How can I make an adjustable top for a bench stay in place?

Jim O'Dell

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Between Aledo and Fort Worth, TX
My idea at this point is to build 2 benches on a 24' long wall in the shop. These will not be deep, about 21", and only about 13" needs to be adjustable. And by adjustable, I'm talking about the ability to have enough movement to level them out an make them on the same plane. I will have a 3 1/2' space or so between them that I can use multiple tools at. For instance: SCMS, lunchbox planer, downdraft sanding station, kreg pocket screw station, scroll saw, router, and I'm sure many more I haven't dreamed of yet. The basic structure will have the front 13" at the level of the TS, then the back 8" will bump up for a built in stationary fence. This will not move.The reason so deep is I will have a 6" duct coming down the wall that will pass through here for the cyclone hookup for what ever tool is being used. I plan on using 2 layers of 3/4" MDF for the top, that will be covered in plastic laminate. I will have 2 mechanical leveling bolts at multiple places. One will pull down on the top, the other push up on the top to make the adjustments I need. I will use T-nuts located between the layers to pull on, and a metal plate where a bolt pushes on to raise up.
But I can't figure out how to keep the top in place. Short pieces of T-track anchored vertically to the base and slide bolt attached to the back of the top? This would allow one more tie down point to keep it where I leveled it. Any other ideas? THANKS!! Jim.
 
Jim, if you mean keeping it in place front to back and left to right, then I think the simplest would be as follows.

1. Laminate the two layers of MDF together and cut to size, (but do not install the plastic laminate yet)
2. place the top on the bench frame where you want it and clamp it in place
3. Drill six 3/8" dia holes through the top and well into the bench frame, one at each corner and one close to the front and back edge at the middle of the length of the bench
4. Countersink the holes with a forstner bit to get the head of a bolt flush with or slightly below the surface of the top
6. Turn the top over and countersink the holes on the bottom side (like the top side) to accomodate a washer and nut
7. install bolts in each of the holes from the top side and tighten a nut on the bottom side. (You could put a little epoxy around the Bolt heads on the top side if you think necessary).
Note: The bolts should be long enough to go well into the holes in the Bench frame)
8. Now install the plastic laminate on the top side of the MDF
9. Set the top in place on the frame, aligning it so the guide bolts in the top go down into the guide holes in the Bench frame.

This will let the Bench top float up and down as needed for leveling adjustments but keep it in place from front/back and left/right movement.

Hope this helps.

Note 2: The bolt size could maybe be smaller, Annnnnd... the two in the middle MIGHT Not be necessary, BUT, since I kinda have the same mentality as "Marty" about building most things, I probably over build, so let your conscience be your guide.
 
Why not leave the bench tops fixed in place & make the platform the tool will set on adjustable. The smaller platform will always be the easiest one to adjust.

Another way to do it is figure the difference of height from machine to machine & cut blocks to match the height needed.Glue the block to the bottom of the plywood base the machine is setting on & the plywood base & blocks stay with the machine. Remove 1 machine & replace it with another use threaded inserts in the fixed part & through holes for the machine base & threaded knobs to fasten it down. When you need more bench space just remove the tool & replace with a piece of plywood with the right spacer blocks on the bottom.

Another novel idea is build them as level & coplaner to each other as you can with threaded leveling feet on the bottom of the legs.

This isn't a lapping plate you know. Jump out of the complicated box. Don't over think it.:wave: people have made real fancy furniture with & on tools that are a whole lot less fancy & complicated than we have or think we need now days.:) :) :)
 
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Norman, that would accomplish the same thing my t-track idea would, and a whole lot simpler!! Thanks!
Bart, I tend to overthink/do things a lot. :wave: I will have leveling feet on the cabinet base, but I don't trust that I can build 2 10' cabinets co-planer with each other. So I would like to have some fine adjustment to the tops, so that I can, say, get the top to match the planer infeed and outfeed tables. It will be the only tool that would be that critical...maybe the router plate second and the RAS, if I can find a way to implement it, third. The others won't be a big deal. The heavy items like the planer will be on carts with a Ridgid Herc-U-Lift for mobility. And the whole unit will slide on to some type of rail, probably 2" angle iron, and when taken off of the lift, will rest on this to hopefully be aligned with the cabinets on either side. I hope the base cabinet will be rigid enough to not be able to use to make the tops co-planer. Anyway, that is the goal.
Thanks for the ideas! I'll keep drawing and try to come to a final idea! Jim.
 
Unistrut?

Jim,

I'm chiming in a bit late here and you've probably already completed your project, but if not then:

Left and right torsion boxes mounted to the wall in Unistrut track on every or every other stud. An access hole(s) in the front of the box would allow you to loosen the fastner and slide the top up or down in the track. Trying to get it level quickly might be troublesome unless you could figure out a way to set stops for your various pieces of equipment.

Kevin
 
Kevin, that is a good idea. But you are right, the benches are done. The way I built them, they are adjustable separately, and not secured to the wall at all. I was able to level them to the height of the TS. So far the one station I have completed, except for the DC hookup, is also independently adjustable to match the benches and therefore the table saw. I got supplies to start the next insert this afternoon. It will also be adjustable this way. Next, I need to make some drop in modules that will sit on braces attached to the sides of the benches in the open area. Things like a down draft table, a place for the scroll saw my Dad gave me, my Kreg pocket hole set up, and other items yet to be determined. :D
Thanks for the idea. Maybe it will help others in the future. Jim.
 
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