and is pretty rigid. it comes standard in 10' lengths and fittings are available for connecting pieces together. i have also seen it in longer lenghths. it's sold at larger electrical & plumbing supply houses. there are different guages and sizes available. search unistrut on the net.

rog